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Sample records for p-toluenesulfonyl isocyanate p-tosyl

  1. Automotive Refinishing Industry: Isocyanates Profile

    Science.gov (United States)

    The isocyanates profile document is part of the DfE Auto Refinishing Shop Project and is intended to provide information on refinishing, control technologies, and regulatory status regarding isocyanate compounds

  2. Skin exposure to isocyanates: reasons for concern.

    Science.gov (United States)

    Bello, Dhimiter; Herrick, Christina A; Smith, Thomas J; Woskie, Susan R; Streicher, Robert P; Cullen, Mark R; Liu, Youcheng; Redlich, Carrie A

    2007-03-01

    Isocyanates (di- and poly-), important chemicals used worldwide to produce polyurethane products, are a leading cause of occupational asthma. Respiratory exposures have been reduced through improved hygiene controls and the use of less-volatile isocyanates. Yet isocyanate asthma continues to occur, not uncommonly in settings with minimal inhalation exposure but opportunity for skin exposure. In this review we evaluate the potential role of skin exposure in the development of isocyanate asthma. We reviewed the published animal and human literature on isocyanate skin-exposure methods, workplace skin exposure, skin absorption, and the role of skin exposure in isocyanate sensitization and asthma. We selected relevant articles from computerized searches on Medline, U.S. Environmental Protection Agency, Occupational Safety and Health Administration, National Institute for Occupational Safety and Health, and Google databases using the keywords "isocyanate," "asthma," "skin," "sensitization," and other synonymous terms, and our own extensive collection of isocyanate publications. Isocyanate production and use continues to increase as the polyurethane industry expands. There is substantial opportunity for isocyanate skin exposure in many work settings, but such exposure is challenging to quantify and continues to be underappreciated. Isocyanate skin exposure can occur at work, even with the use of personal protective equipment, and may also occur with consumer use of certain isocyanate products. In animals, isocyanate skin exposure is an efficient route to induce sensitization, with subsequent inhalation challenge resulting in asthma-like responses. Several lines of evidence support a similar role for human isocyanate skin exposure, namely, that such exposure occurs and can contribute to the development of isocyanate asthma in certain settings, presumably by inducing systemic sensitization. Integrated animal and human research is needed to better understand the role of skin

  3. Functionalized carbon nanotubes containing isocyanate groups

    International Nuclear Information System (INIS)

    Zhao Chungui; Ji Lijun; Liu Huiju; Hu Guangjun; Zhang Shimin; Yang Mingshu; Yang Zhenzhong

    2004-01-01

    Functionalized carbon nanotubes containing isocyanate groups can extend the nanotube chemistry, and may promote their many potential applications such as in polymer composites and coatings. This paper describes a facile method to prepare functionalized carbon nanotubes containing highly reactive isocyanate groups on its surface via the reaction between toluene 2,4-diisocyanate and carboxylated carbon nanotubes. Fourier-transformed infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed that reactive isocyanate groups were covalently attached to carbon nanotubes. The content of isocyanate groups were determined by chemical titration and thermogravimetric analysis (TGA)

  4. Isocyanate toughened pCBT: Reactive blending and tensile properties

    Directory of Open Access Journals (Sweden)

    T. Abt

    2013-02-01

    Full Text Available Cyclic butylene terephthalate oligomers (CBT were reacted in a ring-opening polymerization with three types of isocyanates: a bifunctional aromatic type, a bifunctional aliphatic type and a polymeric aromatic isocyanate. All reactions took place in a batch mixer. The use of 0.5 to 1 wt% isocyanate led to a dramatic increase in elongation at break of polymerized cyclic butylene terephthalate (pCBT, from 8 to above 100%. The stiffness and strength of the modified pCBT, however, were found to slightly decrease. Proton nuclear magnetic resonance (NMR analysis shows that the formation of thermally stable amide groups is the dominant chain extension reaction mechanism. Gel content measurements suggest a linear structure for samples containing bifunctional isocyanates while pCBT modified with polyfunctional isocyanate exhibited some gel formation at higher isocyanate content. Melting and crystallization temperatures as well as degree of crystallinity were found to decrease with increasing isocyanate content. No phase separation was detected by scanning electron microscopy (SEM analysis. Moreover, a high degree of polymerization is deduced due to the absence of CBT oligomer crystals.

  5. Isocyanate leading to Guanidines/Urea derivatives formation

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 128; Issue 6. Zinc catalyzed Guanylation reaction of Amines with Carbodiimides/ Isocyanate leading to Guanidines/Urea derivatives formation. JAYEETA BHATTACHARJEE MITALI SACHDEVA INDRANI BANERJEE TARUN K PANDA. Regular Article Volume 128 ...

  6. Respiratory symptoms, sensitization, and exposure-response relationships in spray painters exposed to isocyanates

    NARCIS (Netherlands)

    Pronk, A.; Preller, L.; Raulf-Heimsoth, M.; Jonkers, I.C.L.; Lammers, J.-W.; Wouters, I.M.; Doekes, G.; Wisnewski, A.V.; Heederik, D.

    2007-01-01

    Rationale: Associations between oligomeric isocyanate exposure, sensitization, and respiratory disease have received little attention, despite the extensive use of isocyanate oligomers. Objectives: To investigate exposure-response relationships of respiratory symptoms and sensitization in a large

  7. Isocyanate exposure and respiratory symptoms in Dutch car spray painters

    NARCIS (Netherlands)

    Heederik, D.; Pronk, A.; Doekes, G.; Bobbeldijk, I.; Preller, L.

    2005-01-01

    Isocyanate allergy and asthma is an important respiratory disease in most industrialized countries. Little information about its importance is available for the Netherlands. A baseline survey, part of a larger longitudinal epidemiological survey, shows that exposure to mainly HDI monomers and

  8. Functionalized TiO2 nanoparticle containing isocyanate groups

    International Nuclear Information System (INIS)

    Ou, Baoli; Li, Duxin; Liu, Qingquan; Zhou, Zhihua; Liao, Bo

    2012-01-01

    Functionalized TiO 2 nanoparticle containing isocyanate groups can extend the TiO 2 nanoparticle chemistry, and may promote their many potential applications such as in polymer composites and coatings. This paper describes a facile method to prepare functionalized TiO 2 nanoparticle with highly reactive isocyanate groups on its surface, via the reaction between toluene-2, 4-diisocyanate (TDI) and hydroxyl on TiO 2 nanoparticle surface. The main effect factors on the reaction of TiO 2 with TDI were studied by determining the reaction extent of hydroxyl groups on TiO 2 surface. Fourier-transformed infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) confirmed that reactive isocyanate groups were covalently attached to the TiO 2 nanoparticle surface. The dispersion of the TDI-functionalized TiO 2 nanoparticle was studied by transmission electron microscopy (TEM). Owing to the TDI molecules covalently bonded on TiO 2 nanoparticle surface, it was established that the TiO 2 nanoparticle can be uniformly dispersed in toluene, thus indicating that this functionalization method can prevent TiO 2 nanoparticle from agglomerating. -- Highlights: ► TiO 2 nanoparticle was functionalized with toluene-2, 4-diisocyanate. ► Functionalized TiO 2 nanoparticle can be uniformly dispersed in xylene. ► Compatibility of TiO 2 nanoparticle and organic solvent is significantly improved. ► TiO 2 containing isocyanate groups can extend the TiO 2 nanoparticle chemistry.

  9. Antimutagenic effect of isocyanates and related compounds in escherichia coli

    International Nuclear Information System (INIS)

    Kawazoe, Yutaka; Kato, Masanari

    1982-01-01

    Isocyanates and isothiocyanates have been suggested to inactivate enzymes involved in the metabolic activation of chemical carcinogens and the repair of DNA damage. These compounds decrease the mutability of a tester strain of Escherichia coli B under UV irradiation. This paper deals with the antimutagenicity of acylating agents, including isocyanates and isothiocyanates, and some anti-oxidants which are suspected to be anticarcinogenic. The results can be summarized as follows. (1) The antimutagenic effect observed in the present study operates on UV-induced mutagenesis but not on X-ray-induced mutagenesis. (2) This effect operates only on the wild-type strain, H/r30R, but not on Hs30R deficient in the excision repair system. (3) This effect may function through giving the irradiated cells a greater chance to carry out excision repair by prolonging the lag-period before entry into the S-phase. (4) The carbamoylating ability of isocyanates and isothiocyanates may be responsible for the antimutagenicity, but other type of reactivities may also be involved. These antimutagens also participate in inactivating enzymes relevant to the metabolic activation of mutagens, resulting in a decrease in the frequency of chemically induced mutagenesis. (author)

  10. Residual Isocyanates in Medical Devices and Products: A Qualitative and Quantitative Assessment

    Directory of Open Access Journals (Sweden)

    Gillian Franklin

    2016-01-01

    Full Text Available We conducted a pilot qualitative and quantitative assessment of residual isocyanates and their potential initial exposures in neonates, as little is known about their contact effect. After a neonatal intensive care unit (NICU stockroom inventory, polyurethane (PU and PU foam (PUF devices and products were qualitatively evaluated for residual isocyanates using Surface SWYPE ™ . Those containing isocyanates were quantitatively tested for methylene diphenyl diisocyanate (MDI species, using UPLC-UV-MS/MS method. Ten of 37 products and devices tested, indicated both free and bound residual surface isocyanates; PU/PUF pieces contained aromatic isocyanates; one product contained aliphatic isocyanates. Overall, quantified mean MDI concentrations were low (4,4‘-MDI = 0.52 to 140.1 pg/mg and (2,4‘-MDI = 0.01 to 4.48 pg/mg. The 4,4‘-MDI species had the highest measured concentration (280 pg/mg. Commonly used medical devices/products contain low, but measurable concentrations of residual isocyanates. Quantifying other isocyanate species and neonatal skin exposure to isocyanates from these devices and products requires further investigation.

  11. Determination of airborne isocyanates generated during the thermal degradation of car paint in body repair shops.

    Science.gov (United States)

    Boutin, Michel; Dufresne, André; Ostiguy, Claude; Lesage, Jacques

    2006-06-01

    Polyurethanes are widely used in car paint formulations. During thermal degradation, such polymeric systems can generate powerful asthmatic sensitizing agents named isocyanates. In body repair shops, the thermal degradation of car paint can occur during abrasive processes that generate enough heat to involve release of isocyanates in air. An environmental monitoring study was performed in two body repair training schools and in a body repair shop to evaluate the workers' exposure to isocyanates during cutting, grinding and orbital sanding operations. For sampling, cassettes containing two 1-(2-methoxyphenyl)piperazine (MOPIP)-coated glass fiber filters (MFs) ( approximately 5 mg of MOPIP per filter) and bubblers containing 15 ml of MOPIP solution in toluene (1.0 mg ml(-1)) backed at the outlet with cassettes containing two MFs were used. Tandem mass spectrometry was used to analyze the MOPIP derivatives of isocyanic acid (HNCO), all the linear aliphatic isocyanates ranging from methyl isocyanate (Me-i) to hexyl isocyanate, all the alkenyl isocyanates ranging from propylene isocyanate to hexylene isocyanate, 1,6-hexamethylene diisocyanate (HDI), trans- and cis-isophorone diisocyanate (IPDI), 2,4- and 2,6-toluene diisocyanate (TDI), 2,4'-; 2,2'- and 4,4'-methylenediphenyl diisocyanate (MDI), phenyl isocyanate (Ph-i) and p-toluene isocyanate (p-Tol-i). The instrumental detection limits (LOD) were in the 0.13-0.75 microg of NCO per m(3) range for 15 l air samples converted into 3 ml liquid samples. The isocyanate concentrations detected in the workers' breathing zone were in the 1.07-9.80 microg of NCO per m(3) range for cutting, 0.63-3.62 microg of NCO per m(3) range for grinding and 0-1.29 microg of NCO per m(3) range for sanding. However, a rapid decrease of the isocyanate concentration was observed while moving away from the emission source. Among the isocyanates detected the most abundant were the monomers (MDI, HDI, TDI and IPDI) and Me-i.

  12. Isocyanates and work-related asthma: Findings from California, Massachusetts, Michigan, and New Jersey, 1993-2008.

    Science.gov (United States)

    Lefkowitz, Daniel; Pechter, Elise; Fitzsimmons, Kathleen; Lumia, Margaret; Stephens, Alicia C; Davis, Letitia; Flattery, Jennifer; Weinberg, Justine; Harrison, Robert J; Reilly, Mary Jo; Filios, Margaret S; White, Gretchen E; Rosenman, Kenneth D

    2015-11-01

    Isocyanates remain a leading cause of work-related asthma (WRA). Two independent data systems were analyzed for the period 1993-2008: (1) State-based WRA case surveillance data on persons with isocyanate-induced WRA from four states, and (2) Occupational Safety and Health Administration (OSHA) Integrated Management Information System (IMIS) isocyanate air sampling results. We identified 368 cases of isocyanate-induced WRA from 32 industries and 678 OSHA isocyanate air samples with detectable levels from 31 industries. Seventeen industries were unique to one or the other dataset. Isocyanate-induced WRA continues to occur in a wide variety of industries. Two data systems uncovered industries with isocyanate exposures and/or illness. Improved control measures and standards, including medical surveillance, are needed. More emphasis is needed on task-specific guidance, spill clean-up procedures, skin and respiratory protection, and targeted medical monitoring to mitigate the hazards of isocyanate use. © 2015 Wiley Periodicals, Inc.

  13. Isocyanates and Work-Related Asthma: Findings From California, Massachusetts, Michigan, and New Jersey, 1993–2008

    Science.gov (United States)

    Lefkowitz, Daniel; Pechter, Elise; Fitzsimmons, Kathleen; Lumia, Margaret; Stephens, Alicia C.; Davis, Letitia; Flattery, Jennifer; Weinberg, Justine; Harrison, Robert J.; Reilly, Mary Jo; Filios, Margaret S.; White, Gretchen E.; Rosenman, Kenneth D.

    2015-01-01

    Background Isocyanates remain a leading cause of work-related asthma (WRA). Methods Two independent data systems were analyzed for the period 1993–2008: (1) State-based WRA case surveillance data on persons with isocyanate-induced WRA from four states, and (2) Occupational Safety and Health Administration (OSHA) Integrated Management Information System (IMIS) isocyanate air sampling results. Results We identified 368 cases of isocyanate-induced WRA from 32 industries and 678 OSHA isocyanate air samples with detectable levels from 31 industries. Seventeen industries were unique to one or the other dataset. Conclusion Isocyanate-induced WRA continues to occur in a wide variety of industries. Two data systems uncovered industries with isocyanate exposures and/or illness. Improved control measures and standards, including medical surveillance, are needed. More emphasis is needed on task-specific guidance, spill clean-up procedures, skin and respiratory protection, and targeted medical monitoring to mitigate the hazards of isocyanate use. PMID:26351141

  14. Inhalation exposure to isocyanates of car body repair shop workers and industrial spray painters

    NARCIS (Netherlands)

    Pronk, A.; Tielemans, E.; Skarping, G.; Bobeldijk, I.; Hemmen, J. van; Heederik, D.; Preller, L.

    2006-01-01

    As part of a large-scale epidemiological study, occupational isocyanate exposure was assessed in spray-painting environments. The aim was to assess which compounds contribute to isocyanate exposure in car body repair shops and industrial painting companies, and to identify tasks with high risk of

  15. Isocyanate exposure and respiratory health effects in the spray painting industry

    NARCIS (Netherlands)

    Pronk, A.

    2007-01-01

    In this thesis exposure-response relationships between isocyanate exposure and respiratory health end-points and specific sensitization in spray painters were investigated. Isocyanates, a group of compounds characterized by reactive N=C=O groups, are among the most frequently identified causes of

  16. Mass spectrometric identification of isocyanate-induced modifications of keratins in human skin

    NARCIS (Netherlands)

    Hulst, A.G.; Verstappen, D.R.W.; Riet-van Oeveren, D. van der; Vermeulen, N.P.E.; Noort, D.

    2015-01-01

    In the current paper we show that exposure of human callus to isocyanates leads to covalent modifications within keratin proteins. Mass spectrometric analyses of pronase digests of keratin isolated from exposed callus show that both mono- and di-adducts (for di-isocyanates) are predominantly formed

  17. Isocyanate exposure and asthma in the UK vehicle repair industry.

    Science.gov (United States)

    Stocks, S J; Jones, K; Piney, M; Agius, R M

    2015-12-01

    Organic diisocyanates are a common cause of occupational asthma, particularly in motor vehicle repair (MVR) workers. The UK Health & Safety Laboratory provides screening for urinary hexamethylenediamine (UHDA), a biomarker of exposure to 1,6-hexamethylene diisocyanate (HDI). The UK Surveillance of Work-related and Occupational Respiratory Disease scheme (SWORD) has collected reports of occupational asthma since 1996. To compare trends in HDI exposure with trends in the incidence of work-related asthma attributed to isocyanates or paint spraying in MVR workers reported to SWORD. Two-level regression models were used to estimate trends in UHDA levels and work-related asthma in MVR workers reported to SWORD. The direction and magnitude of the trends were compared descriptively. From 2006 to 2014, there was a significant decline in the number of urine samples with detectable levels of UHDA (odds ratio = 0.96; 95% confidence intervals 0.94-0.98) and minimal change in those over the guidance value (1.03; 1.00-1.06). Over the same period, there was a significant decline in all asthma cases attributed to isocyanates or paint spraying reported to SWORD (0.90; 0.86-0.94) and a non-significant decline among MVR workers (0.94; 0.86-1.02). The simultaneous decrease in HDI exposure and incident cases of asthma reported to SWORD is temporally consistent with a reduction in exposure to airborne isocyanate leading to a reduction in asthma. Although this is not direct evidence of a causal relationship between the two trends, it is suggestive. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine.

  18. Isocyanates useful for forming synthetic antigens receptive to radiolabelling

    International Nuclear Information System (INIS)

    Eisenhardt, W.A. Jr.; Hedaya, E.; Theodoropulos, S.

    1981-01-01

    This patent claim on behalf of Union Carbide Corporation, relates to synthesizing isocyantes useful for forming synthetic antigens receptive to radio labelling. The claim is for an isocyanate having the structural formula (R) 3 SiO-R' -N=C=O, wherein each R is independently selected from alkyl, alicyclic, aryl, alkaryl and aralkyl groups, each having no more than 10 carbon atoms and being optionally substituted by one or more halogen atoms, and R' is selected from -C 6 H 4 -CH 2 -CH 2 - and -C 6 H 4 -CH 2 -CH-COOCH 3 . (U.K.)

  19. Reaction of tantalum-alkyne complexes with isocyanates or acyl cyanides

    International Nuclear Information System (INIS)

    Kataoka, Yasutaka; Oguchi, Yoshiyuki; Yoshizumi, Kazuyuki; Miwatashi, Seiji; Takai, Kazuhiko; Utimoto, Kiitiro

    1992-01-01

    Treatment of alkynes with low-valent tantalum derived from TiCl 5 and zinc produces tantalum-alkyne complexes (not isolated), which react in situ with phenyl isocyanate (or butyl isocyanate) to give (E)-α, β-unsaturated amides stereoselectively. The tantalum-alkyne complexes also react with acyl cyanides in the presence of BF 3 ·OEt 2 to give α-cyanohydrins. In both reactions, filtration of the reaction mixture containing the tantalum-alkyne complexes before addition of isocyanates (or acyl cyanides) is indispensable to obtain good yields. (author)

  20. Structure-property relationships for n-alkyl-isocyanate-containing polymers

    Science.gov (United States)

    Aronson, Carl Lawrence

    Poly(n-hexyl isocyanate) (PHIC), poly(n-butyl-isocyanate) (PBIC), poly(n-butyl-co-cyclohexyl isocyanate) (PBCHIC), poly(n-hexyl isocyanate-b-isoprene) (HI), poly(n-butyl isocyanate-b-isoprene) (BI) and poly(n-hexyl isocyanate-b-isoprene- b-styrene) (MS) were synthesized and characterized with respect to composition, molecular Weight and polydispersity. PHIC, HI and HIS were found to be lyotropic liquid crystalline whereas PBIC, PBCHIC and BI were found to be non-lyotropic. A lyotropic-nematic liquid crystalline phase diagram was determined for the PHIC/xylene system. A novel and reversible electric-field-induced biphasic-paranematic phase transition was found for the PHIC/xylene system from the dynamics of topological defects. The electric-field-induced phase diagram for PHIC/xylene agreed with the theoretically predicted field-induced phase diagram of Khokhlov and Semenov for semiflexible-persistent polymers. The dielectric characteristics, steady-state electrically induced birefringence and steady-state electroheological (ER) activity of PHIC, PBIC and PBCHIC solutions were compared as a function of polymer concentration. The role of lyotropic liquid crystalline ordering in the functional ER mechanism of poly( n-hexyl isocyanate) solutions is presented. PBCHIC was found to thermally decompose by a first-order rate process which became slower with increasing cyclohexyl isocyanate content from thermal gravimetric analysis. Competition between monomer dissociation and degradative trimerization as well as a non-alternating sequence distribution were determined for PBCHIC from direct pyrolysis/mass spectrometry. The Arrhenius activation energy, pre-exponential factor and entropy for diffusion and evaporation of xylene from PHIC, were found to be functions of initial polymer concentration whereas the intrinsic diffusion coefficient of the solvent was found to be independent of initial polymer concentration. The cross polarized/magic angle spinning solid state 13C

  1. A study on the grafting reaction of isocyanates with hydroxyapatite particles

    NARCIS (Netherlands)

    Liu, Q.; de Wijn, J.R.; van Blitterswijk, Clemens

    1998-01-01

    The surface grafting reactions of a series of isocyanates with hydroxyapatite particles at different temperatures were studied by Infrared spectrophotometry (IR) and thermal gravimetric analysis (TGA). The study results show that both hexamethylene diisocyanate (HMDI) and isocyanatoethyl

  2. Developing an Efficient and General Strategy for Immobilization of Small Molecules onto Microarrays Using Isocyanate Chemistry.

    Science.gov (United States)

    Zhu, Chenggang; Zhu, Xiangdong; Landry, James P; Cui, Zhaomeng; Li, Quanfu; Dang, Yongjun; Mi, Lan; Zheng, Fengyun; Fei, Yiyan

    2016-03-16

    Small-molecule microarray (SMM) is an effective platform for identifying lead compounds from large collections of small molecules in drug discovery, and efficient immobilization of molecular compounds is a pre-requisite for the success of such a platform. On an isocyanate functionalized surface, we studied the dependence of immobilization efficiency on chemical residues on molecular compounds, terminal residues on isocyanate functionalized surface, lengths of spacer molecules, and post-printing treatment conditions, and we identified a set of optimized conditions that enable us to immobilize small molecules with significantly improved efficiencies, particularly for those molecules with carboxylic acid residues that are known to have low isocyanate reactivity. We fabricated microarrays of 3375 bioactive compounds on isocyanate functionalized glass slides under these optimized conditions and confirmed that immobilization percentage is over 73%.

  3. Inhalation exposure to isocyanates of car body repair shop workers and industrial spray painters.

    Science.gov (United States)

    Pronk, Anjoeka; Tielemans, Erik; Skarping, Gunnar; Bobeldijk, Ivana; VAN Hemmen, Joop; Heederik, Dick; Preller, Liesbeth

    2006-01-01

    As part of a large-scale epidemiological study, occupational isocyanate exposure was assessed in spray-painting environments. The aim was to assess which compounds contribute to isocyanate exposure in car body repair shops and industrial painting companies, and to identify tasks with high risk of isocyanate exposure. Mainly personal task-based samples (n = 566) were collected from 24 car body repair shops and five industrial painting companies using impingers with DBA in toluene. Samples were analysed by LC-MS for isocyanate monomers, oligomers and products of thermal degradation. From the 23 analysed compounds, 20 were detected. Exploratory factor analysis resulted in a HDI, TDI and MDI factor with the thermal degradation products divided over the TDI and MDI factors. The HDI factor mainly consisted of HDI oligomers and was dominant in frequency and exposure levels in both industries. Spray painting of PU lacquers resulted in the highest exposures for the HDI factor (car body repair shops than in industrial painting companies. Exposure levels were low (car body repair shops (isocyanate exposure in both industries with highest exposures during PU spraying. However, since respiratory protection is less extensively used during other tasks, lower level exposure during these other tasks may significantly contribute to the internal dose.

  4. The 14C-labelling of 2-chloroethyl isocyanate. Application to the labelling of chloroethyl tetrazinone and chloroethylnitrosoureas

    International Nuclear Information System (INIS)

    Madelmont, J.C.; Moreau, M.F.; Godeneche, D.; Labarre, P.; Veyre, A.

    1988-01-01

    The labelling of 2-chloroethyl isocyanate with 14 C on the carbonyl group from 3-chloro [carboxyl- 14 C] propionic acid is described. The Curtius reaction under phase transfer condition was used. This isocyanate was used to synthesize 2-chloroethyl tetrazinone and 2-chloro-ethyl nitrosourea. (author)

  5. The addition of organotin hydrides to isocyanates and isothiocyanates: synthesis and structure of some organotin-substituted amides

    NARCIS (Netherlands)

    Noltes, J.G.; Janssen, M.J.

    Organotin hydrides add across the carbon---nitrogen double bond of aryl isocyanates (tin---nitrogen bond formation) and hexyl isocyanate (tin---carbon bond formation) and across the carbon---sulfur double bond of phenyl isothiocyanate (tin---sulfur bond formation) to afford in excellent yield 1:1

  6. Assessing isocyanate exposures in polyurethane industry sectors using biological and air monitoring methods.

    Science.gov (United States)

    Creely, K S; Hughson, G W; Cocker, J; Jones, K

    2006-08-01

    Isocyanates, as a chemical group, are considered to be the biggest cause of occupational asthma in the UK. Monitoring of airborne exposures to total isocyanate is costly, requiring considerable expertise, both in terms of sample collection and chemical analysis and cannot be used to assess the effectiveness of protection from wearing respiratory protective equipment (RPE). Biological monitoring by analysis of metabolites in urine can be a relatively simple and inexpensive way to assess exposure to isocyanates. It may also be a useful way to evaluate the effectiveness of control measures in place. In this study biological and inhalation monitoring were undertaken to assess exposure in a variety of workplaces in the non-motor vehicle repair sector. Companies selected to participate in the survey included only those judged to be using good working practices when using isocyanate formulations. This included companies that used isocyanates to produce moulded polyurethane products, insulation material and those involved in industrial painting. Air samples were collected by personal monitoring and were analysed for total isocyanate content. Urine samples were collected soon after exposure and analysed for the metabolites of different isocyanate species, allowing calculation of the total metabolite concentration. Details of the control measures used and observed contamination of exposed skin were also recorded. A total of 21 companies agreed to participate in the study, with exposure measurements being collected from 22 sites. The airborne isocyanate concentrations were generally very low (range 0.0005-0.066 mg m(-3)). A total of 50 of the 70 samples were polyurethane foam insulation (0.023 mg m(-3)). The most commonly detected isocyanate in the urine was hexamethylene diisocyanate, which was detected in 21 instances. The geometric mean total isocyanate metabolite concentration for the dataset was 0.29 micromol mol(-1) creatinine (range 0.05-12.64 micromol mol(-1

  7. Testing of Disposable Protective Garments Against Isocyanate Permeation From Spray Polyurethane Foam Insulation.

    Science.gov (United States)

    Mellette, Michael P; Bello, Dhimiter; Xue, Yalong; Yost, Michael; Bello, Anila; Woskie, Susan

    2018-05-12

    Diisocyanates (isocyanates), including methylene diphenyl diisocyanate (MDI), are the primary reactive components of spray polyurethane foam (SPF) insulation. They are potent immune sensitizers and a leading cause of occupational asthma. Skin exposure to isocyanates may lead to both irritant and allergic contact dermatitis and possibly contribute to systemic sensitization. More than sufficient evidence exists to justify the use of protective garments to minimize skin contact with aerosolized and raw isocyanate containing materials during SPF applications. Studies evaluating the permeation of protective garments following exposure to SPF insulation do not currently exist. To conduct permeation testing under controlled conditions to assess the effectiveness of common protective gloves and coveralls during SPF applications using realistic SPF product formulations. Five common disposable garment materials [disposable latex gloves (0.07 mm thickness), nitrile gloves (0.07 mm), vinyl gloves (0.07 mm), polypropylene coveralls (0.13 mm) and Tyvek coveralls (0.13 mm)] were selected for testing. These materials were cut into small pieces and assembled into a permeation test cell system and coated with a two-part slow-rise spray polyurethane foam insulation. Glass fiber filters (GFF) pretreated with 1-(9-anthracenylmethyl)piperazine) (MAP) were used underneath the garment to collect permeating isocyanates. GFF filters were collected at predetermined test intervals between 0.75 and 20.00 min and subsequently analyzed using liquid chromatography-tandem mass spectrometry. For each garment material, we assessed (i) the cumulative concentration of total isocyanate, including phenyl isocyanate and three MDI isomers, that effectively permeated the material over the test time; (ii) estimated breakthrough detection time, average permeation rate, and standardized breakthrough time; from which (iii) recommendations were developed for the use of similar protective garments following

  8. Exhaled nitric oxide in spray painters exposed to isocyanates : Effect modification by atopy and smoking

    NARCIS (Netherlands)

    Jonaid, Badri Sadat; Pronk, Anjoeka; Doekes, Gert; Heederik, Dick

    2014-01-01

    Background: Isocyanate asthma is one of the most frequently identified forms of occupational asthma in industrialised countries. The underlying mechanisms have not been clarified. There is only limited information about the relationship between exhaled nitric oxide (eNO) and occupational exposure to

  9. Exhaled nitric oxide in spray painters exposed to isocyanates: Effect modification by atopy and smoking

    NARCIS (Netherlands)

    Jonaid, B.S.; Pronk, A.; Doekes, G.; Heederik, D.

    2014-01-01

    Background: Isocyanate asthma is one of the most frequently identified forms of occupational asthma in industrialised countries. The underlying mechanisms have not been clarified. There is only limited information about the relationship between exhaled nitric oxide (eNO) and occupational exposure to

  10. Effects of humidity and filter material on diffusive sampling of isocyanates using reagent-coated filters

    NARCIS (Netherlands)

    Henneken, H.; Vogel, M.; Karst, U.

    2006-01-01

    Diffusive sampling of methyl isocyanate (MIC) on 4-nitro-7-piperazinobenzo-2-oxa-1,3-diazole (NBDPZ)-coated glass fibre (GF) filters is strongly affected by high relative humidity (RH) conditions. It is shown that the humidity interference is a physical phenomenon, based on displacement of reagent

  11. Homochiral Acyl Isocyanates as Diagnostic NMR Probes for the Enantiomeric Purity of Chiral Alcohols

    Directory of Open Access Journals (Sweden)

    Gregory H. P. Roos

    2000-12-01

    Full Text Available The first reported acyl and sulfonylisocyanates were developed and tested in reactions with chiral alcohols to afford diastereomeric carbamates. NMR analysis of these investigates the chemical shift discrimination that would allow these activated isocyanates to be used as diagnostic probes of enantiomeric purity.

  12. Rh(III-catalyzed directed C–H bond amidation of ferrocenes with isocyanates

    Directory of Open Access Journals (Sweden)

    Satoshi Takebayashi

    2012-10-01

    Full Text Available [RhCp*(OAc2(H2O] [Cp* = pentamethylcyclopentadienyl] catalyzed the C–H bond amidation of ferrocenes possessing directing groups with isocyanates in the presence of 2 equiv/Rh of HBF4·OEt2. A variety of disubstituted ferrocenes were prepared in high yields, or excellent diastereoselectivities.

  13. Isocyanate toughening of pCBT/organoclay nanocomposites with exfoliated structure and enhanced mechanical properties

    Directory of Open Access Journals (Sweden)

    T. Abt

    2014-12-01

    Full Text Available Cyclic butylene terephthalate (CBT® is an interesting matrix material for the preparation of nanocomposites due to its very low, water-like melt viscosity which favours clay exfoliation. Nevertheless, polymerized CBT (pCBT is inherently brittle. This paper reports the preparation of isocyanate-toughened nanocomposites made from CBT and organo-modified montmorillonite. The role of the organoclay as reinforcement and the polymeric isocyanate (PMDI as toughening agent on the properties of pCBT was studied. The organoclay increased the stiffness and strength by up to 20% whereas the PMDI improved the deformation behaviour. However, the PMDI did not affect the degree of clay dispersion or exfoliation and flocculated-intercalated structures were observed. The compatibility between the pCBT matrix and clay was further increased by preparing PMDI-tethered intercalated organoclay. The modified organoclay then exfoliated during ring-opening polymerization and yielded true pCBT/clay nanocomposites. This work demonstrates that reactive chain extension of CBT with a polyfunctional isocyanate is an effective method to obtain toughened pCBT nanocomposites. Moreover, isocyanates can enhance the compatibility between pCBT and nanofiller as well as the degree of exfoliation.

  14. Airborne Isocyanate Exposures in the Collision Repair Industry and a Comparison to Occupational Exposure Limits

    Science.gov (United States)

    Reeb-Whitaker, Carolyn; Whittaker, Stephen G.; Ceballos, Diana M.; Weiland, Elisa C.; Flack, Sheila L.; Fent, Kenneth W.; Thomasen, Jennifer M.; Gaines, Linda G. Trelles; Nylander-French, Leena A.

    2014-01-01

    Isocyanate exposure was evaluated in 33 spray painters from 25 Washington State autobody shops. Personal breathing zone samples (n = 228) were analyzed for isophorone diisocyanate (IPDI) monomer, 1,6-hexamethylene diisocyanate (HDI) monomer, IPDI polyisocyanate, and three polyisocyanate forms of HDI. The objective was to describe exposures to isocyanates while spray painting, compare them with short-term exposure limits (STELs), and describe the isocyanate composition in the samples. The composition of polyisocyanates (IPDI and HDI) in the samples varied greatly, with maximum amounts ranging from up to 58% for HDI biuret to 96% for HDI isocyanurate. There was a significant inverse relationship between the percentage composition of HDI isocyanurate to IPDI and to HDI uretdione. Two 15-min STELs were compared: (1) Oregon's Occupational Safety and Health Administration (OR-OSHA) STEL of 1000 μg/m3 for HDI polyisocyanate, and (2) the United Kingdom's Health and Safety Executive (UK-HSE) STEL of 70 μg NCO/m3 for all isocyanates. Eighty percent of samples containing HDI polyisocyanate exceeded the OR-OSHA STEL while 98% of samples exceeded the UKHSE STEL. The majority of painters (67%) wore half-face air-purifying respirators while spray painting. Using the OROSHA and the UK-HSE STELs as benchmarks, 21% and 67% of painters, respectively, had at least one exposure that exceeded the respirator's OSHA-assigned protection factor. A critical review of the STELs revealed the following limitations: (1) the OR-OSHA STEL does not include all polyisocyanates, and (2) the UK-HSE STEL is derived from monomeric isocyanates, whereas the species present in typical spray coatings are polyisocyanates. In conclusion, the variable mixtures of isocyanates used by autobody painters suggest that an occupational exposure limit is required that includes all polyisocyanates. Despite the limitations of the STELs, we determined that a respirator with an assigned protection factor of 25 or

  15. Airborne isocyanate exposures in the collision repair industry and a comparison to occupational exposure limits.

    Science.gov (United States)

    Reeb-Whitaker, Carolyn; Whittaker, Stephen G; Ceballos, Diana M; Weiland, Elisa C; Flack, Sheila L; Fent, Kenneth W; Thomasen, Jennifer M; Trelles Gaines, Linda G; Nylander-French, Leena A

    2012-01-01

    Isocyanate exposure was evaluated in 33 spray painters from 25 Washington State autobody shops. Personal breathing zone samples (n = 228) were analyzed for isophorone diisocyanate (IPDI) monomer, 1,6-hexamethylene diisocyanate (HDI) monomer, IPDI polyisocyanate, and three polyisocyanate forms of HDI. The objective was to describe exposures to isocyanates while spray painting, compare them with short-term exposure limits (STELs), and describe the isocyanate composition in the samples. The composition of polyisocyanates (IPDI and HDI) in the samples varied greatly, with maximum amounts ranging from up to 58% for HDI biuret to 96% for HDI isocyanurate. There was a significant inverse relationship between the percentage composition of HDI isocyanurate to IPDI and to HDI uretdione. Two 15-min STELs were compared: (1) Oregon's Occupational Safety and Health Administration (OR-OSHA) STEL of 1000 μg/m(3) for HDI polyisocyanate, and (2) the United Kingdom's Health and Safety Executive (UK-HSE) STEL of 70 μg NCO/m(3) for all isocyanates. Eighty percent of samples containing HDI polyisocyanate exceeded the OR-OSHA STEL while 98% of samples exceeded the UK-HSE STEL. The majority of painters (67%) wore half-face air-purifying respirators while spray painting. Using the OR-OSHA and the UK-HSE STELs as benchmarks, 21% and 67% of painters, respectively, had at least one exposure that exceeded the respirator's OSHA-assigned protection factor. A critical review of the STELs revealed the following limitations: (1) the OR-OSHA STEL does not include all polyisocyanates, and (2) the UK-HSE STEL is derived from monomeric isocyanates, whereas the species present in typical spray coatings are polyisocyanates. In conclusion, the variable mixtures of isocyanates used by autobody painters suggest that an occupational exposure limit is required that includes all polyisocyanates. Despite the limitations of the STELs, we determined that a respirator with an assigned protection factor of 25 or

  16. Comprehensive Biological Monitoring to Assess Isocyanates and Solvents Exposure in the NSW Australia Motor Vehicle Repair Industry.

    Science.gov (United States)

    Hu, Jimmy; Cantrell, Phillip; Nand, Aklesh

    2017-10-01

    Urethane products that contain isocyanates are extensively used in the motor vehicle repair (MVR) industry and other industries such as furniture and cabinet-making as two-pack spray paints, clears, and adhesives. Attention has recently been refocussed on isocyanate-containing chemicals, particularly in paints. The spray painters in the MVR industry had a propensity to develop industrial asthma at a rate 80 times higher than the general public, which was previously reported in the UK. To track workers exposure to isocyanates, urine samples were collected from 196 spray painters who worked mainly in 78 MVR shops across 54 New South Wales (NSW) towns and suburbs. The biological monitoring also covered exposure testing to a wide variety of solvents including aromatic hydrocarbons, ketones, and alcohols. The main finding of the study was that 2.6% of the spray painters surveyed in the MVR industry in NSW that handled isocyanate-containing paints showed exposure to isocyanates; with 1.0% being moderately exposed, which is more than twice the current UK's Health and Safety Executive (HSE) Biological Monitoring Guidance Value (BMGV) of 1 µmol mol-1 creatinine. Potential exposures to toluene (a solvent often found in paint thinners) was monitored via hippuric acid (HA) urine levels and showed 2.6% of the spray painters surveyed to be over the US' American Conference of Government Industrial Hygienists (ACGIH) Biological Exposure Index (BEI) of 1010 mmol/mole creatinine for HA. The other solvents or their metabolites were all below their respective BEI; these comprised benzene, xylene, ethyl benzene, methyl ethyl ketone, acetone, methanol, and ethanol. These findings indicate that isocyanates and certain solvents exposure were occurring in the NSW Australia vehicle repair industry, albeit at lower levels than previous occupational biological monitoring studies that showed higher exposure levels, particularly for isocyanates. One reason for this could be the increasing use

  17. Chemistry of cobalt bis(1,2-dicarbollide) ion; the synthesis of carbon substituted alkylamino derivatives from hydroxyalkyl derivatives via methylsulfonyl or p-toluenesulfonyl esters

    Czech Academy of Sciences Publication Activity Database

    Nekvinda, Jan; Švehla, Jaroslav; Císařová, I.; Grüner, Bohumír

    2015-01-01

    Roč. 798, č. 1 (2015), s. 112-120 ISSN 0022-328X R&D Projects: GA ČR GA15-05677S Institutional support: RVO:61388980 Keywords : Boranes * Carboranes * Metallacarboranes * Dicarbollide * Building blocks Subject RIV: CA - Inorganic Chemistry Impact factor: 2.336, year: 2015

  18. Transient receptor potential ankyrin 1 antagonists block the noxious effects of toxic industrial isocyanates and tear gases.

    Science.gov (United States)

    Bessac, Bret F; Sivula, Michael; von Hehn, Christian A; Caceres, Ana I; Escalera, Jasmine; Jordt, Sven-Eric

    2009-04-01

    The release of methyl isocyanate in Bhopal, India, caused the worst industrial accident in history. Exposures to industrial isocyanates induce lacrimation, pain, airway irritation, and edema. Similar responses are elicited by chemicals used as tear gases. Despite frequent exposures, the biological targets of isocyanates and tear gases in vivo have not been identified, precluding the development of effective countermeasures. We use Ca(2+) imaging and electrophysiology to show that the noxious effects of isocyanates and those of all major tear gas agents are caused by activation of Ca(2+) influx and membrane currents in mustard oil-sensitive sensory neurons. These responses are mediated by transient receptor potential ankyrin 1 (TRPA1), an ion channel serving as a detector for reactive chemicals. In mice, genetic ablation or pharmacological inhibition of TRPA1 dramatically reduces isocyanate- and tear gas-induced nocifensive behavior after both ocular and cutaneous exposures. We conclude that isocyanates and tear gas agents target the same neuronal receptor, TRPA1. Treatment with TRPA1 antagonists may prevent and alleviate chemical irritation of the eyes, skin, and airways and reduce the adverse health effects of exposures to a wide range of toxic noxious chemicals.

  19. Isocyanates and human health: Multi-stakeholder information needs and research priorities

    Science.gov (United States)

    Lockey, JE; Redlich, CA; Streicher, R; Pfahles-Hutchens, A; Hakkinen, PJ; Ellison, GL; Harber, P; Utell, M; Holland, J; Comai, A; White, Marc

    2014-01-01

    Objective Outline the knowledge gaps and research priorities identified by a broad-base of stakeholders involved in the planning and participation of an international conference and research agenda workshop on isocyanates and human health held in Potomac, Maryland in April 2013. Methods A multi-modal iterative approach was employed for data collection including pre-conference surveys, review of a 2001 consensus conference on isocyanates, oral and poster presentations, focused break-out sessions, panel discussions and post-conference research agenda workshop. Results Participants included representatives of consumer and worker health, health professionals, regulatory agencies, academic and industry scientists, labor, and trade associations. Conclusions Recommendations were summarized regarding knowledge gaps and research priorities in the following areas: worker and consumer exposures; toxicology, animal models, and biomarkers; human cancer risk; environmental exposure and monitoring; and respiratory epidemiology and disease, and occupational health surveillance. PMID:25563538

  20. Preparation of graphite derivatives by selective reduction of graphite oxide and isocyanate functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Santha Kumar, Arunjunai Raja Shankar [Materials Science Centre, Indian Institute of Technology, Kharagpur, 721302, West Bengal (India); Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069, Dresden (Germany); Piana, Francesco [Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069, Dresden (Germany); Organic Chemistry of Polymers, Technische Universität Dresden, 01062, Dresden (Germany); Mičušík, Matej [Polymer Institute, Slovak Academy of Sciences, Dúbravská cesta 9, 845 41, Bratislava (Slovakia); Pionteck, Jürgen, E-mail: pionteck@ipfdd.de [Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069, Dresden (Germany); Banerjee, Susanta [Materials Science Centre, Indian Institute of Technology, Kharagpur, 721302, West Bengal (India); Voit, Brigitte [Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069, Dresden (Germany); Organic Chemistry of Polymers, Technische Universität Dresden, 01062, Dresden (Germany)

    2016-10-01

    Heavily oxidized and ordered graphene nanoplatelets were produced from natural graphite by oxidation using a mixture of phosphoric acid, sulphuric acid, and potassium permanganate (Marcano's method). The atomic percentage of oxygen in the graphite oxide produced was more than 30% confirmed by XPS studies. The graphite oxide produced had intact basal planes and remains in a layered structure with interlayer distance of 0.8 nm, analyzed by WAXS. The graphite oxide was treated with 4,4′-methylenebis(phenyl isocyanate) (MDI) to produce grafted isocyanate functionalization. Introduction of these bulky functional groups widens the interlayer distance to 1.3 nm. In addition, two reduction methods, namely benzyl alcohol mediated reduction and thermal reduction were carried out on isocyanate modified and unmodified graphite oxides and compared to each other. The decrease in the oxygen content and the sp{sup 3} defect-repair were studied with XPS and RAMAN spectroscopy. Compared to the thermal reduction process, which is connected with large material loss, the benzyl alcohol mediated reduction process is highly effective in defect repair. This resulted in an increase of conductivity of at least 9 orders of magnitude compared to the graphite oxide. - Highlights: • Preparation of GO by Marcano's method results in defined interlayer spacing. • Treatment of GO with diisocyanate widens the interlayer spacing to 1.3 nm. • Chemical reduction of GO with benzyl alcohol is effective in defect repair. • Electrical conductivity increases by 9 orders of magnitude during chemical reduction. • The isocyanate functionalization is stable under chemical reducing conditions.

  1. Environmental Isocyanate-Induced Asthma: Morphologic and Pathogenetic Aspects of an Increasing Occupational Disease

    Directory of Open Access Journals (Sweden)

    Joachim Schirren

    2011-09-01

    Full Text Available Occupational diseases affect more and more people every year. According to the International Labour Organization (ILO, in 2000 an estimated amount of at least 160 million people became ill as a result of occupational-related hazards or injuries. Globally, occupational deaths, diseases and injuries account for an estimated loss of 4% of the Gross Domestic Product. Important substances that are related to occupational diseases are isocyanates and their products. These substances, which are used in a lot of different industrial processes, are not only toxic and irritant, but also allergenic. Although the exposure to higher concentrations could be monitored and restricted by technical means, very low concentrations are difficult to monitor and may, over time, lead to allergic reactions in some workers, ending in an occupational disease. In order to prevent the people from sickening, the mechanisms underlying the disease, by patho-physiological and genetical means, have to be known and understood so that high risk groups and early signs in the development of an allergic reaction could be detected before the exposure to isocyanates leads to an occupational disease. Therefore, this paper reviews the so far known facts concerning the patho-physiologic appearance and mechanisms of isocyanate-associated toxic reactions and possible genetic involvement that might trigger the allergic reactions.

  2. Effect of reaction time and polyethylene glycol monooleate-isocyanate composition on the properties of polyurethane-polysiloxane modified epoxy

    Science.gov (United States)

    Triwulandari, Evi; Ramadhan, Mohammad Kemilau; Ghozali, Muhammad

    2017-11-01

    Polyurethane-polysiloxane modified epoxy based on polyethylene glycol monooleate (PSME-PEGMO) was synthesized. Polyethylene glycol monooleate (PEGMO) for the synthesis of PSME-GMO was synthesized via esterification between oleic acid and polyethylene glycol by using sodium hydroxide as catalyst. Synthesis of PSME-PEGMO was conducted by reacting epoxy, isocyanate, PEGMO, and polysiloxane (hydrolyzed and condensable 3-glycidyloxypropyltrimethoxysilane) simultaneously in one step. This synthesis was carried out by varied the reaction time (1, 2, 3 hours), PEGMO-isocyanate composition (PI composition: 10 and 20 % toward epoxy), and isocyanate/PEGMO ratio (NCO/OH ratio: 1.5 and 2.5). Characterization of PSME-PEGMO was conducted by determining the isocyanate conversion, viscosity analysis, mechanical properties (tensile strength and elongation at break) and thermal analysis using thermogravimetric analysis (TGA). The data show that the PI composition and NCO/OH ratio does not affect the isocyanate conversion linearly. The viscosity of PSME-PEGMO product at ratio and composition variation show has tended to increase with increasing of reaction time. The highest tensile strength and elongation at break PSME-PEGMO was shown by PI composition 20%, NCO/OH ratio 2.5 and reaction time 3 hours.

  3. Determination of isocyanate specific albumin-adducts in workers exposed to toluene diisocyanates.

    Science.gov (United States)

    Sabbioni, Gabriele; Gu, Qi; Vanimireddy, Lakshiminiranjan Reddy

    2012-03-01

    Toluene diisocyanates (2,4-TDI and 2,6-TDI) are important intermediates in the chemical industry. Among the main damages after low levels of TDI exposure are lung sensitization and asthma. It is therefore necessary to have sensitive and specific methods to monitor isocyanate exposure of workers. Urinary metabolites or protein adducts have been used as biomarkers in workers exposed to TDI. However, with these methods it was not possible to determine if the biomarkers result from exposure to TDI or to the corresponding toluene diamines (TDA). This work presents a new procedure for the determination of isocyanate-specific albumin adducts. Isotope dilution mass spectrometry was used to measure the adducts in albumin present in workers exposed to TDI. 2,4-TDI and 2,6-TDI formed adducts with lysine: N(ϵ)-[({3-amino-4-methylphenyl}amino)carbonyl]-lysine, N(ϵ)-[({5-amino-2-methylphenyl}amino)carbonyl]-lysine, and N(ϵ)- [({3-amino-2-methylphenyl}amino)carbonyl]-lysine. In future studies, this new method can be applied to measure TDI-exposures in workers.

  4. Quantification of isocyanates and amines in polyurethane foams and coated products by liquid chromatography–tandem mass spectrometry

    Science.gov (United States)

    Mutsuga, Motoh; Yamaguchi, Miku; Kawamura, Yoko

    2014-01-01

    An analytical method for the identification and quantification of 10 different isocyanates and 11 different amines in polyurethane (PUR) foam and PUR-coated products was developed and optimized. Isocyanates were extracted and derivatized with di-n-butylamine, while amines were extracted with methanol. Quantification was subsequently performed by liquid chromatography–tandem mass spectrometry. Using this methodology, residual levels of isocyanates and amines in commercial PUR products were quantified. Although the recoveries of certain isocyanates and amines were low, the main compounds used as monomers in the production of PUR products, and their decomposition species, were clearly identified at quantifiable levels. 2,4-and 2,6-toluenediisocyanate were detected in most PUR foam samples and a pastry bag in the range of 0.02–0.92 mg/kg, with their decomposition compounds, 2,4-and 2,6-toluenediamine, detected in all PUR foam samples in the range of 9.5–59 mg/kg. PUR-coated gloves are manufactured using 4,4′-methylenebisphenyl diisocyanate as the main raw material, and a large amount of this compound, in addition to 4,4′-methylenedianiline and dicyclohexylmethane-4,4′-diamine were found in these samples. PMID:24804074

  5. Investigation of non-isocyanate urethane functional latexes and carbon nanofiller/epoxy coatings

    Science.gov (United States)

    Meng, Lei

    This dissertation consists of two parts. In the first part, a new class of non-isocyanate urethane methacrylates was synthesized and the effect of the new monomers on the urethane functional latex was investigated. The second part focused on a comparison of carbon nanofillers in inorganic/organic epoxy coating system for anticorrosive applications. A new class of non-isocyanate urethane methacrylates (UMAs) monomers was synthesized through an environmentally friendly non-isocyanate pathway. The kinetics of seeded semibatch emulsion polymerization of UMAs with methyl methacrylate (MMA) and butyl acrylate (BA) was monitored. The particle size and morphology were investigated by dynamic light scattering (DLS), ultrasound acoustic attenuation spectroscopy (UAAS) and transmission electron microscopy (TEM). The minimum film formation temperature (MFFT), mechanical and viscoelastic properties were studied. It was found that the emulsion polymerization processes all proceeded via Smith-Ewart control, leading to the uniform morphology and particle size. The glass transition temperature (Tg) and the mechanical properties of poly(MMA/BA/UMA) decreased with the increasing chain length of urethane methacrylate monomers due to the increasing flexibility of side chains. Without the effect of Tg, lower MFFT and improved mechanical properties were observed from urethane functional latexes. The improved mechanical properties were due to the increasing particle interaction by forming hydrogen bonding. Furthermore, the effect of urethane functionality in terms of the polymer composition, the location and the concentration was investigated by the batch, single-stage and two-stage semibatch polymerization of 2-[(butylcarbamoyl)oxy]ethyl methacrylate (BEM) with MMA and BA. The core-shell and homogeneous structures were evaluated by TEM, differential scanning calorimetry (DSC), and solid state nuclear magnetic resonance (SS-NMR). The compositional drift was observed from the batch

  6. Size selective isocyanate aerosols personal air sampling using porous plastic foams

    International Nuclear Information System (INIS)

    Cong Khanh Huynh; Trinh Vu Duc

    2009-01-01

    As part of a European project (SMT4-CT96-2137), various European institutions specialized in occupational hygiene (BGIA, HSL, IOM, INRS, IST, Ambiente e Lavoro) have established a program of scientific collaboration to develop one or more prototypes of European personal samplers for the collection of simultaneous three dust fractions: inhalable, thoracic and respirable. These samplers based on existing sampling heads (IOM, GSP and cassettes) use Polyurethane Plastic Foam (PUF) according to their porosity to support sampling and separator size of the particles. In this study, the authors present an original application of size selective personal air sampling using chemical impregnated PUF to perform isocyanate aerosols capturing and derivatizing in industrial spray-painting shops.

  7. Nucleophilic reactions of hydrazido(2-) complexes of molybdenum and tungsten with succinyl dichloride and phenyl isocyanate

    International Nuclear Information System (INIS)

    Iwanami, Kiyotaka; Mizobe, Yasushi; Takahashi, Tamotsu; Kodama, Teruyuki; Uchida, Yasuzo

    1981-01-01

    Nucleophilic attack of the WNNH 2 group in the hydrazido(2-) complex [WF(NNH 2 )(dpe) 2 ][BF 4 ] (dpe = Ph 2 PCH 2 CH 2 PPh 2 ) on succinyl dichloride gives a novel ethanedioylhydrazido(2-) complex, [WF(NNCOCH 2 CH 2 CO)(dpe) 2 ][BF 4 ]. X-Ray structural analysis shows that the carbon, nitrogen, and oxygen atoms of the ethanedioylhydrazido(2-) ligand lie nearly in the same plane, indicating sp 2 character of the nitrogen atom bearing the two carbonyl groups. Phenyl isocyanate also undergoes nucleophilic attack by the hydrazido(2-) complex [MBr(NNH 2 )(dpe) 2 ]Br (M = Mo or W) to yield the phenylsemicarbazido(2-) type complex, [MBr(NNHCONHPh)(dpe) 2 ]Br. Treatment of the semicarbazido(2-) complex with triethylamine gives a new diazenido complex [MBr(NNCONHPh)(dpe) 2 ]. (author)

  8. Respiratory protection from isocyanate exposure in the autobody repair and refinishing industry.

    Science.gov (United States)

    Liu, Youcheng; Stowe, Meredith H; Bello, Dhimiter; Woskie, Susan R; Sparer, Judy; Gore, Rebecca; Youngs, Fred; Cullen, Mark R; Redlich, Carrie A

    2006-05-01

    This study, part of the Survey of Painters and Repairers of Auto bodies by Yale (SPRAY), evaluated the effectiveness of respiratory protection against exposure to aliphatic polyisocyanates. A total of 36 shops were assessed for respiratory protection program completeness; 142 workers were measured for respirator fit factor (FF) using PortaCount Plus respirator fit tester. Twenty-two painters from 21 shops were sampled using NIOSH method 5525 to determine the workplace protection factor (WPF) of negative pressure, air-purifying half-facepiece respirators equipped with organic vapor cartridges and paint prefilters during spray-painting and priming activities. Only 11 shops (30%) had written respiratory protection programs. Eighty percent of all fit tested workers passed the test on the first try with FF >or= 100, and 92% passed the second test after respirator use training. Overall geometric mean (GM) FF was 1012 for all fit tested workers. Significant differences on pass rate (92% vs. 72%) and on FF (1990 vs. 736) were found between previously fit tested workers vs. nontested workers. Twenty-nine WPF samples were collected. The outside facepiece GM concentration of total isocyanate group (NCO) was 378.4 micro g NCO/m(3) with 96% concentrations exceeding the U.K. short-term exposure limit, 70 micro g NCO/m(3), but no in-facepiece concentrations exceeded the limit. The GM WPF of total NCO was 319 (GSD 4) and the 5th percentile was 54. WPF of total NCO was positively correlated with the duration of painting task. FF positively correlated with WPF when FF was 450. We conclude that negative pressure, air-purifying half-facepiece respirators equipped with organic vapor cartridges and paint prefilters provide effective protection against isocyanate exposure in spray and priming operations if workers are properly trained and fitted.

  9. Real-time emission factor measurements of isocyanic acid from light duty gasoline vehicles.

    Science.gov (United States)

    Brady, James M; Crisp, Timia A; Collier, Sonya; Kuwayama, Toshihiro; Forestieri, Sara D; Perraud, Véronique; Zhang, Qi; Kleeman, Michael J; Cappa, Christopher D; Bertram, Timothy H

    2014-10-07

    Exposure to gas-phase isocyanic acid (HNCO) has been previously shown to be associated with the development of atherosclerosis, cataracts and rheumatoid arthritis. As such, accurate emission inventories for HNCO are critical for modeling the spatial and temporal distribution of HNCO on a regional and global scale. To date, HNCO emission rates from light duty gasoline vehicles, operated under driving conditions, have not been determined. Here, we present the first measurements of real-time emission factors of isocyanic acid from a fleet of eight light duty gasoline-powered vehicles (LDGVs) tested on a chassis dynamometer using the Unified Driving Cycle (UC) at the California Air Resources Board (CARB) Haagen-Smit test facility, all of which were equipped with three-way catalytic converters. HNCO emissions were observed from all vehicles, in contrast to the idealized laboratory measurements. We report the tested fleet averaged HNCO emission factors, which depend strongly on the phase of the drive cycle; ranging from 0.46 ± 0.13 mg kg fuel(-1) during engine start to 1.70 ± 1.77 mg kg fuel(-1) during hard acceleration after the engine and catalytic converter were warm. The tested eight-car fleet average fuel based HNCO emission factor was 0.91 ± 0.58 mg kg fuel(-1), within the range previously estimated for light duty diesel-powered vehicles (0.21-3.96 mg kg fuel(-1)). Our results suggest that HNCO emissions from LDGVs represent a significant emission source in urban areas that should be accounted for in global and regional models.

  10. Creation of Vapor/Gas Impermeable Coatings for CB Hardening of Existing Structures

    Science.gov (United States)

    2013-04-05

    Standard Test Method for Hydroxyl Groups Using Reaction with p-Toluenesulfonyl Isocyanate and Potentiometric Titration with Tetrabutylammonium...setup The structures of some resins produced as a result of the syntheses were confirmed by titration of their reactive terminal groups. This work...was conducted on a Mettler-Toledo DL-55 titrator . It must be noted that, as all the produced resins were new compounds that had never been

  11. Influence of the prepolymer molecular weight and free isocyanate content on the rheology of polyurethane modified bitumens

    OpenAIRE

    Carrera Páez, Virginia; Cuadri Vega, Antonio Abad; García Morales, Moisés; Partal López, Pedro

    2014-01-01

    Isocyanate-based modification is lately gaining acceptance as a successful way to give added value to bitumen, a crude oil refining by-product. In order to study the influence of prepolymer type on the rheological properties of the resulting binders, six prepolymers synthesized from polypropylene-glycols (PPG) with varying molecular weight (between 440 and 2425) and different molar excess of a polymeric MDI (4,4’-diphenylmethane diisocyanate) were used. Two modification procedures, either inv...

  12. Performance of composite boards from long strand oil palm trunk bonded by isocyanate and urea formaldehyde adhesives

    Science.gov (United States)

    Hermanto, Indra; Massijaya, M. Y.

    2018-03-01

    In this research, the obtained long strand were produced from the outer part of oil palm trunk and then hot-prepressed. The three-ply composite boards were made from hot-prepressed long strand and use bonded by isocyanate and urea formaldehyde adhesives with a glue spread variation of 150 g/m2, 225 g/m2, and 300 g/m2. The board target density was 0.65 g/cm3, face and back layers orientation is the same and the core layer was perpendicular to the face and back layers. The research results showed that : (1) composite boards bonded by isocyanate performed better physical and mechanical properties compared to those of bonded by urea formaldehyde, (2) utilization of higher glue spread level would improve the physical and mechanical properties of the composite board. (3) composite boards bonded by isocyanate and urea formaldehyde adhesives at glue spread of 225 g/m2, 300 g/m2, respectively were enough to fulfill the JIS A 5908 (2003) standard.

  13. Radiation cross-linking of ethylene vinyl alcohol copolymer functionalized with m-isopropenyl-α,α-dimethyl benzyl isocyanate

    International Nuclear Information System (INIS)

    Ekman, K.B.; Naesman, J.H.

    1993-01-01

    An ethylene vinyl alcohol copolymer was functionalized with m-isopropenyl-α,α-dimethyl benzyl isocyanate using reactive processing in a mixer. The functionalization introduces pendant unsaturation to the polymer, which allows radiation cross-linked to gel contents >70% at radiation doses below 100 kGy. Unfunctionalized ethylene vinyl alcohol copolymer, on the other hand, forms no gel upon irradiation. The functionalization was completed within a few minutes of reactive mixing, which was confirmed with both FTIR and 13 C-NMR measurements. The oxygen permeability of ethylene vinyl alcohol copolymer increased with increasing degree of functionalization, and irradiation of the samples formed trapped radicals, which act as oxygen scavengers. Consequently no oxygen permeability was detected. However, radical activity was inhibited by annealing the samples at 110 C resulting in a 24% higher oxygen permeability value for the irradiated unfunctionalized copolymer. The oxygen permeability values of the irradiated functionalized samples were approximately 13% lower. Laminates of m-isopropenyl-α,α-dimethyl benzyl isocyanate functionalized ethylene vinyl alcohol copolymer and m-isopropenyl-α,α-dimethyl benzyl isocyanate functionalized ethylene hydroxyethyl methacrylate copolymer acquired improved adhesive strength both at dry and wet conditions as well as at elevated temperature upon exposure to radiation

  14. Ytterbium triflate as a new catalyst on the curing of epoxy-isocyanate based thermosets

    Energy Technology Data Exchange (ETDEWEB)

    Flores, Marjorie; Fernandez-Francos, Xavier [Departament de Quimica Analitica i Quimica Organica, Universitat Rovira i Virgili, Marcelli Domingo s/n, 43007 Tarragona (Spain); Morancho, Josep M. [Laboratori de Termodinamica, ETSEIB, Universitat Politecnica de Catalunya, Diagonal 647, 08028 Barcelona (Spain); Serra, Angels [Departament de Quimica Analitica i Quimica Organica, Universitat Rovira i Virgili, Marcelli Domingo s/n, 43007 Tarragona (Spain); Ramis, Xavier, E-mail: ramis@mmt.upc.es [Laboratori de Termodinamica, ETSEIB, Universitat Politecnica de Catalunya, Diagonal 647, 08028 Barcelona (Spain)

    2012-09-10

    Highlights: Black-Right-Pointing-Pointer Ytterbium triflate is an active catalyst for diepoxides/diisocyanate formulations. Black-Right-Pointing-Pointer Ytterbium triflate promotes the formation of oxazolidone, isocyanurate, urethane and allophanate groups and the polyetherification of epoxides. Black-Right-Pointing-Pointer Diepoxides/diisocyanate formulations catalyzed by ytterbium triflate show higher pot-life than equivalent formulations catalyzed by benzyldimethylamine. - Abstract: Networks containing oxazolidone, isocyanurate, urethane, allophanate and ether groups were prepared by copolymerization of mixtures of diglycidylether of bisphenol A and toluene-2,4-diisocyanate in presence of ytterbium triflate. It has been demonstrated that ytterbium triflate promotes six elemental reactions that coexist during curing and yield the aforementioned groups. Changes during curing, fraction of different groups present in the network and final properties of the cured materials were investigated by thermal analysis and infrared spectroscopy. The influence of the molar ratio of isocyanate to epoxide groups on the properties and curing has been studied. The curing kinetics were analyzed by means of an integral isoconversional non-isothermal procedure. The results obtained were compared with those obtained by using a common catalyst such as the benzyldimethylamine. The structure and the properties of the resulting thermosets are controlled by the initial composition of the formulation and the catalyst used.

  15. Synthesis and Characterization of Starch-based Aqueous Polymer Isocyanate Wood Adhesive

    Directory of Open Access Journals (Sweden)

    Shu-min Wang

    2015-09-01

    Full Text Available Modified starch was prepared in this work by acid-thinning and oxidizing corn starch with ammonium persulfate. Also, starch-based aqueous polymer isocyanate (API wood adhesive was prepared. The effect of the added amount of modified starch, styrene butadiene rubber (SBR, polymeric diphenylmethane diisocyanate (P-MDI, and the mass concentration of polyvinyl alcohol (PVOH on the bonding strength of starch-based API adhesives were determined by orthogonal testing. The starch-based API adhesive performance was found to be the best when the addition of modified starch (mass concentration 35% was 45 g, the amount of SBR was 3%, the PVOH mass concentration was 10%, and the amount of P-MDI was 18%. The compression shearing of glulam produced by starch-based API adhesive reached bonding performance indicators of I type adhesive. A scanning electron microscope (SEM was used to analyze the changes in micro-morphology of the starch surface during each stage. Fourier transform infrared spectroscopy (FT-IR was used to study the changes in absorption peaks and functional groups from starch to starch-based API adhesives. The results showed that during starch-based API adhesive synthesis, corn starch surface was differently changed and it gradually reacted with other materials.

  16. Aryliminopropadienone-C-Amidoketenimine- Amidinoketene-2-Aminoquinolone Cascades and the Ynamine-Isocyanate Reaction.

    Science.gov (United States)

    Wentrup, Curt; Rao, V. V. Ramana; Frank, Wilhelm; Fulloon, Belinda E.; Moloney, Daniel W. J.; Mosandl, Thomas

    1999-05-14

    Imidoylketenes 11 and oxoketenimines 12 are generated by flash vacuum thermolysis of Meldrum's acid derivatives 9, pyrrolediones 17 and 18, and triazole 19 and are observed by IR spectroscopy. Ketenimine-3-carboxylic acid esters 12a are isolable at room temperature. Ketenes 11 and ketenimines 12 undergo rapid interconversion in the gas phase, and the ketenes cyclize to 4-quinolones 13. When using an amine leaving group in Meldrum's acid derivatives 9c, the major reaction products are aryliminopropadienones, ArN=C=C=C=O (15). The latter react with 1 equiv of nucleophile to produce ketenimines 12 and with 2 equiv to afford malonic acid imide derivatives 16. N-Arylketenimine-C-carboxamides 12c cyclize to quinolones 13c via the transient amidinoketenes 11c at temperatures of 25-40 degrees C. This implies rapid interconversion of ketenes and ketenimines by a 1,3-shift of the dimethylamino group, even at room temperature. This interconversion explains previously poorly understood outcomes of the ynamine-isocyanate reaction. The solvent dependence of the tautomerism of 4-quinolones/4-quinolinols is discussed. Rotational barriers of NMe(2) groups in amidoketenimines 12c and malonioc amides and amidines 16 (24) are reported.

  17. Mechanistic studies on the conjugation of methyl isocyanate with N-Acetyl-Cysteine in rats

    International Nuclear Information System (INIS)

    Hu, P.; Davis, M.R.; Baillie, T.A.

    1996-01-01

    In order to investigate the utility of selected thiols as scavengers of MIC, we first assessed the chemical stability of SMG, AMCC and SMC by measuring their rates of reaction in vitro with thiorphan. The initial rates of carbamoylation of thiorpan (0.5 mM) by the above conjugates (0.5 mM) in aqeous buffer at pH 7.4 and 37 deg C were 2.51, 0.76 and 8.47 μmol L -1 min -1 , repectively, indicating that the mercapturate AMCC was the most stable of the three MIC conjugates. In light of these results, studies were conducted to examine the effect of pretreatment with N-acetyl-L-cysteine (L-NAC; 500 mg kg -1 , i.p.) on the urinary elimination of AMCC in rats dosed with MIC (15 mg kg -1 , i.p.). In separate experiments, groups of rats were pretreated with either N-acetyl-D-cysteine (D-NAC) or N-trideuteroacetyl-L-cysteine (d 3 -L-NAC) in order to explore the mechanism by which MIC undergoes conjugation to AMCC in vivo. The results indicated that exogenous NAC effectively enhancess the urinary excretion of MIC in the form of AMCC, and that it does so lagerly by direct conjugation with the isocyanate, rather than via biosynthesis to GSH. (author). 9 refs., 5 figs

  18. Highly efficient isocyanate-free microwave-assisted synthesis of [6]-oligourea

    KAUST Repository

    Qaroush, Abdussalam K.

    2013-01-01

    A new eco-friendly, isocyanate-free, energy-saving method for the production of [6]-oligourea, utilizing a green carbonylating agent, viz. propylene carbonate, is reported. It comprises an organocatalyzed, microwave-assisted, solvent-free synthesis. Two modes of microwave-assisted synthesis, viz. dynamic and fixed energy modes, were applied. Upon optimization, the dynamic mode gave 79% yields of [6]-oligourea. On the other hand, almost quantitative yields were obtained using the fixed mode, within 20 min, at 10 W and with the same catalyst loading. Combination of both organocatalysis and microwave energy input appears to be a key issue for the efficiency of the reaction, with the fixed energy mode being best suited. It should be noted that all data reported are reproducible (due to the homogeneous microwave technology used by CEM Discover S-Class of microwave reactors). To the best of our knowledge, this is the best eco-friendly synthetic approach for the preparation of the title oligomers. It paves the way for using more of the biorenewable and sustainable chemicals as a feedstock for the production of polyureas. The oligomer produced was analyzed by EA, ATR-FTIR, XRD, 1H and 13CNMR. Furthermore, thermal properties of the resulting [6]-oligourea were analyzed using TGA and DSC. © The Royal Society of Chemistry 2013.

  19. Uptake and distribution of 14C during and following exposure to [14C]methyl isocyanate

    International Nuclear Information System (INIS)

    Ferguson, J.S.; Kennedy, A.L.; Stock, M.F.; Brown, W.E.; Alarie, Y.

    1988-01-01

    Guinea pigs were exposed to [ 14 C]methyl isocyanate ( 14 CH 3 -NCO, 14 C MIC) for periods of 1 to 6 hr at concentrations of 0.5 to 15 ppm. Arterial blood samples taken during exposure revealed immediate and rapid uptake of 14 C. Clearance of 14 C was then gradual over a period of 3 days. Similarly 14 C was present in urine and bile immediately following exposure, and clearance paralleled that observed in blood. Guinea pigs fitted with a tracheal cannula and exposed while under anesthesia showed a reduced 14 C uptake in blood indicating that most of the 14 C MIC uptake in normal guinea pigs occurred from retention of this agent in the upper respiratory tract passages. In exposed guinea pigs 14 C was distributed to all examined tissues. In pregnant female mice similarly exposed to 14 C MIC, 14 C was observed in all tissues examined following exposure including the uterus, placenta, and fetus. While the form of 14 C distributed in blood and tissues has not yet been identified, these findings may help to explain the toxicity of MIC or MIC reaction products on organs other than the respiratory tract, as noted by several investigators

  20. Isocyanate-functionalized chitin and chitosan as gelling agents of castor oil.

    Science.gov (United States)

    Gallego, Rocío; Arteaga, Jesús F; Valencia, Concepción; Franco, José M

    2013-06-03

    The main objective of this work was the incorporation of reactive isocyanate groups into chitin and chitosan in order to effectively use the products as reactive thickening agents in castor oil. The resulting gel-like dispersions could be potentially used as biodegradable lubricating greases. Three different NCO-functionalized polymers were obtained: two of them by promoting the reaction of chitosan with 1,6-hexamethylene diisocyanate (HMDI), and the other by using chitin instead of chitosan. These polymers were characterized through 1H-NMR, FTIR and thermogravimetric analysis (TGA). Thermal and rheological behaviours of the oleogels prepared by dispersing these polymers in castor oil were studied by means of TGA and small-amplitude oscillatory shear (SAOS) measurements. The evolution and values of the linear viscoelasticity functions with frequency for -NCO-functionalized chitosan- and chitin-based oleogels are quite similar to those found for standard lubricating greases. In relation to long-term stability of these oleogels, no phase separation was observed and the values of viscoelastic functions increase significantly during the first seven days of ageing, and then remain almost constant. TGA analysis showed that the degradation temperature of the resulting oleogels is higher than that found for traditional lubricating greases.

  1. Investigating Diesel Engines as an Atmospheric Source of Isocyanic Acid in Urban Areas

    Science.gov (United States)

    Farmer, D.; Jathar, S.; Heppding, C.; Link, M.; Akherati, A.; Kleeman, M.; De Gouw, J. A.; Veres, P. R.; Roberts, J. M.

    2017-12-01

    Isocyanic acid (HNCO), an acidic gas found in tobacco smoke, urban environments and biomass burning-affected regions, has been linked to adverse health outcomes. Gasoline- and diesel-powered engines and biomass burning are known to emit HNCO and hypothesized to emit precursors such as amides that can photochemically react to produce HNCO in the atmosphere. Increasingly, diesel engines in developed countries like the United States are required to use Selective Catalytic Reduction (SCR) systems to reduce tailpipe emissions of oxides of nitrogen. SCR chemistry is known to produce HNCO as an intermediate product, and SCR systems have been implicated as an atmospheric source of HNCO. In this work, we measure HNCO emissions from an SCR system-equipped diesel engine and, in combination with earlier data, use a three-dimensional chemical transport model (CTM) to simulate the ambient concentrations and source/pathway contributions to HNCO in an urban environment. Engine tests were conducted at three different engine loads, using two different fuels and at multiple operating points. HNCO was measured using an acetate chemical ionization mass spectrometer. The diesel engine was found to emit primary HNCO (3-90 mg kg-fuel-1) but we did not find any evidence that the SCR system or other aftertreatment devices (i.e., oxidation catalyst and particle filter) produced or enhanced HNCO emissions. The CTM predictions compared well with the only available observational data sets for HNCO in urban areas but under-predicted the contribution from secondary processes. The comparison implied that diesel-powered engines were the largest source of HNCO in urban areas. The CTM also predicted that daily-averaged concentrations of HNCO reached a maximum of 110 pptv but were an order of magnitude lower than the 1 ppbv level that could be associated with physiological effects in humans. Precursor contributions from other combustion sources (gasoline and biomass burning) and wintertime conditions

  2. Investigating diesel engines as an atmospheric source of isocyanic acid in urban areas

    Directory of Open Access Journals (Sweden)

    S. H. Jathar

    2017-07-01

    Full Text Available Isocyanic acid (HNCO, an acidic gas found in tobacco smoke, urban environments, and biomass-burning-affected regions, has been linked to adverse health outcomes. Gasoline- and diesel-powered engines and biomass burning are known to emit HNCO and hypothesized to emit precursors such as amides that can photochemically react to produce HNCO in the atmosphere. Increasingly, diesel engines in developed countries like the United States are required to use selective catalytic reduction (SCR systems to reduce tailpipe emissions of oxides of nitrogen. SCR chemistry is known to produce HNCO as an intermediate product, and SCR systems have been implicated as an atmospheric source of HNCO. In this work, we measure HNCO emissions from an SCR system-equipped diesel engine and, in combination with earlier data, use a three-dimensional chemical transport model (CTM to simulate the ambient concentrations and source/pathway contributions to HNCO in an urban environment. Engine tests were conducted at three different engine loads, using two different fuels and at multiple operating points. HNCO was measured using an acetate chemical ionization mass spectrometer. The diesel engine was found to emit primary HNCO (3–90 mg kg fuel−1 but we did not find any evidence that the SCR system or other aftertreatment devices (i.e., oxidation catalyst and particle filter produced or enhanced HNCO emissions. The CTM predictions compared well with the only available observational datasets for HNCO in urban areas but underpredicted the contribution from secondary processes. The comparison implied that diesel-powered engines were the largest source of HNCO in urban areas. The CTM also predicted that daily-averaged concentrations of HNCO reached a maximum of ∼ 110 pptv but were an order of magnitude lower than the 1 ppbv level that could be associated with physiological effects in humans. Precursor contributions from other combustion sources (gasoline and biomass

  3. Effect of spatial distribution of wax and PEG-isocyanate on the morphology and hydrophobicity of starch films.

    Science.gov (United States)

    Muscat, Delina; Adhikari, Raju; Tobin, Mark J; McKnight, Stafford; Wakeling, Lara; Adhikari, Benu

    2014-10-13

    This study proposes a novel method for improving surface hydrophobicity of glycerol plasticized high amylose (HAG) films. We used polyethylene glycol isocyanate (PEG-iso) crosslinker to link HAG and three natural waxes (beeswax, candelilla wax and carnauba wax) to produce HAG+wax+PEG-iso films. The spatial distributions of wax and PEG-iso across the thickness of these films were determined using Synchrotron-based Fourier transform infrared spectroscopy. The hydrophobicity and surface morphology of the films were determined using contact angle (CA) and scanning electron microscopic measurements, respectively. The distribution patterns of wax and the PEG-iso across the thickness of the film, and the nature of crystalline patterns formed on the surface of these films were found to be the key factors affecting surface hydrophobicity. The highest hydrophobicity (CA >90°) was created when the PEG-iso was primarily distributed in the interior of the films and a hierarchical circular pinnacle structure of solidified wax was formed on the surface. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Isocyanic acid in a global chemistry transport model: Tropospheric distribution, budget, and identification of regions with potential health impacts

    Science.gov (United States)

    Young, Paul. J.; Emmons, Louisa K.; Roberts, James M.; Lamarque, Jean-FrançOis; Wiedinmyer, Christine; Veres, Patrick; Vandenboer, Trevor C.

    2012-05-01

    This study uses a global chemical transport model to estimate the distribution of isocyanic acid (HNCO). HNCO is toxic, and concentrations exceeding 1 ppbv have been suggested to have negative health effects. Based on fire studies, HNCO emissions were scaled to those of hydrogen cyanide (30%), resulting in yearly total emissions of 1.5 Tg for 2008, from both anthropogenic and biomass burning sources. Loss processes included heterogeneous uptake (pH dependent), dry deposition (like formic acid), and reaction with the OH radical (k = 1 × 10-15 molecule-1 cm3 s-1). Annual mean surface HNCO concentrations were highest over parts of China (maximum of 470 pptv), but episodic fire emissions gave much higher levels, exceeding 4 ppbv in tropical Africa and the Amazon, and exceeding 10 ppbv in Southeast Asia and Siberia. This suggests that large biomass burning events could result in deleterious health effects for populations in these regions. For the tropospheric budget, using the model-calculated pH the HNCO lifetime was 37 days, with the split between dry deposition and heterogeneous loss being 95%:5%. Fixing the heterogeneous loss rate at pH = 7 meant that this process dominated, accounting for ˜70% of the total loss, giving a lifetime of 6 days, and resulting in upper tropospheric concentrations that were essentially zero. However, changing the pH does not notably impact the high concentrations found in biomass burning regions. More observational data is needed to evaluate the model, as well as a better representation of the likely underestimated biofuel emissions, which could mean more populations exposed to elevated HNCO concentrations.

  5. Excess Substrate is a Spectator Ligand in a Rhodium-Catalyzed Asymmetric [2+2+2] Cycloaddition of Alkenyl Isocyanates with Tolanes

    Science.gov (United States)

    Oinen, Mark Emil; Yu, Robert T.; Rovis, Tomislav

    2009-01-01

    Excess substrate has been identified as an unintended spectator ligand affecting enantioselectivity in the [2+2+2] cycloaddition of alkenyl isocyanates with tolanes. Replacement of excess substrate with an exogenous additive affords products with consistent and higher ee’s. The increase in enantioselectivity is the result of a change in composition of a proposed rhodium(III) intermediate on the catalytic cycle. The net result is a rational probe of a short-lived rhodium(III) intermediate, and gives insight that may have applications in many rhodium catalyzed reactions. PMID:19803471

  6. Tin oxide surfaces--8. An infrared study of the mechanism of formation of a surface isocyanate species on SnO/sub 2//0. 55 CuO during catalysis of the oxidation of carbon monoxide by nitric oxide

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, P.G.; Thornton, E.W.

    1978-01-01

    In studies carried out at 470/sup 0/K, the measurements of the isotopic shifts of the 2189/cm pseudo-antisymmetric stretching vibration for carbon-13, nitrogen-15, and oxygen-18 substitution indicated that the oxygen atom of the surface isocyanate, formed as an intermediate in the reaction of CO with NO, originated from NO, not from CO as previously believed. The mechanism proposed involves the dissociative chemisorption of CO, the formation of a fulminate by the reaction of NO with the surface carbon atom, and rapid isomerization to the isocyanate.

  7. Linear uranium complexes X2UL5 with L=cyanide, iso-cyanate: DFT evidence for similarities between uranyl (X = O) and uranocene (X = Cp) derivatives

    International Nuclear Information System (INIS)

    Iche-Tarrat, N.; Marsden, Colin J.; Barros, N.; Maron, L.; Barros, N.

    2008-01-01

    A DFT study of the isostructural compounds [UO 2 L 5 ] n- with n=3-5 and linear [Cp 2 UL 5 ] m- with m=1-3 has been carried out for two different anionic ligands. Structurally stable structures are obtained for all systems. The coordination competition between cyanide (CN - ) and isocyanide (NC - ) as well as between cyanate (OCN - ) and iso-cyanate (NCO - ) has been studied in the uranyl case. A clear preference for cyanide and iso-cyanate complexes is reported. The coordination of five ligands in the equatorial plane is rationalized by the analysis of the MO diagram of both systems. Moreover, the qualitative comparison of the two MO diagrams shows a high similarity in agreement with the isolobality concept. The existence of linear [Cp 2 UL 5 ] - organometallic U(VI) complexes is thus proposed, as well as the possibility of obtaining complexes of both types for U(VI) and U(V) with OCN - ligands. In addition, the U(IV) linear metallocene is calculated to be stable for the latter ligand. (authors)

  8. Selective activation of human heat shock gene transcription by nitrosourea antitumor drugs mediated by isocyanate-induced damage and activation of heat shock transcription factor.

    Science.gov (United States)

    Kroes, R A; Abravaya, K; Seidenfeld, J; Morimoto, R I

    1991-01-01

    Treatment of cultured human tumor cells with the chloroethylnitrosourea antitumor drug 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) selectively induces transcription and protein synthesis of a subset of the human heat shock or stress-induced genes (HSP90 and HSP70) with little effect on other stress genes or on expression of the c-fos, c-myc, or beta-actin genes. The active component of BCNU and related compounds appears to be the isocyanate moiety that causes carbamoylation of proteins and nucleic acids. Transcriptional activation of the human HSP70 gene by BCNU is dependent on the heat shock element and correlates with the level of heat shock transcription factor and its binding to the heat shock element in vivo. Unlike activation by heat or heavy metals, BCNU-mediated activation is strongly dependent upon new protein synthesis. This suggests that BCNU-induced, isocyanate-mediated damage to newly synthesized protein(s) may be responsible for activation of the heat shock transcription factor and increased transcription of the HSP90 and HSP70 genes. Images PMID:2052560

  9. Contribution of post-harvest agricultural paddy residue fires in the N.W. Indo-Gangetic Plain to ambient carcinogenic benzenoids, toxic isocyanic acid and carbon monoxide

    Science.gov (United States)

    Praphulla Chandra, Boggarapu; Sinha, Vinayak

    2016-04-01

    In the North West Indo-Gangetic Plain (N.W.IGP), large scale post-harvest paddy residue fires occur every year during the months of October-November. This anthropogenic perturbation causes contamination of the atmospheric environment with adverse impacts on regional air quality posing health risks for the population exposed to high concentrations of carcinogens such as benzene and toxic VOCs such as isocyanic acid. These gases and carbon monoxide are known to be emitted from biomass fires along with acetonitrile. Yet no long-term in-situ measurements quantifying the impact of this activity have been carried out in the N.W. IGP. Using high quality continuous online in-situ measurements of these gases at a strategic downwind site over a three year period from 2012 to 2014, we demonstrate the strong impact of this anthropogenic emission activity on ambient concentrations of these gases. In contrast to the pre-paddy harvest period, excellent correlation of benzenoids, isocyanic acid and CO with acetonitrile (a biomass burning chemical tracer); (r ≥ 0.82) and distinct VOC/acetonitrile emission ratios were observed for the post-paddy harvest period which was also characterized by high ambient concentrations of these species. The average concentrations of acetonitrile (1.62 ± 0.18 ppb), benzene (2.51 ± 0.28 ppb), toluene (3.72 ± 0.41 ppb), C8-aromatics (2.88 ± 0.30 ppb), C9-aromatics (1.55 ± 0.19 ppb) and CO (552 ± 113 ppb) in the post-paddy harvest periods were about 1.5 times higher than the annual average concentrations. For isocyanic acid, a compound with both primary and secondary sources, the concentration in the post-paddy harvest period was 0.97 ± 0.17 ppb. The annual average concentrations of benzene, a class A carcinogen, exceeded the annual exposure limit of 1.6 ppb at NTP mandated by the National Ambient Air Quality Standard of India (NAAQS). We show that mitigating the post-harvest paddy residue fires can lower the annual average concentration of

  10. Isocyanate test antigens

    International Nuclear Information System (INIS)

    Karol, M.H.; Alarie, Y.C.

    1980-01-01

    A test antigen for detecting antibodies to a diisocyanate comprises the reaction product of a protein and a monoisocyanate derived from the same radical as the diisocyanate. The diisocyanates most usually encountered and therefore calling for antibody detection are those of toluene, hexamethylene, methylene, isophorone and naphthylene. The preferred protein is human serum albumin. (author)

  11. Contribution of post-harvest agricultural paddy residue fires in the N.W. Indo-Gangetic Plain to ambient carcinogenic benzenoids, toxic isocyanic acid and carbon monoxide.

    Science.gov (United States)

    Chandra, B P; Sinha, Vinayak

    2016-03-01

    In the north west Indo-Gangetic Plain (N.W.IGP), large scale post-harvest paddy residue fires occur every year during the months of October-November. This anthropogenic perturbation causes contamination of the atmospheric environment with adverse impacts on regional air quality posing health risks for the population exposed to high concentrations of carcinogens such as benzene and toxic VOCs such as isocyanic acid. These gases and carbon monoxide are known to be emitted from biomass fires along with acetonitrile. Yet no long-term in-situ measurements quantifying the impact of this activity have been carried out in the N.W. IGP. Using high quality continuous online in-situ measurements of these gases at a strategic downwind site over a three year period from 2012 to 2014, we demonstrate the strong impact of this anthropogenic emission activity on ambient concentrations of these gases. In contrast to the pre-paddy harvest period, excellent correlation of benzenoids, isocyanic acid and CO with acetonitrile (a biomass burning chemical tracer); (r≥0.82) and distinct VOC/acetonitrile emission ratios were observed for the post-paddy harvest period which was also characterized by high ambient concentrations of these species. The average concentrations of acetonitrile (1.62±0.18ppb), benzene (2.51±0.28ppb), toluene (3.72±0.41ppb), C8-aromatics (2.88±0.30ppb), C9-aromatics (1.55±0.19ppb) and CO (552±113ppb) in the post-paddy harvest periods were about 1.5 times higher than the annual average concentrations. For isocyanic acid, a compound with both primary and secondary sources, the concentration in the post-paddy harvest period was 0.97±0.17ppb. The annual average concentrations of benzene, a class A carcinogen, exceeded the annual exposure limit of 1.6ppb at NTP mandated by the National Ambient Air Quality Standard of India (NAAQS). We show that mitigating the post-harvest paddy residue fires can lower the annual average concentration of benzene and ensure

  12. Enantioselective Rhodium-Catalyzed [2+2+2] Cycloadditions of Terminal Alkynes and Alkenyl Isocyanates: Mechanistic Insights Lead to a Unified Model that Rationalizes Product Selectivity

    Science.gov (United States)

    Dalton, Derek M.; Oberg, Kevin M.; Yu, Robert T.; Lee, Ernest E.; Perreault, Stéphane; Oinen, Mark Emil; Pease, Melissa L.; Malik, Guillaume; Rovis, Tomislav

    2009-01-01

    This manuscript describes the development and scope of the asymmetric rhodium-catalyzed [2+2+2] cycloaddition of terminal alkynes and alkenyl isocyanates leading to the formation of indolizidine and quinolizidine scaffolds. The use of phosphoramidite ligands proved crucial for avoiding competitive terminal alkyne dimerization. Both aliphatic and aromatic terminal alkynes participate well, with product selectivity a function of both the steric and electronic character of the alkyne. Manipulation of the phosphoramidite ligand leads to tuning of enantio- and product selectivity, with a complete turnover in product selectivity seen with aliphatic alkynes when moving from Taddol-based to biphenol-based phosphoramidites. Terminal and 1,1-disubstituted olefins are tolerated with nearly equal efficacy. Examination of a series of competition experiments in combination with analysis of reaction outcome shed considerable light on the operative catalytic cycle. Through a detailed study of a series of X-ray structures of rhodium(cod)chloride/phosphoramidite complexes, we have formulated a mechanistic hypothesis that rationalizes the observed product selectivity. PMID:19817441

  13. Laboratory study of isocyanic acid ions: Rotational spectroscopy of NCO{sup −}, H{sub 2}NCO{sup +}, and HNCOH{sup +}

    Energy Technology Data Exchange (ETDEWEB)

    Lattanzi, Valerio; Gottlieb, Carl A.; Thaddeus, Patrick; McCarthy, Michael C. [Harvard-Smithsonian Center for Astrophysics, and School of Engineering and Applied Sciences, Harvard University (United States); Thorwirth, Sven [I. Physikalisches Institut Universität zu Köln, and Max-Planck-Institut für Radioastronomie (Germany)

    2015-01-22

    We report detection of protonated isocyanic acid in two isomeric forms, H{sub 2}NCO{sup +} and HNCOH{sup +}, by high-resolution spectroscopy. The two ions were first observed at centimeter wavelengths by Fourier Transform (FT) microwave spectroscopy, in a discharge through HNCO heavily diluted in hydrogen in the throat of a supersonic nozzle. Spectroscopic constants derived from the two lowest rotational transitions of both isomers agree very well with those derived from theoretical structures computed at the coupled cluster level of theory. In the same molecular beam, the fundamental rotational transition of NCO{sup −} was observed with well-resolved nitrogen quadrupole hyperfine structure. Detection of NCO{sup −} and H{sub 2}NCO{sup +} in our beam was subsequently confirmed by observation of several millimeter-wave transitions in a low pressure discharge through cyanogen and water. The spectroscopic constants of NCO{sup −} obtained earlier by infrared laser spectroscopy are in good agreement with the highly accurate constants derived here. Owing to the high abundance of HNCO in many galactic molecular sources, both ions are excellent candidates for astronomical detection in the radio band.

  14. Influence of Functionalization Degree on the Rheological Properties of Isocyanate-Functionalized Chitin- and Chitosan-Based Chemical Oleogels for Lubricant Applications

    Directory of Open Access Journals (Sweden)

    Rocío Gallego

    2014-07-01

    Full Text Available This work deals with the influence of functionalization degree on the thermogravimetric and rheological behaviour of NCO-functionalized chitosan- and chitin-based oleogels. Chitosan and chitin were functionalized using different proportions of 1,6-hexamethylene diisocyanate (HMDI and subsequently dispersed in castor oil to promote the chemical reaction between the –NCO group of the modified biopolymer and the –OH group located in the ricinoleic fatty acid chain of castor oil, thus resulting in different oleogels with specific thermogravimetric and rheological characteristics. Biopolymers and oleogels were characterized through Fourier transform infrared spectroscopy (FTIR and thermogravimetric analysis (TGA. Small-amplitude oscillatory shear (SAOS measurements were performed on the oleogels. Oleogels presented suitable thermal resistance, despite the fact that the inclusion of HMDI moieties in the polymer structure led to a reduction in the onset temperature of thermal degradation. The insertion of low amounts of HMDI in both chitin and chitosan produces a drastic reduction in the values of oleogel viscoelastic functions but, above a critical threshold, they increase with the functionalization degree so that isocyanate functionalization results in a chemical tool to modulate oleogel rheological response. Several NCO-functionalized chitosan- and chitin-based oleogel formulations present suitable thermal resistance and rheological characteristics to be proposed as bio-based alternatives to traditional lubricating greases.

  15. Pyrrolizidine alkaloids in herbal teas for infants, pregnant or lactating women.

    Science.gov (United States)

    Mädge, Inga; Cramer, Luise; Rahaus, Ines; Jerz, Gerold; Winterhalter, Peter; Beuerle, Till

    2015-11-15

    A general contamination of tea with pyrrolizidine alkaloids (PA) has just become known. Here, we report the application and modification of a new HPLC-ESI-MS/MS sum parameter method to quantitate PA content of herbal teas intended for infants, pregnant and lactating women. Using p-toluenesulfonyl isocyanate for derivatization and a stable isotope labeled internal standard, the total retronecine-/heliotridine-type PA content of the samples is expressed in form of a single sum parameter (retronecine equivalents: RE). The new methods were applied to analyze 44 tea samples for such consumer groups. Thirty eight products (86%) were tested PA positive showing PA concentrations ranging from 0 to 391 μg RE/kg (average: 50 μg RE/kg). The dataset is discussed in the view of the current discussion on PA in the food chain with special focus on those particular vulnerable consumer groups. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Overview of VOC emissions and chemistry from PTR-TOF-MS measurements during the SusKat-ABC campaign: high acetaldehyde, isoprene and isocyanic acid in wintertime air of the Kathmandu Valley

    Science.gov (United States)

    Sarkar, Chinmoy; Sinha, Vinayak; Kumar, Vinod; Rupakheti, Maheswar; Panday, Arnico; Mahata, Khadak S.; Rupakheti, Dipesh; Kathayat, Bhogendra; Lawrence, Mark G.

    2016-03-01

    = 60.051), which can photochemically produce isocyanic acid in the atmosphere, are reported in this study along with nitromethane (a tracer for diesel exhaust), which has only recently been detected in ambient studies. Two distinct periods were selected during the campaign for detailed analysis: the first was associated with high wintertime emissions of biogenic isoprene and the second with elevated levels of ambient acetonitrile, benzene and isocyanic acid from biomass burning activities. Emissions from biomass burning and biomass co-fired brick kilns were found to be the dominant sources for compounds such as propyne, propene, benzene and propanenitrile, which correlated strongly with acetonitrile (r2 > 0.7), a chemical tracer for biomass burning. The calculated total VOC OH reactivity was dominated by acetaldehyde (24.0 %), isoprene (20.2 %) and propene (18.7 %), while oxygenated VOCs and isoprene collectively contributed to more than 68 % of the total ozone production potential. Based on known secondary organic aerosol (SOA) yields and measured ambient concentrations in the Kathmandu Valley, the relative SOA production potential of VOCs were benzene > naphthalene > toluene > xylenes > monoterpenes > trimethylbenzenes > styrene > isoprene. The first ambient measurements from any site in South Asia of compounds with significant health effects such as isocyanic acid, formamide, acetamide, naphthalene and nitromethane have been reported in this study. Our results suggest that mitigation of intense wintertime biomass burning activities, in particular point sources such biomass co-fired brick kilns, would be important to reduce the emission and formation of toxic VOCs (such as benzene and isocyanic acid) in the Kathmandu Valley.

  17. Modificação do acetato de celulose em meio homogêneo via reações de condensação com diferentes isocianatos Homogeneous chemical modification of cellulose acetate using different isocyanates

    Directory of Open Access Journals (Sweden)

    Vagner R. Botaro

    1998-01-01

    Full Text Available Este estudo descreve uma série de reações envolvendo os grupos isocianatos (NCO e os grupos hidroxílicos do acetato de celulose com grau de substituição (DS igual a 2,4. As reações foram realizadas em meio homogêneo e utilizaram dois isocianatos estruturalmente diferentes: o 3-isopropenil-,'-dimetilbenzil isocianato (TMI e o 2-isocianato-etil metacrilato (IEM. Um acompanhamento cinético das reações foi realizado por espectroscopia na região do infravermelho, onde acompanhou-se o desaparecimento da banda típica de isocianato a aproximadamente 2260 cm-1. Filmes de acetato de celulose modificados foram obtidos após as reações, sendo posteriormente caracterizados por análises de ângulos de contato, espectroscopia na região do infravermelho e ensaios de tração.This investigation describes a series of homogeneous reactions involving the OH groups of cellulose acetate with a DS of 2.4 and two alkenyl isocyanates, viz. 3-isopropyl a,a-dimethylbenzyl isocyanate (TMI and 2-isocyanato-ethyl methacrylate (IEM. The kinetics of these reactions were followed by FTIR spectroscopy by monitoring the decrease in intensity with time of the band around 2260 cm-1. The product of these condensations were isolated as thin films which were characterized by FTIR spectroscopy, surface hydrophilic-hydrophobic evaluation through contact angle measurements and tensile strength.

  18. Overview of VOC emissions and chemistry from PTR-TOF-MS measurements during the SusKat-ABC campaign: high acetaldehyde, isoprene and isocyanic acid in wintertime air of the Kathmandu Valley

    Directory of Open Access Journals (Sweden)

    C. Sarkar

    2016-03-01

    ( ∼  1 ppb to be among the highest reported to date. Two "new" ambient compounds, namely formamide (m ∕ z  =  46.029 and acetamide (m ∕ z  =  60.051, which can photochemically produce isocyanic acid in the atmosphere, are reported in this study along with nitromethane (a tracer for diesel exhaust, which has only recently been detected in ambient studies. Two distinct periods were selected during the campaign for detailed analysis: the first was associated with high wintertime emissions of biogenic isoprene and the second with elevated levels of ambient acetonitrile, benzene and isocyanic acid from biomass burning activities. Emissions from biomass burning and biomass co-fired brick kilns were found to be the dominant sources for compounds such as propyne, propene, benzene and propanenitrile, which correlated strongly with acetonitrile (r2 > 0.7, a chemical tracer for biomass burning. The calculated total VOC OH reactivity was dominated by acetaldehyde (24.0 %, isoprene (20.2 % and propene (18.7 %, while oxygenated VOCs and isoprene collectively contributed to more than 68 % of the total ozone production potential. Based on known secondary organic aerosol (SOA yields and measured ambient concentrations in the Kathmandu Valley, the relative SOA production potential of VOCs were benzene  >  naphthalene  >  toluene  >  xylenes  >  monoterpenes  >  trimethylbenzenes  >  styrene  >  isoprene. The first ambient measurements from any site in South Asia of compounds with significant health effects such as isocyanic acid, formamide, acetamide, naphthalene and nitromethane have been reported in this study. Our results suggest that mitigation of intense wintertime biomass burning activities, in particular point sources such biomass co-fired brick kilns, would be important to reduce the emission and formation of toxic VOCs (such as benzene and isocyanic acid in the Kathmandu Valley.

  19. Corrosion protection and adhesion properties of the epoxy coating applied on the steel substrate pre-treated by a sol-gel based silane coating filled with amino and isocyanate silane functionalized graphene oxide nanosheets

    Science.gov (United States)

    Parhizkar, Nafise; Ramezanzadeh, Bahram; Shahrabi, Taghi

    2018-05-01

    This research has focused on the effect of graphene oxide (GO) nano-fillers embedded in the sol-gel based silane coating on the corrosion protection and adhesion properties of the epoxy coating applied on the steel substrate pre-treated by silane coatings. For this purpose, a mixture of Methyltriethoxysilane (MTES) and Tetraethylorthosilicate (TEOS) silane precursors was used for preparation of composite matrix and the GO nanosheets, which are covalently functionalized with 3-(Triethoxysilyl)propyl isocyanate (TEPI, IGO nano-fillers) and 3-aminopropyltriethoxysilane (APTES, AGO nano-fillers), were used as filler. The GO, AGO and IGO nanosheets were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), UV-Visible analysis and field emission-scanning electron microscopy techniques. The performance of the silane/epoxy coatings was investigated by pull-off adhesion, cathodic delamination, salt spray and electrochemical impedance spectroscopy (EIS) tests. Results revealed that AGO and IGO nano-fillers significantly improved the corrosion resistance and adhesion properties of the top epoxy coating due to better compatibility with silane matrix, excellent barrier properties and the formation of covalent bonds with the top epoxy coating.

  20. Crystal structures and DFT calculations of mixed chloride-azide zinc(II) and chloride-isocyanate cadmium(II) complexes with the condensation product of 2-quinolinecarboxaldehyde and Girard's T reagent

    Science.gov (United States)

    Anđelković, Katarina; Pevec, Andrej; Grubišić, Sonja; Turel, Iztok; Čobeljić, Božidar; Milenković, Milica R.; Keškić, Tanja; Radanović, Dušanka

    2018-06-01

    The mixed chloride-azide [ZnL(N3)1.65Cl0.35] (1) and chloride-isocyanate [CdL(NCO)1.64Cl0.36] (2) complexes with the condensation product of 2-quinolinecarboxaldehyde and trimethylammonium acetohydrazide chloride (Girard's T reagent) (HLCl) have been prepared and characterized by X-ray crystallography. In complexes 1 and 2, Zn1 and Cd1 ions, respectively, are five-coordinated in a distorted square based pyramidal geometry with NNO set of donor atoms of deprotonated hydrazone ligand and two monodentate ligands N3- and/or N3- and Cl- in the case of 1 and OCN- and/or OCN- and Cl- in the case of 2. The structural parameters of 1 and 2 have been discussed in relation to those of previously reported M(II) complexes with the same hydrazone ligand. Density functional theory calculations have been employed to study the interaction between the Zn2+ and Cd2+ ions and ligands. High affinity of ligands towards the Zn2+ and Cd2+ ions are predicted for both complexes.

  1. Hydrolysis of isocyanic acid on SCR catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Elsener, M; Kleemann, M; Koebel, M [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Standard SCR catalysts possess high activity for the hydrolysis of HNCO and thus explain the suitability of urea as a selective reducing agent for NO{sub x}. At high space velocities HNCO-slip can get perceptible over the entire temperature range. This can be attributed to the fact that the temperature dependence is strong for the SCR reaction, but weak for the hydrolysis reaction. (author) 3 figs., 5 refs.

  2. Isocyanate-functionalized castor oil as a novel bitumen modifier

    OpenAIRE

    Cuadri Vega, Antonio Abad; García Morales, Moisés; Navarro Domínguez, Francisco Javier; Partal López, Pedro

    2013-01-01

    The use of biomaterials from renewable sources in the synthesis of polyurethane-derived polymers is lately receiving great attention from social, environmental and economic standpoints. In this work, prepolymers having different -NCO/-OH ratio were synthesized, by reaction of 4,4´-diphenylmethane diisocyanate (MDI) with castor oil (CO), to be used as modifying agent of asphaltic bitumen. Reactions between MDI and CO, performed with -NCO/-OH molar ratios of 8:1 and 4:1, have led to suitable bi...

  3. Vibrational spectroscopy and intramolecular energy transfer in isocyanic acid (HNCO)

    International Nuclear Information System (INIS)

    Coffey, M.J.; Berghout, H.L.; Woods, E. III; Crim, F.F.

    1999-01-01

    Room temperature photoacoustic spectra in the region of the first through the fourth overtones (2ν 1 to 5ν 1 ) and free-jet action spectra of the second through the fourth overtones (3ν 1 to 5ν 1 ) of the N - H stretching vibration permit analysis of the vibrational and rotational structure of HNCO. The analysis identifies the strong intramolecular couplings that control the early stages of intramolecular vibrational energy redistribution (IVR) and gives the interaction matrix elements between the zero-order N - H stretching states and the other zero-order states with which they interact. The experimentally determined couplings and zero-order state separations are consistent with ab initio calculations of East, Johnson, and Allen [J. Chem. Phys. 98, 1299 (1993)], and comparison with the calculation identifies the coupled states and likely interactions. The states most strongly coupled to the pure N - H stretching zero-order states are ones with a quantum of N - H stretching excitation (ν 1 ) replaced by different combinations of N - C - O asymmetric or symmetric stretching excitation (ν 2 or ν 3 ) and trans-bending excitation (ν 4 ). The two strongest couplings of the nν 1 state are to the states (n-1)ν 1 +ν 2 +ν 4 and (n-1)ν 1 +ν 3 +2ν 4 , and sequential couplings through a series of low order resonances potentially play a role. The analysis shows that if the pure N - H stretch zero-order state were excited, energy would initially flow out of that mode into the strongly coupled mode in 100 fs to 700 fs, depending on the level of initial excitation. copyright 1999 American Institute of Physics

  4. Face to Face Of Mechanisms, Microscopes and Methyl isocyanate

    Indian Academy of Sciences (India)

    Working as an independent research student at a time when medical research was .... Luckily, another important person who came in my life's way was a teacher by the name Dr. ..... Research Projects in the wake of the Sino–Indian conflict.

  5. Face to Face Of Mechanisms, Microscopes and Methyl isocyanate

    Indian Academy of Sciences (India)

    college, I had my regular study and was also active in political work – that was the pre .... involved treating the section with alcohol, xylol, paraffin and in the process the fat is ..... Polyethylene Glycols as embedding media in Histochemical work.

  6. Olefin copolymerization via controlled radical polymerization : copolymerization of methyl methacrylate and 1-octene

    NARCIS (Netherlands)

    Venkatesh, R.; Klumperman, B.

    2004-01-01

    The atom transfer radical (co)polymerization (ATRP) of methyl methacrylate (MMA) with 1-octene was investigated. Well controlled homopolymer of MMA was obtained with 2,2,2-trichoroethanol (TCE) and p-toluenesulfonyl chloride (pTsCl), although, uncontrolled copolymerization occurred when pTsCl was

  7. Benzyl 2-((E-Tosyliminomethylphenylcarbamate

    Directory of Open Access Journals (Sweden)

    Kwang Min Ko

    2016-10-01

    Full Text Available Benzyl 2-((E-tosyliminomethylpenylcarbamate was prepared in good yield and characterized by the condensation reaction of benzyl 2-formylphenylcarbamate with p-toluenesulfonyl amine. The structure of the newly synthesized compound was determined using 1H, 13C-NMR, IR and mass spectral data.

  8. 40 CFR 721.10029 - Isocyanate compound, modified with methoxysilane (generic).

    Science.gov (United States)

    2010-07-01

    ... Institute for Occupational Safety and Health (NIOSH)-approved respirators meet the minimum requirement for... significant new uses are: (i) Protection in the workplace. Requirements as specified in § 721.63 (a)(1), (a)(2... (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for...

  9. Highly efficient isocyanate-free microwave-assisted synthesis of [6]-oligourea

    KAUST Repository

    Qaroush, Abdussalam K.; Al-Hamayda, Asmaa S.; Khashman, Yasmeen K.; Vagin, Sergei I.; Troll, Carsten; Rieger, Bernhard

    2013-01-01

    data reported are reproducible (due to the homogeneous microwave technology used by CEM Discover S-Class of microwave reactors). To the best of our knowledge, this is the best eco-friendly synthetic approach for the preparation of the title oligomers

  10. Biodegradation and anticholinesrerase activity of methyl isocyanate in the aquatic environment of Bhopal

    Digital Repository Service at National Institute of Oceanography (India)

    SenGupta, R.; Sarkar, A.; Kureishy, T.W.

    )ethyl O,O-diparanitrophenyl phosphorothionate. Pesticides XIII, 34-37. Glasstone S. and Lewis D. (1964) Elements of Physical Chemistry. Macmillan, London. Grasshoff K., Ehrhardt M. and Kremling K. (1984) Methods of Seawater Analysis. Chemic, Weinheim...

  11. Preparation of graphite derivatives by selective reduction of graphite oxide and isocyanate functionalization

    Czech Academy of Sciences Publication Activity Database

    Kumar, A. R. S. S.; Piana, Francesco; Mičušík, M.; Pionteck, J.; Banerjee, S.; Voit, B.

    2016-01-01

    Roč. 182, 1 October (2016), s. 237-245 ISSN 0254-0584 Institutional support: RVO:61389013 Keywords : graphite oxide * surface modification * conductive nanoparticles Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.084, year: 2016

  12. Isocyanate and total inhalable particulate air measurements in the European wood panel industry.

    Science.gov (United States)

    Vangronsveld, E; Berckmans, S; Verbinnen, K; Van Leeuw, C; Bormans, C

    2010-11-01

    It is well known that the use of MDI (methylene diphenyldiisocyanate) as an alternative for formaldehyde-based resins is seen as a responsible option to reduce formaldehyde emissions for CWP (Composite Wood Products) in buildings. However, there are concerns raised regarding the exposure risk of workers. The purpose of this article is to provide the reader with factual information to demonstrate that the use of MDI compared to other agents used in CWP production processes does not pose increased inhalation exposure risks for workers. Personal and area air measurements were carried out at nine Composite Wood Panel plants throughout Europe to assess potential inhalation exposures to MDI and wood dust as Total Inhalable Particulates (TIP). In total, 446 pairs of samples were collected for MDI and TIP of which 283 pairs were personal samples and the remaining 163 pairs were area samples collected at key locations along the production line. This data together with published formaldehyde exposure data has been used to evaluate the exposure safety margin opposite what are considered relevant occupational exposure limits. The methods used for sampling and analysing MDI and TIP are based on internationally accepted methods, i.e. MDHS 25/3 (or ISO 16702) for MDI, and MDHS 14/3 for TIP. The job functions with an increased exposure profile for TIP were the cleaners, drying operators and quality control staff, and for MDI, the cleaners and quality control staff. The areas with an increased exposure profile for TIP are the conveyor area from OSB blender to former area and the OSB press infeed, and for MDI the OSB weigh belt and OSB former bin area. The exposure safety margin opposite the selected exposure limits can be ranked as MDI>TIP>formaldehyde (high margin of safety to low margin of safety), indicating that the use of MDI also reduces the exposure risks to workers during production of CWP compared to formaldehyde. By reducing the airborne TIP concentrations, a respiratory sensitiser, MDI workplace concentrations in general can be reduced further. This can be achieved by improving design and/or maintenance and testing programmes of existing control measures, which should be in place already to effectively control exposure to TIP and formaldehyde. The airborne concentration of MDI at workstations situated after pressing (curing) is regarded as extremely low and likely mainly constituted by workplace emissions from elsewhere in the plant. Copyright © 2010 Elsevier GmbH. All rights reserved.

  13. Predictable and Regioselective Insertion of Internal Unsymmetrical Alkynes in Rhodium-Catalyzed Cycloadditions with Alkenyl Isocyanates

    Science.gov (United States)

    Friedman, Rebecca Keller; Rovis, Tomislav

    2009-01-01

    A regioselective, rhodium-catalyzed cycloaddition between a variety of internal, unsymmetrical alkynes is described. We document the impact of both steric and electronic properties of the alkyne on reaction course, efficiency and enantioselectivity. The substituent that better stabilizes a positive charge or the larger group, all else being equal, inserts distal to the carbonyl moiety in a predictable and controllable fashion. The reaction scope is broad and the enantioselectivities are high, providing an ‘instruction manual’ for substrate choice when utilizing this reaction as a synthetic tool. PMID:19569692

  14. Effect of pMDI isocyanate additive on mechanical and thermal ...

    Indian Academy of Sciences (India)

    Incompatibility of natural fibres and polymers is one of the main barriers facing this industry. Researchers have tried to overcome this problem by many ways such as pre-treating fibres, using additives, coupling agents and binders. Various fibre pre-treatments and coupling agents have been used to enhance the fibre matrix ...

  15. Study of Reactive Melt Processing Behavior of Externally Plasticized Cellulose Acetate in Presence of Isocyanate

    Directory of Open Access Journals (Sweden)

    Rafael Erdmann

    2014-12-01

    Full Text Available Two types of externally plasticized cellulose acetate (CA were chemically modified using 4,4'-methylene diphenyl diisocyanate (MDI as crosslinking agent. Crosslinking was performed in the molten state by means of melt mixing in an internal mixer. The viscoelastic properties of the non-crosslinked, externally plasticized CA show typical temperature dependence, similar to conventional thermoplastics. A strong increase in storage modulus is observed with increasing crosslink density indicating that the crosslinked compounds exhibit predominately elastic response. The complex viscosity also increases considerably with increasing crosslink density and does not reach the typical Newtonian plateau at low radial frequencies any more. The viscoelastic properties correlate well with the data recorded online during reactive melt processing in the internal mixer. In comparison to the non-crosslinked CA, the crosslinked compounds show higher glass transition temperature, higher VICAT softening temperatures, improved thermal stability and lower plasticizer evaporation at evaluated temperatures.

  16. A novel kind of concrete superplasticizer based on aryl isocyanate polycondensates

    Science.gov (United States)

    Ding, Bei; Qian, Shanshan; Qiu, Ying; Wang, Yi; Zheng, Chunyang; Wang, Gaoming

    2017-03-01

    A novel superplasticizer was synthesized by polycondensation of Alkyl phenol phosphate and toluene diisocyanate grafting with methoxy polyoxyethylene ether (MPEG). The chemical structure and molecular weight of polycondensates molecules were determined by 1H nuclear magnetic resonance (NMR) and gel permeation chromatography respectively. The experimental results indicated that the polycondensates of Alkyl phenol phosphate and toluene diisocyanate grafting with MPEG not only exhibited good water-reducing properties but also demonstrated effective anti-clay abilities alone. Furthermore, the polycondensates showed good fluidity maintaining abilities within 1-3 h and good workability of concrete. The results of T500 Time experiments show that lower plastic viscosity of the polycondensates leads to fresh concrete much “looser” than conventional PCEs in self-compacting concrete.

  17. Actinic radiation-curable formulations from the reaction product of organic isocyanate, poly(alkylene oxide) polyol and an unsaturated addition-polymerizable monomeric compound having a single isocyanate-reactive hydrogen group

    International Nuclear Information System (INIS)

    Howard, D.D.

    1979-01-01

    Energy-curable compositions which can be cured in the presence of air by exposure to actinic radiation contain at least one unsaturated urethane oligomer. The oligomer comprises the reaction product of at least one poly(alkylene oxide) polyol, at least one polyisocyanate, and at least one unsaturated active hydrogen-containing compound

  18. Associations of symptoms related to isocyanate, ureaformol, and formophenolic exposures with respiratory symptoms and lung function in coal miners

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, J.P.; Simon, V.; Chau, N. [Houilleres Bassin Lorraine, Freyming Merlebach (France)

    2007-04-15

    The respiratory effects of diphenylmethane diisocyanate (MDI)-based resins and ureaformol- and formophenolic-based resins, used in coal mining, are unknown. This cross-sectional study of 354 miners evaluated respiratory health in miners with MDI-related symptoms (IS) and ureaformol/formophenolic-related symptoms (UFS). The protocol included clinical examination, chest radiograph, questionnaire on respiratory symptoms, smoking habit, job history, resin handling, and spirometry. Resin handling concerned 27.7% of the miners. IS affected 5.6%, and 1.4% also after work. UFS affected 22.6%, and 2.3% also after work. Wheezing affected 35.6%; chronic cough, expectoration, or bronchitis about 10%; dyspnea 5.4%; and asthma 2.8%. The miners with UFS had significantly more frequent chronic cough, expectoration, chronic bronchitis, dyspnea, and wheezing, whereas those with IS at and after work had markedly lower FVC, FEV1, MMEF, FEF50% and FEF25%. These findings raise the possibility of deleterious effects of exposures to MDI and ureaformol/ ormophenolic resins on respiratory health and lung function in coal miners during their working life.

  19. Protection efficacy of gloves against components of the solvent in a sprayed isocyanate coating utilizing a reciprocating permeation panel.

    Science.gov (United States)

    Ceballos, Diana M; Reeb-Whitaker, Carolyn; Sasakura, Miyoko; Dills, Russell; Yost, Michael G

    2015-04-01

    Determine protection effectiveness of 5-mil natural rubber latex (0.13-mm), 5-mil nitrile rubber (0.13-mm), and 13-mil butyl rubber (0.33-mm) glove materials against solvents present in a commonly used automotive clear coat formulation using a novel permeation panel. The latex and nitrile gloves were the type commonly used by local autobody spray painters. Glove materials were tested by spraying an automotive clear coat onto an automated reciprocating permeation panel (permeation panel II). Temperature, relative humidity, and spray conditions were controlled to optimize clear coat loading homogeneity as evaluated by gravimetric analysis. Solvent permeation was measured using charcoal cloth analyzed by the National Institute for Occupational Safety and Health 1501 method. Natural rubber latex allowed 3-5 times the permeation of solvents relative to nitrile rubber for all 10 solvents evaluated: ethyl benzene, 2-heptanone, 1-methoxy-2-propyl acetate, o-xylene, m-xylene, p-xylene, n-butyl acetate, methyl isobutyl ketone, petroleum distillates, and toluene. There is a distinct behavior in solvent permeation before and after the coating dry time. Solvent permeation increased steadily before coating dry time and remained fairly constant after coating dry time. Butyl was not permeated by any of the solvents under the conditions tested. Commonly used 5-mil thick (0.13-mm) latex and nitrile gloves were ineffective barriers to solvents found in a commonly used clear coat formulation. Conversely, 13-mil (0.33-mm) butyl gloves were found to be protective against all solvents in the clear coat formulation. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  20. Effect of Nanodisperse Carbon Fillers and Isocyanate Chain Extender on Structure and Properties of Poly(ethylene terephthalate

    Directory of Open Access Journals (Sweden)

    Vladimir Agabekov

    2012-01-01

    Full Text Available The effect of diisocyanate chain extender (CE on the mechanical, rheological, and relaxation properties, as well as on molecular weight and crystallizability, of starting poly(ethylene terephthalate (PET and its composites containing carbon nanomaterials (CNM such as carbon nanotubes (CNTs and commercial carbon (CC has been studied. The composites were compounded in molten PET using twin-screw extruder (screw diameter 35 mm; L/D=40. To improve the distribution of CNM in the polymeric matrix (before introduction into the melt, they were blended with PET powder and subjected to an ultrasonic treatment in methylene chloride. The salient features of the materials structure were estimated based on DSC and relaxation spectrometry (dynamic mechanical analysis data. It has been found that CNM additives partly suppress the PET-chain extension reactions which take place during interaction between macromolecular end groups and CE. Besides, both CNT and CC favour crystallizability of the modified PET owing to nucleation of the crystallization process. The influence of CNT appears to be more effective than that of CC. Enhancements in true mechanical strength and deformability of PET/CE/CNM composites, as against PET/CE materials, were found to be most clearly exhibited by the CNT-containing composites.

  1. Thermal properties of hydrogenated liquid natural rubber

    Science.gov (United States)

    Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

    2015-09-01

    Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion.

  2. Thermal properties of hydrogenated liquid natural rubber

    International Nuclear Information System (INIS)

    Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M.

    2015-01-01

    Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion

  3. Thermal properties of hydrogenated liquid natural rubber

    Energy Technology Data Exchange (ETDEWEB)

    Jamaluddin, Naharullah; Abdullah, Ibrahim; Yusoff, Siti Fairus M. [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2015-09-25

    Natural rubber (NR) was modified to form liquid natural rubber (LNR) via photooxidative degradation. Hydrogenated liquid natural rubber (HLNR) was synthesized by using diimide as source of hydrogen which the diimide is produced by thermolysis of p-toluenesulfonyl hydrazide (TSH). The structure of HLNR was characterized by determining the changes of main peaks in Fourier Transform infrared and nuclear magnetic resonance spectra after hydrogenation. Thermogravimetric analysis showed that the HLNR had higher decomposition temperature compared to LNR and the decomposition temperature is directly proportional to the percentage of conversion.

  4. In Vitro and In Vivo Characterization of Biodegradable Reactive Isocyanate-Terminated Three-Armed- and Hyperbranched Block Copolymeric Tissue Adhesives

    NARCIS (Netherlands)

    Bochynska, Agnieszka I.; Hannink, Gerjon; Rongen, Jan J.; Grijpma, Dirk W.; Buma, Pieter

    2017-01-01

    Tissue adhesives are an attractive class of biomaterials, which can serve as a treatment for meniscus tears. In this study, physicochemical and adhesive properties of novel biodegradable three-armed- and hyperbranched block copolymeric adhesives are evaluated. Additionally, their degradation in

  5. Adhesion of nitrile rubber (NBR) to polyethylene terephthalate (PET) fabric. Part 1: PET surface modification by methylenediphenyl di-isocyanate (MDI)

    Science.gov (United States)

    Razavizadeh, Mahmoud; Jamshidi, Masoud

    2016-01-01

    Fiber to rubber adhesion is an important subject in rubber composite industry. It is well known that surface physical, mechanical and chemical treatments are effective methods to improve interfacial bonding. Ultra violet (UV) light irradiation is an efficient method which is used to increase interfacial interactions. In this research UV assisted chemical modification of PET fabric was used to increase its bonding to nitrile rubber (NBR). NBR is perfect selection to produce fuel and oil resistant rubber parts but it has weak bonding to fabrics. For this purpose at first, the PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was reacted and grafted to carboxylated PET. T-peel test was used to evaluate PET fabric to NBR bonding strength. Attenuated total reflectance-Fourier transform infrared spectroscopy (FTIR-AT) was used to assess surface modifications of the PET fabrics. The chemical composition of the PET surfaces before and after carboxylation and MDI grafting was investigated by X-ray photoelectron spectroscopy (XPS). It was found that at vulcanizing temperature of 150 °C, carboxylation in contrary to MDI grafting, improved considerably PET to NBR adhesion. Finally effect of curing temperature on PET to NBR bonding strength was determined. It was found that increasing vulcanizing temperature to 170 °C caused considerable improvement (about 134%) in bonding strength.

  6. Adhesion of nitrile rubber (NBR) to polyethylene terephthalate (PET) fabric. Part 1: PET surface modification by methylenediphenyl di-isocyanate (MDI)

    International Nuclear Information System (INIS)

    Razavizadeh, Mahmoud; Jamshidi, Masoud

    2016-01-01

    Graphical abstract: - Highlights: • Glutaric anhydride peroxide (GAP) was grafted on PET surface by UV irradiation method. Then MDI was attached to GAP on PET surface. • The fabric was vulcanized by nitrile rubber. • Peet test was performed after each stage of surface modification. • Curing temperature was increased and the tests were repeated. • Effect of MDI coating on PET without carboxylation was evaluated. Effect of vulcanizing temperature on this product was also studied. - Abstract: Fiber to rubber adhesion is an important subject in rubber composite industry. It is well known that surface physical, mechanical and chemical treatments are effective methods to improve interfacial bonding. Ultra violet (UV) light irradiation is an efficient method which is used to increase interfacial interactions. In this research UV assisted chemical modification of PET fabric was used to increase its bonding to nitrile rubber (NBR). NBR is perfect selection to produce fuel and oil resistant rubber parts but it has weak bonding to fabrics. For this purpose at first, the PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was reacted and grafted to carboxylated PET. T-peel test was used to evaluate PET fabric to NBR bonding strength. Attenuated total reflectance-Fourier transform infrared spectroscopy (FTIR-AT) was used to assess surface modifications of the PET fabrics. The chemical composition of the PET surfaces before and after carboxylation and MDI grafting was investigated by X-ray photoelectron spectroscopy (XPS). It was found that at vulcanizing temperature of 150 °C, carboxylation in contrary to MDI grafting, improved considerably PET to NBR adhesion. Finally effect of curing temperature on PET to NBR bonding strength was determined. It was found that increasing vulcanizing temperature to 170 °C caused considerable improvement (about 134%) in bonding strength.

  7. Reactivity of Hydroxy and Amino Derivatives of 2-Phenyl-1H-imidazoline and 2-Phenyl-1H-imidazole toward Isocyanates: Synthesis of Appropriate Carbamates and Ureas

    Czech Academy of Sciences Publication Activity Database

    Pařík, P.; Jansa, J.; Holešová, S.; Marek, Aleš; Klimešová, V.

    2013-01-01

    Roč. 50, č. 4 (2013), s. 903-910 ISSN 0022-152X Grant - others:GA ČR(CZ) GA205/08/0869 Institutional support: RVO:61388963 Keywords : elevated-temperature * hydrolysis * imidazoles * alkylation Subject RIV: CC - Organic Chemistry Impact factor: 0.873, year: 2013

  8. Feasibility study of respiratory questionnaire and peak flow recordings in autobody shop workers exposed to isocyanate-containing spray paint: observations and limitations.

    Science.gov (United States)

    Cullen, M R; Redlich, C A; Beckett, W S; Weltmann, B; Sparer, J; Jackson, G; Ruff, T; Rubinstein, E; Holden, W

    1996-06-01

    Diisocyanates, highly reactive monomers which cross-link polyurethane, are the most widely recognized causes of occupational asthma. Many exposed workers are end-users, including autobody spray painters who form a large population at risk. Neither the factors which determine incidence rate nor strategies for control have been adequately studied in this setting. We have conducted a cross-sectional survey of 23 (about one in five) autobody shops in the New Haven area to determine the feasibility of clinical epidemiological studies in this population. Among 102 workers, there was a high rate of airway symptoms consistent with occupational asthma (19.6%). Symptoms were most prevalent among those with the greatest opportunity for exposure (dedicated spray painters) and least among office workers; part-time painters had intermediate rates. Atopy was not associated with risk while smoking seemed to correlate with symptoms. Regular use of air-supplied respirators appeared to be associated with lower risk among workers who painted part- or full-time. We were unable to validate the questionnaire responses with peak expiratory flow record data attempted on a 1/3 sample of the workers. Despite intensive training and effort, subject compliance was limited. Among those who provided adequate data (24 of 38), only two demonstrated unequivocal evidence of labile airways; two others demonstrated lesser changes consistent with an occupational effect on flow rates. There was no clear association between these findings and either questionnaire responses or exposure classification. Overall, the survey suggests that there is a high prevalence of airway symptoms among workers in autobody shops, at least in part due to work-related asthma. However, there is need for both methodological and substantive research in this setting to document rates of occupational asthma and to develop a scientific basis for its effective control.

  9. Biological monitoring of isocyanates and related amines. I. Determination of 1,6-hexamethylene diamine (HDA) in hydrolysed human urine after oral administration of HDA.

    Science.gov (United States)

    Brorson, T; Skarping, G; Sandström, J F; Stenberg, M

    1990-01-01

    1,6-Hexamethylene diamine (HDA), used as raw material in industrial manufacturing operations, was orally administered to six healthy volunteers. After acid hydrolysis of the urine by hydrochloric acid, HDA and the metabolite 6-aminohexanoic acid were quantified. HDA was determined as an ethyl-chloroformate derivative by capillary gas chromatography using thermionic specific detection (TSD), and 6-aminohexanoic acid was quantified by ion chromatography using the ninhydrin reaction. In nonhydrolysed urine, monoacetylated HDA (N-acetyl-1,6-hexamethylene diamine) and HDA, were verified as heptafluorobutyric anhydride derivatives by gas chromatography-mass spectrometry (GC-MS), in a chemical ionization mode using isobutane and ammonia as reagent gases. In hydrolysed urine, a mean of 0.28 mg (range 1-6%) of the administered dose (8.2 mg) was recovered as HDA, and a mean of 0.8 mg (range less than 1-27%) as 6-aminohexanoic acid. The urinary excretion of both the determined compounds was rapid, and the principal part (greater than 90%) of the elimination was completed within 10 h. There was a considerable inter-individual variation in the excreted amounts, but the intra-individual variation in the excretion of HDA was limited. The subjects N-acetylator phenotype was determined by a dapsone test. Three slow acetylators excreted lower amounts (mean 2% of given dose) of HDA than three rapid ones (mean 5%).

  10. Site-selective modification of cellulose nanocrystals with isophorone diisocyanate and formation of polyurethane-CNC composites

    Science.gov (United States)

    Natalie M. Girouard; Shanhong Xu; Gregory T. Schueneman; Meisha L. Shofner; J. Carson. Meredith

    2016-01-01

    The unequal reactivity of the two isocyanate groups in an isophorone diisocyante (IPDI) monomer was exploited to yield modified cellulose nanocrystals (CNCs) with both urethane and isocyanate functionality. The chemical functionality of the modified CNCs was verified with ATR-FTIR analysis and elemental analysis. The selectivity for the secondary isocyanate group using...

  11. I. Use of m- and p-azidobenzamidines, 4-fluoro-3-nitro-phenylazide, and 3-azido-1,2,4-triazole as photoaffinity probes of tryptic binding site conformation. II. Analysis of tryptophan in proteins by an acidic reaction of 3-diazonium-1,2,4-triazole

    Energy Technology Data Exchange (ETDEWEB)

    DeTraglia, M.C.

    1979-01-01

    Meta- and para-azidobenzamidine have been prepared and evaluated as photoaffinity labels. The compounds inhibit trypsin reversibly in the dark and are competitive with substrate binding. Upon photolysis, irreversible noncompetitive inhibition is observed and is dependent upon concentration, photolysis time, and pH. Specificity of the probes is indicated by experiments in which p-tosyl-L-arginine methyl ester, a trypsin substrate, is used to protect against photoinactivation.

  12. New series of Tc-99m-labeled hepatobiliary tracers: N'-acyl- and N'-sulfonyl ethylenediamine-N,N-diacetic acids

    International Nuclear Information System (INIS)

    Karube, Y.; Kono, A.; Maeda, T.; Ohya, M.; Matsushima, Y.

    1981-01-01

    Various Tc-99m-labeled N'-substituted derivatives of ethylenediamine-N,N-diacetic acid (EDDA) are evaluated as hepatobiliary imaging agents. N-substituted aromatic acyl and aromatic sulfonyl derivatives of EDDA, labeled with Tc-99m, were administered to rabbits and golden hamsters, and the distribution indicated clearance by the hepatobiliary system. N'-aromatic sulfonyl EDDAs were labeled with Tc-99m by the SnCl 2 method with more than 99% yield. Clearance of Tc-99m-p-toluenesulfonyl EDDA from the blood and the liver was as rapid as that of TC-99m N-(2,6-diethylphenylcarbamoylmethyl)iminodiacetic acid (Tc-99m benzenesulfonyl EDDA lowered urinary excretion. It is concluded that the sulfonyl EDDAs provide a fruitful source for Tc-99m-labeled hepatobiliary radiopharmaceuticals

  13. New series of Tc-99m-labeled hepatobiliary tracers: N'-acyl- and N'-sulfonyl ethylenediamine-N,N-diacetic acids

    International Nuclear Information System (INIS)

    Karube, Y.; Kono, A.; Maeda, T.; Ohya, M.; Matsushima, Y.

    1981-01-01

    Various Tc-99m-labeled N'-substituted derivatives of ethylenediamine-N,N-diacetic acid (EDDA) are evaluated as hepatobiliary imaging agents. N'-substituted aromatic acyl and aromatic sulfonyl derivatives of EDDA, labeled with Tc-99m, were administered to rabbits and golden hamsters, and the distribution indicated clearance by the hepatobiliary system. N'-aromatic sulfonyl EDDAs were labeled with Tc-99m by the SnCl 2 method with more than 99% yield. Clearance of Tc-99m-p-toluenesulfonyl EDDA from the blood and the liver was as rapid as that of Tc-99m N-(2,6-diethylphenylcarbamoylmethyl)iminodiacetic acid (Tc-99m diethyl IDA). Substitution of a bulky group at the aromatic ring in Tc-99m benzene-sulfonyl EDDA lowered urinary excretion. It is concluded that the sulfonyl EDDAs provide a fruitful source for Tc-99m-labeled hepatobiliary radiopharmaceuticals

  14. Synthesis of amide-functionalized cellulose esters by olefin cross-metathesis.

    Science.gov (United States)

    Meng, Xiangtao; Edgar, Kevin J

    2015-11-05

    Cellulose esters with amide functionalities were synthesized by cross-metathesis (CM) reaction of terminally olefinic esters with different acrylamides, catalyzed by Hoveyda-Grubbs 2nd generation catalyst. Chelation by amides of the catalyst ruthenium center caused low conversions using conventional solvents. The effects of both solvent and structure of acrylamide on reaction conversion were investigated. While the inherent tendency of acrylamides to chelate Ru is governed by the acrylamide N-substituents, employing acetic acid as a solvent significantly improved the conversion of certain acrylamides, from 50% to up to 99%. Homogeneous hydrogenation using p-toluenesulfonyl hydrazide successfully eliminated the α,β-unsaturation of the CM products to give stable amide-functionalized cellulose esters. The amide-functionalized product showed higher Tg than its starting terminally olefinic counterpart, which may have resulted from strong hydrogen bonding interactions of the amide functional groups. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Additive manufacturing of short and mixed fibre-reinforced polymer

    Science.gov (United States)

    Lewicki, James; Duoss, Eric B.; Rodriguez, Jennifer Nicole; Worsley, Marcus A.; King, Michael J.

    2018-01-09

    Additive manufacturing of a fiber-reinforced polymer (FRP) product using an additive manufacturing print head; a reservoir in the additive manufacturing print head; short carbon fibers in the reservoir, wherein the short carbon fibers are randomly aligned in the reservoir; an acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin in the reservoir, wherein the short carbon fibers are dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin; a tapered nozzle in the additive manufacturing print head operatively connected to the reservoir, the tapered nozzle produces an extruded material that forms the fiber-reinforced polymer product; baffles in the tapered nozzle that receive the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin with the short carbon fibers dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin; and a system for driving the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin with the short carbon fibers dispersed in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin from the reservoir through the tapered nozzle wherein the randomly aligned short carbon fibers in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin are aligned by the baffles and wherein the extruded material has the short carbon fibers aligned in the acrylate, methacrylate, epoxy, cyanate ester or isocyanate resin that forms the fiber-reinforced polymer product.

  16. 40 CFR 63.1292 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... added to assist foaming by generating gas beyond that resulting from the isocyanate-water reaction..., material safety data sheets, or engineering calculations. High-pressure mixhead means a mixhead where.... Isocyanate means a reactive chemical grouping composed of a nitrogen atom bonded to a carbon atom bonded to...

  17. Study of the formation of lignin-based polyurethanes

    OpenAIRE

    Cateto, C.A.; Barreiro, M.F.; Rodrigues, A.E.

    2004-01-01

    The main objective of this work was to study the reactivity of lignin with isocyanates in the presence of a polyesther as the flexible segment. The course of the polymerization reaction was followed by FTIR working in the ATR mode. The decay in the isocyanate absorbance was measured during 30 minutes at a temperature of 80 ºC.

  18. 77 FR 5091 - Certain New Chemicals; Receipt and Status Information

    Science.gov (United States)

    2012-02-01

    ...) Component of coatings.... (G) Isocyanate polymer, alcohol- blocked. P-12-0057 11/18/2011 02/15/2012 CBI (G) Component of coatings.... (G) Hydroxyalkenoate, polymer with isocyanate and diglycol, alcohol- blocked. P-12... substance is used (G) Aromatic substituted in liquid and polymer-based isobenzofuranone. sensors that change...

  19. Study of the catalytic selectivity of an aqueous two-component polyurethane system by ftir spectroscopy

    Directory of Open Access Journals (Sweden)

    Stamenković Jakov V.

    2003-01-01

    Full Text Available The difficulty in formulating a two component waterborne polyurethane, is the isocyanate-water side reaction, which can lead to gassing/foaming, loss of isocyanate functionality, low gloss and a reduced pot life. To compensate for this side reaction, these formulations usually contain a large excess of isocyanate. Tin compounds, especially dibutyltin dilaurate, are widely used in coatings as catalysts for the isocyanate/hydroxyl reaction. Because of the high aquatic toxicity of some organotin compounds, there has been an attempt to ban organotin compounds from all coating applications. As a general rule, organotin catalysts are not selective, they catalyze the reaction of isocyanates with both hydroxyl groups and water and also catalyze the hydrolysis of ester groups. One novel approach to control the water side reaction is the use of catalysts which selectively catalyze the isocyanate-polyol reaction and not the isocyanate-water reaction. The selectivity of a variety of metal catalysts (metal octoates, metal acetylacetonates and mangan chelates with mixed ligands to catalyze the preferred reaction was measured using the FTIR method.

  20. Development and validation of an LC-MS/MS method for the determination of biogenic amines in wines and beers.

    Science.gov (United States)

    Nalazek-Rudnicka, Katarzyna; Wasik, Andrzej

    2017-01-01

    Biogenic amines are group of organic, basic, nitrogenous compounds that naturally occur in plant, microorganism, and animal organisms. Biogenic amines are mainly produced through decarboxylation of amino acids. They are formed during manufacturing of some kind of food and beverages such as cheese, wine, or beer. Histamine, cadaverine, agmatine, tyramine, putrescine, and β -phenylethylamine are the most common biogenic amines found in wines and beers. This group of compounds can be toxic at high concentrations; therefore, their control is very important. Analysis of biogenic amines in alcoholic drinks (beers and wines) was carried out by HPLC-MS/MS after their derivatization with p -toluenesulfonyl chloride (tosyl chloride). The developed method has been applied for analysis of seventeen biogenic amines in twenty-eight samples of lager beers and in twelve samples of different homemade wines (white grape, red grape, strawberry, chokeberry, black currant, plum, apple, raspberry, and quince). The developed method is sensitive and repeatable for majority of the analytes. It is versatile and can be used for the determination of biogenic amines in various alcoholic beverages.

  1. Mefenamic acid conjugates based on a hydrophilic biopolymer hydroxypropylcellulose: novel prodrug design, characterization and thermal analysis

    International Nuclear Information System (INIS)

    Hussain, M.A.; Kausar, R.; Amin, M.

    2015-01-01

    Macromolecular prodrugs (MPDs) of mefenamic acid were designed onto a cellulose ether derivative hydroxypropylcellulose (HPC) as ester conjugates. Fabrication of HPC-mefenamic acid conjugates was achieved by using p-toluenesulfonyl chloride as carboxylic acid (a functional group in drug) activator at 80 degree C for 24 h under nitrogen atmosphere. Reaction was preceded under homogeneous reaction conditions as HPC was dissolved before use in DMAc solvent. Imidazole was used as a base. Easy workup reactions resulted in good yields (55-65%) and degree of substitution (DS) of drug (0.37-0.99) onto HPC. The DS was calculated by acid-base titration after saponification and UV/Vis spectrophotometry after hydrolysis. DS by both of the methods was found in good agreement with each other. Aqueous and organic soluble novel prodrugs of mefenamic acid were purified and characterized by different spectroscopic and thermal analysis techniques. The initial, maximum and final degradation temperatures of HPC, mefenamic acid and HPC-mefenamic acid conjugates were drawn from thermogravimetric (TG) and derivative TG curves and compared to access relative thermal stability. The TG analysis has indicated that samples obtained were thermally more stable especially with increased stability of mefenamic acid in HPC-mefenamic acid conjugates. These novel MPDs of mefenamic acid (i.e., HPC-mefenamic acid conjugates) may have potential applications in pharmaceutically viable drug design due to wide range of solubility and extra thermal stability imparted after MPD formation. (author)

  2. Long-circulating liposomes radiolabeled with [18F]fluorodipalmitin ([18F]FDP)

    International Nuclear Information System (INIS)

    Marik, Jan; Tartis, Michaelann S.; Zhang, Hua; Fung, Jennifer Y.; Kheirolomoom, Azadeh; Sutcliffe, Julie L.; Ferrara, Katherine W.

    2007-01-01

    Synthesis of a radiolabeled diglyceride, 3-[ 18 F]fluoro-1,2-dipalmitoylglycerol [[ 18 F]fluorodipalmitin ([ 18 F]FDP)], and its potential as a reagent for radiolabeling long-circulating liposomes were investigated. The incorporation of 18 F into the lipid molecule was accomplished by nucleophilic substitution of the p-toluenesulfonyl moiety with a decay-corrected yield of 43±10% (n=12). Radiolabeled, long-circulating polyethylene-glycol-coated liposomes were prepared using a mixture of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, cholesterol, 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N- [methoxy(polyethyleneglycol)-2000] ammonium salt (61:30:9) and [ 18 F]FDP with a decay-corrected yield of 70±8% (n=4). PET imaging and biodistribution studies were performed with free [ 18 F]FDP and liposome-incorporated [ 18 F]FDP. Freely injected [ 18 F]FDP had the highest uptake in the liver, spleen and lungs. Liposomal [ 18 F]FDP remained in blood circulation at near-constant levels for at least 90 min, with a peak concentration near 2.5%ID/cc. Since [ 18 F]FDP was incorporated into the phospholipid bilayer, it could potentially be used for radiolabeling a variety of lipid-based drug carriers

  3. Efficient Synthesis of Differentiated syn-1,2-Diol Derivatives by Asymmetric Transfer Hydrogenation-Dynamic Kinetic Resolution of α-Alkoxy-Substituted β-Ketoesters.

    Science.gov (United States)

    Monnereau, Laure; Cartigny, Damien; Scalone, Michelangelo; Ayad, Tahar; Ratovelomanana-Vidal, Virginie

    2015-08-10

    Asymmetric transfer hydrogenation was applied to a wide range of racemic aryl α-alkoxy-β-ketoesters in the presence of well-defined, commercially available, chiral catalyst Ru(II) -(N-p-toluenesulfonyl-1,2-diphenylethylenediamine) and a 5:2 mixture of formic acid and triethylamine as the hydrogen source. Under these conditions, dynamic kinetic resolution was efficiently promoted to provide the corresponding syn α-alkoxy-β-hydroxyesters derived from substituted aromatic and heteroaromatic aldehydes with a high level of diastereoselectivity (diastereomeric ratio (d.r.)>99:1) and an almost perfect enantioselectivity (enantiomeric excess (ee)>99 %). Additionally, after extensive screening of the reaction conditions, the use of Ru(II) - and Rh(III) -tethered precatalysts extended this process to more-challenging substrates that bore alkenyl-, alkynyl-, and alkyl substituents to provide the corresponding syn α-alkoxy-β-hydroxyesters with excellent enantiocontrol (up to 99 % ee) and good to perfect diastereocontrol (d.r.>99:1). Lastly, the synthetic utility of the present protocol was demonstrated by application to the asymmetric synthesis of chiral ester ethyl (2S)-2-ethoxy-3-(4-hydroxyphenyl)-propanoate, which is an important pharmacophore in a number of peroxisome proliferator-activated receptor α/γ dual agonist advanced drug candidates used for the treatment of type-II diabetes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Asymmetric transfer hydrogenation by synthetic catalysts in cancer cells

    Science.gov (United States)

    Coverdale, James P. C.; Romero-Canelón, Isolda; Sanchez-Cano, Carlos; Clarkson, Guy J.; Habtemariam, Abraha; Wills, Martin; Sadler, Peter J.

    2018-03-01

    Catalytic anticancer metallodrugs active at low doses could minimize side-effects, introduce novel mechanisms of action that combat resistance and widen the spectrum of anticancer-drug activity. Here we use highly stable chiral half-sandwich organometallic Os(II) arene sulfonyl diamine complexes, [Os(arene)(TsDPEN)] (TsDPEN, N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine), to achieve a highly enantioselective reduction of pyruvate, a key intermediate in metabolic pathways. Reduction is shown both in aqueous model systems and in human cancer cells, with non-toxic concentrations of sodium formate used as a hydride source. The catalytic mechanism generates selectivity towards ovarian cancer cells versus non-cancerous fibroblasts (both ovarian and lung), which are commonly used as models of healthy proliferating cells. The formate precursor N-formylmethionine was explored as an alternative to formate in PC3 prostate cancer cells, which are known to overexpress a deformylase enzyme. Transfer-hydrogenation catalysts that generate reductive stress in cancer cells offer a new approach to cancer therapy.

  5. Design, Synthesis, and Characterization of Novel Thiol-Derivatized Ibuprofen Monolayer Protected Gold Clusters

    International Nuclear Information System (INIS)

    Lee, K.H.; Lee, K.H.; Lin, Y.Sh.; Huang, P.J.

    2013-01-01

    A series of new thiol-derivatized ibuprofen monolayer protected gold clusters have been prepared by amidation of ibuprofen with alkyl alcohol or aminophenol affording the carboxamide, N-hydroxyalkyl amide 2, and N-hydroxyphenyl amide 6, which were then tosylate with p-toluenesulfonyl chloride at hydroxyl group to give 3 and 7. Reactions of 3 and 7 with NaSH afforded the mercapto derivatives 4 and 8. Conducting Brust’s reaction with a 3:1 mole ratio of thiolate ibuprofen/ AuCl 4 - yielded polydisperse thiol-derivatized ibuprofen-MPCs 5 and 9. All compounds have been identified by NMR, MS, UV, and IR spectroscopies. Compounds 4 and 8 and the MPCs 5 and 9 have been investigated by using the method of 1 H NMR spectroscopy. The broadening of the signals from 0.8 to 2.0 ppm in 1 H NMR spectrum of MPCs 5 and 9 confirmed the success of the conjugation of thiol-containing derivatives with nano gold cluster.

  6. Radiation hardenable coating mixture

    International Nuclear Information System (INIS)

    Howard, D.D.

    1977-01-01

    This invention relates to coatings that harden under radiation and to their compositions. Specifically, this invention concerns unsaturated urethane resins polymerisable by addition and to compositions, hardening under the effect of radiation, containing these resins. These resins feature the presence of at least one unsaturated ethylenic terminal group of structure CH 2 =C and containing the product of the reaction of an organic isocyanate compound with at least two isocyanate groups and one polyester polyol with at least two hydroxyl groups, and one unsaturated monomer compound polymerisable by addition having a single active hydrogen group reacting with the isocyanate [fr

  7. Health Concerns about Spray Polyurethane Foam

    Science.gov (United States)

    Exposures to SPF's key ingredient, isocyanates and other SPF chemicals in vapors, aerosols, and dust created during and after installation, can cause: asthma, sensitization, lung damage, other respiratory and breathing problems, skin and eye irritation.

  8. Synthetic antigens, radiolabelled derivatives thereof, and methods of analysis using such derivatives

    International Nuclear Information System (INIS)

    Eisenhardt, W.A. Jr.; Hedaya, E.; Theodoropulos, S.

    1981-01-01

    This patent claim on behalf of Union Carbide Corporation, relates to a method of carrying out a competitive binding radioassay of a compound of interest in a clinical sample, using isocyanates labelled with radioiodine as synthetic antigens. (U.K.)

  9. Synthesis, mechanical, thermal and chemical properties of ...

    Indian Academy of Sciences (India)

    Unknown

    Cardanol, an excellent monomer for polymer production, has been isolated from CNSL and allowed to ... solution), and 1% glutaric acid catalyst in methanol were refluxed .... volving terminal isocyanate groups with active hydrogen present in ...

  10. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    propanonyl thio)-3-arylquinazol-4(3H)ones (2). Further, the treatment of compound (2) with hydroxylamine hydrochloride gave the corresponding oximes (3) which on reaction with phenyl isocyanate in THF yielded corresponding oxime ...

  11. Design of self-dispersible charged-polymer building blocks for waterborne polyurethane dispersions

    NARCIS (Netherlands)

    Jiménez-Pardo, I.; Sun, P.; van Benthem, R.A.T.M.; Esteves, A.C.C.

    2018-01-01

    Waterborne polyurethane dispersions (PUDs) currently have a wide spectrum of applications as coating resins for biomedical products, food packaging, cosmetics and traditional coatings. At present, PUDs are commonly prepared by the “prepolymer extension” method in which isocyanate terminated

  12. Aliphatic isocyanurates and polyisocyanurate networks

    NARCIS (Netherlands)

    Driest, Pieter Job; Lenzi, V.; Marques, L.S.A.; Ramos, M.M.D; Dijkstra, D.J.; Richter, F.U.; Stamatialis, Dimitrios; Grijpma, Dirk W.

    2016-01-01

    The production, processing, and application of aliphatic isocyanate (NCO)-based thermosets such as polyurethane coatings and adhesives are generally limited by the surprisingly high viscosity of tri-functionality and higher-functionality isocyanurates. These compounds are essential crosslinking

  13. Aliphatic isocyanurates and polyisocyanurate networks

    NARCIS (Netherlands)

    Driest, P. J.; Lenzi, V.; Marques, L. S. A.; Ramos, M. M. D.; Dijkstra, D. J.; Richter, F. U.; Stamatialis, D.; Grijpma, D. W.

    2017-01-01

    The production, processing, and application of aliphatic isocyanate (NCO)-based thermosets such as polyurethane coatings and adhesives are generally limited by the surprisingly high viscosity of tri-functionality and higher-functionality isocyanurates. These compounds are essential crosslinking

  14. Interference with effects of amphotericin B on Candida albicans cells by 2-chloroethyl-1-nitrosoureas.

    OpenAIRE

    Brajtburg, J; Elberg, S; Kobayashi, G S; Medoff, G

    1988-01-01

    Two nitrosoureas, 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU) and 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU), with strong carbamoylating and weak alkylating activities, interfered with the induction of potassium leakage and lethal action of amphotericin B (AmB) on Candida albicans. 2-Cyclohexyl isocyanate, the product of decomposition of CCNU, and 2-chloroethyl isocyanate, the product of decomposition of BCNU, also interfered with the anticandidal actions of AmB. In contrast, two ni...

  15. Differential production of proteolytic enzymes by normal human fibroblasts and their counterparts transformed by treatment with 60Co gamma rays

    International Nuclear Information System (INIS)

    Nishitani, Koji; Namba, Masayoshi; Ohkubo, Shigeki; Kimoto, Tetsuo

    1985-01-01

    Production of proteolytic enzymes by human fibroblasts in the process of transformation was investigated. The cells used were normal human fibroblasts (KSM-6) and their in vitro counterparts transformed by treatment with 60 Co gamma rays (KMST-6). Cells seeded by treatment with EDTA were cultured in a serum free medium. Proteolytic enzymes in the culture medium of cells were assayed using a synthetic substrate, N-α-(p-tosyl)-L-arginine ( 3 H) methyl ester hydrochloride. The transformed cells (KMST-6) produced a larger amount of enzymes than normal cells (KMS-6). The enzyme production in both cell lines was high in the exponential growth stage and then decreased as the cells reached confluency. The proteolytic enzymes produced by these cells were trypsin- and thrombin-like enzymes. Cell growth of KMST-6 or KMS-6 was not inhibited by the addition of protease inhibitors to the culture medium. (author)

  16. Spectroscopic evidence of xanthine compounds fluorescence quenching effect on water-soluble porphyrins

    Science.gov (United States)

    Makarska-Bialokoz, Magdalena

    2015-02-01

    The formation of π-stacked complexes between water-soluble porphyrins: 4,4‧,4″,4″‧-(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis-(benzoic acid) (H2TCPP), 5,10,15,20-tetrakis(4-sulfonatophenyl)-21H,23H-porphine (H2TPPS4), 5,10,15,20-tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine tetra-p-tosylate (H2TTMePP), 5,10,15,20-tetrakis(1-methyl-4-pyridyl)-21H,23H-porphine tetra-p-tosylate (H2TMePyP), the Cu(II) complexes of H2TTMePP and H2TMePyP, as well as chlorophyll a with xanthine, theophylline (1,3-dimethylxanthine) and theobromine (3,7-dimethylxanthine) has been studied analysing their absorption and steady-state fluorescence spectra in aqueous (or acetone in case of chlorophyll a) solution. During titration by the compounds from xanthine group the bathochromic effect in the porphyrin absorption spectra as well as the hypochromicity of the porphyrin Soret maximum can be noticed. The fluorescence quenching effect observed during interactions in the systems examined suggests the process of static quenching. The association and fluorescence quenching constants are of the order of magnitude of 103 - 102 mol-1. The results obtained show that xanthine and its derivatives can quench the fluorescence of the porphyrins according to the number of methyl groups in the molecule of quencher.

  17. Airborne thermal degradation products of polyurethene coatings in car repair shops.

    Science.gov (United States)

    Karlsson, D; Spanne, M; Dalene, M; Skarping, G

    2000-10-01

    A methodology for workplace air monitoring of aromatic and aliphatic, mono- and polyisocyanates by derivatisation with di-n-butylamine (DBA) is presented. Air sampling was performed using midget impinger flasks containing 10 ml of 0.01 mol l(-1) DBA in toluene and a glass-fibre filter in series after the impinger flask, thereby providing the possibility of collecting and derivatising isocyanates in both the gas and particle phases. Quantification was made by LC-MS, monitoring the molecular ions [MH]+. Air samples taken with this method in car repair shops showed that many different isocyanates are formed during thermal decomposition of polyurethane (PUR) coatings. In addition to isocyanates such as hexamethylene (HDI), isophorone (IPDI), toluene (TDI) and methylenediphenyl diisocyanate (MDI), monoisocyanates such as methyl (MIC), ethyl (EIC), propyl (PIC), butyl (BIC) and phenyl isocyanate (PhI) were found. In many air samples the aliphatic monoisocyanates dominated. During cutting and welding operations, the highest levels of isocyanates were observed. In a single air sample from a welding operation in a car repair shop, the highest concentrations found were: MIC, 290; EIC, 60; PIC, 20; BIC, 9; PhI, 27; HDI, 105; IPDI, 39; MDI, 4; and 2,4-TDI and 2,6-TDI 140 microg m(-3). Monitoring the particle size distribution and concentration during grinding, welding and cutting operations showed that ultrafine particles (< 0.1 microm) were formed at high concentrations. Isocyanates with low volatility were mainly found in the particle phase, but isocyanates with a relatively high volatility such as TDI, were found in both the particle and gas phases.

  18. Sensitive Determination of Onco-metabolites of D- and L-2-hydroxyglutarate Enantiomers by Chiral Derivatization Combined with Liquid Chromatography/Mass Spectrometry Analysis

    Science.gov (United States)

    Cheng, Qing-Yun; Xiong, Jun; Huang, Wei; Ma, Qin; Ci, Weimin; Feng, Yu-Qi; Yuan, Bi-Feng

    2015-01-01

    2-hydroxyglutarate (2HG) is a potent competitor of α-ketoglutarate (α-KG) and can inhibit multiple α-KG dependent dioxygenases that function on the epigenetic modifications. The accumulation of 2HG contributes to elevated risk of malignant tumors. 2HG carries an asymmetric carbon atom in its carbon backbone and differentiation between D-2-hydroxyglutarate (D-2HG) and L-2-hydroxyglutarate (L-2HG) is crucially important for accurate diagnosis of 2HG related diseases. Here we developed a strategy by chiral derivatization combined with liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) analysis for highly sensitive determination of D-2HG and L-2HG enantiomers. N-(p-toluenesulfonyl)-L-phenylalanyl chloride (TSPC) was used to derivatize 2HG. The formed diastereomers by TSPC labeling can efficiently improve the chromatographic separation of D-2HG and L-2HG. And derivatization by TSPC could also markedly increase the detection sensitivities by 291 and 346 folds for D-2HG and L-2HG, respectively. Using the developed method, we measured the contents of D-2HG and L-2HG in clear cell renal cell carcinoma (ccRCC) tissues. We observed 12.9 and 29.8 folds increase of D-2HG and L-2HG, respectively, in human ccRCC tissues compared to adjacent normal tissues. The developed chiral derivatization combined with LC-ESI-MS/MS analysis offers sensitive determination of D-2HG and L-2HG enantiomers, which benefits the precise diagnosis of 2HG related metabolic diseases. PMID:26458332

  19. Novel HPC-ibuprofen conjugates: synthesis, characterization, thermal analysis and degradation kinetics

    International Nuclear Information System (INIS)

    Hussain, M.A.; Lodhi, B.A.; Abbas, K.

    2014-01-01

    Naturally occurring hydrophilic polysaccharides are advantageously used as drug carriers because they provide a mechanism to improve drug action. Hydroxypropylcellulose (HPC) is water-soluble, biocompatible and bears hydroxyl groups for drug conjugation outside the parent polymeric chains. This unique geometry allows the attachment of drug molecules with higher covalent loading. The HPC-Ibuprofen conjugates as macromolecular prodrugs were therefore synthesized employing homogenous and one pot reaction methodologies using p-toluenesulfonyl chloride in N,N-dimethylacetamide solvent at 80 degree C for 24 h under nitrogen atmosphere. The imidazole was used as a base for neutralization of acidic impurities. Present strategy appeared effective to get high yield (77-81%) and high degree of drug substitution (DS 0.88-1.40) onto the HPC polymer as determined by the acid-base titration and verified by 1H-NMR spectroscopy. The gel permeation chromatography has shown uni-modal absorption which indicates no significant degradation of polymer during reaction. Macromolecular prodrugs with different DS of ibuprofen were synthesized, purified, characterized and found soluble in organic solvents. From thermogravimetric analysis, initial, maximum and final degradation temperatures of the conjugates were calculated and compared for relative thermal stability. Thermal degradation kinetics was also studied and results have indicated that degradation of conjugates follows about first order kinetics as calculated by Kissinger model. The energy of activation was also found moderate 92.38, 99.34 and 87.34 kJ/mol as calculated using Friedman, Broido and Chang models. It was found that these novel prodrugs of ibuprofen were thermally stable therefore these may have potential pharmaceutical applications. (author)

  20. Analytical insight into degradation processes of aminopolyphosphonates as potential factors that induce cyanobacterial blooms.

    Science.gov (United States)

    Drzyzga, Damian; Lipok, Jacek

    2017-11-01

    Aminopolyphosphonates (AAPs) are commonly used industrial complexones of metal ions, which upon the action of biotic and abiotic factors undergo a breakdown and release their substructures. Despite the low toxicity of AAPs towards vertebrates, products of their transformations, especially those that contain phosphorus and nitrogen, can affect algal communities. To verify whether such chemical entities are present in water ecosystems, much effort has been made in developing fast, inexpensive, and reliable methods for analyzing phosphonates. However, unfortunately, the methods described thus far require time-consuming sample pretreatment and offer relatively high values of the limit of detection (LOD). The aim of this study was to develop an analytical approach to study the environmental fate of AAPs. Four phosphonic acids, N,N-bis(phosphonomethyl)glycine (GBMP), aminotris(methylenephosphonic) acid (ATMP), hexamethylenediamine-N,N,N',N'-tetrakis(methylphosphonic) acid (HDTMP), and diethylenetriamine penta(methylenephosphonic) acid (DTPMP) were selected and examined in a water matrix. In addition, the susceptibility of these compounds to biotransformations was tested in colonies of five freshwater cyanobacteria-microorganisms responsible for the so-called blooms in the water. Our efforts to track the AAP decomposition were based on derivatization of N-alkyl moieties with p-toluenesulfonyl chloride (tosylation) followed by chromatographic (HPLC-UV) separation of derivatives. This approach allowed us to determine seven products of the breakdown of popular phosphonate chelators, in nanomolar concentrations and in one step. It should be noted that the LOD of four of those products, aminemethylphosphonic acid (AMPA), N-phosphomethyl glycine (NPMG), N-(methyl)aminemethanephosphonic acid (MAMPA), and N-(methyl) glycine (SAR), was set below the concentration of 50 nM. Among those substances, N-(methylamino)methanephosphonic acid (MAMPA) was identified for the first time as

  1. Carbamoylating activity associated with the activation of the antitumor agent laromustine inhibits angiogenesis by inducing ASK1-dependent endothelial cell death.

    Directory of Open Access Journals (Sweden)

    Weidong Ji

    Full Text Available The anticancer agent 1,2-bis(methylsulfonyl-1-(2-chloroethyl-2-[(methylaminocarbonyl]hydrazine (laromustine, upon decomposition in situ, yields methyl isocyanate and the chloroethylating species 1,2-bis(methylsulfonyl-1-(2-chloroethylhydrazine (90CE. 90CE has been shown to kill tumor cells via a proposed mechanism that involves interstrand DNA cross-linking. However, the role of methyl isocyanate in the antineoplastic function of laromustine has not been delineated. Herein, we show that 1,2-bis(methylsulfonyl-1-[(methylaminocarbonyl]hydrazine (101MDCE, an analog of laromustine that generates only methyl isocyanate, activates ASK1-JNK/p38 signaling in endothelial cells (EC. We have previously shown that ASK1 forms a complex with reduced thioredoxin (Trx1 in resting EC, and that the Cys residues in ASK1 and Trx1 are critical for their interaction. 101MDCE dissociated ASK1 from Trx1, but not from the phosphoserine-binding inhibitor 14-3-3, in whole cells and in cell lysates, consistent with the known ability of methyl isocyanate to carbamoylate free thiol groups of proteins. 101MDCE had no effect on the kinase activity of purified ASK1, JNK, or the catalytic activity of Trx1. However, 101MDCE, but not 90CE, significantly decreased the activity of Trx reductase-1 (TrxR1. We conclude that methyl isocyanate induces dissociation of ASK1 from Trx1 either directly by carbamoylating the critical Cys groups in the ASK1-Trx1 complex or indirectly by inhibiting TrxR1. Furthermore, 101MDCE (but not 90CE induced EC death through a non-apoptotic (necroptotic pathway leading to inhibition of angiogenesis in vitro. Our study has identified methyl isocyanates may contribute to the anticancer activity in part by interfering with tumor angiogenesis.

  2. Chemical structure of carbamoylating groups and their relationship to bone marrow toxicity and antiglioma activity of bifunctionally alkylating and carbamoylating nitrosoureas.

    Science.gov (United States)

    Ali-Osman, F; Giblin, J; Berger, M; Murphy, M J; Rosenblum, M L

    1985-09-01

    Although the antitumor effects of chloroethylnitrosoureas have been shown to be due primarily to DNA-DNA cross-linking by the alkylating moieties of these agents, the basis of the often accompanying bone marrow toxicity has been more controversial. We report on the relative bone marrow toxicity of four model nitrosoureas with different alkylating and carbamoylating activities: 1,3-bis(2-chloroethyl)-1-nitrosourea; 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea; chlorozotozin, (2-[3-(2-chloroethyl)-3 -nitrosoureido]-2-deoxy-D-glucopyranose); and -3-(beta-D-glucopyranosyl)-1-nitrosourea. Inhibitions of DNA, RNA, and protein synthesis in murine bone marrow cells and of colony growth of myeloid precursor cells (granulocyte-macrophage colony-forming units) were used as in vitro end points of myelotoxicity. Further, we determined the antiglioma activity of the four nitrosoureas on two human gliomas in a clonogenic tumor cell assay and studied the effect of the non-nitrosourea carbamoylators potassium cyanate, chloroethyl isocyanate, cyclohexyl isocyanate, ethyl isocyanate, and ethyl isothiocyanate on granulocyte-macrophage colony-forming units. The results show that, at equivalent drug exposures, clonogenic glioma cell kill was significant and comparative for 1,3-bis(2-chloroethyl)-1-nitrosourea, 1-(2-chloroethyl)-3-(beta-D-glucopyranosyl)-1-nitrosourea, and chlorozotocin; 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea showed little activity. In contrast, granulocyte-macrophage colony-forming unit toxicity was low with chlorozotocin and 1-(2-chloroethyl)-3-(beta-D-glucopyranosyl)-1-nitrosourea and very high with 1,3-bis(2-chloroethyl)-1-nitrosourea and 1,3-bis(trans-4-hydroxycyclohexyl)-1-nitrosourea. Of the isocyanates, bone marrow toxicity was highest with chloroethyl isocyanate and cyclohexyl isocyanate, intermediate with ethyl isocyanate, and lowest with KOCN and ethyl isothiocyanate. Our results indicate that (a) bifunctional alkylation is essential for

  3. Casting materials

    Science.gov (United States)

    Chaudhry, Anil R [Xenia, OH; Dzugan, Robert [Cincinnati, OH; Harrington, Richard M [Cincinnati, OH; Neece, Faurice D [Lyndurst, OH; Singh, Nipendra P [Pepper Pike, OH

    2011-06-14

    A foam material comprises a liquid polymer and a liquid isocyanate which is mixed to make a solution that is poured, injected or otherwise deposited into a corresponding mold. A reaction from the mixture of the liquid polymer and liquid isocyanate inside the mold forms a thermally collapsible foam structure having a shape that corresponds to the inside surface configuration of the mold and a skin that is continuous and unbroken. Once the reaction is complete, the foam pattern is removed from the mold and may be used as a pattern in any number of conventional casting processes.

  4. Polyurethane Binder Systems for Polymer Bonded Explosives

    Science.gov (United States)

    2006-12-01

    Propulsion (2005), Santiago , Chile . 8. Huang, C.-C., Hwu, W.-H., Cheng, C.-S., Shyy, I.-N., and Yang, K.-K., Study on Thermal Decomposition of Composite...water or amines to form ureas (Figure 2). R NCO R N C O H+ H2O O H R NH2 - CO2 R NCO R N C O NR’ H H ureaamine Figure 2. Reaction of an isocyanate...Monoisocyanates are present as impurities in low concentration in most diisocyanates. Table 1. Common diisocyanates Isocyanate Structure B.p. (ºC

  5. Alkylating HIV-1 Nef - a potential way of HIV intervention

    Directory of Open Access Journals (Sweden)

    Cai Catherine

    2010-07-01

    Full Text Available Abstract Background Nef is a 27 KDa HIV-1 accessory protein. It downregulates CD4 from infected cell surface, a mechanism critical for efficient viral replication and pathogenicity. Agents that antagonize the Nef-mediated CD4 downregulation may offer a new class of drug to combat HIV infection and disease. TPCK (N-α-p-tosyl-L-phenylalanine chloromethyl ketone and TLCK (N-α-p-tosyl-L-lysine chloromethyl ketone are alkylation reagents that chemically modify the side chain of His or Cys residues in a protein. In search of chemicals that inhibit Nef function, we discovered that TPCK and TLCK alkylated HIV Nef. Methods Nef modification by TPCK was demonstrated on reducing SDS-PAGE. The specific cysteine residues modified were determined by site-directed mutagenesis and mass spectrometry (MS. The effect of TPCK modification on Nef-CD4 interaction was studied using fluorescence titration of a synthetic CD4 tail peptide with recombinant Nef-His protein. The conformational change of Nef-His protein upon TPCK-modification was monitored using CD spectrometry Results Incubation of Nef-transfected T cells, or recombinant Nef-His protein, with TPCK resulted in mobility shift of Nef on SDS-PAGE. Mutagenesis analysis indicated that the modification occurred at Cys55 and Cys206 in Nef. Mass spectrometry demonstrated that the modification was a covalent attachment (alkylation of TPCK at Cys55 and Cys206. Cys55 is next to the CD4 binding motif (A56W57L58 in Nef required for Nef-mediated CD4 downregulation and for AIDS development. This implies that the addition of a bulky TPCK molecule to Nef at Cys55 would impair Nef function and reduce HIV pathogenicity. As expected, Cys55 modification reduced the strength of the interaction between Nef-His and CD4 tail peptide by 50%. Conclusions Our data suggest that this Cys55-specific alkylation mechanism may be exploited to develop a new class of anti HIV drugs.

  6. CHRIS: Hazardous Chemical Data

    Science.gov (United States)

    1978-10-01

    CPLORD-O-TOLUICIfE FAST RED Z& BASE = ’-1-ITRCAMILINE FERMENTAITION ALCOH!OL - ETHYL ALCOHOL FERMENTATION AMYL ALCOHCL -ISCANYL ALCOJIGI FERMENTATION BUTYL...ACID ETHYLENEDIAMINE IETRACETIC ACID VIC-H-XYLENOL XYLENOL VIENNA GREEN COPPER ACETOARSE1ITE VILRATHANE 4300 -CIPHENYLETHAME01ISOCYANATE (MDIl VINEGAR

  7. Industrial Hygiene.

    Science.gov (United States)

    Langhorst, Marsha L.; Coyne, Linda B.

    1989-01-01

    Presents a review focusing on some of the most widely used analytical techniques in monitoring personal exposures in the workplace for assessing human health risk. Discusses several basic techniques: solid sorbents, calibration standards, derivatizations, dosimeters, biomonitoring, gas monitoring, particulates, isocyanates, formaldehyde, and…

  8. A multistep continuous-flow system for rapid on-demand synthesis of receptor ligands

    DEFF Research Database (Denmark)

    Petersen, Trine P; Ritzén, Andreas; Ulven, Trond

    2009-01-01

    A multistep continuous-flow system for synthesis of receptor ligands by assembly of three variable building blocks in a single unbroken flow is described. The sequence consists of three reactions and two scavenger steps, where a Cbz-protected diamine is reacted with an isocyanate, deprotected, an......, and reacted further with an alkylating agent....

  9. 77 FR 40033 - Certain New Chemicals; Receipt and Status Information

    Science.gov (United States)

    2012-07-06

    .../02/2012 07/30/2012 CBI (G) Coating (G) Acid anhydride, additive. polymer with aromatic isocyanate and... pigment. earth doped. P-12-0345 05/09/2012 08/06/2012 CBI (G) Coating for (G) Ultra violet- open non...) Crosslinker (S) 2-propenone, Corporation. in moisture o,o',o- cure sealant (ethylsilylidyne) formulation...

  10. Reusable Mg-Al hydrotalcites for the catalytic synthesis of diglycerol dicarbonate from diglycerol and dimethyl carbonate

    NARCIS (Netherlands)

    Stewart, Joseph A.; Weckhuysen, Bert M.; Bruijnincx, Pieter C A

    2014-01-01

    Diglycerol dicarbonate, which has been highlighted as a potential monomer for the production of non-isocyanate polyurethanes, has been synthesised using as-synthesised hydrotalcites of varying magnesium-to-aluminium ratio as catalyst materials. The hydrotalcite materials were aged for two different

  11. Sustainable Intensified Process Retrofit for the Production of MDI

    DEFF Research Database (Denmark)

    Babi, Deenesh Kavi; Woodley, John; Gani, Rafiqul

    Process intensification (PI) is a means by which processes can be made more efficient and sustainable at different levels, the unit operations, functional and phenomena levels. Therefore PI can be used for making process improvements at the functional level for the production of an important poly...... polyurethane, methylene diphenyldi-isocyanate (MDI)....

  12. European Scientific Notes. Volume 37, Number 9.

    Science.gov (United States)

    1983-09-30

    isocyanates, have been crosslinked production of ethyl alcohol from glucose with water (See Klein and Manecke, using whole yeast cells in epoxy-based 1982...more specialized studies ic particles. Dr. J.L. Sarmiento were presented. (Princeton Univ., US) presented prelim- Dr. P.G. Brewer (National Science inary

  13. A Military Guide to Terrorism in the Twenty-First Century. U.S. Army DCSINT Handbook No. 1 (Version 3.0)

    Science.gov (United States)

    2005-08-15

    or varnished brown Length: 102mm Width: 61mm Weight: 773g Filler: Amatol Characteristics Color: Black and unmarked Length: 131mm Width: 55mm...isocyanate Diborane Boron tribromide Nitrogen dioxide Ethylene oxide Carbon monoxide Phosphine Fluorine Carbonyl sulfide Phosphorus oxychloride

  14. Free radical and thermal curing of terpyridine-modified terpolymers

    NARCIS (Netherlands)

    Hofmeier, H.; El-Ghayoury, A.; Schubert, U.S.

    2004-01-01

    Terpolymers bearing terpyridine as well as (meth)acrylates as free radical curable groups (UV-curing) or hydroxyl groups (thermal curing with bis-isocyanates) were synthesized and characterized using 1H NMR, IR and UV-vis spectroscopy as well as GPC. Subsequently, the ability of covalent

  15. Covalent bonding of PMMA, PBMA, and poly(HEMA) to hydroxyapatite particles

    NARCIS (Netherlands)

    Liu, Q.; de Wijn, J.R.; van Blitterswijk, Clemens

    1998-01-01

    In our earlier study, we showed that the surface hydroxyl groups of hydroxyapatite have the ability to react with organic isocyanate groups. In this study, the feasibility of grafting poly(methyl methacrylate) (PMMA), poly(n-butyl methacrylate) (PBMA), and Poly(hydroxyethyl methacrylate)

  16. Towards Green Cyclic Carbonate Synthesis : Heterogeneous and Homogeneous Catalyst Development

    NARCIS (Netherlands)

    Stewart, J.A.

    2015-01-01

    This PhD research serves to implement both known and novel catalytic systems for the purpose of cyclic carbonate synthesis from biomass-derived substrates. Such products have been earmarked as potential monomers for non-isocyanate polyurethanes (NIPUs), amongst other uses. Particular attention has

  17. Determination of albumin adducts of 4,4'-methylenediphenyl diisocyanate after specific inhalative challenge tests in workers.

    Science.gov (United States)

    Sabbioni, Gabriele; Dongari, Nagaraju; Kumar, Anoop; Baur, Xaver

    2016-10-17

    4,4'-Methylenediphenyl diisocyanate (MDI) is the most important isocyanate used in the industry. Lung sensitization with bronchial asthma is the main disorder in exposed workers. Albumin adducts of MDI might be involved in specific immunological reactions. MDI adducts with lysine (MDI-Lys) of albumin have been found in MDI-workers and construction workers. MDI-Lys is an isocyanate-specific adduct of MDI with albumin. In the present study, we report MDI-adducts in workers undergoing diagnostic MDI challenge tests. The workers were exposed for 2h to 5ppb of MDI. The adduct levels increase significantly after the exposure to MDI in the challenge chamber. About 0.6% of the dose was bound to albumin. So far, only urinary metabolites of MDI were measured to monitor isocyanate workers. However, such urinary metabolites are not isocyanate specific. Therefore, we propose to measure albumin adducts for monitoring MDI exposed subjects. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Synthesis and antimicrobial activities of new oxime carbamates of 3 ...

    Indian Academy of Sciences (India)

    Abstract. S-alkylation of 3-aryl-2-thioquinazolin-4(3H)-one (1) with chloroacetone gave 2-(propanonyl thio)-3-arylquinazol-4(3H)ones (2). Further, the treatment of compound (2) with hydroxylamine hydrochloride gave the corresponding oximes (3) which on reaction with phenyl isocyanate in THF yielded corresponding.

  19. Laboratory Tests to Determine the Chemical and Physical Characteristics of Propellant-Solvent-Fuel Oil Mixtures

    Science.gov (United States)

    1990-02-01

    isocyanates and many heterocyclic alcohols and ketones such as furfural and camphor also possess some I solvent power for nitrocellulose. Amines...34Estimation of Solvent Power by the Dilution-Ratio Method," J. Appl. Chem. (London) 7, 332 (1957). U R.P. Teulings, "A Multivariable Study of the Adsorption of

  20. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2018-04-18

    Apr 18, 2018 ... prepared by coating the mixed solution on transparent polycarbonate substrate using spinning ... The sensitivity (speed of color changing), fatigue resistance to UV source and color ... to add isocyanate crosslinking agent for curing process. ... The average thickness of coated layer is less than 150 micron.

  1. Physico-chemical, thermal and electrical properties of the fabricated ...

    African Journals Online (AJOL)

    We successfully fabricated polyurethane (PU) thin films deposited on glass substrates utilizing bio-based epoxidized soybean oil (ESBO) via spin coating technique. Prior to deposition, one-shot polymerization condensation reaction was made by reacting varied amount of ESBO-based polyols with isocyanate.

  2. Plastic Models Designed to Produce Large Height-to-Length Ratio Steady-State Planar and Axisymmetric (Radial) Viscous Liquid Laminar Flow Gravity Currents

    Science.gov (United States)

    Blanck, Harvey F.

    2012-01-01

    Naturally occurring gravity currents include events such as air flowing through an open front door, a volcanic eruption's pyroclastic flow down a mountainside, and the spread of the Bhopal disaster's methyl isocyanate gas. Gravity currents typically have a small height-to-distance ratio. Plastic models were designed and constructed with a…

  3. Carbamylation of proteins – mechanism, causes and consequences

    Directory of Open Access Journals (Sweden)

    Anna Pieniążek

    2016-05-01

    Full Text Available Carbamylation (carbamoylation is a post-translational modification resulting from the nonenzymatic reaction between isocyanic acid and free functional groups of proteins, in particular with the free amino groups. This reaction alters structural and functional properties of proteins and results in faster aging of proteins.Urea present in the body can be transformed into cyanate and its more reactive form, isocyanic acid. High concentration of urea is associated with some diseases, especially with chronic renal failure and atherosclerosis. In human tissues, urea and cyanate are in equilibrium in aqueous solutions. Surprisingly, concentration of isocyanate in the body is much lower than it would appear from the kinetic parameters of urea decomposition. The low concentration of isocyanic acid results from its high reactivity and short half-life.In this review we describe the biochemical mechanism of carbamylation of proteins and freeamino acids. We summarize the literature data for carbamylation of hemoglobin, lipoproteins,albumin, membrane proteins and erythropoietin in chronic renal failure.In summary, the carbamylation of proteins may have a negative impact on their biologicalactivity and may contribute to the deterioration of patients with chronic renal failure.

  4. A Modular Synthesis of N-Benzotriazole Ureas Using Alkylation of 5-Nitrobenzotriazole

    Czech Academy of Sciences Publication Activity Database

    Machara, A.; Konvalinka, Jan; Kotora, M.

    2016-01-01

    Roč. 1, č. 1 (2016), s. 101-107 ISSN 2365-6549 R&D Projects: GA ČR GA13-19561S Institutional support: RVO:61388963 Keywords : benzotriazole * alkylation * urea * isocyanate * reduction Subject RIV: CE - Biochemistry

  5. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    The insertion reactions of zirconium(IV) -butoxide and titanium(IV) -butoxide with a heterocumulene like carbodiimide, carbon dioxide or phenyl isocyanate are compared. Both give an intermediate which carries out metathesis at elevated temperatures by inserting a second heterocumulene in a head-to-head fashion.

  6. Light-controlled supramolecular helicity of a liquid crystalline phase using a helical polymer functionalized with a single chiroptical molecular switch

    NARCIS (Netherlands)

    Pijper, Dirk; Jongejan, Mahthild G. M.; Meetsma, Auke; Feringa, Ben L.

    2008-01-01

    Control over the preferred helical sense of a poly(n-hexyl isocyanate) (PHIC) by using a single light-driven molecular motor, covalently attached at the polymer's terminus, has been accomplished in solution via a combination of photochemical and thermal isomerizations. Here, we report that after

  7. Mechanisms with discrete nitrene species

    Indian Academy of Sciences (India)

    identifying a dissociation path involving singlet acyl- nitrene. However, CCSD(T) and CBS-QB3 studies62 predicted acetyl azide decomposes by methyl group migration to give methyl isocyanate and N2 with a bar- rier of 27 kcal/mol. Experimentally, photolysis of pival- oyl azide gives singlet pivaloyl nitrene,45 which adds to.

  8. Multivalent contrast agents based on Gd-DTPA-terminated poly (propylene imine) dendrimers for Magnetic Resonance Imaging

    NARCIS (Netherlands)

    Langereis, S.; Lussanet, de Q.G; Genderen, van M.H.P.; Backes, W.H.; Meijer, E.W.

    2004-01-01

    A convenient methodol. has been developed for the synthesis of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA)-terminated poly(propylene imine) dendrimers as contrast agents for magnetic resonance imaging (MRI). In our strategy, isocyanate-activated, tert-butyl-protected DTPA analogs were

  9. Skin exposure to aliphatic polyisocyanates in the auto body repair and refinishing industry: II. A quantitative assessment.

    Science.gov (United States)

    Bello, Dhimiter; Redlich, Carrie A; Stowe, Meredith H; Sparer, Judy; Woskie, Susan R; Streicher, Robert P; Hosgood, H Dean; Liu, Youcheng

    2008-03-01

    Skin exposure to isocyanates, in addition to respiratory exposures, may contribute to sensitization and asthma. Quantitative skin exposure data are scarce and quantitative methods limited. As part of the Survey of Painters and Repairers of Autobodies by Yale study, a method to sample and quantify human isocyanate skin exposure was developed (based on NIOSH 5525 method) and used to evaluate aliphatic isocyanate skin exposure in 81 auto body shop painters and body technicians. Wipe samples were collected from unprotected skin and from under PPE (gloves, clothing and respirator) using a polypropylene glycol-impregnated wipe. Hexamethylene diisocyanate (HDI), its polyisocyanates [HDI-derived polyisocyanates (pHDI)], isophorone diisocyanate (IPDI) and its polyisocyanates and IPDI-derived polyisocyanates (pIPDI) were quantified separately and also expressed as the total free isocyanate groups (total NCO). For unprotected skin areas, 49 samples were collected for spray painting, 13 for mixing, 27 for paint-related tasks (e.g. sanding and compounding) and 53 for non-paint-related tasks. Forty-three samples were also collected under PPE. The geometric mean (GM) [geometric standard deviation (GSD)] total NCO concentrations (ng NCO cm(-2)) for unprotected skin (hands, face and forearms) was 1.9 (10.9) and range 0.0-64.4. pHDI species were the major contributor to the total NCO content. Levels were very variable, with the highest concentrations measured for clear coating and paint mixing tasks. Isocyanate skin exposure was also commonly detected under PPE, with 92% of samples above the limit of detection. Levels were very variable with the overall GM (GSD) total NCO (ng NCO cm(-2)) under PPE 1.0 (5.2) and range (0.0-47.0) and similar under the different PPE (glove, respirator and clothing). The highest concentrations were detected for mixing and spraying tasks, 6.9 (5.3) and 1.0 (5.2), respectively. Levels under PPE were generally lower than unpaired samples obtained with no

  10. Preclinical in vivo and in vitro comparison of the translocator protein PET ligands [{sup 18}F]PBR102 and [{sup 18}F]PBR111

    Energy Technology Data Exchange (ETDEWEB)

    Eberl, S.; Wen, L. [Royal Prince Alfred Hospital, Department of Molecular Imaging (PET and Nuclear Medicine), Camperdown, NSW (Australia); University of Sydney, Faculty of Engineering and Information Technologies, Sydney, NSW (Australia); Katsifis, A. [Royal Prince Alfred Hospital, Department of Molecular Imaging (PET and Nuclear Medicine), Camperdown, NSW (Australia); University of Sydney, Faculty of Pharmacy, Sydney, NSW (Australia); Peyronneau, M.A. [Universite Paris-Saclay, CEA-SHFJ, IMIV, CEA, Inserm, Univ. Paris-Sud, CNRS, Orsay (France); Henderson, D.; Loc' h, C.; Verschuer, J.; Lam, P.; Mattner, F. [Royal Prince Alfred Hospital, Department of Molecular Imaging (PET and Nuclear Medicine), Camperdown, NSW (Australia); Greguric, I.; Pham, T. [ANSTO, Radiochemistry and Radiotracers Platform, Lucas Heights, NSW (Australia); Mohamed, A. [Royal Prince Alfred Hospital, Department of Molecular Imaging (PET and Nuclear Medicine), Camperdown, NSW (Australia); University of Sydney, Sydney Medical School, Sydney, NSW (Australia); Fulham, M.J. [Royal Prince Alfred Hospital, Department of Molecular Imaging (PET and Nuclear Medicine), Camperdown, NSW (Australia); University of Sydney, Faculty of Engineering and Information Technologies, Sydney, NSW (Australia); University of Sydney, Sydney Medical School, Sydney, NSW (Australia)

    2017-02-15

    To determine the metabolic profiles of the translocator protein ligands PBR102 and PBR111 in rat and human microsomes and compare their in vivo binding and metabolite uptake in the brain of non-human primates (Papio hamadryas) using PET-CT. In vitro metabolic profiles of PBR102 and PBR111 in rat and human liver microsomes were assessed by liquid chromatography-tandem mass spectrometry. [{sup 18}F]PBR102 and [{sup 18}F]PBR111 were prepared by nucleophilic substitution of their corresponding p-toluenesulfonyl precursors with [{sup 18}F]fluoride. List mode PET-CT brain imaging with arterial blood sampling was performed in non-human primates. Blood plasma measurements and metabolite analysis, using solid-phase extraction, provided the metabolite profile and metabolite-corrected input functions for kinetic model fitting. Blocking and displacement PET-CT scans, using PK11195, were performed. Microsomal analyses identified the O-de-alkylated, hydroxylated and N-de-ethyl derivatives of PBR102 and PBR111 as the main metabolites. The O-de-alkylated compounds were the major metabolites in both species; human liver microsomes were less active than those from rat. Metabolic profiles in vivo in non-human primates and previously published rat experiments were consistent with the microsomal results. PET-CT studies showed that K{sub 1} was similar for baseline and blocking studies for both radiotracers; V{sub T} was reduced during the blocking study, suggesting low non-specific binding and lack of appreciable metabolite uptake in the brain. [{sup 18}F]PBR102 and [{sup 18}F]PBR111 have distinct metabolic profiles in rat and non-human primates. Radiometabolites contributed to non-specific binding and confounded in vivo brain analysis of [{sup 18}F]PBR102 in rodents; the impact in primates was less pronounced. Both [{sup 18}F]PBR102 and [{sup 18}F]PBR111 are suitable for PET imaging of TSPO in vivo. In vitro metabolite studies can be used to predict in vivo radioligand metabolism and

  11. Understanding Factors that Influence Protective Glove Use among Automotive Spray Painters

    Science.gov (United States)

    Ceballos, Diana; Reeb-Whitaker, Carolyn; Glazer, Patricia; Murphy-Robinson, Helen; Yost, Michael

    2017-01-01

    Dermal contact with isocyanate-based coatings may lead to systemic respiratory sensitization. The most common isocyanates found in sprayed automotive coatings are monomeric and oligomeric 1,6-hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI). Most spray painters use thin (4–5 mil) latex gloves that are not effective at preventing dermal exposures when spraying isocyanate paints. Personal interviews with collision repair industry personnel and focus groups with spray painters were held to characterize risk awareness, to examine perceptions and challenges concerning protective glove use and selection, and to generate ideas for protective glove use interventions. The most popular gloves among spray painters were thin (4–5 mil) and thick (14 mil) latex. We found that medium to thick (6–8 mil) nitrile were not always perceived as comfortable and were expected to be more expensive than thin (4–5 mil) latex gloves. Of concern is the users’ difficulty to distinguish between nitrile and latex gloves; latex gloves are now sold in different colors including blue, which has traditionally been associated with nitrile gloves. Even though spray painters were familiar with the health hazards related to working with isocyanate paints; most were not always aware that dermal exposure to isocyanates could contribute to the development of occupational asthma. There is a need for more research to identify dermal materials that are protective against sprayed automotive coatings. Automotive spray painters and their employers need to be educated in the selection and use of protective gloves, specifically on attributes such as glove material, color, and thickness. PMID:24215135

  12. Non-covalent interactions between thio-caffeine derivatives and water-soluble porphyrin in ethanol-water environment

    Science.gov (United States)

    Lipke, Agnieszka; Makarska-Bialokoz, Magdalena; Sierakowska, Arleta; Jasiewicz, Beata

    2018-03-01

    To determine the binding interactions and ability to form the non-covalent systems, the association process between 5,10,15,20-tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine tetra-p-tosylate (H2TTMePP) and a series of five structurally diverse thio-caffeine analogues has been studied in ethanol and ethanol-water solutions, analyzing its absorption and steady-state fluorescence spectra. The porphyrin fluorescence lifetimes in the systems studied were established as well. During the titration with thio-caffeine compounds the slight bathochromic effect and considerable hypochromicity of the porphyrin Soret band maximum can be noted. The fluorescence quenching effect observed for interactions in H2TTMePP - thio-caffeine derivative systems, as well as the order of binding and fluorescence quenching constants (of 105-103 mol- 1) suggest the existence of the mechanism of static quenching due to the formation of non-covalent and non-fluorescent stacking complexes. In all the systems studied the phenomenon of the fractional accessibility of the fluorophore for the quencher was observed as well. Additionally, the specific binding interactions, due to the changes in reaction environment polarity, can be observed. It was found that thio-caffeine compounds can quench the porphyrin fluorescence according to the structure of thio-substituent in caffeine molecule. The obtained results can be potentially useful from scientific, therapeutic or environmental points of view.

  13. γ-irradiation-induced mortality: protective effect of protease inhibitors in chickens and mice

    International Nuclear Information System (INIS)

    Palladino, M.A.; Galton, J.E.; Troll, W.; Thorbecke, G.J.

    1982-01-01

    Chickens (Gallus domesticus) were protected from the acute γ-irradiation-induced mortality (within 24 hours) by the proteolytic enzyme inhibitors, soy-bean trypsin inhibitor (SBTI), lima bean inhibitor (LBTI), antipain, α-N-benzoyl-L-arginine ethyl ester HCl (BAEE), trasylol, and leupeptin. Several other enzyme inhibitors, p-tosyl-L-arginine methyl ester HCl (TAME), α-tosyl-lysyl-chloromethyl ketone HCl (TLCK) and epsilon-amino caproic acid (EACA), did not protect. EACA even increased the mortality caused by γ-irradiation. The pattern of protective enzyme inhibitors suggests involvement of a kallikrein-like enzyme. SBTI and antipain also protected against low range lethal γ-irradiation exposures, 690 R in BALB/c and 880 R in SJL/J mice. It is suggested that enhanced vascular permeability, which in chickens is known to be the cause of the irradiation mortality during the first 24 hours, may also contribute to the mortality in mice during the first week after irradiation. (author)

  14. Synthesis and anti-HIV activity of novel N-1 side chain-modified analogs of 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (HEPT).

    Science.gov (United States)

    Pontikis, R; Benhida, R; Aubertin, A M; Grierson, D S; Monneret, C

    1997-06-06

    A series of 33 N-1 side chain-modified analogs of 1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine (1, HEPT) were synthesized and evaluated for their anti-HIV-1 activity. In particular, the influence of substitution of the terminal hydroxy group of the acyclic structure of HEPT and the structural rigidity of this side chain were investigated. Halo (7, 8), azido (9), and amino (10-15) derivatives were synthesized from HEPT via the p-tosylate derivative 6. Acylation of the primary amine 15 afforded the amido analogs 16-20. The diaryl derivatives 26-29 were prepared by reaction of HEPT, or of the 6-(2-pyridylthio) analog 23, with diaryl disulfides in the presence of tri-n-butylphosphine. Compounds 39-41, in which the N-1 side chain is rigidified by incorporation of an E-configured double bond, were obtained by palladium(0)-catalyzed coupling of several different 6-(arylthio)uracil derivatives (37, 38) with allyl acetates 33. Compounds 13, 40a,c,d,f, and 41, incorporating an aromatic ring at the end of the acyclic side chain, were found to be more potent than the known diphenyl-substituted HEPT analog BPT (2), two of them, 40c,d, being 10-fold more active.

  15. Fluorescence quenching behaviour of uric acid interacting with water-soluble cationic porphyrin

    International Nuclear Information System (INIS)

    Makarska-Bialokoz, Magdalena; Borowski, Piotr

    2015-01-01

    The process of association between 5,10,15,20-tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine tetra-p-tosylate (H 2 TTMePP) and uric acid as well as its sodium salt has been studied in aqueous NaOH solution analysing its absorption and steady-state fluorescence spectra. The fluorescence quenching effect observed during interactions porphyrin-uric acid compounds points at the fractional accessibility of the fluorophore for the quencher. The association and fluorescence quenching constants are of the order of magnitude of 10 5 mol −1 . The fluorescence lifetimes and the quantum yields of the porphyrin anionic form were established. The results demonstrate that uric acid and its sodium salt can interact with H 2 TTMePP at basic pH and through formation of stacking complexes are able to quench its ability to emission. - Highlights: • Association study of water soluble cationic porphyrin with uric acid. • Porphyrin absorption spectra undergo the bathochromic and hypochromic effects. • Uric acid interacts with porphyrin in inhibiting manner, quenching its emission. • Fluorescence quenching effect testifies for the partial inactivation of a porphyrin. • The association and fluorescence quenching constants were calculated

  16. Fluorescence quenching behaviour of uric acid interacting with water-soluble cationic porphyrin

    Energy Technology Data Exchange (ETDEWEB)

    Makarska-Bialokoz, Magdalena, E-mail: makarska@hektor.umcs.lublin.pl [Department of Inorganic Chemistry, Maria Curie-Sklodowska University M. C. Sklodowska Sq. 2, 20-031 Lublin (Poland); Borowski, Piotr [Faculty of Chemistry, Maria Curie-Sklodowska University M. C. Sklodowska Sq. 3, 20-031 Lublin (Poland)

    2015-04-15

    The process of association between 5,10,15,20-tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine tetra-p-tosylate (H{sub 2}TTMePP) and uric acid as well as its sodium salt has been studied in aqueous NaOH solution analysing its absorption and steady-state fluorescence spectra. The fluorescence quenching effect observed during interactions porphyrin-uric acid compounds points at the fractional accessibility of the fluorophore for the quencher. The association and fluorescence quenching constants are of the order of magnitude of 10{sup 5} mol{sup −1}. The fluorescence lifetimes and the quantum yields of the porphyrin anionic form were established. The results demonstrate that uric acid and its sodium salt can interact with H{sub 2}TTMePP at basic pH and through formation of stacking complexes are able to quench its ability to emission. - Highlights: • Association study of water soluble cationic porphyrin with uric acid. • Porphyrin absorption spectra undergo the bathochromic and hypochromic effects. • Uric acid interacts with porphyrin in inhibiting manner, quenching its emission. • Fluorescence quenching effect testifies for the partial inactivation of a porphyrin. • The association and fluorescence quenching constants were calculated.

  17. Elastase production by B16-F10 melanoma cells

    International Nuclear Information System (INIS)

    Shrager, J.B.; Yusa, T.; Netland, P.A.; Zetter, B.R.

    1986-01-01

    Elastolytic activity was found in sonicates of mouse B16-F10 melanoma cells and in medium conditioned by these cells. Degradation of elastin was determined by measuring the release of soluble 3 H-peptides from labelled insoluble elastin. The activity secreted from B16-F10 cells was soluble and was not associated with membrane vesicles. The secreted activity was partially inhibited by incubation with phenymethylsulfonylfluoride (PMSF) and was abolished by incubation with the alpha-1-protease inhibitor, with pepstatin A or with L-1-tosylamide-2-phenylethyl chloromethyl ketone (TPCK). In contrast, the activity was unaffected by incubation with elastatinal, with the plasmin inhibitor Σ-aminocaproic acid (EACA), the metalloproteinase inhibitor ethylenediamine-tetra-acetic acid (EDTA), the soybean trypsin inhibitor or the trypsin inhibitor N proportional to-p-tosyl-L-lysine chloromethyl ketone (TLCK). These results suggest that the majority of the tumor cell-derived elastolytic activity is attributable to a serine protease that differs in specificity from the well characterized elastases previously isolated from neutrophils, macrophages or from mammalian pancreas. The authors postulate that the release of elastase from lung-colonizing B16-F10 cells may facilitate their invasion of elastin-rich lung tissue

  18. Purification of a toxic metalloprotease produced by the pathogenic Photobacterium damselae subsp. piscicida isolated from cobia (Rachycentron canadum).

    Science.gov (United States)

    Liu, Ping-Chung; Chuang, Wen-Hsiao; Lee, Kuo-Kau

    2011-01-01

    The aim of the present study was to purify and characterize a toxic protease secreted by the pathogenic Photobacterium damselae subsp. piscicida strain CP1 originally isolated from diseased cobia (Rachycentron canadum). The toxin isolated by anion exchange chromatography, was a metalloprotease, inhibited by L-cysteine, ethylenediaminetetraacetic acid (EDTA), ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetraacetic acid (EGTA), 1,10-phenanthroline, N-tosyl-L-phenylalanine-chloromethyl ketone (TPCK), and N-alpha-p-tosyl-L-lysine-chloromethyl ketone (TLCK), and showed maximal activity at pH 6.0-8.0 and an apparent molecular mass of about 34.3 kDa. The toxin was also completely inhibited by HgCl2, and partially by sodium dodecyl sulfate (SDS) and CuCl2. The extracellular products and the partially purified protease were lethal to cobia with LD50 values of 1.26 and 6.8 microg protein/g body weight, respectively. The addition of EDTA completely inhibited the lethal toxicity of the purified protease, indicating that this metalloprotease was a lethal toxin produced by the bacterium.

  19. Trypsin from viscera of vermiculated sailfin catfish, Pterygoplichthys disjunctivus, Weber, 1991: its purification and characterization.

    Science.gov (United States)

    Villalba-Villalba, Ana Gloria; Ramírez-Suárez, Juan Carlos; Valenzuela-Soto, Elisa Miriam; Sánchez, Guillermina García; Ruiz, Gisela Carvallo; Pacheco-Aguilar, Ramón

    2013-11-15

    Pterygoplichthys disjunctivus viscera trypsin was purified by fractionation with ammonium sulphate, gel filtration, affinity and ion exchange chromatography (DEAE-Sepharose). Trypsin molecular weight was approximately 27.5kDa according to SDS-PAGE, shown a single band in zymography. It exhibited maximal activity at pH 9.5 and 40°C, using N-benzoyl-dl-arginine-p-nitroanilide (BAPNA) as substrate. Enzyme was effectively inhibited by phenyl methyl sulphonyl fluoride (PMSF) (100%), N-α-p-tosyl-l-lysine chloromethyl ketone (TLCK) (85.4%), benzamidine (80.2%), and soybean trypsin inhibitor (75.6%) and partially inhibited by N-tosyl-l-phenylalanine chloromethyl ketone (TPCK) (10.3%), ethylendiaminetetraacetic acid (EDTA) (8.7%) and pepstatin A (1.2%). Enzyme activity was slightly affected by metal ions (Fe(2+)>Hg(2+)>Mn(2+)>K(+)>Mg(2+)>Li(+)>Cu(2+)). Trypsin activity decreased continuously as NaCl concentration increased (0-30%). Km and kcat values were 0.13mM and 1.46s(-1), respectively. Results suggest the enzyme have a potential application where room processing temperatures (25-35°C) or high salt (30%) concentration are needed, such as in fish sauce production. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Evaluation of the neuronal apoptotic pathways involved in cytoskeletal disruption-induced apoptosis.

    Science.gov (United States)

    Jordà, Elvira G; Verdaguer, Ester; Jimenez, Andrés; Arriba, S Garcia de; Allgaier, Clemens; Pallàs, Mercè; Camins, Antoni

    2005-08-01

    The cytoskeleton is critical to neuronal functioning and survival. Cytoskeletal alterations are involved in several neurodegenerative diseases such as Alzheimer's and Parkinson's diseases. We studied the possible pathways involved in colchicine-induced apoptosis in cerebellar granule neurons (CGNs). Although colchicine evoked an increase in caspase-3, caspase-6 and caspase-9 activation, selective caspase inhibitors did not attenuate apoptosis. Inhibitors of other cysteine proteases such as PD150606 (a calpain-specific inhibitor), Z-Phe-Ala fluoromethyl ketone (a cathepsins-inhibitors) and N(alpha)-p-tosyl-l-lysine chloromethyl ketone (serine-proteases inhibitor) also had no effect on cell death/apoptosis induced by colchicine. However, BAPTA-AM 10 microM (intracellular calcium chelator) prevented apoptosis mediated by cytoskeletal alteration. These data indicate that calcium modulates colchicine-induced apoptosis in CGNs. PARP-1 inhibitors did not prevent apoptosis mediated by colchicine. Finally, colchicine-induced apoptosis in CGNs was attenuated by kenpaullone, a cdk5 inhibitor. Kenpaullone and indirubin also prevented cdk5/p25 activation mediated by colchicine. These findings indicate that cytoskeletal alteration can compromise cdk5 activation, regulating p25 formation and suggest that cdk5 inhibitors attenuate apoptosis mediated by cytoskeletal alteration. The present data indicate the potential therapeutic value of drugs that prevent the formation of p25 for the treatment of neurodegenerative disorders.

  1. Trypsin from the pyloric caeca of bluefish (Pomatomus saltatrix).

    Science.gov (United States)

    Klomklao, Sappasith; Benjakul, Soottawat; Visessanguan, Wonnop; Kishimura, Hideki; Simpson, Benjamin K

    2007-12-01

    Trypsin was purified from the pyloric caeca of bluefish (Pomatomus saltatrix) by ammonium sulfate precipitation, acetone precipitation and soybean trypsin inhibitor-Sepharose 4B affinity chromatography. Bluefish trypsin migrated as a single band using both sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and native-PAGE and had a molecular mass of 28 kDa. The optima pH and temperature for the hydrolysis of benzoyl-dl-arginine-p-nitroanilide (BAPNA) were 9.5 and 55 degrees C, respectively. The enzyme was stable over a broad pH range (7 to 12), but was unstable at acidic pH, and at temperatures greater than 40 degrees C. The enzyme was inhibited by specific trypsin inhibitors: soybean trypsin inhibitor (SBTI), N-p-tosyl-l-lysine chloromethyl ketone (TLCK) and the serine protease inhibitor phenylmethyl sulfonylfluoride (PMSF). CaCl2 partially protected trypsin against activity loss at 40 degrees C, but NaCl (0 to 30%) decreased the activity in a concentration dependent manner. The N-terminal amino acid sequence of trypsin was determined as IVGGYECKPKSAPVQVSLNL and was highly homologous to other known vertebrate trypsins.

  2. SYNTHESIS AND CHARACTERIZATION OF BIO-BASED POLYESTER POLYOL

    Directory of Open Access Journals (Sweden)

    MİTHAT ÇELEBİ

    2016-11-01

    Full Text Available Polyurethanes are versatile polymeric materials and are usually synthesised by isocyanate reactions with polyols. Due to the variety of isocyanates and polyols, particularly polyols, polyurethanes can be easily tailored for wide applications, such as rigid and flexible foams, coatings, adhesives, and elastomers. Considerable efforts have been recently devoted to developing bio-based substitutes for petroleum-based polyuretahanes due to increasing concerns over the depletion of petroleum resources, environment, and sustainability. Polyester polyols based on aliphatic and aromatic dicarboxylic acids are one of the most important materials in polymer technologies. Large volume of plants oils are used as renewable resources to produce various chemicals which are industrially important to make soaps, cosmetic products, surfactants, lubricants, diluents, plasticizers, inks, agrochemicals, composite materials, food industry. This study introduces synthesis and properties of bio-based polyols from different renewable feedstocks including vegetable oils and derivatives. A comparison of bio-based polyol properties with their petroleum-based analogues were investigated.

  3. SYNTHESIS AND CHARACTERIZATION OF NEW STABILIZERS WITH OPTIMAL MOLECULAR WEIGHT

    Institute of Scientific and Technical Information of China (English)

    Jiang-qing Pan

    2001-01-01

    Over 2 × l08 tons of polymers are produced every year, and a large portion of polymers faces the degradation problem. There are many effective methods to protect polymers against degradation and the addition of stabilizers to polymer remains the most convenient and effective way of enhancing polymer life and performance. In this article, a series of effective stabilizers with optimal molecular weight (MW), including common, monomeric and polymeric stabilizers (antioxidant and light stabilizer) were synthesized using isocyanation, controlled isocyanation, hydrosilylation, epoxide addition, macroreaction of stabilizing functional compounds and polymerization of monomeric stabilizers. The sructure and performance of these new stabilizers were characterized by using IR, NMR, MS, UV-spectra, XPS and elemental analysis. The current development of stabilizer synthesis was also reviewed.``

  4. Coal and biomass-based chemicals via carbonylation, hydroformylation and homologation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Sunavala, P.D.; Raghunath, B.

    The paper emphasizes the importance of carbonylation, hydroformylation and homologation reactions in the manufacture of organic chemicals (such as acetic acid, acetic anhydride, cellulose acetate, vinyl acetate monomer, aliphatic amines, isocyanates, methanol, ethanol, n-butanol, ethylene glycol, acrylic acid, etc.) from coal and biomass feedstocks. Topics covered are: synthesis of acetic acid; manufacture of acetic anhydride; synthesis of vinyl acetate monomer by carbonylation; synthesis of aliphatic amines by hydroformylation; synthesis of organic diisocyanates; ethanol synthesis by homologation of methanol; synthesis of ethylene glycol via hydroformylation of formaldehyde; synthesis of n- butanol and n-butyraldehyde by propylene formylation; synthesis of acrylic acid; homologation reaction of carboxylic acid esters with ruthenium catalysts; and synthesis of phenyl isocyanate from nitrobenzene by reductive carbonylation. 26 refs.

  5. Efficient Synthesis of Single-Chain Polymer Nanoparticles via Amide Formation

    Directory of Open Access Journals (Sweden)

    Ana Sanchez-Sanchez

    2015-01-01

    Full Text Available Single-chain technology (SCT allows the transformation of individual polymer chains to folded/collapsed unimolecular soft nanoparticles. In this work we contribute to the enlargement of the SCT toolbox by demonstrating the efficient synthesis of single-chain polymer nanoparticles (SCNPs via intrachain amide formation. In particular, we exploit cross-linking between active methylene groups and isocyanate moieties as powerful “click” chemistry driving force for SCNP construction. By employing poly(methyl methacrylate- (PMMA- based copolymers bearing β-ketoester units distributed randomly along the copolymer chains and bifunctional isocyanate cross-linkers, SCNPs were successfully synthesized at r.t. under appropriate reaction conditions. Characterization of the resulting SCNPs was carried out by means of a combination of techniques including size exclusion chromatography (SEC, infrared (IR spectroscopy, proton nuclear magnetic resonance (1H NMR spectroscopy, dynamic light scattering (DLS, and elemental analysis (EA.

  6. Protic Cationic Oligomeric Ionic Liquids of the Urethane Type

    DEFF Research Database (Denmark)

    Shevchenko, V. V.; Stryutsky, A. V.; Klymenko, N. S.

    2014-01-01

    Protic oligomeric cationic ionic liquids of the oligo(ether urethane) type are synthesized via the reaction of an isocyanate prepolymer based on oligo(oxy ethylene)glycol with M = 1000 with hexamethylene-diisocyanate followed by blocking of the terminal isocyanate groups with the use of amine...... derivatives of imidazole, pyridine, and 3-methylpyridine and neutralization of heterocycles with ethanesulfonic acid and p-toluenesulfonic acid. The structures and properties of the synthesized oligomeric ionic liquids substantially depend on the structures of the ionic groups. They are amorphous at room...... temperature, but ethanesulfonate imidazolium and pyridinium oligomeric ionic liquids form a low melting crystalline phase. The proton conductivities of the oligomeric ionic liquids are determined by the type of cation in the temperature range 80-120 degrees C under anhydrous conditions and vary within five...

  7. Solid radiation curable polyene compositions containing liquid polythiols and solid styrene-allyl copolymer based polyenes

    International Nuclear Information System (INIS)

    Morgan, C.R.

    1977-01-01

    Novel styrene-allyl alcohol copolymer based solid polyene compositions which when mixed with liquid polythiols can form solid curable polyene-polythiol systems are claimed. These solid polyenes, containing at least two reactive carbon-to-carbon unsaturated bonds, are urethane or ester derivatives of styrene-allyl alcohol copolymers. The solid polyenes are prepared by treating the hydroxyl groups of a styrene-allyl alcohol copolymer with a reactive unsaturated isocyanate, e.g., allyl isocyanate or a reactive unsaturated carboxylic acid, e.g., acrylic acid. Upon exposure to a free radical generator, e.g., actinic radiation, the solid polyene-polythiol compositions cure to solid, insoluble, chemically resistant, cross-linked polythioether products. Since the solid polyene-liquid polythiol composition can be cured in a solid state, such a curable system finds particular use in preparation of coatings, imaged surfaces such as photoresists, particularly solder-resistant photoresists, printing plates, etc

  8. SPECIFIC FEATURES OF OLIGOMERIC PRODUCT SOLIDIFICATION FROM POLYURETHANE WASTES AND THEIR PRACTICAL APPLICATION

    OpenAIRE

    V. Belyatsky; Yu. Kryvogus

    2012-01-01

    The paper considers a possibility to use secondary polyurethane obtained by  thermal depolymerization of wastes on the basis of cross-linked polyurethane (polyurethane adduct) and isocyanate. An effect of density dependence of the obtained polyurethane samples on nature and quantity of solvent has been revealed and it is significantly observed while using low-boiling solvents. The influence of adduct/solidification agent ratio on mechanical hardness of the obtained samples has been studied in...

  9. The development of polyurethane modified bitumen emulsions for cold mix applications

    OpenAIRE

    Carrera Páez, Virginia; Cuadri Vega, Antonio Abad; García Morales, Moisés; Partal López, Pedro

    2015-01-01

    Bitumen emulsions stand for an alternative paving practice to the traditional hot-mix asphalts. In addition, modified bitumen emulsions show a better performance than unmodified ones. This work studies the feasibility of obtaining polyurethane modified bitumen emulsions, in which an isocyanate-functionalized polyol constitutes the bitumen modifier (in varying concentration from 1 to 4 wt.%). Storage stability and high in-service performance are evaluated by means of evolution of droplet size ...

  10. Polyurethane foams obtained from residues of PET manufacturing and modified with carbon nanotubes

    International Nuclear Information System (INIS)

    Stiebra, L; Cabulis, U; Knite, M

    2016-01-01

    In this work we report the preparation of rigid microcellular polyurethane/carbon nanotube nanocomposites with different CNT loadings (0.09-0.46%) and various isocyanate indexes (110-260). Water was used as a blowing agent for samples. Density of all obtained samples – 200 ± 10 kg/m 3 . Electrical properties, as well as heat conductivity, cellular structure and mechanical properties of these nanocomposites were investigated. (paper)

  11. Reactive formulations for a neutralization of toxic industrial chemicals

    Science.gov (United States)

    Tucker, Mark D [Albuqueruqe, NM; Betty, Rita G [Rio Rancho, NM

    2006-10-24

    Decontamination formulations for neutralization of toxic industrial chemicals, and methods of making and using same. The formulations are effective for neutralizing malathion, hydrogen cyanide, sodium cyanide, butyl isocyanate, carbon disulfide, phosgene gas, capsaicin in commercial pepper spray, chlorine gas, anhydrous ammonia gas; and may be effective at neutralizing hydrogen sulfide, sulfur dioxide, formaldehyde, ethylene oxide, methyl bromide, boron trichloride, fluorine, tetraethyl pyrophosphate, phosphorous trichloride, arsine, and tungsten hexafluoride.

  12. Poly(Lactic Acid) Based Flexible Films

    OpenAIRE

    Fathilah binti Ali; Jamarosliza Jamaluddin; Arun Kumar Upadhyay

    2014-01-01

    Poly(lactic acid) (PLA) is a biodegradable polymer which has good mechanical properties, however, its brittleness limits its usage especially in packaging materials. Therefore, in this work, PLA based polyurethane films were prepared by synthesizing with different types of isocyanates; methylene diisocyanate (MDI) and hexamethylene diisocyanates (HDI). For this purpose, PLA based polyurethane must have good strength and flexibility. Therefore, polycaprolactone which has b...

  13. European Scientific Notes. Volume 37, Number 7.

    Science.gov (United States)

    1983-07-31

    glycol with isophorone heat given off by immobilized urease as isocyanate bridges. The same crosslink it encounters the substrate. Antigen system can...34Development of a A model with seven degrees of Solute Transport Model for a Multi- layer freedom has been developed for the Ground Water Basin." Many...insufficient device (Figure 1). The amplifier has activation efficiencies, while 900WC two gate "fingers" of 150 jm each and is anneals produce layer

  14. Free radical explosive composition

    Science.gov (United States)

    Walker, Franklin E.; Wasley, Richard J.

    1979-01-01

    An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1500 and 10,000 meters per second and a minor amount of a getter additive comprising a compound or mixture of compounds capable of capturing or deactivating free radicals or ions under mechanical or electrical shock conditions and which is not an explosive. Exemplary getter additives are isocyanates, olefins and iodine.

  15. Gamma-ray irradiation, autoclave and ethylene oxide sterilization to thermosetting polyurethane: sterilization to polyurethane

    International Nuclear Information System (INIS)

    Hirata, Noriko; Matsumoto, Ken-Ichi; Inishita, Takashi; Takenaka, Yoshinori; Suma, Yasunori; Shintani, Hideharu; National Inst. of Health Sciences, Tokyo

    1995-01-01

    Thermosetting polyurethane (PU) is widely used in a large variety of medical devices. 4,4'-methylenedianiline (MDA) was produced from PU by sterilization and it was studied for the relationship between urethane components or polymer characteristics and formation of MDA upon sterilization, using the commercially available dialyzers fabricated with different combination of isocyanate and polyol. We confirmed that the molecular-weight of polyol influenced the production of MDA upon sterilization. (author)

  16. Advanced Powder Coating Systems for Military Applications

    Science.gov (United States)

    2011-05-01

    UVCPC • Conclusions • DoD spends billions of dollars annually on protective organic coatings – Hexavalent chrome primer use still widespread – Contains...Elimination of Hazardous Air Pollutants (HAP) • Reduction/Elimination of ESOH Concerns – Elimination of hexavalent chromium – Elimination of free...production and release; hexavalent chromium; free isocyanates; up to 72 hrs “dry to fly” time Longer cure times than traditional primers and

  17. Polyurethane foams obtained from residues of PET manufacturing and modified with carbon nanotubes

    Science.gov (United States)

    Stiebra, L.; Cabulis, U.; Knite, M.

    2016-04-01

    In this work we report the preparation of rigid microcellular polyurethane/carbon nanotube nanocomposites with different CNT loadings (0.09-0.46%) and various isocyanate indexes (110-260). Water was used as a blowing agent for samples. Density of all obtained samples - 200 ± 10 kg/m3. Electrical properties, as well as heat conductivity, cellular structure and mechanical properties of these nanocomposites were investigated.

  18. New Drugs for CML

    Science.gov (United States)

    2007-02-01

    to a fulminant acute leukemic disorder in which patients die of bleeding and infection (1). Allogeneic bone marrow transplantation was the first...acetylenes were created in one step by the coupling of a propiolate anion and isocyanate. These acetylenes were then used as a precursor in the synthesis of...the furans. The furan synthesis was based on early research in the Austin laboratory, which was centered on the concept of adapting the 1,3-dipolar

  19. Fluorous Parallel Synthesis of A Hydantoin/Thiohydantoin Library

    OpenAIRE

    Lu, Yimin; Zhang, Wei

    2005-01-01

    Fluorous tagging strategy is applied to solution-phase parallel synthesis of a library containing hydantoin and thiohydantoin analogs. Two perfluoroalkyl (Rf)-tagged α-amino esters each react with 6 aromatic aldehydes under reductive amination conditions. Twelve amino esters then each react with 10 isocyanates and isothiocyanates in parallel. The resulting 120 ureas and thioureas undergo spontaneous cyclization to form the corresponding hydantoins and thiohydantoins. The intermediate and fina...

  20. Hybrid Ultra-Low VOC and Non-HAP Rain Erosion Coatings

    Science.gov (United States)

    2018-01-12

    provide excellent rain erosion resistance, superior mechanical properties, good adhesion to the substrate and meet a host of other metrics outlined in MIL... common urethane and/or epoxy topcoat systems based on their high impact energy and erosive nature. Specialty formulations are thus required to...in films having excellent performance properties. The most common high performance two-component coatings are epoxy systems and isocyanate based

  1. Toxic Industrial Chemicals: A Future Weapons of Mass Destruction Threat

    Science.gov (United States)

    2002-05-31

    1937 by Dr. Gerhard Schrader, a chemist conducting insecticide research with organophosphates (Stockholm International Peace Research Institute 1971...International Peace Research Institute 1971 and 1973). Phosgene oxime is known as “ nettle gas,” so named because of its property of intensely irritating...as a WMD. Common TICs Effects of CW Agents Organophosphate Insecticide Nerve Dimethyl Sulfate Blister Methyl Isocyanate Blood Anhydrous Ammonia

  2. Aliphatic isocyanurates and polyisocyanurate networks

    OpenAIRE

    Driest, P. J.; Lenzi, V.; Marques, L.; Ramos, M. M. D.; Dijkstra, D. J.; Richter, F. U.; Stamatialis, D.; Grijpma, D. W.

    2017-01-01

    The production, processing, and application of aliphatic isocyanate (NCO)-based thermosets such as polyurethane coatings and adhesives are generally limited by the surprisingly high viscosity of tri-functionality and higher-functionality isocyanurates. These compounds are essential crosslinking additives for network formation. However, the mechanism by which these high viscosities are caused is not yet understood. In this work, model aliphatic isocyanurates were synthesized and isolated in hi...

  3. MALDI-TOF and 13C NMR Analysis of Tannin–Furanic–Polyurethane Foams Adapted for Industrial Continuous Lines Application

    Directory of Open Access Journals (Sweden)

    Maria Cecilia Basso

    2014-12-01

    Full Text Available Mixed phenolic-polyurethane-type rigid foams were developed using tannin-furfuryl alcohol natural materials co-reacted with polymeric isocyanate in the proportions imposed by the limitations inherent to continuous industrial plants for polyurethane foams. A variety of different copolymerization oligomers formed. Urethanes appeared to have been formed with two flavonoid tannin sites, mainly at the flavonoid hydroxyl group at C3, but also, although less, on the phenolic hydroxyl groups of the flavonoid oligomers. Urethanes are also formed with (i glyoxal in the formulation, be it pre-reacted or not with the tannin; (ii with phenolsulfonic acid and (iii with furfural. This latter one, however, greatly favors reaction with the A-ring of the flavonoids through a methylene bridge rather than reaction with the isocyanate groups to form urethanes. All of the materials appeared to have co-reacted in a manner to form urethane and methylene bridges between all of the main components used. Thus, the tannin, the furfuryl alcohol, the isocyanate, the glyoxal and even the phenol sulfonic acid hardener formed a number of mixed species linked by the two bridge types. Several mixed species comprised of 2, 3 and even 4 co-reacted different components have been observed.

  4. Chemically modified cellulose paper as a thin film microextraction phase.

    Science.gov (United States)

    Saraji, Mohammad; Farajmand, Bahman

    2013-11-01

    In this paper, chemically modified cellulose paper was introduced as a novel extracting phase for thin film microextraction (TFME). Different reagents (Octadecyltrichlorosilane, diphenyldichlorosilane, cyclohexyl isocyanate and phenyl isocyanate) were used to modify the cellulose papers. The modified papers were evaluated as a sorbent for the extraction of some synthetic and natural estrogenic hormones (17α-ethynylestradiol, estriol and estradiol) from aqueous samples. Liquid chromatography-fluorescence detection was used for the quantification of the extracted compounds. The cellulose paper modified with phenyl isocyanate showed the best affinity to the target compounds. TEME parameters such as desorption condition, shaking rate, sample ionic strength and extraction time were investigated and optimized. Limit of detections were between 0.05 and 0.23μgL(-1) and relative standard deviations were less than 11.1% under the optimized condition. The calibration curves were obtained in the range of 0.2-100μgL(-1) with a good linearity (r(2)>0.9935). Wastewater, human urine, pool and river water samples were studied as real samples for the evaluation of the method. Relative recoveries were found to be between 75% and 101%. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Site-Selective Modification of Cellulose Nanocrystals with Isophorone Diisocyanate and Formation of Polyurethane-CNC Composites.

    Science.gov (United States)

    Girouard, Natalie M; Xu, Shanhong; Schueneman, Gregory T; Shofner, Meisha L; Meredith, J Carson

    2016-01-20

    The unequal reactivity of the two isocyanate groups in an isophorone diisocyante (IPDI) monomer was exploited to yield modified cellulose nanocrystals (CNCs) with both urethane and isocyanate functionality. The chemical functionality of the modified CNCs was verified with ATR-FTIR analysis and elemental analysis. The selectivity for the secondary isocyanate group using dibutyl tin dilaurate (DBTDL) as the reaction catalyst was confirmed with (13)C NMR. The modified CNCs showed improvements in the onset of thermal degradation by 35 °C compared to the unmodified CNCs. Polyurethane composites based on IPDI and a trifunctional polyether alcohol were synthesized using unmodified (um-CNC) and modified CNCs (m-CNC). The degree of nanoparticle dispersion was qualitatively assessed with polarized optical microscopy. It was found that the modification step facilitated superior nanoparticle dispersion compared to the um-CNCs, which resulted in increases in the tensile strength and work of fracture of over 200% compared to the neat matrix without degradation of elongation at break.

  6. New method to measure the carbamoylating activity of nitrosoureas by electron paramagnetic resonance spectroscopy.

    Science.gov (United States)

    Gadzheva, V; Ichimori, K; Raikov, Z; Nakazawa, H

    1997-08-01

    A new method for measuring the carbamoylating activity of nitrosoureas and isocyanates using electron paramagnetic resonance (EPR) spectroscopy is described. The extent and time course of carbamoylation reaction of chloroethyl isocyanate and a series of 9 nitrosoureas toward amino group of 4-amino-2,2,6,6-tetramethyl-piperidine-1-oxyl were examined with both the EPR method and the HPLC method which has been proposed by Brubaker et al. [Biochem. Pharmacol. 35:2359 (1986)]. Spin-labeled nitrosoureas we synthesized are included in this study since they have less toxicity or more efficiency than commercially available drug in some cases. The concentration of carbamoylated product was easily determined with the EPR spectra. There is a very high correlation (r = 0.982, t = 2.58, N = 10, p nitrosoureas showed lower carbamoylating activity than non-labeled analogues. The carbamoylating activity for these nitrosourea depended on the reactivity of isocyanate intermediate and almost independent of their half life. This rapid and simple EPR method is suitable for the detailed investigation of the rate and extent of carbamoylation reaction.

  7. The role of nanocrystalline cellulose on the microstructure of foamed castor-oil polyurethane nanocomposites.

    Science.gov (United States)

    Cordero, Andrés Ignacio; Amalvy, Javier Ignacio; Fortunati, Elena; Kenny, José María; Chiacchiarelli, Leonel Matías

    2015-12-10

    Nanocrystalline cellulose (CNC), obtained by sulphuric acid hydrolysis, was used to synthesize polyurethane foams (PUFs) based on a functionalized castor oil polyol and a Methylene diphenyl diisocyanate (MDI). Formulations with varying isocyanate index (FI) and NCO number were prepared. At 0.5 wt.%, SEM's of the fractured surface underlined that the CNC acted both as a nucleation agent and as a particulate surfactant with cell geometries and apparent density changing selectively. The chemical structure of the PUF (FTIR) changed after the incorporation of CNC by a relative change of the amount of urea, urethane and isocyanurate groups. A low NCO number and isocyanate index contributed to the migration of the CNC to the Hard Segment (HS), acting as reinforcement and improving substantially the compressive mechanical properties (Ec and σc improvements of 63 and 50%, respectively). For a high NCO number or isocyanate index, the CNC migrated to the Soft Segment (SS), without causing a reinforcement effect. The migration of the CNC was also detected with DSC, TGA and DMA, furtherly supporting the hypothesis that a low NCO number and index contributed both to the formation of a microstructure with a higher content of urethane groups. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Specific cell components of Bacteroides gingivalis mediate binding and degradation of human fibrinogen

    International Nuclear Information System (INIS)

    Lantz, M.S.; Allen, R.D.; Vail, T.A.; Switalski, L.M.; Hook, M.

    1991-01-01

    Bacteroides (Porphyromonas) gingivalis, which has been implicated as an etiologic agent in human periodontal diseases, has been shown to bind and degrade human fibrinogen. B. gingivalis strains bind fibrinogen reversibly and with high affinity and bind to a specific region of the fibrinogen molecule that appears to be located between the D and E domains. The authors now report that human fibrinogen is bound and then degraded by specific B. gingivalis components that appear to be localized at the cell surface. Fibrinogen binding to bacterial cells occurred at 4, 22, and 37 degree C. A functional fibrinogen-binding component (M r , 150 000) was identified when sodium dodecyl sulfate-solubilized bacteria were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose membranes, and probed with 125 I-fibrinogen. Fibrinogen degradation did not occur at 4 degree C but did occur at 22 and 37 degree C. When bacteria and iodinated fibrinogen were incubated at 37 degree C, two major fibrinogen fragments (M r , 97 000 and 50 000) accumulated in incubation mixture supernatant fractions. Two major fibrinogen-degrading components (M r , 120 000 and 150 000) have been identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in substrate-containing gels. Fibrinogen degradation by the M r -120 000 and -150 000 proteases was enhanced by reducing agents, completely inhibited by N-α-p-tosyl-L-lysyl chloromethyl ketone, and partially inhibited by n-ethyl maleimide, suggesting that these enzymes are thiol-dependent proteases with trypsinlike substrate specificity. The fibrinogen-binding component could be separated from the fibrinogen-degrading components by selective solubilization of bacteria in sodium deoxycholate

  9. Specific cell components of Bacteroides gingivalis mediate binding and degradation of human fibrinogen

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, M.S.; Allen, R.D.; Vail, T.A.; Switalski, L.M.; Hook, M. (Univ. of Alabama at Birmingham (USA))

    1991-01-01

    Bacteroides (Porphyromonas) gingivalis, which has been implicated as an etiologic agent in human periodontal diseases, has been shown to bind and degrade human fibrinogen. B. gingivalis strains bind fibrinogen reversibly and with high affinity and bind to a specific region of the fibrinogen molecule that appears to be located between the D and E domains. The authors now report that human fibrinogen is bound and then degraded by specific B. gingivalis components that appear to be localized at the cell surface. Fibrinogen binding to bacterial cells occurred at 4, 22, and 37{degree}C. A functional fibrinogen-binding component (M{sub r}, 150 000) was identified when sodium dodecyl sulfate-solubilized bacteria were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose membranes, and probed with {sup 125}I-fibrinogen. Fibrinogen degradation did not occur at 4{degree}C but did occur at 22 and 37{degree}C. When bacteria and iodinated fibrinogen were incubated at 37{degree}C, two major fibrinogen fragments (M{sub r}, 97 000 and 50 000) accumulated in incubation mixture supernatant fractions. Two major fibrinogen-degrading components (M{sub r}, 120 000 and 150 000) have been identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in substrate-containing gels. Fibrinogen degradation by the M{sub r}-120 000 and -150 000 proteases was enhanced by reducing agents, completely inhibited by N-{alpha}-p-tosyl-L-lysyl chloromethyl ketone, and partially inhibited by n-ethyl maleimide, suggesting that these enzymes are thiol-dependent proteases with trypsinlike substrate specificity. The fibrinogen-binding component could be separated from the fibrinogen-degrading components by selective solubilization of bacteria in sodium deoxycholate.

  10. Trypsin from unicorn leatherjacket (Aluterus monoceros) pyloric caeca: purification and its use for preparation of fish protein hydrolysate with antioxidative activity.

    Science.gov (United States)

    Zamani, Abbas; Benjakul, Soottawat

    2016-02-01

    Fish proteases, especially trypsin, could be used to prepare fish protein hydrolysates with antioxidative activities. In this study, trypsin from the pyloric caeca of unicorn leatherjacket was purified by ammonium sulfate precipitation and soybean trypsin inhibitor (SBTI)-Sepharose 4B affinity chromatography. Hydrolysate from Indian mackerel protein isolate with different degrees of hydrolysis (20, 30 and 40% DH) was prepared using the purified trypsin, and antioxidative activities (1,1-diphenyl-2-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical-scavenging activities, ferric-reducing antioxidant power and ferrous-chelating activity) of the hydrolysate were determined. Trypsin was purified 26.43-fold with a yield of 13.43%. The purified trypsin had a molecular weight (MW) of 23.5 kDa and optimal activity at pH 8.0 and 55 °C. It displayed high stability in the pH range of 6.0-11.0 and was thermally stable up to 50 °C. Both SBTI (0.05 mmol L(-1)) and N-p-tosyl-L-lysine-chloromethylketone (5 mmol L(-1)) completely inhibited trypsin activity. Antioxidative activities of the hydrolysate from Indian mackerel protein isolate increased with increasing DH up to 40% (P unicorn leatherjacket pyloric caeca was identified as trypsin based on its ability to hydrolyze a specific synthetic substrate and the response to specific trypsin inhibitors. The purified trypsin could hydrolyze Indian mackerel protein isolate, and the resulting hydrolysate exhibited antioxidative activity depending on its DH. © 2015 Society of Chemical Industry.

  11. Properties Of A Midgut Trypanolysin From The Tsetse Fly Glossina Morsitans Morsitans

    Directory of Open Access Journals (Sweden)

    Mahamat H.Abakar

    2015-08-01

    Full Text Available The properties of a bloodmeal-induced trypanolysin from the midgut of the tsetse G. m. morsitans was studied in vitro. The semi-purified trypanolysin from twice-fed tsetse had the highest trypanolysin activity against bloodstream trypanosomes followed by those once-fed and the unfed flies. Serum found to display trypanolysin activity. The trypanolysin had no trypsin activity nor even affected by the enzyme. In addition trypanolysin was not affected by protease inhibitors such as soy bean trypsin inhibitor STI N-a-p-Tosyl-L-lysine chromethyl ketone TLCK phenylmethyl sulphonyl fluoride PMSF diisopropyl fluoro-phosphate DFP and tosylamide-2-phenylethyl chloromethyl ketone TPCK. However the activity was completely inhibited by diethyl pyrocarbonate DEPC and partially by aprotinin. The induction of trypanolysin activity by bloodmeal increased gradually reaching a peak at 72-120 h after the bloodmeal and then decreased rapidly with only 25 of the peak activity remaining after 192 h. The trypanolysin was inactivated during storage at 27amp8451 and 4amp8451 after 15 and 32 days respectively. Similarly heating the midguts trypanolysin to 60 - 80amp8451 led to loss of activity. On the other hand 50amp8451 was found to be the optimum temperature for trypanolysin activity. The activity was also unstable by freeze-thaw at 80amp8451 -70amp8451 -20amp8451 and 0amp8451 after 33 41 55 and 63 days respectively. Trypanolysin caused lyses of bloodstream-form T. b. brucei while the procyclic trypanosomes were unaffected. The highest trypanolysin activity in different tsetse species was found with Glossina longipennis followed by Glossina pallidipes Glossina morsitans centralis Glossina fuscipes fuscipes and G. m. morsitans. When the midgut homogenate was separated by anion-exchange chromatography the trypanolysin activity was recovered in the bound fraction. These results suggest that the midgut trypanolysin plays an important role in the establishment of

  12. Identification of a trypsin-like site associated with acetylcholinesterase by affinity labelling with (/sup 3/H)diisopropyl fluorophosphate

    Energy Technology Data Exchange (ETDEWEB)

    Small, D.H.; Chubb, I.W.

    1988-07-01

    In addition to its ability to hydrolyze acetylcholine, purified eel acetylcholinesterase possesses a trypsin-like endopeptidase activity. The tryptic activity is associated with a serine residue at a site that is distinct from the esteratic site. To label both the esteratic and tryptic sites, the enzyme was incubated with the serine hydrolase inhibitor (/sup 3/H)diisopropyl fluorophosphate. This compound labelled the protein in a biphasic manner, with both slow and rapid labelling kinetics. The time course of the rapid phase was similar to the time course of inactivation of the esteratic activity. The time course of the slow phase was similar to the time course of inactivation of the tryptic activity. Labelling of the nonesteratic site was inhibited by the trypsin inhibitor N alpha-p-tosyl-L-lysine chloromethyl ketone. The total number of sites labelled by (/sup 3/H)diisopropyl fluorophosphate on eel acetylcholinesterase was 2.6 mol/280,000 g protein, whereas the number of tryptic sites was less (0.52 mol/280,000 g). The results suggest that a subpopulation of acetylcholinesterase molecules may possess tryptic activity. Extensive chromatography of the purified enzyme by ion-exchange and gel filtration failed to separate the labelled tryptic component from acetylcholinesterase. On sodium dodecyl sulfate-polyacrylamide gels, the labelled tryptic component comigrated with a polypeptide of 50,000 molecular weight, which is a major proteolytic digestion product derived from the intact acetylcholinesterase monomer. Because of its localization in many noncholinergic peptide-containing cells, acetylcholinesterase could act as a neuropeptide processing enzyme in these cells.

  13. Gene expression profiling in mouse lung following polymeric hexamethylene diisocyanate exposure

    International Nuclear Information System (INIS)

    Lee, C.-T.; Ylostalo, Joni; Friedman, Mitchell; Hoyle, Gary W.

    2005-01-01

    Isocyanates are a common cause of occupational lung disease. Hexamethylene diisocyanate (HDI), a component of polyurethane spray paints, can induce respiratory symptoms, inflammation, lung function impairment, and isocyanate asthma. The predominant form of HDI in polyurethane paints is a nonvolatile polyisocyanate known as HDI biuret trimer (HDI-BT). Exposure of mice to aerosolized HDI-BT results in pathological effects, including pulmonary edema, lung inflammation, cellular proliferation, and fibrotic lesions, which occur with distinct time courses following exposure. To identify genes that mediate lung pathology in the distinct temporal phases after exposure, gene expression profiles in HDI-BT-exposed C57BL/6J mouse lungs were analyzed. RNase protection assay (RPA) of genes involved in apoptosis, cell survival, and inflammation revealed increased expression of IκBα, Fas, Bcl-X L , TNFα, KC, MIP-2, IL-6, and GM-CSF following HDI-BT exposure. Microarray analysis of approximately 10 000 genes was performed on lung RNA collected from mice 6, 18, and 90 h after HDI-BT exposure and from unexposed mice. Classes of genes whose expression was increased 6 h after exposure included those involved in stress responses (particularly oxidative stress and thiol redox balance), growth arrest, apoptosis, signal transduction, and inflammation. Types of genes whose expression was increased at 18 h included proteinases, anti-proteinases, cytoskeletal molecules, and inflammatory mediators. Transcripts increased at 90 h included extracellular matrix components, transcription factors, inflammatory mediators, and cell cycle regulators. This characterization of the gene expression profile in lungs exposed to HDI-BT will provide a basis for investigating injury and repair pathways that are operative during isocyanate-induced lung disease

  14. Physical and mechanical properties of parallel strand lumber made from hot pre-pressed long strand oil palm trunk waste

    Science.gov (United States)

    Fridiyanti, Inayah; Massijaya, M. Y.

    2018-03-01

    This research was focused on the utilization of oil palm trunk waste as a Parallel Strand Lumber (PSL) raw material. This research aimed to analyze the effect of adhesive types and glue spreads to the physical and mechanical properties of PSL. The adhesive types used were isocyanate and urea formaldehyde adhesives. The glue spreads used were 150 g/m2 and 300 g/m2. The research results showed that the moisture content of PSL ranged from 9.30% to 11.80%. The PSL density ranged from 0.64 to 0.78 g/cm3. The volume shrinkage ranged from 5.69 to 7.17%. Modulus of Elasticity (MOE) parallel to the grain and edge side ranged from 51.6 × 103 to 98.3 × 103 kg/cm2, and 62.1 × 103 to 99.9 × 103 kg/cm2, respectively. The Modulus of Rupture (MOR) parallel to the grain and edge side ranged from 269 to 724 kg/cm2 and 342 to 728 kg/cm2, respectively. The PSL hardness perpendicular to the grain, parallel to the grain and the edge side ranged from 135 to 300 kg/cm2, 87 to 321 kg/cm2, and 128 to 251 kg/cm2, respectively. The compressive strength ranged from 181 to 231 kg/cm2. The best adhesive and glue spreads of PSL was isocyanate with glue spread 300 g/m2. PSL made from hot pre-pressed long strand of oil palm trunk waste bonded by isocyanate fulfill JAS 1152: 2007. However, those of bonded by urea formaldehyde failed to fulfill the standard. The physical and mechanical properties of PSL made from oil palm trunk were better compared to those of solid oil palm trunk.

  15. Biomimetic PDMS-hydroxyurethane terminated with catecholic moieties for chemical grafting on transition metal oxide-based surfaces

    Science.gov (United States)

    de Aguiar, Kelen R.; Rischka, Klaus; Gätjen, Linda; Noeske, Paul-Ludwig Michael; Cavalcanti, Welchy Leite; Rodrigues-Filho, Ubirajara P.

    2018-01-01

    The aim of this work was to synthesize a non-isocyanate poly(dimethylsiloxane) hydroxyurethane with biomimetic terminal catechol moieties, as a candidate for inorganic and metallic surface modification. Such surface modifier is capable to strongly attach onto metallic and inorganic substrates forming layers and, in addition, providing water-repellent surfaces. The non-isocyanate route is based on carbon dioxide cycloaddition into bis-epoxide, resulting in a precursor bis(cyclic carbonate)-polydimethylsiloxane (CCPDMS), thus fully replacing isocyanate in the manufacture process. A biomimetic approach was chosen with the molecular composition being inspired by terminal peptides present in adhesive proteins of mussels, like Mefp (Mytilus edulis foot protein), which bear catechol moieties and are strong adhesives even under natural and saline water. The catechol terminal groups were grafted by aminolysis reaction into a polydimethylsiloxane backbone. The product, PDMSUr-Dopamine, presented high affinity towards inhomogeneous alloy surfaces terminated by native oxide layers as demonstrated by quartz crystal microbalance (QCM-D), as well as stability against desorption by rinsing with ethanol. As revealed by QCM-D, X-ray photoelectron spectroscopy (XPS) and computational studies, the thickness and composition of the resulting nanolayers indicated an attachment of PDMSUr-Dopamine molecules to the substrate through both terminal catechol groups, with the adsorbate exposing the hydrophobic PDMS backbone. This hypothesis was investigated by classical molecular dynamic simulation (MD) of pure PDMSUr-Dopamine molecules on SiO2 surfaces. The computationally obtained PDMSUr-Dopamine assembly is in agreement with the conclusions from the experiments regarding the conformation of PDMSUr-Dopamine towards the surface. The tendency of the terminal catechol groups to approach the surface is in agreement with proposed model for the attachment PDMSUr-Dopamine. Remarkably, the versatile

  16. Experimental and theoretical understanding of the gas phase oxidation of atmospheric amides with OH radicals: kinetics, products, and mechanisms.

    Science.gov (United States)

    Borduas, Nadine; da Silva, Gabriel; Murphy, Jennifer G; Abbatt, Jonathan P D

    2015-05-14

    Atmospheric amides have primary and secondary sources and are present in ambient air at low pptv levels. To better assess the fate of amides in the atmosphere, the room temperature (298 ± 3 K) rate coefficients of five different amides with OH radicals were determined in a 1 m(3) smog chamber using online proton-transfer-reaction mass spectrometry (PTR-MS). Formamide, the simplest amide, has a rate coefficient of (4.44 ± 0.46) × 10(-12) cm(3) molec(-1) s(-1) against OH, translating to an atmospheric lifetime of ∼1 day. N-methylformamide, N-methylacetamide and propanamide, alkyl versions of formamide, have rate coefficients of (10.1 ± 0.6) × 10(-12), (5.42 ± 0.19) × 10(-12), and (1.78 ± 0.43) × 10(-12) cm(3) molec(-1) s(-1), respectively. Acetamide was also investigated, but due to its slow oxidation kinetics, we report a range of (0.4-1.1) × 10(-12) cm(3) molec(-1) s(-1) for its rate coefficient with OH radicals. Oxidation products were monitored and quantified and their time traces were fitted using a simple kinetic box model. To further probe the mechanism, ab initio calculations are used to identify the initial radical products of the amide reactions with OH. Our results indicate that N-H abstractions are negligible in all cases, in contrast to what is predicted by structure-activity relationships. Instead, the reactions proceed via C-H abstraction from alkyl groups and from formyl C(O)-H bonds when available. The latter process leads to radicals that can readily react with O2 to form isocyanates, explaining the detection of toxic compounds such as isocyanic acid (HNCO) and methyl isocyanate (CH3NCO). These contaminants of significant interest are primary oxidation products in the photochemical oxidation of formamide and N-methylformamide, respectively.

  17. Development of a fast curing tissue adhesive for meniscus tear repair.

    Science.gov (United States)

    Bochyńska, Agnieszka Izabela; Hannink, Gerjon; Janssen, Dennis; Buma, Pieter; Grijpma, Dirk W

    2017-01-01

    Isocyanate-terminated adhesive amphiphilic block copolymers are attractive materials to treat meniscus tears due to their tuneable mechanical properties and good adhesive characteristics. However, a drawback of this class of materials is their relatively long curing time. In this study, we evaluate the use of an amine cross-linker and addition of catalysts as two strategies to accelerate the curing rates of a recently developed biodegradable reactive isocyanate-terminated hyper-branched adhesive block copolymer prepared from polyethylene glycol (PEG), trimethylene carbonate, citric acid and hexamethylene diisocyanate. The curing kinetics of the hyper-branched adhesive alone and in combination with different concentrations of spermidine solutions, and after addition of 2,2-dimorpholinodiethylether (DMDEE) or 1,4-diazabicyclo [2.2.2] octane (DABCO) were determined using FTIR. Additionally, lap-shear adhesion tests using all compositions at various time points were performed. The two most promising compositions of the fast curing adhesives were evaluated in a meniscus bucket handle lesion model and their performance was compared with that of fibrin glue. The results showed that addition of both spermidine and catalysts to the adhesive copolymer can accelerate the curing rate and that firm adhesion can already be achieved after 2 h. The adhesive strength to meniscus tissue of 3.2-3.7 N was considerably higher for the newly developed compositions than for fibrin glue (0.3 N). The proposed combination of an adhesive component and a cross-linking component or catalyst is a promising way to accelerate curing rates of isocyanate-terminated tissue adhesives.

  18. Coating compositions hardenable by ionization beams

    International Nuclear Information System (INIS)

    Chaudhari, D.; Haering, E.; Dobbelstein, A.; Hoselmann, W.

    1976-01-01

    Coating compositions hardenable by ionizing radiation are described which contain as binding agents a mixture of at least 1 unsaturated olefin compound containing urethane groups, and at least 1 further unsaturated olefin compound that may be copolymerized. The unsaturated olefin compound containing the urethane groups is a reaction product of a compound containing carboxylic acid groups and a compound containing at least 1 isocyanate group where the mixture of the two olefins may contain conventional additives of the lacquer industry. 6 claims, no drawings

  19. Second harmonic generation and photochromic grating in polyurethane films containing diazo isoxazole chromophore

    Science.gov (United States)

    Marański, Krzysztof; Kucharski, Stanisław; Ortyl, Ewelina; Nunzi, Jean-Michel; Ahmadi-Kandjani, Sohrab; Dabos-Seignon, Sylvie; Chan, Siu-Wai; Barille, Regis

    2008-08-01

    The chromophoric intermediate: 2,2'-({4-[( E)-(5-methylisoxazol-3-yl)diazenyl]phenyl}-imino)diethanol was used in polyaddition reaction with di-isocyanate to obtain a new polyurethane polymeric material showing nonlinear optical and photochromic properties. The maximum absorption band of the polymer film was at 418 nm. The illumination of the film with crossed beams of the 488 nm Ar + laser yielded surface relief grating of regular structure. Measurement of the frequency doubling signal with 1064 nm laser indicated the polymer as interesting material for photooptical applications. The measured nonlinear optical coefficient, d33, reached 90.2 pm/V.

  20. Polyurethane Foams with Pyrimidine Rings

    Directory of Open Access Journals (Sweden)

    Kania Ewelina

    2014-09-01

    Full Text Available Oligoetherols based on pyrimidine ring were obtained upon reaction of barbituric acid with glycidol and alkylene carbonates. These oligoetherols were then used to obtain polyurethane foams in the reaction of oligoetherols with isocyanates and water. The protocol of foam synthesis was optimized by the choice of proper kind of oligoetherol and synthetic composition. The thermal resistance was studied by dynamic and static methods with concomitant monitoring of compressive strength. The polyurethane foams have similar physical properties as the classic ones except their enhanced thermal resistance. They stand long-time heating even at 200°C. Moreover thermal exposition of foams results generally in increase of their compressive strength.

  1. Photochemical Ring-Opening Reaction in 2(1H)-Pyrimidinones: A Matrix Isolation Study

    OpenAIRE

    Lapinski, Leszek; Rostkowska, Hanna; Khvorostov, Artem; Fausto, Rui; Nowak, Maciej J.

    2003-01-01

    Photoreactions induced by UV-B (290−320 nm) irradiation were studied for 1-methyl-2(1H)-pyrimidinone and 1-methylcytosine monomers isolated in low-temperature inert gas matrixes. A Norrish type I α-cleavage reaction leading to open-ring conjugated isocyanate was observed for 1-methyl-2(1H)-pyrimidinone. The structure of the photoproduct was identified by comparison of its experimental IR spectrum with the spectrum theoretically calculated at the DFT(B3LYP)/6-31++G(d,p) level. The main indicat...

  2. Castor oil polyurethane as a coating option for spent nuclear fuel disposal containment

    Energy Technology Data Exchange (ETDEWEB)

    Mortley, A.; Bonin, H.W.; Bui, V.T. [Dept. of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, Ontario (Canada)

    2009-07-01

    Castor oil polyurethane (COPU) coatings are being proposed as an additional barrier in the design of the copper containers to store spent nuclear fuel in Canada. The present work investigates the variation in the physicomechanical properties of two COPUs, based on an aliphatic and aromatic diisocyanate, as a function of ionizing radiation dose and dose rate. The changes in physicomechanical properties have shown that radiation, regardless of dose rate and isocyanate structure, increases the values of the modulus and the ultimate tensile strength when compared with those of the unirradiated samples, with aromatic based polyurethanes being more susceptible to variation than aliphatic based ones. (author)

  3. EB curable laminating adhesives

    International Nuclear Information System (INIS)

    Matsuyama, Asao; Kobayashi, Masahide; Gotoh, Sakiko

    1992-01-01

    New developed solvent free EB curable laminating adhesives have two liquid components, A with hydroxy and acryloyl group, B with isocyanate and acryloyl group in a molecule. These EB laminating adhesives do not need any aging process, which is a big advantage, and are very suitable for environment, safety, and health because of no heating process and solvent free formulas. And we have made basic research about the relation of peel strength or heat seal strength versus Tg of cured film, elongation at break, elastic modulus, and so on. Basic specifications of the new developed adhesives are shown. (author)

  4. Palladium-catalyzed cyclization reactions of 2-vinylthiiranes with heterocumulenes. Regioselective and enantioselective formation of thiazolidine, oxathiolane, and dithiolane derivatives.

    Science.gov (United States)

    Larksarp, C; Sellier, O; Alper, H

    2001-05-18

    The first palladium-catalyzed ring-expansion reaction of 2-vinylthiiranes with heterocumulenes to form sulfur-containing five-membered-ring heterocycles is described. This regioselective reaction requires 5 mol % of Pd(2)(dba)(3).CHCl(3) and 10 mol % of bidendate phosphine ligand (dppp, BINAP), at 50-80 degrees C, in THF. The reaction of 2-vinylthiiranes with carbodiimides, isocyanates, and ketenimines affords 1,3-thiazolidine derivatives, whereas the reaction with diphenylketene or isothiocyanates results in the formation of 1,3-oxathiolane or 1,3-dithiolane compounds in good to excellent isolated yields and in up to 78% ee.

  5. A review of syntheses of 1,5-disubstituted tetrazole derivatives.

    Science.gov (United States)

    Sarvary, Afshin; Maleki, Ali

    2015-02-01

    This report provides a brief overview of the various representative literature procedures for the synthesis of 1,5-disubstituted tetrazoles (1,5-DSTs) and fused 1,5-disubstituted tetrazoles with more than 120 references. Most of the published methods for the synthesis of 1,5-DSTs include the use of nitriles, amides, thioamides, imidoyl chlorides, heterocumulenes, isocyanates, isothiocyanates, carbodiimides, ketenimines, ketones, amines, and alkenes as the starting materials. The transformation of 1- and 5-substituted tetrazoles into 1,5-DSTs is also covered in this report.

  6. Synthesis of 2,3-Disubstituted Quinolines via Ketenimine or Carbodiimide Intermediates.

    Science.gov (United States)

    Zhao, Hongyang; Xing, Yanpeng; Lu, Ping; Wang, Yanguang

    2016-10-10

    Cyclopenta[b]quinolines and cyclohexa[b]quinolines were prepared via the reactions of α-diazo ketones with N-(2-cyclopropylidenemethylphenyl)phosphanimines and N-(2-cyclobutylidenemethylphenyl) phosphanimine, respectively. The reaction proceeds in a cascade involving ketenimine formation, 6 π-electron ring closure, and 1,3-alkyl shift. A similar approach was developed for the synthesis of dihydropyrrolo-[2,3-b]quinolines from N-(2-cyclopropylidenemethylphenyl)phosphanimines and isocyanates. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Mechanistic studies of carbon monoxide reduction

    Energy Technology Data Exchange (ETDEWEB)

    Geoffroy, G.L.

    1990-06-12

    The progress made during the current grant period (1 January 1988--1 April 1990) in three different areas of research is summarized. The research areas are: (1) oxidatively-induced double carbonylation reactions to form {alpha}-ketoacyl complexes and studies of the reactivity of the resulting compounds, (2) mechanistic studies of the carbonylation of nitroaromatics to form isocyanates, carbamates, and ureas, and (3) studies of the formation and reactivity of unusual metallacycles and alkylidene ligands supported on binuclear iron carbonyl fragments. 18 refs., 5 figs., 1 tab.

  8. Fabrication and characterization of cellulose nanocrystal based transparent electroactive polyurethane

    Science.gov (United States)

    Ko, Hyun-U.; Kim, Hyun Chan; Kim, Jung Woong; Zhai, Lindong; Jayaramudu, Tippabattini; Kim, Jaehwan

    2017-08-01

    This paper reports cellulose nanocrystal (CNC) based transparent and electroactive polyurethane (CPPU), suitable for actively tunable optical lens. CNC is used for high dielectric filler to improve electromechanical behavior of CPPU. For high transparency and homogeneous distribution of CNC in polyurethane, CNC-poly[di(ethylene glycol) adipate] is used to play a role of polyol and isocyanate salt. The fabricated CPPU exhibits high transparency (>90%) and 10% of electromechanical strain under 3 V μm-1 electric field. Mechanical, dielectric properties as well as physical and chemical characteristics are investigated to prove the electromechanical behavior of CPPU.

  9. Mechanical and morphological characterization of a bio-nanocomposite hydroxyapatite / polyurethane; Caracterizacao mecanica e morfologica de um bionanocomposito hidroxiapatita/poliuretano

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Sabina da Memoria Cardoso de, E-mail: sabina_memoria@yahoo.com.br [Instituto Federal de Educacao Ciencia e Tecnologia do Para (IFPA), Belem, PA (Brazil); Dias, Carmen Gilda Barroso Tavares [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Departamento de Engenharia Mecanica; Zavaglia, Cecilia Amelia de Carvalho [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Departamento de Engenharia Mecanica

    2011-07-01

    Nanocomposites based on biocompatible polymers and hydroxyapatite are wide acceptance as bone grafts, the composition, structure and similarity to natural bone and also due to the properties functional, such as surface and mechanical strength. This work there was the making of a bionanocomposite, using nanostructured hydroxyapatite interconnected by polyurethane, generated from the actions of poly(vinylalcohol) and toluene isocyanate HDT. The formation kinetics was monitored by the bionanocomposite spectroscopy and Fourier transform infrared FTIR. The material showed good properties both mechanical and morphology. (author)

  10. Synthesis of New Imidazolidin-2,4-dione and 2-Thioxoimidazolidin-4-ones via C-Phenylglycine Derivatives

    Directory of Open Access Journals (Sweden)

    José Alixandre de Sousa Luis

    2009-12-01

    Full Text Available Hydantoins and their derivatives constitute a group of pharmaceutical compounds with anticonvulsant and antiarrhythmic properties, and are also used against diabetes. N-3 and C-5 substituted imidazolidines are examples of such products. As such, we have developed a synthesis of 2,4-dione and 2-thioxo-4-one imidazolidinic derivatives by reaction of amino acids with C-phenylglycine, phenyl isocyanate and phenyl isothiocyanate. Four amino-derivatives IG(1-4 and eight imidazolidinic derivatives, IM(1-8, were obtained in yields of 70–74%. The mass, infrared, 1H and 13C-NMR spectra of representative products are discussed.

  11. Biomonitoring at the UK Health and Safety Laboratory.

    Science.gov (United States)

    Cocker, J; Jones, K; Morton, J; Mason, H J

    2007-05-01

    The UK Health and Safety Laboratory (HSL) provides research and analytical support to the Health and Safety Executive, other Government Departments and employers. In the area of biomonitoring HSL conducts research studies and provides an analytical service for regular surveillance of worker exposure to hazardous substances. This paper gives brief examples of how data from such studies can be used to develop biological monitoring guidance values for isocyanates, polycyclic aromatic hydrocarbons and hexavalent chromium. In addition, a study of occupational exposure to copper chrome arsenic wood preservatives is briefly described to show how biological monitoring can be used for post-approval surveillance of a biocide.

  12. Mechanical and morphological characterization of a bio-nanocomposite hydroxyapatite / polyurethane

    International Nuclear Information System (INIS)

    Andrade, Sabina da Memoria Cardoso de; Dias, Carmen Gilda Barroso Tavares; Zavaglia, Cecilia Amelia de Carvalho

    2011-01-01

    Nanocomposites based on biocompatible polymers and hydroxyapatite are wide acceptance as bone grafts, the composition, structure and similarity to natural bone and also due to the properties functional, such as surface and mechanical strength. This work there was the making of a bionanocomposite, using nanostructured hydroxyapatite interconnected by polyurethane, generated from the actions of poly(vinylalcohol) and toluene isocyanate HDT. The formation kinetics was monitored by the bionanocomposite spectroscopy and Fourier transform infrared FTIR. The material showed good properties both mechanical and morphology. (author)

  13. Electrochemical supercapacitor application of electroless surface polymerization of polyaniline nanostructures

    International Nuclear Information System (INIS)

    Amarnath, Chellachamy A.; Chang, Jin Ho; Kim, Doyoung; Mane, Rajaram S.; Han, Sung-Hwan; Sohn, Daewon

    2009-01-01

    Electrochemical supercapacitive behaviour of polyaniline nanostructures, i.e., nanorods and nanospheres fabricated on aniline-primed conducting indium-tin oxide substrate via electroless surface polymerization using ammonium persulfate as initiator and selenious acid as efficient dopant is investigated. The self-assembled monolayer of urea derivative in presence of 3-(triethoxysilyl)-propyl isocyanate and aniline plays role of aniline-primed substrate. Polyaniline electrode composed of nanorods of excess surface area responsible for large redox reactions has shown 592 F g -1 specific capacitance which is significantly greater than closely compact polyaniline nanospheres, i.e., 214 F g -1

  14. [Information content of immunologic parameters in the evaluation of the effects of hazardous substances].

    Science.gov (United States)

    Litovskaia, A V; Sadovskiĭ, V V; Vifleemskiĭ, A B

    1995-01-01

    Clinical and immunologic examination including 1 and 2 level tests covered 429 staffers of chemical enterprises and 1122 of those engaged into microbiological synthesis of proteins, both the groups exposed to some irritating gases and isocyanates. Using calculation of Kulbak's criterion, the studies selected informative parameters to diagnose immune disturbances caused by occupational hazards. For integral evaluation of immune state, the authors applied general immunologic parameter, meanings of which can serve as criteria for early diagnosis of various immune disorders and for definition of risk groups among industrial workers exposed to occupational biologic and chemical hazards.

  15. Formation and spectroscopy of {alpha}-muoniated radicals

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, I.; Brodovitch, J.C.; Ghandi, K.; Kecman, S.; Percival, P.W

    2003-02-01

    Several novel {alpha}-muoniated radicals have been produced by the reaction of muonium with compounds containing diazo, isocyanate or carbene functional groups. In {alpha}-muoniated radicals the muon is attached directly to the radical centre; they can be formed either directly or indirectly via a {beta}-muoniated radical intermediate. The hyperfine coupling constants of the resulting radicals have been measured by transverse field muon spin rotation and muon avoided level-crossing resonance. The effect of muonium substitution was investigated for cases where ESR data are available for comparison.

  16. Formation and spectroscopy of α-muoniated radicals

    International Nuclear Information System (INIS)

    McKenzie, I.; Brodovitch, J.C.; Ghandi, K.; Kecman, S.; Percival, P.W.

    2003-01-01

    Several novel α-muoniated radicals have been produced by the reaction of muonium with compounds containing diazo, isocyanate or carbene functional groups. In α-muoniated radicals the muon is attached directly to the radical centre; they can be formed either directly or indirectly via a β-muoniated radical intermediate. The hyperfine coupling constants of the resulting radicals have been measured by transverse field muon spin rotation and muon avoided level-crossing resonance. The effect of muonium substitution was investigated for cases where ESR data are available for comparison

  17. Palm oil based polyols for acrylated polyurethane production

    International Nuclear Information System (INIS)

    Rida Tajau; Mohd Hilmi Mahmood; Mek Zah Salleh; Khairul Zaman Mohd Dahlan; Rosley Che Ismail

    2006-01-01

    Palm oil becomes important renewable resources for the production of polyols for the polyurethane manufacturing industry. The main raw materials used for the production of acrylated polyurethane are polyols, isocyanates and hydroxyl terminated acrylate compounds. In these studies, polyurethane based natural polymer (palm oil), i.e., POBUA (Palm Oil Based Urethane Acrylate) were prepared from three different types of palm oil based polyols i.e., epoxidised palm oil (EPOP), palm oil oleic acid and refined, bleached and deodorized (RBD) palm olein based polyols. The performances of these three acrylated polyurethanes when used for coatings and adhesives were determined and compared with each other. (Author)

  18. Microwave-assisted synthesis of N-pyrazole ureas and the p38alpha inhibitor BIRB 796 for study into accelerated cell ageing.

    Science.gov (United States)

    Bagley, Mark C; Davis, Terence; Dix, Matthew C; Widdowson, Caroline S; Kipling, David

    2006-11-21

    Microwave irradiation of substituted hydrazines and beta-ketoesters gives 5-aminopyrazoles in excellent yield, which can be transformed to the corresponding N-carbonyl derivatives by treatment with an isocyanate or chloroformate. Derivatization of 4-nitronaphth-1-ol using predominantly microwave heating methods and reaction with an N-pyrazole carbamate provides a rapid route to the N-pyrazole urea BIRB 796 in high purity, as a potent and selective inhibitor of p38alpha mitogen-activated protein kinase for the study of accelerated ageing in Werner syndrome cells.

  19. The preparation of new functionalized [2.2]paracyclophane derivatives with N-containing functional groups

    Directory of Open Access Journals (Sweden)

    Henning Hopf

    2015-04-01

    Full Text Available The two isomeric bis(isocyanates 4,12- and 4,16-di-isocyanato[2.2]paracyclophane, 16 and 28, have been prepared from their corresponding diacids by simple routes. The two isomers are versatile intermediates for the preparation of various cyclophanes bearing substituents with nitrogen-containing functional groups, e.g., the pseudo-ortho diamine 8, the bis secondary amine 23, and the crownophanes 18 and 19. Several of these new cyclophane derivatives (18, 19, 22, 26, 28 have been characterized by X-ray structural analysis.

  20. Inhale while Dreaming: Human Exposure to Pollutants while Sleeping

    DEFF Research Database (Denmark)

    Corsi, Richard; Spilak, Michal; Boor, E., Brandon

    2012-01-01

    of indoor pollutants, e.g., flame retardants to isocyanates. As such, there is a need for increased dialogue on this subject, end-point relevant research, and action to reduce exposures to high-risk contaminants for most of humanity. This workshop will involve an opening 5–minute presentation related...... discussion related to practical implications of new findings as well as past studies, geographic variations in emissions from mattresses and beddings, methods for reducing population exposures, and suggestions for future research that has practical endpoints and that can lead to reduced exposures....

  1. Method of making a cyanate ester foam

    Science.gov (United States)

    Celina, Mathias C.; Giron, Nicholas Henry

    2014-08-05

    A cyanate ester resin mixture with at least one cyanate ester resin, an isocyanate foaming resin, other co-curatives such as polyol or epoxy compounds, a surfactant, and a catalyst/water can react to form a foaming resin that can be cured at a temperature greater than 50.degree. C. to form a cyanate ester foam. The cyanate ester foam can be heated to a temperature greater than 400.degree. C. in a non-oxidative atmosphere to provide a carbonaceous char foam.

  2. Method for providing a low density high strength polyurethane foam

    Science.gov (United States)

    Whinnery, Jr., Leroy L.; Goods, Steven H.; Skala, Dawn M.; Henderson, Craig C.; Keifer, Patrick N.

    2013-06-18

    Disclosed is a method for making a polyurethane closed-cell foam material exhibiting a bulk density below 4 lbs/ft.sup.3 and high strength. The present embodiment uses the reaction product of a modified MDI and a sucrose/glycerine based polyether polyol resin wherein a small measured quantity of the polyol resin is "pre-reacted" with a larger quantity of the isocyanate in a defined ratio such that when the necessary remaining quantity of the polyol resin is added to the "pre-reacted" resin together with a tertiary amine catalyst and water as a blowing agent, the polymerization proceeds slowly enough to provide a stable foam body.

  3. Mechanical and Physical Properties of Low Density Kenaf Core Particleboards Bonded with Different Resins

    OpenAIRE

    Mohamad Jani Saad; Izran Kamal

    2012-01-01

    Single layer kenaf (Hibiscus cannabinus) core particleboards bonded with urea formaldehyde (UF), phenol formaldehyde (PF) and polymeric 4,4-methyl phenylmethane di-isocyanate (PMDI) resins were manufactured. The boards were fabricated with three different densities i.e 350 kg/m3, 450 kg/m3 and 550 kg/m3. Each type of the resin used was sprayed at three different resin loadings on the kenaf core particles. The boards produced was evaluated for its modulus of rupture (MOR), modulus of elasticit...

  4. Castor oil polyurethane as a coating option for spent nuclear fuel disposal containment

    International Nuclear Information System (INIS)

    Mortley, A.; Bonin, H.W.; Bui, V.T.

    2009-01-01

    Castor oil polyurethane (COPU) coatings are being proposed as an additional barrier in the design of the copper containers to store spent nuclear fuel in Canada. The present work investigates the variation in the physicomechanical properties of two COPUs, based on an aliphatic and aromatic diisocyanate, as a function of ionizing radiation dose and dose rate. The changes in physicomechanical properties have shown that radiation, regardless of dose rate and isocyanate structure, increases the values of the modulus and the ultimate tensile strength when compared with those of the unirradiated samples, with aromatic based polyurethanes being more susceptible to variation than aliphatic based ones. (author)

  5. Mechanisms of carcinogenesis prevention by flavonoids

    Directory of Open Access Journals (Sweden)

    G. A. Belitsky

    2014-01-01

    Full Text Available The mechanisms of anticancerogenic effects of flavanoids and isocyanates from the plants widely consumed in the midland belt of Russia were reviewed. Data of studies both in vitro and in vivo were analyzed. Special attention was paid to inhibition of targets responsible for carcinogen metabolic activation, carcinogenesis promotion and tumor progression as well as neoangiogenesis. Besides that the antioxidant properties of flavonoids and their effects on cell cycle regulation, apoptosis initiation and cell mobility were considered.

  6. Photodynamic inactivation of Candida albicans sensitized by tri- and tetra-cationic porphyrin derivatives.

    Science.gov (United States)

    Cormick, M Paula; Alvarez, M Gabriela; Rovera, Marisa; Durantini, Edgardo N

    2009-04-01

    The photodynamic action of 5-(4-trifluorophenyl)-10,15,20-tris(4-trimethylammoniumphenyl)porphyrin iodide (TFAP(3+)) and 5,10,15,20-tetra(4-N,N,N-trimethylammonium phenyl)porphyrin p-tosylate (TMAP(4+)) has been studied in vitro on Candida albicans. The results of these cationic porphyrins were compared with those of 5,10,15,20-tetra(4-sulphonatophenyl)porphyrin (TPPS(4-)), which characterizes an anionic sensitizer. In vitro investigations show that these cationic porphyrins are rapidly bound to C. albicans cells, reaching a value of approximately 1.4 nmol/10(6) cells, when the cellular suspensions were incubated with 5 microM sensitizer for 30 min. In contrast, TPPS(4-) is poorly uptaken by yeast cells. The fluorescence spectra of these sensitizers into the cells confirm this behaviour. The amount of porphyrin binds to cells is dependent on both sensitizer concentrations (1-5 microM) and cells densities (10(6)-10(8) cells/mL). Photosensitized inactivation of C. albicans cellular suspensions increases with sensitizer concentration, causing a approximately 5 log decrease of cell survival, when the cultures are treated with 5 microM of cationic porphyrin and irradiated for 30 min. However, the photocytotoxicity decreases with an increase in the cell density, according to its low binding to cells. Under these conditions, the photodynamic activity of TFAP(3+) is quite similar to that produced by TMAP(4+), whereas no important inactivation effect was found for TPPS(4)(-). The high photodynamic activity of cationic porphyrins was confirmed by growth delay experiments. Thus, C. albicans cell growth was not detected in the presence of 5 microM TFAP(3+). Photodynamic inactivation capacities of these sensitizers were also evaluated on C. albicans cells growing in colonies on agar surfaces. Cationic porphyrins produce a growth delay of C. albicans colonies and viability of cells was not observed after 3 h irradiation, indicating a complete inactivation of yeast cells

  7. Selective albumin-binding surfaces modified with a thrombin-inhibiting peptide.

    Science.gov (United States)

    Freitas, Sidónio C; Maia, Sílvia; Figueiredo, Ana C; Gomes, Paula; Pereira, Pedro J B; Barbosa, Mário A; Martins, M Cristina L

    2014-03-01

    Blood-contacting medical devices have been associated with severe clinical complications, such as thrombus formation, triggered by the activation of the coagulation cascade due to the adsorption of certain plasma proteins on the surface of biomaterials. Hence, the coating of such surfaces with antithrombotic agents has been used to increase biomaterial haemocompatibility. Biomaterial-induced clotting may also be decreased by albumin adsorption from blood plasma in a selective and reversible way, since this protein is not involved in the coagulation cascade. In this context, this paper reports that the immobilization of the thrombin inhibitor D-Phe-Pro-D-Arg-D-Thr-CONH2 (fPrt) onto nanostructured surfaces induces selective and reversible adsorption of albumin, delaying the clotting time when compared to peptide-free surfaces. fPrt, synthesized with two glycine residues attached to the N-terminus (GGfPrt), was covalently immobilized onto self-assembled monolayers (SAMs) having different ratios of carboxylate-hexa(ethylene glycol)- and tri(ethylene glycol)-terminated thiols (EG6-COOH/EG3) that were specifically designed to control GGfPrt orientation, exposure and density at the molecular level. In solution, GGfPrt was able to inactivate the enzymatic activity of thrombin and to delay plasma clotting time in a concentration-dependent way. After surface immobilization, and independently of its concentration, GGfPrt lost its selectivity to thrombin and its capacity to inhibit thrombin enzymatic activity against the chromogenic substrate n-p-tosyl-Gly-Pro-Arg-p-nitroanilide. Nevertheless, surfaces with low concentrations of GGfPrt could delay the capacity of adsorbed thrombin to cleave fibrinogen. In contrast, GGfPrt immobilized in high concentrations was found to induce the procoagulant activity of the adsorbed thrombin. However, all surfaces containing GGfPrt have a plasma clotting time similar to the negative control (empty polystyrene wells), showing resistance to

  8. On a novel method to synthesize POSS-based hybrids: An example of the preparation of TPU based system

    Directory of Open Access Journals (Sweden)

    O. Monticelli

    2013-12-01

    Full Text Available A novel method to prepare polymer/polyhedral oligomeric silsesquioxanes (POSS hybrids by melt reactive blending is proposed in this paper, by the controlled polymer chain scission and reaction of chain ends with functional silsesquioxanes. Application to thermoplastic polyurethanes (TPU is addressed, taking advantage of the polyurethane chain scission equilibrium reaction, leading to the formation of highly reactive isocyanate and hydroxyl chain ends. Despite the isocyanate chemistry has been widely studied for the preparation of polymer/POSS hybrids by in situ copolymerisation, the exploitation of similar chemical processes in an industrially viable and environmental friendly melt blending process is currently an open research field. In this work, the reaction in the molten state of dihydroxyl-functionalised POSS with the polyurethane chain is demonstrated to produce a TPU/POSS hybrids. The effect of POSS concentration on nanomorphology, thermal properties and surface properties is studied, showing significant changes compared to pristine TPU. In particular, an increase of glass transition temperature is observed in the presence of reactive POSS (ΔT up to about 10°C in the presence of 10 wt% loading. Furthermore, an increase of surface water wettability, evidenced by the decrease of water contact angle from 95° for pristine TPU to 70° in TPU containing 10"wt% of reactive POSS, is found.

  9. Synthesis of Polyurethane/Silica Modified Epoxy Polymer Based on 1,3-Propanediol for Coating Application

    Directory of Open Access Journals (Sweden)

    Lutviasari Nuraini

    2017-11-01

    Full Text Available Studies on the synthesis of polyurethane/silica modified epoxy polymer using 1,3-propanediol has been conducted. Synthesis of polymers made by reaction of tolonate and 1,3-propanediol (ratio NCO/OH=2.5 as the building blocks of polyurethane with diglycidyl ether bisphenol A (DGEBA epoxy and catalyst dibutyltin dilaurate (DBTL.The total weight of the polyurethane used was 20% (w/w of the total epoxy. Based on Fourier Transform Infrared (FTIR and 1H-Nuclear Magnetic Resonance (1H-NMR spectra indicated the existence of a new bond that is formed from the reaction of isocyanate group and hydroxyl group, where the hydroxyl groups derived from epoxy and 1,3-propanediol. The addition of silica (5, 10, and 15% w/w to epoxy into the epoxy-modified polyurethane has been carried out through sol-gel reaction of tetraethyl orthosilicate (TEOS. The isocyanate conversion rate for the addition of silica 5, 10, and 15% are 95.69; 100, and 100%, respectively. The morphology and element identification by Scanning Electron Microscopy/Energy Dispersive X-Ray Analysis (SEM/EDX, showed that Si element has been successfully added in the polymer. From the tensile strength and elongation analysis, also thermal stability analysis using Thermal Gravimetric Analyzer (TGA, the increase of silica amount into the polyurethane modified epoxy did not significantly affect to thermal properties, but decrease the tensile strength of the polymer.

  10. Morphological effects of single-layer graphene oxide in the formation of covalently bonded polypyrrole composites using intermediate diisocyanate chemistry

    International Nuclear Information System (INIS)

    Whitby, Raymond L. D.; Korobeinyk, Alina; Mikhalovsky, Sergey V.; Fukuda, Takahiro; Maekawa, Toru

    2011-01-01

    Single-layer graphene oxide (SLGO) possesses carboxylic and hydroxyl groups suitable for reactions with aliphatic or aromatic diisocyanate molecules. TEM analysis reveals that aliphatic diisocyanate molecules caused SLGO to scroll into star-like formations, whereas aromatic diisocyanate molecules retained SGLO in a flat-sheet morphology. TGA confirms the stabilisation of the formed urea and urethane groups on SLGO, but the onset of sheet pyrolysis occurs at a lower temperature due to isocyanate reactions with anhydride and epoxide groups embedded in the sheet. Pendant isocyanate groups act as bridging units to facilitate the attachment of pyrrole molecules, which are then used as anchor sites for the covalent polymerisation of pyrrole to polypyrrole (PPy). The use of FeCl 3 as the polymerisation catalyst generated both covalent and free PPy, but also iron hydroxide nanoparticles were observed decorating the SLGO surface. When using ammonium persulfate as a catalyst and dodecylbenzenesulfonate as a dopant, free PPy could be removed under treatment with solvents to leave a purely covalent system. Discrete regions of SLGO were observed decorated with nanoparticles of PPy along the edge or across the surface of individual sheets. It was found that the flexibility of the SLGO sheet and the type of diisocyanate used directly affected the electrical resistance of the final composite.

  11. LDRD final report on "Pumping up CO2 and conversion into useful molecules" (LDRD 105932).

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, Richard Alan; Stewart, Constantine A.; Dickie, Diane A. (University of New Mexico, Albuquerque, NM)

    2009-11-01

    Group 12 metal cyclam complexes and their derivatives as well as (octyl){sub 2}Sn(OMe){sub 2} were examined as potential catalysts for the production of dimethyl carbonate (DMC) using CO{sub 2} and methanol. The zinc cyclams will readily take up carbon dioxide and methanol at room temperature and atmospheric pressure to give the metal methyl carbonate. The tin exhibited an improvement in DMC yields. Studies involving the reaction of bis-phosphino- and (phosphino)(silyl)-amido group 2 and 12 complexes with CO{sub 2} and CS{sub 2} were performed. Notable results include formation of phosphino-substituted isocyanates, fixation of three moles of CO{sub 2} in an unprecedented [N(CO{sub 2}){sub 3}]{sup 3-} anion, and rapid splitting of CS{sub 2} by main group elements under extremely mild conditions. Similar investigations of divalent group 14 silyl amides led to room temperature splitting of CO{sub 2} into CO and metal oxide clusters, and the formation of isocyanates and carbodiimides.

  12. Emission of organic substances from chip-boards

    Energy Technology Data Exchange (ETDEWEB)

    Deppe, H.J.

    1982-01-01

    A relatively small number of investigations on emissions of organic substances from chip-board is available up to now. The emissions known to date are caused by glues or other additives rather than by the wood itself. As concerns aminoplast glues (urea-formaldehyde or melamine-formaldehyde resins) the most important point of public interest has been the off-gassing of formaldehyde from chip-board. Chip-board with phenol-formaldehyde glues has been known in some cases to give off phenol. The formation of diamino diphenyl methane from isocyanate glues is still a matter of discussion. A further source for possible emissions are wood and fire protectives which are added during the manufacturing process. Finally, coating of chip-board may lead to emissions of organic substances. The lack of adequate detection methods has so far delayed the treatment of questions in relation to emissions from chip-board. Even now, there are numerous problems in this field especially when investigating isocyanate glues. Problems in relation to the origin of emissions due to the kind of glue used and the manufacturing process are discussed, and proposals are made how to solve some of these problems. The question of the health risk is dealt with from the view-point of the civil engineer and in an general economic context.

  13. N-halamine-based rechargeable antimicrobial and biofilm-controlling polyurethane

    Science.gov (United States)

    Sun, Xinbo; Cao, Zhengbing; Porteous, Nuala; Sun, Yuyu

    2012-01-01

    An N-halamine precursor, 5, 5-dimethyl hydantoin (DMH), was covalently linked to the surface of polyurethane (PU) with 1,6-hexamethylene diisocyanate (HDI) as a coupling agent. The reaction pathways were investigated using propyl isocyanate (PI) as a model compound, and the results suggested that the imide and amide groups of DMH had very similar reactivity toward the isocyanate groups on PU surfaces activated with HDI. After bleach treatment, the covalently bound DMH moieties were transformed into N-halamines. The new N-halmaine-based PU provided potent antimicrobial effects against Staphylococcus aureus (S. aureus, Gram-positive), Escherichia coli (E. coli, Gram-negative), methicillin-resistant staphylococcus aureus (MRSA, drug resistant Gram-positive bacteria), vancomycin-resistant enterococcus (VRE, drug resistant Gram-positive bacteria), and Candida albicans (C. ablicans, fungi), and successfully prevented bacterial and fungal biofilm formation. The antimicrobial and biofilm-controlling effects were stable for longer than 6 months under normal storage in open air. Furthermore, if the functions were lost due to prolonged use, they could be recharged by another chlorination treatment. The recharging could be repeated as needed to achieve long-term protection against microbial contamination and biofilm-formation. PMID:22244984

  14. Solid phase syntheses of oligoureas

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, K.; Linthicum, D.S.; Russell, D.H.; Shin, H.; Shitangkoon, A.; Totani, R.; Zhang, A.J.; Ibarzo, J. [Texas A& M Univ., College Station, TX (United States)

    1997-02-19

    Isocyanates 7 were formed from monoprotected diamines 3 or 6, which in turn can be easily prepared from commercially available N-BOC- or N-FMOC-protected amino acid derivatives. Isocyanates 7, formed in situ, could be coupled directly to a solid support functionalized with amine groups or to amino acids anchored on resins using CH{sub 2}Cl{sub 2} as solvent and an 11 h coupling time at 25 {degree}C. Such couplings afforded peptidomimetics with an N-phthaloyl group at the N-terminus. The optimal conditions identified for removal of the N-phthaloyl group were to use 60% hydrazine in DMF for 1-3 h. Several sequences of amino acids coupled to ureas (`peptidic ureas`) and of sequential urea units (`oligoureas`) were prepared via solid phase syntheses and isolated by HPLC. Partition coefficients were measured for two of these peptidomimetics, and their water solubilities were found to be similar to the corresponding peptides. A small library of 160 analogues of the YGGFL-amide sequence was prepared via Houghten`s tea bag methodology. This library was tested for binding to the anti-{beta}-endorphin monoclonal antibody. Overall, this paper describes methodology for solid phase syntheses of oligourea derivatives with side chains corresponding to some of the protein amino acids. The chemistry involved is ideal for high-throughput syntheses and screening operations. 51 refs., 3 figs., 2 tabs.

  15. Workplace protection of air-fed visors used in paint spraying operations.

    Science.gov (United States)

    Bolsover, J; Rajan-Sithamparanadarajah, B; Vaughan, N

    2006-04-01

    Air-fed visors are commonly used for protection against exposure to airborne isocyanates during paint spraying. Protection levels for this class of equipment are theoretically adequate, yet isocyanate sensitization in this occupation still occurs. The work reported here set out to establish the level of respiratory protection that is achieved during real paint spraying activities when air-fed visors are used. The work also examined the effects of reduced air supply flow rates on this type of respiratory protection. The workplace study highlighted common problems that occur when attempting to measure protection factors, and process and interpret the collected data. Many of the environments included in this study did not exhibit challenge concentrations high enough to reliably measure the workplace protection factor of this class of device. When detection limits are taken into consideration, the remaining field data suggest that an assigned protection factor in the region of 40 may be appropriate. When well maintained and used in accordance with the manufacturer's instructions, air-fed visors are capable of providing a good level of respiratory protection. The protection given by air-fed visors is strongly dependent on the air flow supplied to them. Laboratory measurements demonstrate that protection falls as the air supply falls. This is a gradual process and does not suddenly occur at any particular air supply flow. Observations made during the field tests indicate that there may be other activities associated with the spraying process that need to be taken into consideration when looking for sources of respiratory sensitization.

  16. Synthesis and Application of Jatropha Oil based Polyurethane as Paint Coating Material

    Directory of Open Access Journals (Sweden)

    Zainal Alim Mas’ud

    2012-08-01

    Full Text Available Recently, the use of renewable sources in the preparation of various industrial materials has been revitalized in response to environmental concerns. Natural oils are considered to be the most important genre of renewable sources. Jatropha curcas oil (JPO based polyol is an alternative material that may possibly replace petrochemical-based polyol for polyurethane coating material. Polyurethane was synthesized by reacting JPO-based polyol with isocyanate. To produce JPO-based polyol, JPO was first epoxidized to form epoxidized J. curcas oil (EJP, subsequently it was converted to polyol by the opening ring reaction with acrylic acid (AA using triethylamine (TEA as a catalyst. The JPO-based polyurethane film resulting from this study is compared with polyurethane film from commercial polyol for gloss, hardness, and adhesion quality. The result showed that the source of polyol has an influence on gloss, hardness, and adhesion of polyurethane film, but the differences with using isocyanate has less influence. Using visual observation, polyurethane film produced from L.OHV polyol, H.OHV polyol and commercial polyol have similar quality.

  17. Direct synthesis of hydrophobic graphene-based nanosheets via chemical modification of exfoliated graphene oxide.

    Science.gov (United States)

    Wang, Jigang; Wang, Yongsheng; He, Dawei; Liu, Zhiyong; Wu, Hongpeng; Wang, Haiteng; Zhao, Yu; Zhang, Hui; Yang, Bingyang; Xu, Haiteng; Fu, Ming

    2012-08-01

    Hydrophobic graphene-based material at the nanoscale was prepared by treatment of exfoliated graphene oxide with organic isocyanates. The lipophilic modified graphene oxide (LMGO) can then be exfoliated into the functionalized graphene nanoplatelets that can form a stable dispersion in polar aprotic solvents. AFM image shows the thickness of LMGO is approximately 1 nm. Characterization of LMGO by elemental analysis suggested that the chemical treatment results in the functionalization of the carboxyl and hydroxyl groups in GO via formation of amides and carbamate esters, respectively. The degree of GO functionalization can be controlled via either the reactivity of the isocyanate or the reaction time. Then we investigated the thermal properties of the SPFGraphene by using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), the TGA curve shows a greater weight loss of approximately 20% occurred indicating removal of functional groups from the LMGO sheets and an obvious exothermic peak at 176 degrees can be observed from 150 to 250 degrees. We also compared the structure of graphene oxide with the structure of chemical treated graphene oxide by FT-IR spectroscopy. The morphology and microstructure of the LMGO nanosheets were also characterized by SEM and XRD. Graphene can be used to fabricate a wide range of simple electronic devices such as field-effect transistors, resonators, quantum dots and some other extensive industrial manufacture such as super capacitor, li ion battery, solar cells and even transparent electrodes in device applications.

  18. Adducts of nitrogenous ligands with rhodium(II) tetracarboxylates and tetraformamidinate: NMR spectroscopy and density functional theory calculations.

    Science.gov (United States)

    Cmoch, Piotr; Głaszczka, Rafał; Jaźwiński, Jarosław; Kamieński, Bohdan; Senkara, Elżbieta

    2014-03-01

    Complexation of tetrakis(μ2-N,N'-diphenylformamidinato-N,N')-di-rhodium(II) with ligands containing nitrile, isonitrile, amine, hydroxyl, sulfhydryl, isocyanate, and isothiocyanate functional groups has been studied in liquid and solid phases using (1)H, (13)C and (15)N NMR, (13)C and (15)N cross polarisation-magic angle spinning NMR, and absorption spectroscopy in the visible range. The complexation was monitored using various NMR physicochemical parameters, such as chemical shifts, longitudinal relaxation times T1 , and NOE enhancements. Rhodium(II) tetraformamidinate selectively bonded only unbranched amine (propan-1-amine), pentanenitrile, and (1-isocyanoethyl)benzene. No complexation occurred in the case of ligands having hydroxyl, sulfhydryl, isocyanate, and isothiocyanate functional groups, and more expanded amine molecules such as butan-2-amine and 1-azabicyclo[2.2.2]octane. Such features were opposite to those observed in rhodium(II) tetracarboxylates, forming adducts with all kind of ligands. Special attention was focused on the analysis of Δδ parameters, defined as a chemical shift difference between signal in adduct and corresponding signal in free ligand. In the case of (1)H NMR, Δδ values were either negative in adducts of rhodium(II) tetraformamidinate or positive in adducts of rhodium(II) tetracarboxylates. Experimental findings were supported by density functional theory molecular modelling and gauge independent atomic orbitals chemical shift calculations. The calculation of chemical shifts combined with scaling procedure allowed to reproduce qualitatively Δδ parameters. Copyright © 2013 John Wiley & Sons, Ltd.

  19. Properties of Lignin from Oil Palm Empty Fruit Bunch and Its Application for Plywood Adhesive

    Directory of Open Access Journals (Sweden)

    Lucky Risanto

    2014-10-01

    Full Text Available Lignin from lignocellulosic biomass is a potential biopolymer for wood adhesive. The aims of this study were to characterize lignin isolated from the black liquor of oil palm empty fruit bunch fiber pretreated with steam explosion in alkaline conditions and to examine the bond quality of aqueous polymer isocyanate (API adhesive prepared from lignin, natural rubber latex (NRL, and polyvinyl alcohol (PVA as base polymers with isocyanate crosslinkers. Lignin was precipitated from the black liquor by adding hydrochloric acid; then the precipitate was separated by filtration, thoroughly washed with water up to pH 2 and pH 5, and dried. The isolated lignin was characterized by ultimate analysis, UV spectroscopy, FT-IR spectroscopy, and thermal analysis. Three-layer plywood samples were prepared, and the bond strengths of the plywood samples were determined in dry conditions and after cyclic boiling. The lignin isolates with different pH values did not have significantly different chemical and thermal properties. Both lignin isolates had similar C, H, and O contents, identical functional groups in the FTIR spectra, similar absorption in the UV spectra, and high decomposition temperatures. The base polymers composition that could produce API adhesive for exterior applications was NRL/PVA/lignin (4/4/2. The use of more lignin in the adhesive formulation decreased the bond strength of the plywood.

  20. Biomaterial based novel polyurethane adhesives for wood to wood and metal to metal bonding

    Directory of Open Access Journals (Sweden)

    Mitesh Ramanlal Patel

    2009-01-01

    Full Text Available Polyurethane adhesives made from synthetic chemicals are non-biodegradable, costly and difficult to find raw materials from local market. To avoid solid pollution problem, cost effectiveness and easy availability of raw materials, biomaterials based polyurethane adhesives are used in current industrial interest. Direct use of castor oil in polyurethane adhesive gives limited hardness. Modification on active sites of castor oil to utilize double bond of unsaturated fatty acid and carboxyl group yields new modified or activated polyols, which can be utilized for polyurethane adhesive formulation. In view of this, we have synthesized polyurethane adhesives from polyester polyols, castor oil based polyols and epoxy based polyols with Isocyanate adducts based on castor oil and trimethylolpropane. To study the effects of polyurethane adhesive strength (i.e. lap shear strength on wood-to-wood and metal-to-metal bonding through various types of polyols, cross-linking density, isocyanate adducts and also to compare adhesive strength between wood to wood and metal to metal surface. These polyols and polyurethanes were characterized through GPC, NMR and IR-spectroscopy, gel and surface drying time. Thermal stability of PU adhesives was determined under the effect of cross-linking density (NCO/OH ratio. The NCO/OH ratio (1.5 was optimized for adhesives as the higher NCO/OH ratio (2.0 increasing cross-linking density and decreases adhesion. Lower NCO/OH ratio (1.0 provideslow cross-linking density and low strength of adhesives.

  1. ASSESSMENT OF HUMAN EXPOSURE TO TOLUENE DIISOCYANATE

    Directory of Open Access Journals (Sweden)

    OLIVIA ANCA RUSU

    2011-03-01

    Full Text Available Assessment of human exposure to toluene diisocyanate. Toluene diisocyanate (TDI, an aromatic compound, may be dangerous for human health. Diisocyanates have wide industrial use in the fabrication of flexible and rigid foams, fibers, elastomers, and coatings such as paints and varnishes. Isocyanates are known skin and respiratory sensitizers, and proper engineering controls should be in place to prevent exposure to isocyanate liquid and vapor; exposure to TDI vapors is well documented to increase asthma risk. The study focused on the exposure of workers and nearby populations to toluene diisocyanate in a Polyurethane Foam Factory located in Baia Mare, Romania. Workplace air measurements were performed in different departments of the plant, after sampling either in fixed points or as personal monitoring. Sampling in four different locations of Baia Mare town was carried out, - during and after the foaming process. TDI sampling was performed on silica cartridge followed by GC-MS analysis. TDI concentration at workplace was lower than 0,035 mg/m³, which represents the permissible exposure limit, while in the city the TDI concentration had shown values below 0,20 μg/m³. Health assessment of a group of 49 workers was based on questionnaire interview, determination of TDI antibodies and lung function tests. Data collected until this stage do not show any negative effects of TDI on the employees health. Since this plant had only recently begun operating, continuous workplace and ambient air TDI monitoring, along with workers health surveillance, is deemed necessary.

  2. Experiments to populate and validate a processing model for polyurethane foam. BKC 44306 PMDI-10

    Energy Technology Data Exchange (ETDEWEB)

    Mondy, Lisa Ann [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rao, Rekha Ranjana [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shelden, Bion [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Soehnel, Melissa Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); O' Hern, Timothy J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Grillet, Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wyatt, Nicholas B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Russick, Edward Mark [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Stephen J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hileman, Michael Bryan [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Urquhart, Alexander [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Thompson, Kyle Richard [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Smith, David Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-03-01

    We are developing computational models to elucidate the expansion and dynamic filling process of a polyurethane foam, PMDI. The polyurethane of interest is chemically blown, where carbon dioxide is produced via the reaction of water, the blowing agent, and isocyanate. The isocyanate also reacts with polyol in a competing reaction, which produces the polymer. Here we detail the experiments needed to populate a processing model and provide parameters for the model based on these experiments. The model entails solving the conservation equations, including the equations of motion, an energy balance, and two rate equations for the polymerization and foaming reactions, following a simplified mathematical formalism that decouples these two reactions. Parameters for the polymerization kinetics model are reported based on infrared spectrophotometry. Parameters describing the gas generating reaction are reported based on measurements of volume, temperature and pressure evolution with time. A foam rheology model is proposed and parameters determined through steady-shear and oscillatory tests. Heat of reaction and heat capacity are determined through differential scanning calorimetry. Thermal conductivity of the foam as a function of density is measured using a transient method based on the theory of the transient plane source technique. Finally, density variations of the resulting solid foam in several simple geometries are directly measured by sectioning and sampling mass, as well as through x-ray computed tomography. These density measurements will be useful for model validation once the complete model is implemented in an engineering code.

  3. ELECTRON IRRADIATION OF KUIPER BELT SURFACE ICES: TERNARY N2-CH4-CO MIXTURES AS A CASE STUDY

    International Nuclear Information System (INIS)

    Kim, Y. S.; Kaiser, R. I.

    2012-01-01

    The space weathering of icy Kuiper Belt Objects was investigated in this case study by exposing methane (CH 4 ) and carbon monoxide (CO) doped nitrogen (N 2 ) ices at 10 K to ionizing radiation in the form of energetic electrons. Online and in situ Fourier transform infrared spectroscopy was utilized to monitor the radiation-induced chemical processing of these ices. Along with isocyanic acid (HNCO), the products could be mainly derived from those formed in irradiated binary ices of the N 2 -CH 4 and CO-CH 4 systems: nitrogen-bearing products were found in the form of hydrogen cyanide (HCN), hydrogen isocyanide (HNC), diazomethane (CH 2 N 2 ), and its radical fragment (HCN 2 ); oxygen-bearing products were of acetaldehyde (CH 3 CHO), formyl radical (HCO), and formaldehyde (H 2 CO). As in the pure ices, the methyl radical (CH 3 ) and ethane (C 2 H 6 ) were also detected, as were carbon dioxide (CO 2 ) and the azide radical (N 3 ). Based on the temporal evolution of the newly formed products, kinetic reaction schemes were then developed to fit the temporal profiles of the newly formed species, resulting in numerical sets of rate constants. The current study highlights important constraints on the preferential formation of isocyanic acid (HNCO) over hydrogen cyanide (HCN) and hydrogen isocyanide (HNC), thus guiding the astrobiological and chemical evolution of those distant bodies.

  4. Síntesis de microcápsulas de poliurea a partir de aminas renovables, mediante doble emulsificación Synthesis of polyurea microcapsules from renewable amines by double emulsification

    Directory of Open Access Journals (Sweden)

    Paula Mazo

    2011-01-01

    Full Text Available En este trabajo se realizó la microencapsulación de un perfume comercial mediante una doble emulsificación, la coraza de poliurea fue sintetizada por la reacción de Lisina con dos diisocianatos comerciales, uno aromático y otro alifático. En la síntesis se evaluó el efecto que tiene la relación molar amina:diisocianato y el tipo de emulsificante. Se optimizó el tamaño de partícula utilizando un diseño factorial 32 y análisis de superficie de respuesta, las variables fueron: cantidad de alcohol polivinílico y la relación de fase dispersa a fase continua. Las microcápsulas se caracterizaron mediante: análisis de calorimetría diferencial de barrido (DSC, espectroscopía infrarroja (IR, microscopía electrónica de barrido (SEM y tamaño medio de partícula. La doble emulsificación permite un mayor rendimiento de encapsulación del perfume, las micropartículas presentan un menor tamaño de partícula cuando: se emplea diisocianato aromático, un aumento de coloide protector (PVA y una disminución de la fase dispersa.This paper reports on the microencapsulation of a commercial perfume by means of a double emulsification, where the polyurea shell was synthesized by the reaction of lysine with two commercial di-isocyanates (aromatic and aliphatic. In the synthesis the factors evaluated were the amine:di-isocyanate molar ratio and the type of emulsifier. The particle size was optimized using a 3² factorial design and response surface analysis, with the following variables: amount of polyvinyl alcohol and the relationship of the disperse phase to continuous phase. The microcapsules were characterized using differential scanning calorimetry analysis (DSC, infrared spectroscopy (IR, scanning electron microscopy (SEM and mean particle size. The double emulsification allows for a greater yield in the encapsulation of perfume. Furthermore, the microparticles have a smaller particle size when the aromatic di-isocyanate was used, also

  5. Generation of biogas from coffee-pulp and cow-dung co-digestion: Infrared studies of postcombustion emissions

    International Nuclear Information System (INIS)

    Corro, Grisel; Paniagua, Laura; Pal, Umapada; Bañuelos, Fortino; Rosas, Minerva

    2013-01-01

    Graphical abstract: Batch digester with coffee pulp/cow dung produced high amounts of methane for 8 months. The FTIR gas spectroscopy analysis revealed the presence of over 70 chemical compounds in biogas generated after 4 months of coffee pulp and cow dung mixture co-digestion, several being hazardous to environment and human and animal health (e.g. isocyanic acid, bromomethane). Biogas produced was burned in a laboratory combustor. The FTIR gas spectroscopy analysis showed that combustion emissions contained: CH 4 , C 3 H 8 , CO, SO 2 , HI, and probably Br 2 which are strongly harmful to human and animal health. - Highlights: • Batch digester with coffee pulp/cow dung produced high amounts of methane for 8 months. • Biogas from coffee pulp/cow dung codigestion contained 60% methane and 20% propane. • Biogas FTIR analysis revealed the presence of isocyanic acid and bromomethane. • Biogas FTIR analysis showed also the presence of HI. • Biogas combustion emissions contained CH 4 , HI, SO 2 and probably Br 2 . - Abstract: Biogas could be produced by the co-digestion of coffee-pulp and cow-dung mixture under solar radiation. Gas chromatography and FTIR spectroscopy were used to analyze the chemical compositions of the generated biogas and its postcombustion emissions. From the first month of co-digestion at mesophylic conditions, methane content in the biogas attains 50% of the yield. This content increased up to 60% and remained almost constant for at least 8 months of further digestion. The FTIR gas spectroscopy analysis revealed the presence of over 70 chemical compounds in the biogas generated after 4 months of co-digestion along with several compounds hazardous to environment and animal health like isocyanic acid, and bromomethane. Combustion emission of the biogas contained several components like CH 4 , C 3 H 8 , CO, SO 2 , HI, and probably Br 2 which are strongly harmful to human and animal health. Results presented in this work indicate that if the

  6. SPECIFIC FEATURES OF OLIGOMERIC PRODUCT SOLIDIFICATION FROM POLYURETHANE WASTES AND THEIR PRACTICAL APPLICATION

    Directory of Open Access Journals (Sweden)

    V. Belyatsky

    2012-01-01

    Full Text Available The paper considers a possibility to use secondary polyurethane obtained by  thermal depolymerization of wastes on the basis of cross-linked polyurethane (polyurethane adduct and isocyanate. An effect of density dependence of the obtained polyurethane samples on nature and quantity of solvent has been revealed and it is significantly observed while using low-boiling solvents. The influence of adduct/solidification agent ratio on mechanical hardness of the obtained samples has been studied in the paper. The paper shows that the most optimal ratio is within the following limits – from 7/1 to 10/1. Plasticizing effect of polyurethane adduct on bitumen materials has been also found in the paper.A conclusion has been made that there is a possibility of practical usage of composites in building and road-building materials. 

  7. Coating compositions hardenable by ionization beams

    International Nuclear Information System (INIS)

    Chaudhari, D.; Haering, E.; Dobbelstein, A.; Hoselmann, W.

    1976-01-01

    Coating compositions hardenable by ionizing radiation comprise as binding agents a mixture of A. at least 1 unsaturated olefin compound containing urethane groups, and B. at least 1 further unsaturated olefin compound that may be copolymerized. The unsaturated olefin compound A. containing the urethane groups in a reaction product of (a) a compound of the general formula (CHR 1 = CR 2 COOCH 2 CH(OH)CH 2 O CO-)/sub n/R where n is 1 or 2, where R stands for a straight chain or branched alkyl group of valence n, where R 1 is hydrogen, methyl; or the group -COOCH 2 CH(OH)CH 2 OCOR 3 - where R 3 is a monovalent alkyl residue and where R 2 is hydrogen or methyl, and (b) a compound containing at least 1 isocyanate group where the mixture of (A) and (B) may contain conventional additives of the lacquer industry. 6 claims

  8. The evolution of palm oil acrylates within 20 years in Nuclear Malaysia

    International Nuclear Information System (INIS)

    Mek Zah Salleh; Rida Tajau; Nurul Huda Mudri

    2016-01-01

    Acrylated palm oil was synthesized from epoxidized palm oil (EPOP), in early 1989, through acrylation/methacrylation process at Radiation Technology Division laboratory. The acrylated products namely Epoxidized Palm Oil Acrylate/Methacrylate (EPOLA/ EPOMA), with the molecular weight around 2000-3000 g/mol, was found curable when subjected to UV or EB irradiations. Isocyanation of EPOLAs resulted in a resin called Palm Oil Based Urethane Acrylate (POBUA). POBUA possess certain advantages over EPOLA such as much higher molecular weight between 5000 to 20000 g/ mol, better curing speed, crosslinking density, higher abrasion resistance and also higher pendulum hardness. Hyper branched polyurethane acrylate (HBPUA) from palm oil oleic was synthesized by a three-step reaction in 2012. The reaction was confirmed by several analytical data; hydroxyl value (OHV), FTIR, GPC and NMR spectroscopy analyses. The thermal decomposition of HBPUA formulations shows good thermal stability up to 450 degree Celsius. (author)

  9. Remarkable promoting effect of rhodium on the catalytic performance of Ag/Al2O3 for the selective reduction of NO with decane

    International Nuclear Information System (INIS)

    Sato, Kazuhito; Yoshinari, Tomohiro; Kintaichi, Yoshiaki; Haneda, Masaaki; Hamada, Hideaki

    2003-01-01

    The addition of small amounts of rhodium enhanced the activity of Ag/Al 2 O 3 catalyst for the selective reduction of NO with decane at low temperatures. The Rh-promoted Ag/Al 2 O 3 showed its high performance even in the presence of low concentrations of SO 2 . Based on the catalytic activity for elementary reactions, it was suggested that the role of added rhodium is to enhance the reaction between NO x and decane-derived species, leading to NO reduction. Catalyst characterization by UV-Vis spectroscopy indicated that the major silver species on Rh-promoted Ag/Al 2 O 3 is Ag nn δ+ clusters, which would be responsible for the high activity. FT-IR measurements revealed that the formation rate of isocyanate species, which is a major reaction intermediate, is higher on Rh-promoted Ag/Al 2 O 3

  10. Development of segmented polyurethane elastomers with low iodine content exhibiting radiopacity and blood compatibility.

    Science.gov (United States)

    Dawlee, S; Jayabalan, Muthu

    2011-10-01

    Biofunctionally active and inherently radiopaque polymers are the emerging need for biomedical applications. Novel segmented polyurethane elastomer with inherent radiopacity was prepared using aliphatic chain extender 2,3-diiodo-2-butene-1,4-diol, polyol polytetramethylene glycol and 4,4'-methylenebis(phenyl isocyanate) (MDI) for blood compatible applications. Aliphatic polyurethane was also prepared using hexamethylene diisocyanate for comparison. X-ray analysis of the polyurethanes revealed good radiopacity even at a relatively low concentration of 3% iodine in aromatic polyurethane and 10% in aliphatic polyurethane. The polyurethanes also possessed excellent thermal stability. MDI-based polyurethane showed considerably higher tensile strength than the analogous HDI-based polyurethane. MDI-based aromatic polyurethane exhibited a dynamic surface morphology in aqueous medium, resulting in the segregation of hydrophilic domains which was more conducive to anti-thrombogenic properties. The polyurethane was cytocompatible with L929 fibroblast cells, non-hemolytic, and possessed good blood compatibility.

  11. Development of segmented polyurethane elastomers with low iodine content exhibiting radiopacity and blood compatibility

    International Nuclear Information System (INIS)

    Dawlee, S; Jayabalan, Muthu

    2011-01-01

    Biofunctionally active and inherently radiopaque polymers are the emerging need for biomedical applications. Novel segmented polyurethane elastomer with inherent radiopacity was prepared using aliphatic chain extender 2,3-diiodo-2-butene-1,4-diol, polyol polytetramethylene glycol and 4,4'-methylenebis(phenyl isocyanate) (MDI) for blood compatible applications. Aliphatic polyurethane was also prepared using hexamethylene diisocyanate for comparison. X-ray analysis of the polyurethanes revealed good radiopacity even at a relatively low concentration of 3% iodine in aromatic polyurethane and 10% in aliphatic polyurethane. The polyurethanes also possessed excellent thermal stability. MDI-based polyurethane showed considerably higher tensile strength than the analogous HDI-based polyurethane. MDI-based aromatic polyurethane exhibited a dynamic surface morphology in aqueous medium, resulting in the segregation of hydrophilic domains which was more conducive to anti-thrombogenic properties. The polyurethane was cytocompatible with L929 fibroblast cells, non-hemolytic, and possessed good blood compatibility.

  12. Synthesis of palm-based polyurethane-LiClO{sub 4} via prepolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Sien, Jason Wong Chee [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi (Malaysia); School of Biosciences, Taylor’s University, Subang Jaya (Malaysia); Badri, Khairiah Haji [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi (Malaysia); Polymer Research Center, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi (Malaysia); Su’ait, Mohd Sukor [Polymer Research Center, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi (Malaysia); Solar Energy Research Institute Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi (Malaysia); Hassan, Nurul Izzati [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi (Malaysia)

    2015-09-25

    Palm-based polyurethane (pPU) with varying lithium salt (LiClO{sub 4}) content was synthesized. Higher loading percentage of LiClO{sub 4} in the pPU led to the inhibition of prepolymerization process from taking place. Hydrogen bonded C=O was detected in the FTIR spectrum indicating the hydrogen bonding between the urethane bonds. Ordered complexed C=O was observed in the FTIR spectrum confirming the complex formation between urethane bond and Li{sup +} ion. DSC thermogram showed the increase in the LiClO{sub 4} content could increase the glass transition temperature. SEM micrographs exhibited that more bubbles were formed when the LiClO{sub 4} increased from 10 to 30wt% indicating the reaction between free isocyanate groups with moisture presence in the salt due to the hygroscopic properties of LiClO{sub 4}.

  13. Cellulose-reinforced composites: from micro-to nanoscale

    Directory of Open Access Journals (Sweden)

    Alain Dufresne

    2013-01-01

    Full Text Available This paper present the most relevant advances in the fields of: i cellulose fibres surface modification; ii cellulose fibres-based composite materials; and iii nanocomposites based on cellulose whiskers or starch platelet-like nanoparticles. The real breakthroughs achieved in the first topic concern the use of solvent-free grafting process (plasma and the grafting of the matrix at the surface of cellulose fibres through isocyanate-mediated grafting or thanks to "click chemistry". Concerning the second topic, it is worth to mention that for some cellulose/matrix combination and in the presence of adequate aids or specific surface treatment, high performance composite materials could be obtained. Finally, nanocomposites allow using the semi-crystalline nature and hierarchical structure of lignocellulosic fibres and starch granules to more deeply achieve this goal profitably exploited by Mother Nature

  14. Castor oil and commercial thermoplastic polyurethane membranes modified with polyaniline: a comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Almeida Junior, Jose Humberto Santos; Meneguzzi, Alvaro; Ferreira, Carlos Arthur, E-mail: jhsajunior@globomail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegtre, RS (Brazil). Dept. de Engenharia de Materiais; Bertuol, Daniel Assumpcao [Universidade Federal de Santa Maria (UFSM), RS (Brazil). Dept. de Engenharia Quimica; Amado, Franco Dani Rico [Universidade Estadual de Santa Cruz (UESC), Ilheus, BA (Brazil). Dept. de Ciencias Exatas e Tecnologia

    2013-11-01

    The study of conducting polymeric membranes is decisive in some areas, as in fuel cells and electrodialysis. This work aims the study of membranes using conventional and conductive polymers blends. Two types of polyurethane were used as conventional polymers, commercial thermoplastic polyurethane and polyurethane synthesized from castor oil and 4-4-dicyclohexylmethane isocyanate. Two kinds of conducting polymers were used, polyaniline doped with organic acid and a self doped polyaniline. The polymers and the membranes were characterized by electrical conductivity, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). The synthesis of the membranes produced was proper, featuring a complete reaction, analyzed by FTIR. The membranes also showed good mechanical properties and thermal stability ( Almost-Equal-To 220 Degree-Sign C). Among the membranes studied, the polyaniline doped with p-toluenesulphonic acid obtained higher thermal and viscoelastic properties. Thus they can be used in separation techniques using membranes. (author)

  15. Automated Production of Insulated Footwear

    Science.gov (United States)

    1977-06-01

    td 0 -* -^ -H ♦* «0 >-4 « as H 5 .* § £ s 0CM W Ü •« -< 0 -H c o S. is. a. y: 5B -* oo — öS Q...No. of equivalents of MDI Isocyanate Index ■ ___________———— No. of equivalents of (PTMG, 1- 4BD , TMP) B. Outsole Formula a- Ingredients...faift*Jkäl GDA >4QJPA _Cf&Jh* td - *Ä*/> 9«J&LE**L TkL’*** A /#s?ttT&W’** K>UPA ►0CI1PAI v—i. rt OOGDA 0?DPA[ 03>Q]DA 0$DF>A 0$QI>A OODDA

  16. Degradation mechanism and thermal stability of urea nitrate below the melting point

    International Nuclear Information System (INIS)

    Desilets, Sylvain; Brousseau, Patrick; Chamberland, Daniel; Singh, Shanti; Feng, Hongtu; Turcotte, Richard; Anderson, John

    2011-01-01

    Highlights: → Decomposition mechanism of urea nitrate. → Spectral characterization of the decomposition mechanism. → Thermal stability of urea nitrate at 50, 70 and 100 o C. → Chemical balance of decomposed products released. - Abstract: Aging and degradation of urea nitrate below the melting point, at 100 o C, was studied by using thermal analysis and spectroscopic methods including IR, Raman, 1 H and 13 C NMR techniques. It was found that urea nitrate was completely degraded after 72 h at 100 o C into a mixture of solids (69%) and released gaseous species (31%). The degradation mechanism below the melting point was clearly identified. The remaining solid mixture was composed of ammonium nitrate, urea and biuret while unreacted residual nitric and isocyanic acids as well as traces of ammonia were released as gaseous species at 100 o C. The thermal stability of urea nitrate, under extreme storage conditions (50 o C), was also examined by isothermal nano-calorimetry.

  17. Sustained-release microsphere formulation containing an agrochemical by polyurethane polymerization during an agitation granulation process.

    Science.gov (United States)

    Terada, Takatoshi; Tagami, Manabu; Ohtsubo, Toshiro; Iwao, Yasunori; Noguchi, Shuji; Itai, Shigeru

    2016-07-25

    In this report, a new solventless microencapsulation method by synthesizing polyurethane (PU) from polyol and isocyanate during an agglomeration process in a high-speed mixing apparatus was developed. Clothianidin (CTD), which is a neonicotinoid insecticide and highly effective against a wide variety of insect pests, was used as the model compound. The microencapsulated samples covered with PU (CTD microspheres) had a median diameter of <75μm and sustained-release properties. The CTD microspheres were analyzed by synchrotron X-ray computed tomography measurements. Multiple cores of CTD and other solid excipient were dispersed in PU. Although voids appeared in the CTD microspheres after CTD release, the spherical shape of the microspheres remained stable and no change in its framework was observed. The experimental release data were highly consistent with the Baker-Lonsdale model derived from drug release of spherical monolithic dispersions and consistent with the computed tomography measurements. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Palladium-catalyzed cyclocarbonylation of o-iodoanilines with heterocumulenes: regioselective preparation of 4(3H)-quinazolinone derivatives

    Science.gov (United States)

    Larksarp; Alper

    2000-05-09

    A catalyst system comprising palladium acetate-bidentate phosphine is effective for the cyclocarbonylation of o-iodoanilines with heterocumulenes at 70-100 degrees C for 12-24 h to give the corresponding 4(3H)-quinazolinone derivatives in good yields. Utilizing o-iodoaniline with isocyanates, carbodiimides, and ketenimines for the reaction, 2,4-(1H,3H)-quinazolinediones, 2-amino-4(3H)-quinazolinones and 2-alkyl-4(3H)-quinazolinones were obtained, respectively. The nature of the substrates including the electrophilicity of the carbon center of the carbodiimide, and the stability of the ketenimine, influence the product yields of this reaction. Urea-type intermediates are believed to be generated first in situ from the reaction of o-iodoanilines with heterocumulenes, followed by palladium-catalyzed carbonylation and cyclization to yield the products.

  19. Orthogonal Clickable Iron Oxide Nanoparticle Platform for Targeting, Imaging, and On-Demand Release.

    Science.gov (United States)

    Guldris, Noelia; Gallo, Juan; García-Hevia, Lorena; Rivas, José; Bañobre-López, Manuel; Salonen, Laura M

    2018-04-12

    A versatile iron oxide nanoparticle platform is reported that can be orthogonally functionalized to obtain highly derivatized nanomaterials required for a wide variety of applications, such as drug delivery, targeted therapy, or imaging. Facile functionalization of the nanoparticles with two ligands containing isocyanate moieties allows for high coverage of the surface with maleimide and alkyne groups. As a proof-of-principle, the nanoparticles were subsequently functionalized with a fluorophore as a drug model and with biotin as a targeting ligand towards tumor cells through Diels-Alder and azide-alkyne cycloaddition reactions, respectively. The thermoreversibility of the Diels-Alder product was exploited to induce the on-demand release of the loaded molecules by magnetic hyperthermia. Additionally, the nanoparticles were shown to target cancer cells through in vitro experiments, as analyzed by magnetic resonance imaging. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Polyurethane Production from Waste Bale Fibers

    Directory of Open Access Journals (Sweden)

    İbrahim BİLİCİ

    2017-12-01

    Full Text Available Nowadays, the methods of eliminating the pollution from wastes of the materials produced as much as the production methods are important. This requires efficiently use of sources economical and ecologically. Polyester based polymers, which is one of the most important consumed plastic materials in the world, have lots of number of recycling methods. Basically it is called chemical and physical recycling. Chemical recycle methods include glycolysis, aminolysis, methanolysis, hydrolysis and etc.. In this study aromatic polyester polyols produced from bale fiber wastes via glycolysis method. Zinc Acetate used as a catalysts and diethylene glycol used for the glycolysis reaction and moiety of glycol investigated as an experimental parameter. Polyurethane material produced via obtained polyol and TDI (Toluene di Isocyanate reaction. Obtained polyurethane material investigated via FTIR and TGA and compared with the commercial polyurethane. As a result, it has been decided that glycolysis is usable and applicable method for the waste bale fibers.

  1. Atmospheric analyzer, carbon monoxide monitor and toluene diisocyanate monitor

    Science.gov (United States)

    Shannon, A. V.

    1977-01-01

    The purpose of the atmospheric analyzer and the carbon monoxide and toluene diisocyanate monitors is to analyze the atmospheric volatiles and to monitor carbon monoxide and toluene diisocyanate levels in the cabin atmosphere of Skylab. The carbon monoxide monitor was used on Skylab 2, 3, and 4 to detect any carbon monoxide levels above 25 ppm. Air samples were taken once each week. The toluene diisocyanate monitor was used only on Skylab 2. The loss of a micrometeoroid shield following the launch of Skylab 1 resulted in overheating of the interior walls of the Orbital Workshop. A potential hazard existed from outgassing of an isocyanate derivative resulting from heat-decomposition of the rigid polyurethane wall insulation. The toluene diisocyanate monitor was used to detect any polymer decomposition. The atmospheric analyzer was used on Skylab 4 because of a suspected leak in the Skylab cabin. An air sample was taken at the beginning, middle, and the end of the mission.

  2. Thermally reversible cross-linked poly(ether-urethanes

    Directory of Open Access Journals (Sweden)

    V. Gaina

    2013-07-01

    Full Text Available Cross-linked poly(ether-urethanes were prepared by Diels-Alder (DA reaction of the furan-containing poly(ether-urethane to bismaleimides and showed thermal reversibility evidenced by differential scanning calorimetry and attenuated total reflectance in conjunction with Fourier transform infrared spectroscopy (ATR-FTIR. The furan-containing poly(ether-urethanes were synthesized by the polyaddition reaction of 1,6-hexamethylene diisocyanate (HMDI or 4,4'- dibenzyl diisocyanate (DBDI to poly(tetramethylene ether glycol (PTMEG having Mn = 250, 650, 1000, 1500 and 2000 and 2-[N,N-bis(2-methyl-2-hydroxyethylamino]furfuryl as chain extender by the solution prepolymer method. The molar ratio of isocyanate: PTMEG:chain extender varied from 2:1:1 to 4:1:3, which produces a molar concentration of furyl group ranging between 3.65•10–4 and 1.25•10–3 mol/g.

  3. Observing Femtosecond Fragmentation Using Ultrafast X-ray-Induced Auger Spectra

    Directory of Open Access Journals (Sweden)

    Thomas J. A. Wolf

    2017-07-01

    Full Text Available Molecules often fragment after photoionization in the gas phase. Usually, this process can only be investigated spectroscopically as long as there exists electron correlation between the photofragments. Important parameters, like their kinetic energy after separation, cannot be investigated. We are reporting on a femtosecond time-resolved Auger electron spectroscopy study concerning the photofragmentation dynamics of thymine. We observe the appearance of clearly distinguishable signatures from thymine′s neutral photofragment isocyanic acid. Furthermore, we observe a time-dependent shift of its spectrum, which we can attribute to the influence of the charged fragment on the Auger electron. This allows us to map our time-dependent dataset onto the fragmentation coordinate. The time dependence of the shift supports efficient transformation of the excess energy gained from photoionization into kinetic energy of the fragments. Our method is broadly applicable to the investigation of photofragmentation processes.

  4. Matrix separation by chelation to prepare biological materials for isotopic zinc analysis by inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Durrant, S.F.; Krushevska, A.; Amarasiriwardena, D.; Argentine, M.D.; Romon-Guesnier, S.; Barnes, R.M.

    1994-01-01

    Following an evaluation of three chelating resins [Chelex-100, poly(dithiocarbamate) (PDTC) and carboxymethylated poly(ethyleneimine)-poly(methylenepolyphenylene) isocyanate (CPPI)], a procedure was established with the last of these for the separation of Zn from biological matrix elements prior to 70 Zn: 68 Zn isotopic analysis by inductively coupled plasma mass spectrometry (ICP-MS). The method was verified by establishing Zn recoveries and by determining its effectiveness in removing Cl and Na from buffered test solutions. Calcium, Na, and Zn concentration data were determined by inductively coupled plasma atomic emission spectrometry. Chlorine was measured by electrothermal vaporization ICP-MS. The efficacy of the technique was demonstrated by the determination of zinc isotope ratios in bovine milk and human urine. (Author)

  5. Preliminary characterization of propellants based on p(GA/BAMO) and pAMMO binders

    Energy Technology Data Exchange (ETDEWEB)

    Barbieri, Ugo; Polacco, Giovanni [Department of Chemical Engineering, University of Pisa (Italy); Keicher, Thomas [Fraunhofer-Institut fuer Chemische Technologie (ICT), Pfinztal (Germany); Massimi, Roberto [AVIO S.p.A., Roma (Italy)

    2009-10-15

    In previous papers, the synthesis and characterization of OH-terminated glycidyl azide-r-(3,3-bis(azidomethyl)oxetane) copolymers (GA/BAMO) and poly-3-azidomethyl-3-methyl oxetane (pAMMO) by azidation of their respective polymeric substrates were described. The main objective was the preparation of amorphous azido-polymers, as substitutes of hydroxy-terminated polybutadiene (HTPB) in new formulations of energetic propellants. Here, the subsequent characterization of both the binders is presented. First of all, several isocyanates were checked in order to optimize the curing reaction, and then two small-scale formulations of a propellant, based on aluminium and ammonium perchlorate, were prepared and characterized. Finally, the mechanical properties and burning rate were compared to those of a similar propellant based on HTPB as binder. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  6. Studies on polyurethane adhesives and surface modification of hydrophobic substrates

    Science.gov (United States)

    Krishnamoorthy, Jayaraman

    This thesis work deals with (a) Curing of reactive, hot-melt polyurethane adhesives and (b) Adsorption studies using different interactions. Research on polyurethanes involves characterization of polyurethane prepolymers and a novel mechanism to cure isocyanate-terminated polyurethane prepolymer by a "trigger" mechanism. Curing of isocyanate-terminated polyurethane prepolymers has been shown to be influenced by morphology and environmental conditions such as temperature and relative humidity. Although the initial composition, final morphology and curing kinetics are known, information regarding the intermediate prepolymer mixture is yet to be established. Polyurethane prepolymers prepared by the reaction of diisocyanates with the primary hydroxyls of polyester diol (PHMA) and secondary hydroxyls of polyether diol (PPG) were characterized. The morphology and crystallization kinetics of a polyurethane prepolymer was compared with a blend of PPG prepolymer (the product obtained by the reaction of PPG with diisocyanate) and a PHMA prepolymer (the product obtained by the reaction of PHMA with diisocyanate) to study the effect of copolymer formed in the polyurethane prepolymer on the above-mentioned properties. Although the morphology of the polyurethane prepolymer is determined in the first few minutes of application, the chemical curing of isocyanate-terminated prepolymer occurs over hours to days. In the literature, different techniques are described to follow the curing kinetics. But there is no established technique to control the curing of polyurethane prepolymer. To make the curing process independent of environmental factors, a novel approach using a trigger mechanism was designed and implemented by using ammonium salts as curing agents. Ammonium salts that are stable at room temperature but decompose on heating to yield active hydrogen-containing compounds, NH3 and H2O, were used as 'Trojan horses' to cure the prepolymer chemically. Research on adsorption

  7. Comparison of Coatings from Reactive Star Shaped PEG-stat-PPG Prepolymers and Grafted Linear PEG for Biological and Medical Applications

    DEFF Research Database (Denmark)

    Groll, J.; Ademovic, Z.; Klee, D.

    2005-01-01

    ). In an alternative approach, surfaces were modified with layers prepared from isocyanate terminated, star shaped poly(ethylene glycol-stat-propylene glycol) prepolymers (80% ethylene glycol, six arms, M. = 3000, 12 000, and 18 000; this compound will be referred to as "Star PEG" in the text). Due to the highly......Grafting of poly(ethylene glycol) (PEG) is a common strategy for reducing nonspecific interactions of surfaces with proteins. We have used grafting at "cloud point" solution conditions that ensures maximum grafting density of linear methoxy terminated PEG-aldehyde (mPEG-ald, M-W = 5000 and 30000....... Protein adsorption was monitored by surface MALDI-TOF MS and fluorescence microscopy. No protein adsorption could be detected on Star PEG coatings and on mPEG-ald 5000, whereas mPEG-ald 30 000 could only prevent adsorption of lysozyme but not of the smaller insulin....

  8. Synthetic Studies Towards the Core Structure of Nakadomarin A by a Thioamide-Based Strategy

    Science.gov (United States)

    Chavda, Jai K; Procopiou, Panayiotis A; Horton, Peter N; Coles, Simon J; Porter, Michael J

    2014-01-01

    The tricyclic BCD substructure of the marine natural product nakadomarin A has been synthesised. The strategy utilised a key carbon–carbon bond-forming reaction between a furan and an N-acyliminium ion derived from a secondary thiolactam. In addition, a novel three-component coupling reaction between a thioamide, an allylic bromide and an isocyanate, leading to the establishment of two new stereogenic centres, is reported. Two key steps in a projected total synthesis of nakadomarin A have been realised by using the unique chemistry of thioamides. Formation of the carbocyclic B ring can be effected by nucleophilic attack of a furan on a thiolactam-derived iminium ion, and the key quaternary centre can be established by a novel three-component coupling reaction. PMID:24829538

  9. In Situ Foaming of Porous (La 0.6 Sr 0.4 ) 0.98 (Co 0.2 Fe 0.8 ) O 3-δ (LSCF) Cathodes for Solid Oxide Fuel Cell Applications

    Energy Technology Data Exchange (ETDEWEB)

    Gandavarapu, Sodith [US DOE-National Energy Technology Laboratory, 3610 Collins Ferry Road P.O.Box.880 Morgantown West Virginia 26507; Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown West Virginia 26506; Sabolsky, Edward [US DOE-National Energy Technology Laboratory, 3610 Collins Ferry Road P.O.Box.880 Morgantown West Virginia 26507; Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown West Virginia 26506; Sabolsky, Katarzyna [Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown West Virginia 26506; Gerdes, Kirk [US DOE-National Energy Technology Laboratory, 3610 Collins Ferry Road P.O.Box.880 Morgantown West Virginia 26507

    2013-07-18

    A binder system containing polyurethane precursors was used to in situ foam (direct foam) a (La{sub 0.6}Sr{sub 0.4}){sub 0.98} (Co{sub 0.2} Fe{sub 0.8}) O{sub 3-{ delta}} (LSCF) composition for solid oxide fuel cell (SOFC) cathode applications. The relation between in situ foaming parameters on the final microstructure and electrochemical properties was characterized by microscopy and electrochemical impedance spectroscopy (EIS), respectively. The optimal porous cathode architecture was formed with a 70 vol% solids loading within a polymer precursor composition with a volume ratio of 8:4:1 (isocyanate: PEG: surfactant) in a terpineol-based ink vehicle. The resultant microstructure displayed a broad pore size distribution with highly elongated pore structure.

  10. Porous double-layer polymer tubing for the potential use in heterogeneous continuous flow reactions.

    Science.gov (United States)

    Herwig, Gordon; Hornung, Christian H; Peeters, Gary; Ebdon, Nicholas; Savage, G Paul

    2014-12-24

    Functional polymer tubing with an OD of 1/16 or 1/8 in. was fabricated by a simple polymer coextrusion process. The tubing was made of an outer impervious polypropylene layer and an inner layer, consisting of a blend of a functional polymer, polyethylene-co-methacrylic acid, and a sacrificial polymer, polystyrene. After a simple solvent leaching step using common organic solvents, the polystyrene was removed, leaving behind a porous inner layer that contains functional carboxylic acid groups, which could then be used for the immobilization of target molecules. Solution-phase reactions using amines or isocyanates have proven successful for the immobilization of a series of small molecules and polymers. This flexible multilayered functional tubing can be easily cut to the desired length and connected via standard microfluidic fittings.

  11. Síntese e caracterização de dispersões aquosas de poliuretanos à base de copolímeros em bloco de poli(glicol etilênico e poli(glicol propilênico Synthesis and characterization of polyurethane aquous dispersions based on poly(ethylene glycol and poly(propylene glycol block copolymers

    Directory of Open Access Journals (Sweden)

    Fernanda M. B. Coutinho

    2008-01-01

    Full Text Available Non-polluting polyurethane aqueous dispersions, with 40% of solids content, were synthesized based on block copolymers of poly(ethylene glycol and poly(propylene glycol (PEG-b-PPG, with PEG hydrophilic segments content of 7 and 25%, poly(propylene glycol (PPG, dimethylolpropionic acid (DMPA, isophorone diisocyanate (IPDI, and hydrazine. Different formulations were synthesized by varying the equivalent-grams ratios between isocyanate and hydroxyl groups (NCO/OH and PPG and (PEG-b-PPG. The presence of high amounts of PEG in the formulations provoked the formation of gels. Average particle size and viscosity of the dispersions were determined. Mechanical properties and water absorption resistance of cast films were evaluated.

  12. Demand and supply of hydrogen as chemical feedstock in USA

    Science.gov (United States)

    Huang, C. J.; Tang, K.; Kelley, J. H.; Berger, B. J.

    1979-01-01

    Projections are made for the demand and supply of hydrogen as chemical feedstock in USA. Industrial sectors considered are petroleum refining, ammonia synthesis, methanol production, isocyanate manufacture, edible oil processing, coal liquefaction, fuel cell electricity generation, and direct iron reduction. Presently, almost all the hydrogen required is produced by reforming of natural gas or petroleum fractions. Specific needs and emphases are recommended for future research and development to produce hydrogen from other sources to meet the requirements of these industrial sectors. The data and the recommendations summarized in this paper are based on the Workshop 'Supply and Demand of Hydrogen as Chemical Feedstock' held at the University of Houston on December 12-14, 1977.

  13. Use of bromine as biocide in cooling waters (Preprint No. CA-19)

    Energy Technology Data Exchange (ETDEWEB)

    Sriraman, A K [Bhabha Atomic Research Centre, Bombay (India). Water Chemistry Div.

    1989-04-01

    In all fresh water circuits, the slime forming bacteria develop an insulating layer on the condenser surfaces. If these bacteria are not controlled, they induce bacterial promoted corrosion of the materials in contact with cooling water. Chlorination is effective against slime forming bacteria, fungi and algae. The algistatic nature of the chlorine is partly compensated by the use of other non-oxidisable biocides. Amongst the various alternative biocides such as bromine, methyl bis-isocyanate, sodium pentachlorophenate etc, bromine is the most simple biocide, which is being increasingly used in cooling water systems. In this context, the chemistry of bromination and its bactericidal properties is examined along with those of chlorination. (author). 7 refs., 3 tabs., 2 figs.

  14. Zero-birefringence pressure-sensitive adhesives

    Directory of Open Access Journals (Sweden)

    Hiroto Ito

    2012-06-01

    Full Text Available We have developed zero-birefringence pressure-sensitive adhesives (PSAs that exhibit almost no birefringence at any orientation of polymer chains. To evaluate the birefringence of PSAs quantitatively, we report a novel birefringence-measurement method utilizing zero–zero-birefringence polymers that exhibit no birefringence at any orientation of polymer chains and in elastic deformation. By employing this method, we designed and synthesized poly(butyl acrylate/phenoxyethyl acrylate/acrylic acid/hydroxyethyl acrylate = 80.0:20.0:1.5:1.0 (by weight that contains 1.8 wt% isocyanate-type crosslinker that exhibited almost zero birefringence. Furthermore, we demonstrated that after the accelerated aging test by applying heat, this zero-birefringence PSA almost completely prevented light leakage through crossed polarizers.

  15. Foam patterns

    Science.gov (United States)

    Chaudhry, Anil R; Dzugan, Robert; Harrington, Richard M; Neece, Faurice D; Singh, Nipendra P; Westendorf, Travis

    2013-11-26

    A method of creating a foam pattern comprises mixing a polyol component and an isocyanate component to form a liquid mixture. The method further comprises placing a temporary core having a shape corresponding to a desired internal feature in a cavity of a mold and inserting the mixture into the cavity of the mold so that the mixture surrounds a portion of the temporary core. The method optionally further comprises using supporting pins made of foam to support the core in the mold cavity, with such pins becoming integral part of the pattern material simplifying subsequent processing. The method further comprises waiting for a predetermined time sufficient for a reaction from the mixture to form a foam pattern structure corresponding to the cavity of the mold, wherein the foam pattern structure encloses a portion of the temporary core and removing the temporary core from the pattern independent of chemical leaching.

  16. Stereospecific high-performance liquid chromatographic assay of sotalol in plasma.

    Science.gov (United States)

    Carr, R A; Foster, R T; Bhanji, N H

    1991-09-01

    A convenient high-performance liquid chromatographic (HPLC) assay was developed for determination of sotalol (STL) enantiomers in plasma. Following addition of the internal standard (IS; racemic atenolol), enantiomers of STL and IS were extracted using ethyl acetate. After evaporation of the organic layer, samples were derivatized with a solution of S-(+)-1-(1-naphthyl)ethyl isocyanate (NEIC). The resulting diastereomers were chromatographed with normal-phase HPLC with chloroform:hexane:methanol [65:33:2 (v/v)] as the mobile phase at a flow rate of 2 ml/min. The fluorescence detection wavelength was set at 220 nm for excitation with no emission filter. The suitability of the assay for pharmacokinetic studies was determined by measuring STL enantiomers in the plasma of a healthy subject after administration of a single 160-mg oral, racemic dose of STL.

  17. Fluorous Parallel Synthesis of A Hydantoin/Thiohydantoin Library

    Science.gov (United States)

    Lu, Yimin; Zhang, Wei

    2007-01-01

    Fluorous tagging strategy is applied to solution-phase parallel synthesis of a library containing hydantoin and thiohydantoin analogs. Two perfluoroalkyl (Rf)-tagged α-amino esters each react with 6 aromatic aldehydes under reductive amination conditions. Twelve amino esters then each react with 10 isocyanates and isothiocyanates in parallel. The resulting 120 ureas and thioureas undergo spontaneous cyclization to form the corresponding hydantoins and thiohydantoins. The intermediate and final product purifications are performed with solid-phase extraction (SPE) over FluoroFlash™ cartridges, no chromatography is required. Using standard instruments and straightforward SPE technique, one chemist accomplished the 120-member library synthesis in less than 5 working days, including starting material synthesis and product analysis. PMID:15789556

  18. Waterborne polyurethane single-ion electrolyte from aliphatic diisocyanate and various molecular length of polyethylene glycol

    Directory of Open Access Journals (Sweden)

    2007-03-01

    Full Text Available The waterborne polyurethane (WPU dispersions from the reaction of cycloaliphatic diisocyanates [4,4’-methylenebis(cyclohexyl isocyanate (H12MDI and isophorone diisocyanate (IPDI] and polyethylene glycol (PEG with various molecular lengths were synthesized using our modified acetone process. Differetial scanning calorimeter (DSC and Fourier transform infrared spectroscopy (FTIR were utilized to characterize WPU films for the behavior of their crystallinity and H-bonding of WPU films. The Tg value of WPU increases with increasing the molecular length of PEG, whereas the Tm of WPU decreases with increasing PEG length. Alternating current (AC impedance experiments were performed to determine the ionic conductivities of WPU films. The WPU gel electrolytes exhibits an ionic conductivity as high as ~ 10-5 S/cm at room temperature.

  19. Radiation sensitive polymers of oxygen-substituted maleimides and elements containing same

    International Nuclear Information System (INIS)

    Wilson, J.C.

    1977-01-01

    Radiation sensitive polymers comprising from about 1 to 100 mole % of a polymerized maleimide monomer consisting of a hydrocarbon group having from 2 to 20 carbon atoms, preferably a bridged hydrocarbon group having from 6 to 10 carbon atoms and from 0 to about 99 mole % of at least one additional polymerized ethylenically unsaturated monomer are described. The polymers are soluble in organic solvents, possess desirably high glass transition temperatures and are capable of undergoing a photochemical reaction to yield polymers having isocyanate and oxy-substituted cyclopropane moieties which are capable of crosslinking in the presence of active hydrogen-containing compounds. The polymers are useful in radiation sensitive compositions and elements containing same

  20. Characterization of polyurethane based on polyol synthesized from glycerol and hexamethylene diisocyanate

    International Nuclear Information System (INIS)

    Carvalho, Sabrina M.; Weber, Vanessa; Silva, Tailu N.; Barreto, Pedro L.M.

    2009-01-01

    A new polyol based on glycerol was synthesized and used in the production of polyurethane by reaction with hexamethylene diisocyanate. The polyol was characterized by nuclear magnetic resonance spectroscopy (NMR) and Fourier transform-infrared spectroscopy (FTIR). The polyurethane produced was characterized by FTIR, thermogravimetry (TG), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The polyol was shown to be reactive with hexamethylene diisocyanate, as the FTIR spectrum showed no free isocyanate groups and identified the presence of group -C=O of urethane groups. Analysis by DSC showed that the sample of polyurethane has a glass transition temperature around -8.53 deg C and SEM micrographs showed fracture and surface continuous and not broken. The thermogravimetric analysis showed that the polyurethane produced has a high thermal stability with a temperature of maximum degradation around 430 deg C. (author)

  1. Crystallization behaviour of nanostructured hybrid SiO2-TiO2 gel glasses to nanocomposites.

    Science.gov (United States)

    Tsvetelina, Gerganova; Yordanka, Ivanova; Yuliya, Vueva; Miranda, Salvado Isabel M; Helena, Fernandes Maria

    2010-04-01

    The crystallization behaviour of hybrid SiO2-TiO2 nanocomposites derived from titanosiloxanes by sol-gel method has been investigated depending on the type of siloxane precursor and the pirolysis temperature. The resulting hybrid titanosiloxanes, crosslinked with trimethylsilil isocyanate (nitrogen-modified) or methyltrietoxisilane (carbon-modified), were pirolyzed in an inert atmosphere in the temperature range between 600 to 1100 degrees C in order to form C-(N)-Si-O-TiO2 nanocomposites. By means of XRD, FTIR, 29Si NMR, SEM, TEM and AFM investigations have been established that the transformation of the nanostructured SiO2-TiO2 hybrid materials into nanocomposites as well as the crystalline size depend on the titanium content and the type of cross-linking agents used in the synthesizes.

  2. Interfacial Adhesion and Damping Characteristics of Laminated Veneer Lumber Intercalated with Rubber Sheets

    Directory of Open Access Journals (Sweden)

    Jingquan Han

    2016-06-01

    Full Text Available Laminated wood veneer lumber intercalated with rubber sheets (LLVR was fabricated using a layered adhesive system composed of polyaryl polymethylene isocyanate (PAPI for wood-rubber inter-bonding and phenol formaldehyde (PF resin to glue the wood veneers. The optimized manufacturing process (chloroprene rubber: CR; PAPI: 80 g/m2; PF: 200 g/m2; and silane: 9.0 wt.% was determined. The process as developed was then utilized to fabricate nine-ply LLVRs of five balanced constructions with two or three CR laminates used as various layers. The physico-mechanical properties of the LLVRs were evaluated, and the results showed that LLVRs had strong shear strength, sound dimensional stability, decent bending strength, and favorable toughening and buffering performances. The newly developed product is an interesting potential alternative to traditional laminated veneer lumber or plywood.

  3. Proton-induced accelerated decay of the fungicide, vinclozolin, on TiO2 surface under solar irradiation: Experimental and DFT study.

    Science.gov (United States)

    Osipov, Ivan; Gorbachev, Mikhail Y; Gorinchoy, Natalia N

    2018-04-03

    The photochemical degradation of vinclozolin by addition of titanium dioxide on silica support has been examined both experimental and quantum-chemically. Solar irradiation of vinclozolin on silica with and without addition of titanium dioxide for 6 h resulted in 21% and 97.8% vinclozolin residues, respectively. In both these cases, phototransformation leads to the formation of (3,5-dichlorophenyl isocyanate) and (3,5-dichloroaniline). The presence of the intermediary product resulted from opening of the 2,4-oxazolidine-dione ring is also confirmed by GS-MS and LC-MS chromatography. The proton-induced mechanism of vinclozolin decay at the above experimental conditions is clarified on the base of DFT calculations.

  4. PET studies of potential chemotherapeutic agents: Pt. 10; Synthesis of ''no-carrier-added'' ( sup 11 C)-HECNU: the hydroxyethyl analog of the chemotherapeutic agent BCNU

    Energy Technology Data Exchange (ETDEWEB)

    Conway, T.; Diksic, M. (Montreal Neurological Inst. and Hospital, PQ (Canada). McConnell Brain Imaging Centre McGill Univ., Montreal, PQ (Canada). Dept. of Neurology and Neurosurgery)

    1991-01-01

    Carbon-11-labeled HECNU (1-(2-chloroethyl)-1-nitroso-3-(2-hydroxyethyl) urea) a potential chemotherapeutic agent, has been prepared by the nitrosation of the corresponding carbon-11-labeled urea, HECU, (1-(2-chloroethyl)-3-(2-hydroxyethyl) urea). The isomeric byproduct of nitrosation, 1-(2-chloroethyl)-3-nitroso-3-(2-hydroxyethyl) urea can be efficiently removed by preparative scale HPLC on a Partisil column. ({sup 11}C)-HECU was prepared by reacting ethanolamine with ({sup 11}C)-2-chloroethyl-isocyanate which was itself prepared by reacting ({sup 11}C)-phosgene with 2-chloroethylamine hydrochloride suspended in dioxane at 60-65{sup o}C. This synthesis yielded ({sup 11}C)-HECNU with an average radiochemical purity of 98% in an average radiochemical yield of 18% relative to the radioactivity measured at the end of the {sup 11}C-phosgene introduction. (author).

  5. PET studies of potential chemotherapeutic agents: Pt. 10

    International Nuclear Information System (INIS)

    Conway, T.; Diksic, M.; McGill Univ., Montreal, PQ

    1991-01-01

    Carbon-11-labeled HECNU [1-(2-chloroethyl)-1-nitroso-3-(2-hydroxyethyl) urea] a potential chemotherapeutic agent, has been prepared by the nitrosation of the corresponding carbon-11-labeled urea, HECU, [1-(2-chloroethyl)-3-(2-hydroxyethyl) urea]. The isomeric byproduct of nitrosation, 1-(2-chloroethyl)-3-nitroso-3-(2-hydroxyethyl) urea can be efficiently removed by preparative scale HPLC on a Partisil column. ( 11 C)-HECU was prepared by reacting ethanolamine with ( 11 C)-2-chloroethyl-isocyanate which was itself prepared by reacting ( 11 C)-phosgene with 2-chloroethylamine hydrochloride suspended in dioxane at 60-65 o C. This synthesis yielded ( 11 C)-HECNU with an average radiochemical purity of 98% in an average radiochemical yield of 18% relative to the radioactivity measured at the end of the 11 C-phosgene introduction. (author)

  6. Constructing Fluorine-Free and Cost-Effective Superhydrophobic Surface with Normal-Alcohol-Modified Hydrophobic SiO2 Nanoparticles.

    Science.gov (United States)

    Ye, Hui; Zhu, Liqun; Li, Weiping; Liu, Huicong; Chen, Haining

    2017-01-11

    Superhydrophobic coatings have drawn much attention in recent years for their wide potential applications. However, a simple, cost-effective, and environmentally friendly approach is still lacked. Herein, a promising approach using nonhazardous chemicals was proposed, in which multiple hydrophobic functionalized silica nanoparticles (SiO 2 NPs) were first prepared as core component, through the efficient reaction between amino group containing SiO 2 NPs and the isocyanate containing hydrophobic surface modifiers synthesized by normal alcohols, followed by simply spraying onto various substrates for superhydrophobic functionalization. Furthermore, to further improve the mechanical durability, an organic-inorganic composite superhydrophobic coating was fabricated by incorporating cross-linking agent (polyisocyanate) into the mixture of hydrophobic-functionalized SiO 2 NPs and hydroxyl acrylic resin. The hybrid coating with cross-linked network structures is very stable with excellent mechanical durability, self-cleaning property and corrosion resistance.

  7. Development of segmented polyurethane elastomers with low iodine content exhibiting radiopacity and blood compatibility

    Energy Technology Data Exchange (ETDEWEB)

    Dawlee, S; Jayabalan, Muthu, E-mail: muthujayabalan@rediffmail.com [Polymer Science Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala 695 012 (India)

    2011-10-15

    Biofunctionally active and inherently radiopaque polymers are the emerging need for biomedical applications. Novel segmented polyurethane elastomer with inherent radiopacity was prepared using aliphatic chain extender 2,3-diiodo-2-butene-1,4-diol, polyol polytetramethylene glycol and 4,4'-methylenebis(phenyl isocyanate) (MDI) for blood compatible applications. Aliphatic polyurethane was also prepared using hexamethylene diisocyanate for comparison. X-ray analysis of the polyurethanes revealed good radiopacity even at a relatively low concentration of 3% iodine in aromatic polyurethane and 10% in aliphatic polyurethane. The polyurethanes also possessed excellent thermal stability. MDI-based polyurethane showed considerably higher tensile strength than the analogous HDI-based polyurethane. MDI-based aromatic polyurethane exhibited a dynamic surface morphology in aqueous medium, resulting in the segregation of hydrophilic domains which was more conducive to anti-thrombogenic properties. The polyurethane was cytocompatible with L929 fibroblast cells, non-hemolytic, and possessed good blood compatibility.

  8. Synthesis and biological evaluation of novel urea and thiourea derivatives of valacyclovir

    Directory of Open Access Journals (Sweden)

    Katla Ramana Venkata

    2014-01-01

    Full Text Available A series of novel urea and thiourea derivatives of valacyclovir were efficiently synthesized in high yields and evaluated their antiviral activity. 2-((6-Amino-4-oxo-4,5-dihydro-1H-imidazo[4,5-c]pyridin-1-ylmethoxyethyl-2-amino-3-ethylbutanoate (valacyclovir 1 is reacted with various aromatic isocyanates/thiocyanates 2 in the presence of N, N- dimethyl piperazine as a base in THF: pyridine (4:1 to obtain valacyclovir urea/thiourea derivatives 3(a-j. The structures of the title compounds 3(a-j were confirmed by IR, NMR (1H, 13C, mass spectral and elemental analysis. The newly synthesized compounds were screened for their antiviral activity against Tobacco mosaic virus (TMV and antioxidant activity was evaluated by DPPH, SOD and GST methods. The title compounds exhibited potent antiviral and good antioxidant activities.

  9. Liquid, urea group-containing polyisocyanate mixtures and plastics derived therefrom

    Energy Technology Data Exchange (ETDEWEB)

    Buethe, I.; Marx, M.; Schoenleben, W.

    1988-04-05

    The invention relates to urea group-containing polyisocyanate mixtures which are liquid at room temperature and have an isocyanate group content of from 15 to 30 weight percent and a diphenylmethane diisocyanate content of from 55 to 90 weight percent. These mixtures are obtained through the reaction of polyoxyalkylene polyamines having a functionality of from 2 to 5 and an amine number from 20 to 250 with a polyisocyanate selected from the group consisting of: a mixture of diphenylmethane diisocyanates and polyphenyl polymethylene polysocyanates having a diphenylmethane diisocyanate content of from 55 to 90 wt%, or at least one diphenylmethane diisocyanate isomer. The polyisocyanate mixtures claimed in the invention are used to prepare dense or cellular polyurethane and/or polyisocyanurate plastics, in particular, flexible polyurethane foams.

  10. Degradation of Adenine on the Martian Surface in the Presence of Perchlorates and Ionizing Radiation: A Reflectron Time-of-flight Mass Spectrometric Study

    Energy Technology Data Exchange (ETDEWEB)

    Góbi, Sándor; Bergantini, Alexandre; Kaiser, Ralf I., E-mail: ralfk@hawaii.edu [Department of Chemistry, University of Hawaii at Mānoa, Honolulu, HI 96822 (United States)

    2017-04-01

    The aim of the present work is to unravel the radiolytic decomposition of adenine (C{sub 5}H{sub 5}N{sub 5}) under conditions relevant to the Martian surface. Being the fundamental building block of (deoxy)ribonucleic acids, the possibility of survival of this biomolecule on the Martian surface is of primary importance to the astrobiology community. Here, neat adenine and adenine–magnesium perchlorate mixtures were prepared and irradiated with energetic electrons that simulate the secondary electrons originating from the interaction of the galactic cosmic rays with the Martian surface. Perchlorates were added to the samples since they are abundant—and therefore relevant oxidizers on the surface of Mars—and they have been previously shown to facilitate the radiolysis of organics such as glycine. The degradation of the samples were monitored in situ via Fourier transformation infrared spectroscopy and the electron ionization quadruple mass spectrometric method; temperature-programmed desorption profiles were then collected by means of the state-of-the-art single photon photoionization reflectron time-of-flight mass spectrometry (PI-ReTOF-MS), allowing for the detection of the species subliming from the sample. The results showed that perchlorates do increase the destruction rate of adenine by opening alternative reaction channels, including the concurrent radiolysis/oxidation of the sample. This new pathway provides a plethora of different radiolysis products that were identified for the first time. These are carbon dioxide (CO{sub 2}), isocyanic acid (HNCO), isocyanate (OCN{sup −}), carbon monoxide (CO), and nitrogen monoxide (NO); an oxidation product containing carbonyl groups (R{sub 1}R{sub 2}–C=O) with a constrained five-membered cyclic structure could also be observed. Cyanamide (H{sub 2}N–C≡N) was detected in both irradiated samples as well.

  11. Neuronal modulation of lung injury induced by polymeric hexamethylene diisocyanate in mice

    International Nuclear Information System (INIS)

    Lee, C.-T.; Poovey, Halet G.; Rando, Roy J.; Hoyle, Gary W.

    2007-01-01

    1,6-Hexamethylene diisocyanate biuret trimer (HDI-BT) is a nonvolatile isocyanate that is a component of polyurethane spray paints. HDI-BT is a potent irritant that when inhaled stimulates sensory nerves of the respiratory tract. The role of sensory nerves in modulating lung injury following inhalation of HDI-BT was assessed in genetically manipulated mice with altered innervation of the lung. Knockout mice with a mutation in the low-affinity nerve growth factor receptor (NGFR), which have decreased innervation by nociceptive nerve fibers, and transgenic mice expressing nerve growth factor (NGF) from the lung-specific Clara cell secretory protein (CCSP) promoter, which have increased innervation of the airways, were exposed to HDI-BT aerosol and evaluated at various times after exposure. NGFR knockout mice exhibited significantly more, and CCSP-NGF transgenic mice exhibited significantly less injury and inflammation compared with wild-type mice, indicative of a protective effect of nociceptive nerves on the lung following HDI-BT inhalation. Transgenic mice overexpressing the tachykinin 1 receptor (Tacr1) in lung epithelial cells also showed less severe injury and inflammation compared with wild-type mice after HDI-BT exposure, establishing a role for released tachykinins acting through Tacr1 in mediating at least part of the protective effect. Treatment of lung fragments from Tacr1 transgenic mice with the Tacr1 ligand substance P resulted in increased cAMP accumulation, suggesting this compound as a possible signaling mediator of protective effects on the lung following nociceptive nerve stimulation. The results indicate that sensory nerves acting through Tacr1 can exert protective or anti-inflammatory effects in the lung following isocyanate exposure

  12. GAP pre-polymer, as an energetic binder and high performance additive for propellants and explosives: A review

    Directory of Open Access Journals (Sweden)

    Mehmet S. Eroglu

    2017-08-01

    Full Text Available In preparation of energetic composite formulations, functionally terminated pre-polymers have been used as binder. After physically mixing the pre-polymers with oxidizing components, metallic fuel, burning rate modifier and other minor ingredients, they are cured with a suitable curing agent to provide physical and chemical stability. These pre-polymers could be functionalized with carboxyl, epoxide or hydroxyl groups at varying average chain functionalities. For carboxyl-terminated pre-polymers, an epoxy functional curing agents could be used. If the pre-polymer possesses hydroxyl groups, isocyanate functional curing agents are the most suitable curing agents in terms of easy and efficient processing. Glycidyl azide polymer (GAP is one of the well-known low-molecular weight energetic liquid pre-polymer, which was developed to use as energetic binder, high performance additive and gas generator for high performance smokeless composite propellant and explosive formulations. Linear or branched GAP can be synthesized by nucleophilic substitution reaction of corresponding poly(epichlorohydrin (PECH with sodium azide through replacement of chloromethyl groups of PECH with pendant energetic azido-methyl groups on the polyether main chain. Positive heat of formation (+957 kJ/kg enables exothermic and rapid decomposition of GAP producing fuel rich gases. Its polyether main chain provides GAP with relatively low glass transition temperature (Tg= - 48 oC and presence of hydroxyl functional groups allows it to have easy processing in curing with isocyanate curing agents to form covalently crosslinked polyurethane structure. These outstanding properties of GAP enable it to be used as energetic polymeric binder and high performance additive in preparation of energetic materials and low vulnerable explosives.

  13. Interference lithography for optical devices and coatings

    Science.gov (United States)

    Juhl, Abigail Therese

    Interference lithography can create large-area, defect-free nanostructures with unique optical properties. In this thesis, interference lithography will be utilized to create photonic crystals for functional devices or coatings. For instance, typical lithographic processing techniques were used to create 1, 2 and 3 dimensional photonic crystals in SU8 photoresist. These structures were in-filled with birefringent liquid crystal to make active devices, and the orientation of the liquid crystal directors within the SU8 matrix was studied. Most of this thesis will be focused on utilizing polymerization induced phase separation as a single-step method for fabrication by interference lithography. For example, layered polymer/nanoparticle composites have been created through the one-step two-beam interference lithographic exposure of a dispersion of 25 and 50 nm silica particles within a photopolymerizable mixture at a wavelength of 532 nm. In the areas of constructive interference, the monomer begins to polymerize via a free-radical process and concurrently the nanoparticles move into the regions of destructive interference. The holographic exposure of the particles within the monomer resin offers a single-step method to anisotropically structure the nanoconstituents within a composite. A one-step holographic exposure was also used to fabricate self-healing coatings that use water from the environment to catalyze polymerization. Polymerization induced phase separation was used to sequester an isocyanate monomer within an acrylate matrix. Due to the periodic modulation of the index of refraction between the monomer and polymer, the coating can reflect a desired wavelength, allowing for tunable coloration. When the coating is scratched, polymerization of the liquid isocyanate is catalyzed by moisture in air; if the indices of the two polymers are matched, the coatings turn transparent after healing. Interference lithography offers a method of creating multifunctional self

  14. Degradation of Adenine on the Martian Surface in the Presence of Perchlorates and Ionizing Radiation: A Reflectron Time-of-flight Mass Spectrometric Study

    International Nuclear Information System (INIS)

    Góbi, Sándor; Bergantini, Alexandre; Kaiser, Ralf I.

    2017-01-01

    The aim of the present work is to unravel the radiolytic decomposition of adenine (C 5 H 5 N 5 ) under conditions relevant to the Martian surface. Being the fundamental building block of (deoxy)ribonucleic acids, the possibility of survival of this biomolecule on the Martian surface is of primary importance to the astrobiology community. Here, neat adenine and adenine–magnesium perchlorate mixtures were prepared and irradiated with energetic electrons that simulate the secondary electrons originating from the interaction of the galactic cosmic rays with the Martian surface. Perchlorates were added to the samples since they are abundant—and therefore relevant oxidizers on the surface of Mars—and they have been previously shown to facilitate the radiolysis of organics such as glycine. The degradation of the samples were monitored in situ via Fourier transformation infrared spectroscopy and the electron ionization quadruple mass spectrometric method; temperature-programmed desorption profiles were then collected by means of the state-of-the-art single photon photoionization reflectron time-of-flight mass spectrometry (PI-ReTOF-MS), allowing for the detection of the species subliming from the sample. The results showed that perchlorates do increase the destruction rate of adenine by opening alternative reaction channels, including the concurrent radiolysis/oxidation of the sample. This new pathway provides a plethora of different radiolysis products that were identified for the first time. These are carbon dioxide (CO 2 ), isocyanic acid (HNCO), isocyanate (OCN − ), carbon monoxide (CO), and nitrogen monoxide (NO); an oxidation product containing carbonyl groups (R 1 R 2 –C=O) with a constrained five-membered cyclic structure could also be observed. Cyanamide (H 2 N–C≡N) was detected in both irradiated samples as well.

  15. Foam, composition and method of production

    Energy Technology Data Exchange (ETDEWEB)

    Ghali, R.

    1991-09-03

    A ternary foam is disclosed which overcomes the disadvantages of conventional heat-insulating foams which are either dense and heavy, expensive to produce, friable, unstable, or have poor fire resistance. The foam of the invention has, by weight of the reaction product, 10-35% polyurethane, 30-55% polyisocyanurate, and 20-45% polyurea. The foam is a reaction product of 100 parts by weight of an organic polyisocyanate with: 15-25 parts by weight of a polyether polyol having a hydroxyl number of ca 28-35 and a molecular weight of not more than 6,000; 5-25 parts by weight of water; 0-25 parts by weight of a blowing agent; 0-50 parts by weight of a filler-plasticizer fire retardant; an effective amount of a low activation catalyst to initiate water-isocyanate reaction to produce polyurea and polyol-isocyanate reaction to produce polyurethane; and an effective amount of a high activation catalyst to retard the low activation catalyst and promote the formation of polyisocyanurate. The low activity catalyst is present in an amount ranging ca 1.5-9 parts per 100 parts by weight of the polyisocyanate, and the high activation catalyst is present in an amount ranging 0.0008-0.002 parts per 100 parts by weight of the polyisocyanate. Water as a reactant and blowing agent can be substituted by an effective amount of a disubstituted amine such as diethanol amine and an inert blowing agent such as fluorocarbon. The resultant foam has excellent heat insulating propeties, is semi-flexible, has a density of 0.5-0.9 lb/ft{sup 3}, and can be inexpensively produced by existing 2-component foam dispensing equipment. 1 fig., 1 tab.

  16. Novel water-soluble polyurethane nanomicelles for cancer chemotherapy: physicochemical characterization and cellular activities

    Directory of Open Access Journals (Sweden)

    Khosroushahi Ahmad

    2012-01-01

    Full Text Available Abstract Background Efficient delivery of anticancer chemotherapies such as paclitaxel (PTX can improve treatment strategy in a variety of tumors such as breast and ovarian cancers. Accordingly, researches on polymeric nanomicelles continue to find suitable delivery systems. However, due to biocompatibility concerns, a few micellar nanoformulations have exquisitely been translated into clinical uses. Here, we report the synthesis of novel water-soluble nanomicelles using bioactive polyurethane (PU polymer and efficient delivery of PTX in the human breast cancer MCF-7 cells. Results The amphiphilic polyurethane was prepared through formation of urethane bounds between hydroxyl groups in poly (tetramethylene ether glycol (PTMEG and dimethylol propionic acid with isocyanate groups in toluene diisocyanate (TDI. The free isocyanate groups were blocked with phenol, while the free carboxyl groups of dimethylol propionic acid were reacted with triethylamine to attain ionic centers in the polymer backbone. These hydrophobic PTMEG blocks displayed self-assembly forming polymeric nanomicelles in water. The PTX loaded PU nanomicelles showed suitable physical stability, negative zeta potential charge (-43 and high loading efficiency (80% with low level of critical micelle concentration (CMC. In vitro drug release profile showed a faster rate of drug liberation at pH 5.4 as compared to that of pH 7.4, implying involvement of a pH-sensitive mechanism for drug release from the nanomicelles. The kinetic of release exquisitely obeyed the Higuchi model, confirming involvement of diffusion and somewhat erosion at pH 5.4. These nanomicelles significantly inhibited the growth and proliferation of the human breast cancer MCF-7 cells, leading them to apoptosis. The real time RT-PCR analysis confirmed the activation of apoptosis as result of liberation of cytochrome c in the cells treated with the PTX loaded PU nanomicelles. The comet assay analysis showed somewhat DNA

  17. Occupational exposure to diisocyanates in polyurethane foam factory workers

    Directory of Open Access Journals (Sweden)

    Dominika Świerczyńska-Machura

    2015-12-01

    Full Text Available Objectives: The aim of the study was to evaluate health effects of occupational exposure to diisocyanates (DIC among polyurethane foam products factory workers. Material and Methods: Thirty workers had a physical examination, skin prick tests with common allergens, allergen-specific immunoglobulin E (IgE antibodies to diisocyanates and pulmonary function tests. Concentrations of selected isocyanates in the workplace air samples as well as concentration of their metabolites in the urine samples collected from the workers of the plant were determined. Results: The most frequent work-related symptoms reported by the examined subjects were rhinitis and skin symptoms. Sensitization to at least 1 common allergen was noted in 26.7% of the subjects. Spirometry changes of bronchial obstruction of a mild degree was observed in 5 workers. The specific IgE antibodies to toluene diisocyanate (TDI and 4,4’-methylenebis(phenyl isocyanate (MDI were not detected in any of the patients’ serum. Cellular profiles of the collected induced sputum (ISP did not reveal any abnormalities. Air concentrations of TDI isomers ranged 0.2–58.9 μg/m3 and in 7 cases they exceeded the Combined Exposure Index (CEI value for those compounds. Concentrations of TDI metabolites in post-shift urine samples were significantly higher than in the case of pre-shift urine samples and in 6 cases they exceeded the British Biological Monitoring Guidance Value (BMGV – 1 μmol amine/mol creatinine. We didn’t find a correlation between urinary concentrations of TDI, concentrations in the air and concentrations of toluenediamine (TDA in the post shift urine samples. Lack of such a correlation may be an effect of the respiratory protective equipment use. Conclusions: Determination of specific IgE in serum is not sensitive enough to serve as a biomarker. Estimation of concentrations of diisocyanate metabolites in urine samples and the presence of work-related allergic symptoms seem to be

  18. Rheological and mechanical properties and interfacial stress development of composite cements modified with thio-urethane oligomers.

    Science.gov (United States)

    Bacchi, Ataís; Pfeifer, Carmem S

    2016-08-01

    Thio-urethane oligomers have been shown to reduce stress and increase toughness in highly filled composite materials. This study evaluated the influence of thio-urethane backbone structure on rheological and mechanical properties of resin cements modified with a fixed concentration of the oligomers. Thio-urethane oligomers (TU) were synthesized by combining thiols - pentaerythritol tetra-3-mercaptopropionate (PETMP) or trimethylol-tris-3-mercaptopropionate (TMP) - with isocyanates - 1,6-hexanediol-diissocyante (HDDI) (aliphatic) or 1,3-bis(1-isocyanato-1-methylethyl)benzene (BDI) (aromatic) or dicyclohexylmethane 4,4'-diisocyanate (HMDI) (cyclic), at 1:2 isocyanate:thiol, leaving pendant thiols. 20wt% TU were added to BisGMA-UDMA-TEGDMA (5:3:2). 60wt% silanated inorganic fillers were added. Near-IR was used to follow methacrylate conversion and rate of polymerization ( [Formula: see text] ). Mechanical properties were evaluated in three-point bending (ISO 4049) for flexural strength/modulus (FS/FM, and toughness), and notched specimens (ASTM Standard E399-90) for fracture toughness (KIC). PS was measured on the Bioman. Viscosity (V) and gel-points (defined as the crossover between storage and loss shear moduli (G'/G″)) were obtained with rheometry. Glass transition temperature (Tg), cross-link density and homogeneity of the network were obtained with dynamic mechanical analysis. Film-thickness was evaluated according to ISO 4049. DC and mechanical properties increased and [Formula: see text] and PS decreased with the addition of TUs. Gelation (G'/G″) was delayed and DC at G'/G″ increased in TU groups. Tg and cross-link density dropped in TU groups, while oligomers let to more homogenous networks. An increase in V was observed, with no effect on film-thickness. Significant reductions in PS were achieved at the same time conversion and mechanical properties increased. The addition of thio-urethane oligomers proved successful in improving several key properties

  19. A kinetic approach to modeling the manufacture of high density strucutral foam: Foaming and polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Rekha R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Mondy, Lisa Ann [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Noble, David R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Brunini, Victor [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Roberts, Christine Cardinal [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Long, Kevin Nicholas [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Soehnel, Melissa Marie [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Celina, Mathias C. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Wyatt, Nicholas B. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Thompson, Kyle R. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Sandia National Laboratories, Livermore, CA (United States); Tinsley, James

    2015-09-01

    We are studying PMDI polyurethane with a fast catalyst, such that filling and polymerization occur simultaneously. The foam is over-packed to tw ice or more of its free rise density to reach the density of interest. Our approach is to co mbine model development closely with experiments to discover new physics, to parameterize models and to validate the models once they have been developed. The model must be able to repres ent the expansion, filling, curing, and final foam properties. PMDI is chemically blown foam, wh ere carbon dioxide is pr oduced via the reaction of water and isocyanate. The isocyanate also re acts with polyol in a competing reaction, which produces the polymer. A new kinetic model is developed and implemented, which follows a simplified mathematical formalism that decouple s these two reactions. The model predicts the polymerization reaction via condensation chemis try, where vitrification and glass transition temperature evolution must be included to correctly predict this quantity. The foam gas generation kinetics are determined by tracking the molar concentration of both water and carbon dioxide. Understanding the therma l history and loads on the foam due to exothermicity and oven heating is very important to the results, since the kinetics and ma terial properties are all very sensitive to temperature. The conservation eq uations, including the e quations of motion, an energy balance, and thr ee rate equations are solved via a stabilized finite element method. We assume generalized-Newtonian rheology that is dependent on the cure, gas fraction, and temperature. The conservation equations are comb ined with a level set method to determine the location of the free surface over time. Results from the model are compared to experimental flow visualization data and post-te st CT data for the density. Seve ral geometries are investigated including a mock encapsulation part, two configur ations of a mock stru ctural part, and a bar geometry to

  20. A finite element/level set model of polyurethane foam expansion and polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Rekha R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Long, Kevin Nicholas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Roberts, Christine Cardinal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Celina, Mathias C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brunini, Victor [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Soehnel, Melissa Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Noble, David R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tinsley, James [Honeywell Federal Manufacturing & Technologies, Kansas City, MO (United States); Mondy, Lisa [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    Polyurethane foams are used widely for encapsulation and structural purposes because they are inexpensive, straightforward to process, amenable to a wide range of density variations (1 lb/ft3 - 50 lb/ft3), and able to fill complex molds quickly and effectively. Computational model of the filling and curing process are needed to reduce defects such as voids, out-of-specification density, density gradients, foam decomposition from high temperatures due to exotherms, and incomplete filling. This paper details the development of a computational fluid dynamics model of a moderate density PMDI structural foam, PMDI-10. PMDI is an isocyanate-based polyurethane foam, which is chemically blown with water. The polyol reacts with isocyanate to produces the polymer. PMDI- 10 is catalyzed giving it a short pot life: it foams and polymerizes to a solid within 5 minutes during normal processing. To achieve a higher density, the foam is over-packed to twice or more of its free rise density of 10 lb/ft3. The goal for modeling is to represent the expansion, filling of molds, and the polymerization of the foam. This will be used to reduce defects, optimize the mold design, troubleshoot the processed, and predict the final foam properties. A homogenized continuum model foaming and curing was developed based on reaction kinetics, documented in a recent paper; it uses a simplified mathematical formalism that decouples these two reactions. The chemo-rheology of PMDI is measured experimentally and fit to a generalized- Newtonian viscosity model that is dependent on the extent of cure, gas fraction, and temperature. The conservation equations, including the equations of motion, an energy balance, and three rate equations are solved via a stabilized finite element method. The equations are combined with a level set method to determine the location of the foam-gas interface as it evolves to fill the mold. Understanding the thermal history and loads on the foam due to exothermicity and oven

  1. Sub-acute occupational hypersensitivity pneumonitis due to low-level exposure to diisocyanates in a secretary.

    Science.gov (United States)

    Schreiber, J; Knolle, J; Sennekamp, J; Schulz, K T; Hahn, J U; Hering, K G; Raulf-Heimsoth, M; Merget, R

    2008-09-01

    There is virtually no information in the literature about the exposure levels needed to induce hypersensitivity pneumonitis (HP) by diisocyanates. The present study reports a case of occupational HP due to diisocyanates after low-level exposure. A 53-yr-old female never-smoker developed progressive shortness of breath on exertion, cough, fatigue and flu-like symptoms shortly after she began work as a secretary of a car body repair shop. A diagnosis of HP was made 2 yrs later, based on a restrictive ventilatory defect, a reticulonodular and discrete ground-glass pattern on high-resolution computed tomography, lymphocytosis in bronchoalveolar lavage and specific immunoglobulin G antibodies to diisocyanate human serum albumin conjugates in the patient's serum. The diagnosis was confirmed by recovery after exposure cessation and deterioration after re-exposure. Ambient monitoring revealed air concentrations of different diisocyanate monomers below the detection limit in both the patient's work station and in front of the paint spray booths, with the exception of one measurement that showed 4,4-methylenediphenyl diisocyanate concentrations of 3 microg x m(-3) in front of one booth (corresponding to a total reactive isocyanate group concentration of 1 microg x m(-3)). The present authors conclude that concentrations of diisocyanates far below current exposure limits may induce hypersensitivity pneumonitis in susceptible subjects.

  2. The synthesis and biological evaluation of new DNA-directed alkylating agents, phenyl N-mustard-4-anilinoquinoline conjugates containing a urea linker.

    Science.gov (United States)

    Marvania, Bhavin; Kakadiya, Rajesh; Christian, Wilson; Chen, Tai-Lin; Wu, Ming-Hsi; Suman, Sharda; Tala, Kiran; Lee, Te-Chang; Shah, Anamik; Su, Tsann-Long

    2014-08-18

    We synthesized a series of phenyl N-mustard-4-anilinoquinoline conjugates to study their antitumorigenic effects. These agents were prepared by the condensation of 4-[N,N-bis(2-chloroethyl)amino]phenyl isocyanate with 6-amino-4-methylamino or 4-anilinoquinolines. The structure-activity relationship (SAR) studies revealed that the C2-methylquinoline derivatives (18a-o) were generally more cytotoxic than the C2-phenylquinoline conjugates (23a-d) in inhibiting the cell growth of various human tumor cell lines in vitro. However, the methylamino or aniline substituents at C4 of quinoline did not influence the cytotoxic effects. The title conjugates were capable of inducing DNA cross-linking and promoting cell-cycle arrest at the G2/M phase. This study demonstrates that phenyl N-mustard-4-anilinoquinoline conjugates are generally more potent than phenyl N-mustard-4-anilinoquinazoline conjugates against the cell growth of various tumor cell-lines. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  3. LiFSI vs. LiPF6 electrolytes in contact with lithiated graphite: Comparing thermal stabilities and identification of specific SEI-reinforcing additives

    International Nuclear Information System (INIS)

    Eshetu, Gebrekidan Gebresilassie; Grugeon, Sylvie; Gachot, Grégory; Mathiron, David; Armand, Michel; Laruelle, Stephane

    2013-01-01

    Lithium bis(fluorosulfonyl) imide (LiFSI) is regarded as an alternative to the classical LiPF 6 salt in today's LiFePO 4 /graphite-based Li-ion batteries electrolyte owing to its slightly higher conductivity and lower fluorine content. In an attempt to better evaluate the safety issues, here we report the comparative study of the LiFSI and LiPF 6 based electrolyte/lithiated graphite interface thermal behavior. DSC measurements with LiFSI-based electrolyte reveal a sharp exotherm with large heat release though at higher onset and peak temperatures compared to LiPF 6 -based electrolyte. With the help of GC/MS, 19 F NMR and ESI-HRMS analyses, we assume that this highly energetic peak around 200 °C, which is dependant upon the lithium content, is mainly related to electrochemical reduction of FSI − anion. In a strategy to limit the probability and damage of thermal runaway event, electrolyte additives such as vinylene carbonate (VC), fluoro ethylene carbonate (FEC), di-isocyanato hexane (DIH) and toluene di-isocyanate (TDI) have been investigated and shown to significantly lower the energy associated with the exothermic phenomenon

  4. Combinatorial and high-throughput screening of the effect of siloxane composition on the surface properties of crosslinked siloxane-polyurethane coatings.

    Science.gov (United States)

    Ekin, Abdullah; Webster, Dean C

    2007-01-01

    Libraries of siloxane-polyurethane coatings were designed, formulated, and screened using high-throughput experimentation. Four independent variables that were analyzed were the molecular weight of poly(dimethylsiloxane) (PDMS), presence or absence of poly(epsilon-caprolactone) (PCL) blocks attached to the PDMS backbone, the length of the PCL blocks, and the siloxane polymer level in the coating formulations. In addition to the siloxane libraries (3-aminopropyl-terminated PDMS and poly(epsilon-caprolactone)-poly(dimethylsiloxane)-poly(epsilon-caprolactone) (PCL-PDMS-PCL) triblock copolymers), the coating formulation included a trifunctional isocyanate crosslinker, trifunctional poly(epsilon-caprolactone) polyol, 2,4-pentanedione (pot-life extender), dibutyltin diacetate (catalyst), and a blend of solvents. The resulting coatings were analyzed for their surface energy and pseudobarnacle adhesion both before and after aging the coatings for 30 days in water. The water and methylene iodide contact angle averages increase with increasing molecular weight of PDMS. Coatings prepared from PCL-PDMS-PCL triblock copolymers have lower surface energies than coatings prepared from 3-aminopropyl-terminated PDMS; however, lower pseudobarnacle adhesion results were obtained for the coatings prepared from 3-aminopropyl-terminated PDMS than coatings prepared from PCL-PDMS-PCL triblock copolymers. The siloxane polymer level in the coating formulations does not have a significant effect on the surface energy of the coatings, but it resulted in higher pseudobarnacle adhesion.

  5. Thermal degradation mechanism of addition-cure liquid silicone rubber with urea-containing silane

    International Nuclear Information System (INIS)

    Fang, Weizhen; Zeng, Xingrong; Lai, Xuejun; Li, Hongqiang; Chen, Wanjuan; Zhang, Yajun

    2015-01-01

    Highlights: • The urea-containing silane was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. • The thermal stability of the ALSR was improved by DEUPAS both in nitrogen and air • The TG–FTIR of evolved gases during degradation was performed. • The possible degradation mechanism of the ALSR samples was proposed. - Abstract: The reactive urea-containing silane, (γ-diethylureidopropyl) allyloxyethoxysilane (DEUPAS), was synthesized by the trans-etherification reaction. The chemical structure was characterized by Fourier transform infrared spectrometry (FTIR) and 1 H nuclear magnetic resonance spectrometry ( 1 H NMR). Subsequently, DEUPAS was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. The thermal stability of the ALSR samples was investigated by thermogravimetry (TG) and thermogravimetry–Fourier transform infrared spectrometry (TG–FTIR). When DEUPAS was incorporated, the temperature of 10% weight loss and 20% weight loss under air atmosphere were respectively increased by 31 °C and 60 °C compared with those of the ALSR without DEUPAS. Meanwhile, the residual weight at 800 °C increased from 33.5% to 58.7%. It was found that the striking enhancement in thermal stability of the ALSR samples was likely attributed to the decomposition of the urea groups to isocyanic acid, which reacted with hydroxyl groups to inhibit the unzipping depolymerization

  6. Thermal degradation mechanism of addition-cure liquid silicone rubber with urea-containing silane

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Weizhen; Zeng, Xingrong, E-mail: psxrzeng@gmail.com; Lai, Xuejun; Li, Hongqiang; Chen, Wanjuan; Zhang, Yajun

    2015-04-10

    Highlights: • The urea-containing silane was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. • The thermal stability of the ALSR was improved by DEUPAS both in nitrogen and air • The TG–FTIR of evolved gases during degradation was performed. • The possible degradation mechanism of the ALSR samples was proposed. - Abstract: The reactive urea-containing silane, (γ-diethylureidopropyl) allyloxyethoxysilane (DEUPAS), was synthesized by the trans-etherification reaction. The chemical structure was characterized by Fourier transform infrared spectrometry (FTIR) and {sup 1}H nuclear magnetic resonance spectrometry ({sup 1}H NMR). Subsequently, DEUPAS was incorporated into addition-cure liquid silicone rubber (ALSR) via hydrosilylation reaction. The thermal stability of the ALSR samples was investigated by thermogravimetry (TG) and thermogravimetry–Fourier transform infrared spectrometry (TG–FTIR). When DEUPAS was incorporated, the temperature of 10% weight loss and 20% weight loss under air atmosphere were respectively increased by 31 °C and 60 °C compared with those of the ALSR without DEUPAS. Meanwhile, the residual weight at 800 °C increased from 33.5% to 58.7%. It was found that the striking enhancement in thermal stability of the ALSR samples was likely attributed to the decomposition of the urea groups to isocyanic acid, which reacted with hydroxyl groups to inhibit the unzipping depolymerization.

  7. Urea, a true uremic toxin: the empire strikes back.

    Science.gov (United States)

    Lau, Wei Ling; Vaziri, Nosratola D

    2017-01-01

    Blood levels of urea rise with progressive decline in kidney function. Older studies examining acute urea infusion suggested that urea was well-tolerated at levels 8-10× above normal values. More recent in vitro and in vivo work argue the opposite and demonstrate both direct and indirect toxicities of urea, which probably promote the premature aging phenotype that is pervasive in chronic kidney disease (CKD). Elevated urea at concentrations typically encountered in uremic patients induces disintegration of the gut epithelial barrier, leading to translocation of bacterial toxins into the bloodstream and systemic inflammation. Urea induces apoptosis of vascular smooth muscle cells as well as endothelial dysfunction, thus directly promoting cardiovascular disease. Further, urea stimulates oxidative stress and dysfunction in adipocytes, leading to insulin resistance. Finally, there are widespread indirect effects of elevated urea as a result of the carbamylation reaction, where isocyanic acid (a product of urea catabolism) alters the structure and function of proteins in the body. Carbamylation has been linked with renal fibrosis, atherosclerosis and anaemia. In summary, urea is a re-emerging Dark Force in CKD pathophysiology. Trials examining low protein diet to minimize accumulation of urea and other toxins suggest a clinical benefit in terms of slowing progression of CKD. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  8. Preparation of polyurethane microcapsule using 1,3 propanediol as the polyol component

    International Nuclear Information System (INIS)

    Ahmad Randy; Dewi Sondari; Evi Triwulandari; Murni Handayani

    2010-01-01

    Self-healing property is the ability of a material to heal damages automatically and autonomously. Its application would be ranged from paint coating, anti corrosion coating, space shuttle material, construction (concrete) and automotive. Extrinsic self healing requires self healing agent pre embedded or incorporated into polymer matrix that would be released and close the damage in the polymer system, where the polymer itself is not healable. Healing agents are encapsulated or embedded into the material prior application. Example of monomer encapsulated to give self healing property is isophorone diisocyanate (IPDI) encapsulated in polyurethane shell. In this study, we studied the possibility of 1,3 propanediol, that can be derived from palm oil as polyol monomer for polyurethane microcapsule shell containing IPDI or stannous octoate as a self healing agent. Microcapsule in this study was prepared by interfacial polymerization technique to form IPDI monomer in polyurethane shell. FT-IR analysis show that polyurethane prepolymer produced still have unreacted isocyanate group necessary for interfacial polymerization of polyurethane. Morphological analyses of the microcapsule products show that the products have spherical shapes with smooth surface and some with wrinkled surface. The particle sizes were ranged from 40.29 to 526.80 μm. (author)

  9. The important parameters of polyurethane's properties and preparation

    International Nuclear Information System (INIS)

    Rad, A.S.

    2009-01-01

    Polyurethane (PU) is a type of plastic rind is formed by reacting a polyol (a polymeric alcohol with more than. two reactive hydroxyl groups per molecule) with diisocyanates or polymeric isocyanate in the presence of suitable catalysts and additives. Variations in the number of substitutions and the spacing between and within branch chains produce PUs ranging from linear to branched and flexible to rigid. Linear PUs are used for the manufacture of fibers and molding. The structure of polyurethane can be medley containing 'hard' and 'soft' sect, which contribute to the harmony between rigid and elastomeric properties. The chemical composition and molecular weight distribution (MWD)- of the incorporated soft block influence the macroscopic properties of the resulting coating. In modifying the backbone structure of PU coatings it is necessary to consider the end use for the coating and the cost of modification: The properties of the modified PU coating, The resistance of the coating towards mechanical and The compatibility of the coating and the substrate over the temperature range of expected application and The between the benefits to be gained and the additional cost are the parameters that must be A surface functionalization of a synthetic polyurethane was carried out by using biofunctional moieties to obtain a material with the appropriate mechanical properties and processing conditions. (author)

  10. Design of Xylose-Based Semisynthetic Polyurethane Tissue Adhesives with Enhanced Bioactivity Properties.

    Science.gov (United States)

    Balcioglu, Sevgi; Parlakpinar, Hakan; Vardi, Nigar; Denkbas, Emir Baki; Karaaslan, Merve Goksin; Gulgen, Selam; Taslidere, Elif; Koytepe, Suleyman; Ates, Burhan

    2016-02-01

    Developing biocompatible tissue adhesives with high adhesion properties is a highly desired goal of the tissue engineering due to adverse effects of the sutures. Therefore, our work involves synthesis, characterization, adhesion properties, protein adsorption, in vitro biodegradation, in vitro and in vivo biocompatibility properties of xylose-based semisynthetic polyurethane (NPU-PEG-X) bioadhesives. Xylose-based semisynthetic polyurethanes were developed by the reaction among 4,4'-methylenebis(cyclohexyl isocyanate) (MCI), xylose and polyethylene glycol 200 (PEG). Synthesized polyurethanes (PUs) showed good thermal stability and high adhesion strength. The highest values in adhesion strength were measured as 415.0 ± 48.8 and 94.0 ± 2.8 kPa for aluminum substrate and muscle tissue in 15% xylose containing PUs (NPU-PEG-X-15%), respectively. The biodegradation of NPU-PEG-X-15% was also determined as 19.96 ± 1.04% after 8 weeks of incubation. Relative cell viability of xylose containing PU was above 86%. Moreover, 10% xylose containing NPU-PEG-X (NPU-PEG-X-10%) sample has favorable tissue response, and inflammatory reaction between 1 and 6 weeks implantation period. With high adhesiveness and biocompatibility properties, NPU-PEG-X can be used in the medical field as supporting materials for preventing the fluid leakage after abdominal surgery or wound closure.

  11. System Description for the K-25/K-27 D and D Project Polyurethane Foam Delivery System, East Tennessee Technology Park, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    Boris, G.

    2008-01-01

    The Foam Delivery System used in the decontamination and decommissioning (D and D) project for the K-25/K-27 Buildings at the East Tennessee Technology Park (ETTP) is comprised of a trailer-mounted Gusmer(reg s ign) H20/35 Pro-TEC Proportioning Unit and the associated equipment to convey electrical power, air, and foam component material to the unit. This high-pressure, plural-component polyurethane foam pouring system will be used to fill process gas and non-process equipment/piping (PGE/P) within the K-25/K-27 Buildings with polyurethane foam to immobilize contaminants prior to removal. The system creates foam by mixing isocyanate and polyol resin (Resin) component materials. Currently, the project plans to utilize up to six foaming units simultaneously during peak foaming activities. Also included in this system description are the foam component material storage containers that will be used for storage of the component material drums in a staging area outside of the K-25/K-27 Buildings. The Foam Delivery System and foam component material storage enclosures (i.e., Foaming Component Protective Enclosures) used to store polymeric methylene diphenyl diisocyanate (PMDI) component material are identified as Safety Significant (SS) Structures, Systems and Components (SSC) in the Documented Safety Analysis (DSA) for the project, Documented Safety Analysis for the K-25 and K-27 Facilities at the East Tennessee Technology Park, Oak Ridge, Tennessee, DSA-ET-K-25/K-27-0001

  12. Honeycomb structured porous interfaces as templates for protein adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Hernandez, J; Munoz-Bonilla, A; Ibarboure, E; Bordege, V; Fernandez-Garcia, M, E-mail: jrodriguez@ictp.csic.es

    2010-11-01

    We prepared breath figure patterns decorated with a statistical glycopolymer, (styrene-co-2-{l_brace}[(D-glucosamin-2-N-yl)carbonyl]oxy{r_brace}ethyl methacrylate, S-HEMAGl). The preparation of the glycopolymer occurs in one single step by using styrene and S-HEMAGl. Blends of this copolymer and high molecular weight polystyrene were spin coated from THF solutions leading to the formation of surfaces with both controlled functionality and topography. AFM studies revealed that both the composition of the blend and the relative humidity play a key role on the size and distribution of the pores at the interface. The porous films shows the hydrophilic glycomonomer units are oriented towards the pore interface since upon soft annealing in water, the holes are partially swelled. The self-organization of the glycopolymer within the pores was additionally confirmed both by reaction of carbohydrate hydroxyl groups with rhodamine-isocyanate and by means of the lectin binding test using Concanavalin A (Con A).

  13. Synthesis and properties of radiation modified thermally cured castor oil based polyurethanes

    Energy Technology Data Exchange (ETDEWEB)

    Mortley, Aba [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, P.O. Box 17000, Stn Forces, Kingston, ON, K7K 7B4 (Canada)], E-mail: aba.mortley@rmc.ca; Bonin, H.W.; Bui, V.T. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, P.O. Box 17000, Stn Forces, Kingston, ON, K7K 7B4 (Canada)

    2007-12-15

    Thermally cured polyurethanes were prepared from castor oil and hexamethylene diisocyanate (HMDI). Due to the long aliphatic chain of the castor oil component of polyurethane, thermal curing of castor oil based polyurethane (COPU) is limited by increasing polymer viscosity. To enhance further crosslinking, COPUs were exposed to doses up to 3.0 MGy produced by the mixed ionizing radiation field of a SLOWPOKE-2 research nuclear reactor. The physico-mechanical properties of castor oil based polyurethanes (COPU), unirradiated and irradiated, were characterized by mechanical tensile tests. A four-fold increase in modulus and tensile strength values from 0.930 to 4.365 MPa and 0.149 to 0.747 MPa, respectively, suggests improved physico-mechanical properties resulting from radiation. The changing areas of the carbonyl and the NH absorbance peaks and the disappearance of the isocyanate peak in the FTIR spectra as radiation progressed, indicates increased hydrogen bonding and intermolecular crosslinking, which is in agreement with the mechanical tests. Unchanging {sup 13}C solid state NMR spectra imply limited sample degradation with increasing radiation.

  14. Radiation effects on polymers for coatings on copper canisters used for the containment of radioactive materials

    Energy Technology Data Exchange (ETDEWEB)

    Mortley, Aba [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, P.O. Box 17000 Station Force, Kingston, ON, K7K 7B4 (Canada)], E-mail: aba.mortley@rmc.ca; Bonin, H.W.; Bui, V.T. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, P.O. Box 17000 Station Force, Kingston, ON, K7K 7B4 (Canada)

    2008-05-31

    The present work proposes applying polyurethane coatings as an additional barrier in the design of Canadian nuclear waste disposal containers. The goal of the present research is to investigate the physico-mechanical integrity of a natural castor oil-based polyurethane (COPU) to be used as a coating material in pH-radiation-temperature environments. As the first part to these inquiries, the present paper investigates the effect of a mixed radiation field supplied by a SLOWPOKE-2 nuclear research reactor on COPUs that differ only by their isocyanate structure. FTIR, DSC, DMA, WAXS, and MALDI are used to characterize the changes that occur as a result of radiation and to relate these changes to polymer structure and composition. The COPUs used in the present work have demonstrated sustained physico-mechanical properties up to accumulated doses of 2.0 MGy and are therefore suitable for end-uses in radiation environments such as those expected in the deep geological repository.

  15. Threshold photoelectron spectroscopy of unstable N-containing compounds: Resolution of ΔK subbands in HNCO+ and vibrational resolution in NCO+

    International Nuclear Information System (INIS)

    Holzmeier, Fabian; Lang, Melanie; Fischer, Ingo; Tang, Xiaofeng; Cunha de Miranda, Barbara; Romanzin, Claire; Alcaraz, Christian; Hemberger, Patrick

    2015-01-01

    The threshold photoelectron spectra (TPES) of two unstable nitrogen-containing species, HNCO and NCO, were recorded utilizing vacuum ultraviolet synchrotron radiation. Both are intermediates in combustion processes and play a role in the removal of nitrogen oxides from exhaust gases. The rovibronic structure of the first band in the TPES of HNCO + was analyzed within the framework of an orbital ionization model, and the resolved structure of the origin band was assigned to ΔK subbands. An ionization energy of 11.602 ± 0.005 eV was determined and the vibrational structure of the cationic ground state was analyzed by a Franck-Condon fit. Low lying electronically excited states of HNCO + were also observed. In a second series of experiments, the NCO radical was generated by flash pyrolysis from chlorine isocyanate. The ionization energy to the X + 3 Σ − ground state was determined to be 11.76 ± 0.02 eV, while for the a +1 Δ state, a value of 12.93 ± 0.02 eV was obtained. Vibrational structure was observed for both states, and bands were assigned by Franck-Condon simulations

  16. FY 2000 report on the results of the development of the next generation chemical process technology/development of the non-halogen chemical process technology; 2000 nendo jisedai kagaku process gijutsu kaihatsu non halogen kagaku process gijutsu kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    For the purpose of conserving energy and reducing environmental loads, the R and D were conducted of a new chemical process (non-halogen chemical process) using new catalytic reaction, etc., and the FY 2000 results were summed up. As to the development of a new method to synthesize isocyanate, the development was proceeded with of a method to synthesize diisocyanate by the dicarbamate reaction and pyrolysis of the carbamate, and the effect of catalyst on the yield of carbamate reaction was grasped. Concerning the development of a new synthetic method of epoxides, the development was proceeded with of the catalyst for synthesizing propylene oxides from propylene and hydrogen/oxygen, and conditions were obtained for preparation of a catalyst of the basic catalytic system and with reproducibility. Moreover, the development was proceeded with of a new catalyst used in doing epoxidation of 1-butene using the organic system hydroperoxide. Concerning the development of a new method to synthesize phenol, a promising system was found out by finding out the basic catalytic system of oxidation acetoxyl reaction and proceeding with the search for co-catalyst, carrier, etc. (NEDO)

  17. Mechanical and swelling behaviour of well characterized polybutadiene networks

    Science.gov (United States)

    Mckenna, Gregory B.; Hinkley, Jeffrey A.

    1986-01-01

    Endlinking of hydroxyl-terminated polybutadiene with the appropriate isocyanate has been used to prepare well characterized networks. Two networks have been studied with molecular weights of the prepolymers being 6100 and 2400 g/mole by g.p.c. Cylindrical specimens were prepared and the derivatives of the stored energy function with respect to the stretch invariants were determined by torque and normal force measurements in torsion. From these data the Valanis-Landel (1967) stored energy function derivatives w-prime(lambda) were determined for both networks. The stored energy function for the junction constraint model of Flory (1953, 1977, 1979, 1985) which is a special form of the Valanis-Landel function, has been fitted to that determined from the experiments. The contributions to the stored energy function from the phantom network and from the junction constraints respectively do not agree with predictions from the topologies of the networks. In spite of this, the form of w-prime(lambda) for the junction constraint model gives an excellent 'curve fit' to the data. Comparison is also made with equilibrium swelling.

  18. Spectroscopic Characteristics of Highly Selective Manganese Catalysis in Acqueous Polyurethane Systems

    Directory of Open Access Journals (Sweden)

    Miroljub Barac

    2006-11-01

    Full Text Available The latest investigations on producing more efficient catalytic aqueouspolyurethane systems are in the domain of metal complexes with mixed ligands. In ourprevious research works, the high selectivity for the isocyanate-hydroxyl reaction inaqueous polyurethane systems has been shown by the manganese(III mixed-ligandcomplexes. The two new complexes have been prepared with two acetylacetonate (acacligands and one maleate ligand and its hydroxylamine derivative of the general formula[Mn(C5H7O22L]. Their structures have been established by using the fundamental analyses,the FTIR and UV/VIS spectroscopic methods, as well as the magnetic measurements. Inorder to explain the different selectivity of the manganese(III mixed-ligand complexes, theUV and ESR spectroscopy have been employed to determine the kinetics of the complexes’decomposition. The thermal stability of the complexes has been determined by way of thedynamic TG method at the heating rate of 5°C⋅min-1 and at the temperature ranged 20-550°C. It suggests the decomposition of the complexes by loss of acid ligand. The main factor in the selective catalysis control in theaqueous polyurethane systems is the nature of the acid ligands and their impact on themanganese(II/manganese(III equilibrium.

  19. Effect of processing temperature on the bitumen/MDI-PEG reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Alfonso, M.J.; Partal, P.; Navarro, F.J.; Garcia-Morales, M. [Departamento de Ingenieria Quimica, Facultad de Ciencias Experimentales, Campus de ' El Carmen' , Universidad de Huelva, 21071, Huelva (Spain); Bordado, J.C.M. [Chemical and Biological Engineering Department, IBB, Instituto Superior Tecnico, Av. Rovisco Pais 1049-001 Lisbon (Portugal); Diogo, A.C. [Materials Engineering Department, Instituto Superior Tecnico, Av. Rovisco Pais 1049-001 Lisbon (Portugal)

    2009-04-15

    Reactive polymers are lately gaining acceptance to give added value to a residue of the crude oil refining process such as bitumen. The resulting material should display enhanced mechanical properties to be considered for advanced applications in construction. In the present paper, we report the effect of processing temperature on the reaction between bitumen compounds and an isocyanate-based reactive polymer, synthesized by reaction of polymeric MDI (4,4'-diphenylmethane diisocyanate) with a low molecular weight polyethylene-glycol (PEG). Rheokinetics experiments, viscosity measurements at 60 C, atomic force microscopy (AFM) characterization, thin layer chromatography (TLC-FID) analysis and thermogravimetric studies (TGA) were performed on the reactive polymer and on samples of MDI-PEG modified bitumen containing 2 wt.% of the polymer. Results showed the existence of an optimum processing temperature arisen as a consequence of opposite effects: microstructural availability for the formation of a polymer-bitumen network, reaction ability and polymer thermal degradation. Consequently, this study aims to serve as a guideline for the refining and asphalt industries facing the stage of selecting the optimum processing parameters. (author)

  20. Synthesis, Multinuclear NMR Characterization and Dynamic Property of Organic–Inorganic Hybrid Electrolyte Membrane Based on Alkoxysilane and Poly(oxyalkylene Diamine

    Directory of Open Access Journals (Sweden)

    Hsien-Ming Kao

    2012-06-01

    Full Text Available Organic–inorganic hybrid electrolyte membranes based on poly(propylene glycol-block-poly(ethylene glycol-block-poly(propylene glycol bis(2-aminopropyl ether complexed with LiClO4 via the co-condensation of tetraethoxysilane (TEOS and 3-(triethoxysilylpropyl isocyanate have been prepared and characterized. A variety of techniques such as differential scanning calorimetry (DSC, Fourier transform infrared (FTIR spectroscopy, alternating current (AC impedance and solid-state nuclear magnetic resonance (NMR spectroscopy are performed to elucidate the relationship between the structural and dynamic properties of the hybrid electrolyte and the ion mobility. A VTF (Vogel-Tamman-Fulcher-like temperature dependence of ionic conductivity is observed for all the compositions studied, implying that the diffusion of charge carriers is assisted by the segmental motions of the polymer chains. A maximum ionic conductivity value of 5.3 × 10−5 Scm−1 is obtained at 30 °C. Solid-state NMR results provide a microscopic view of the effects of salt concentrations on the dynamic behavior of the polymer chains.

  1. Synthesis of polycarbonate urethane elastomers and effects of the chemical structures on their thermal, mechanical and biocompatibility properties.

    Science.gov (United States)

    Zhu, Rong; Wang, Yiyu; Zhang, Zongrui; Ma, Daiwei; Wang, Xinyu

    2016-06-01

    In this study, to obtain biomedical polyurethane elastomers with good mechanical properties and biocompatibility, a series of polycarbonate urethanes were synthesized via a two-step solution of polymerization method using the poly(1,6-hexanediol)carbonate diols (PCDL) as the soft segment, 4,4'-methylenebis(cyclohexyl isocyanate) (H12MDI), 1,6-hexamethylene diisocyanate (HDI) and 1,4-butanediol (BDO) as the hard segment with dibutyltin dilaurate as the catalyst. In this article, we illustrated the physical behaviors were obviously influenced by synthetic routes. And their chemical and physical structures were investigated by gel permeation chromatograph (GPC), differential scanning calorimeter (DSC), fourier transform infrared spectrography (FT-IR) and mechanical properties tests. The surface wettability were studied by contact angle measurement (CA). As a kind of short-term implant biomaterial, the results of the hemolysis and platelet adhesive tests were recorded by spectrophotometer and scanning electron microscopy (SEM), indicating the materials have a great potential for developments and applications in biomedical field.

  2. Synthesis of polycarbonate urethane elastomers and effects of the chemical structures on their thermal, mechanical and biocompatibility properties

    Directory of Open Access Journals (Sweden)

    Rong Zhu

    2016-06-01

    Full Text Available In this study, to obtain biomedical polyurethane elastomers with good mechanical properties and biocompatibility, a series of polycarbonate urethanes were synthesized via a two-step solution of polymerization method using the poly(1,6-hexanediolcarbonate diols (PCDL as the soft segment, 4,4′-methylenebis(cyclohexyl isocyanate (H12MDI, 1,6-hexamethylene diisocyanate (HDI and 1,4-butanediol (BDO as the hard segment with dibutyltin dilaurate as the catalyst. In this article, we illustrated the physical behaviors were obviously influenced by synthetic routes. And their chemical and physical structures were investigated by gel permeation chromatograph (GPC, differential scanning calorimeter (DSC, fourier transform infrared spectrography (FT-IR and mechanical properties tests. The surface wettability were studied by contact angle measurement (CA. As a kind of short-term implant biomaterial, the results of the hemolysis and platelet adhesive tests were recorded by spectrophotometer and scanning electron microscopy (SEM, indicating the materials have a great potential for developments and applications in biomedical field.

  3. Reactions of the melatonin metabolite N(1)-acetyl-5-methoxykynuramine with carbamoyl phosphate and related compounds.

    Science.gov (United States)

    Kuesel, Jana T; Hardeland, Rüdiger; Pfoertner, Henrike; Aeckerle, Nelia

    2010-01-01

    N-[2-(6-methoxyquinazolin-4-yl)-ethyl] acetamide (MQA) is a compound formed from the melatonin metabolite N(1)-acetyl-5-methoxykynuramine (AMK). We followed MQA production in reaction systems containing various putative reaction partners, in the absence and presence of hydrogen peroxide and/or copper(II). Although MQA may be formally described as a condensation product of either N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK) with ammonia, or AMK with formamide, none of these combinations led to substantial quantities of MQA. However, MQA formation was observed in mixtures containing AMK, hydrogen peroxide, hydrogen carbonate and ammonia, or AMK, hydrogen peroxide, copper(II) and potentially carbamoylating agents, such as potassium cyanate or, more efficiently, carbamoyl phosphate. In the presence of hydrogen peroxide, copper(II) and carbamoyl phosphate, MQA was the major product obtained from AMK, but the omission of copper(II) mainly led to another metabolite, 3-acetamidomethyl-6-methoxycinnolinone (AMMC). This was caused by nitric oxide (NO) generated under oxidative conditions from carbamoyl phosphate, as shown by an NO spin trap. MQA formation with carbamoyl phosphate was not due to the possible decomposition product, formamide. The reaction of AMK with carbamoyl phosphate under oxidative conditions, in which inorganic phosphate and water are released and which differs from the typical process of carbamoylation via isocyanate, may be considered as a new physiological route of MQA formation.

  4. Attractive Interactions between Heteroallenes and the Cucurbituril Portal.

    Science.gov (United States)

    Reany, Ofer; Li, Amanda; Yefet, Maayan; Gilson, Michael K; Keinan, Ehud

    2017-06-21

    In this paper, we report on the noteworthy attractive interaction between organic azides and the portal carbonyls of cucurbiturils. Five homologous bis-α,ω-azidoethylammonium alkanes were prepared, where the number of methylene groups between the ammonium groups ranges from 4 to 8. Their interactions with cucurbit[6]uril were studied by NMR spectroscopy, IR spectroscopy, X-ray crystallography, and computational methods. Remarkably, while the distance between the portal plane and most atoms at the guest end groups increases progressively with the molecular size, the β-nitrogen atoms maintain a constant distance from the portal plane in all homologues, pointing at a strong attractive interaction between the azide group and the portal. Both crystallography and NMR support a specific electrostatic interaction between the carbonyl and the azide β-nitrogen, which stabilizes the canonical resonance form with positive charge on the β-nitrogen and negative charge on the γ-nitrogen. Quantum computational analyses strongly support electrostatics, in the form of orthogonal dipole-dipole interaction, as the main driver for this attraction. The alternative mechanism of n → π* orbital delocalization does not seem to play a significant role in this interaction. The computational studies also indicate that the interaction is not limited to azides, but generalizes to other isoelectronic heteroallene functions, such as isocyanate and isothiocyanate. This essentially unexploited attractive interaction could be more broadly utilized as a tool not only in relation to cucurbituril chemistry, but also for the design of novel supramolecular architectures.

  5. Precise synthesis of thermoreversible block copolymers containing reactive furfuryl groups via living anionic polymerization: the countercation effect on block copolymerization behavior

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Beom-Goo [ORNL; Pramanik, Nabendu [Indian Institute of Technology, Kharagpur; Singha, Nikhil K [ORNL; Lee, Jae-Suk [ORNL; Mays, Jimmy [University of Tennessee, Knoxville (UTK)

    2015-08-07

    The anionic block copolymerization of 4,4' -vinylphenyl-N,N-bis(4-tert-butylphenyl)benzenamine (A) with furfuryl isocyanate (B) was carried out using potassium naphthalenide (K-Naph) in tetrahydrofuran at -78 and -98 °C to prepare well-defined block copolymers containing furan groups for the formation of thermoreversible networks via a Diels Alder (DA) reaction. While no block copolymerization was observed in the absence of sodium tetraphenylborate (NaBPh4) due to side reactions, well-defined poly-(B-b-A-b-B) (PBAB) copolymers with controlled molecular weights (Mn = 18 700 19 500 g mol -1) and narrow molecular weight distributions (Mw/Mn = 1.08 -1.17) were successfully synthesized in the presence of excess NaBPh4. We prevented the occurrence of the undesirable side reactions during polymerization of B of NaBPh4, which results in the change in the countercation from K+ to Na+ for further polymerization of B. Moreover, the cross-linking via the DA reaction between the furan groups of PBAB and bismaleimide was proved by FT-IR and differential scanning calorimetry (DSC), and the thermoreversible properties of the cross-linked polymer were subsequently investigated using DSC and solubility testing.

  6. Direct Lactamization of Azido Amides via Staudinger-Type Reductive Cyclization

    Energy Technology Data Exchange (ETDEWEB)

    Heo, In Jung; Lee, Su Jeong; Cho, Chang Woo [Kyungpook National University, Daegu (Korea, Republic of)

    2012-01-15

    The direct lactamization of 1,3- and 1,4-azido amides has been achieved using triphenylphosphine and water, affording various γ- and δ-lactams in good to excellent yields. The direct lactamization of the azido amides was performed via the Staudinger-type reductive cyclization in which the amide group acts as the electrophile for lactam synthesis. This lactamization provides a mild, functional group tolerant and efficient route for the synthesis of various γ- and δ-lactams found in natural products and pharmaceuticals. Further studies will be conducted to develop new synthetic routes for the synthesis of various lactams. The lactam ring system is one of the most ubiquitous structural motifs found in natural products and pharmaceuticals. Owing to the prevalence of lactams, their synthesis has attracted considerable attention. Lactams are usually prepared by the coupling of activated carboxylic acid derivatives with amines. Alternative routes include the Beckmann rearrangement of oximes, the Schmidt reaction of cyclic ketones and hydrazoic acid, the Kinugasa reaction of nitrones and terminal acetylenes, the Diels-Alder reaction of cyclopentadiene and chlorosulfonyl isocyanate, transition metal catalyzed lactamization of amino alcohols, and iodolactamization of amides and alkenes. In particular, the intramolecular Staudinger ligation of azides and activated carboxy acids, including esters, is well known as an environmentally friendly and mild protocol for lactam synthesis.

  7. The relative safety of gamma-ray, autoclave, and ethylene oxide gas sterilization of thermosetting polyurethane.

    Science.gov (United States)

    Shintani, H

    1995-01-01

    Sterilization of polyurethane (PU) produces 4,4'-methylenedianiline (MDA), a known carcinogen, and various other compounds. The relationships of the components of PU to the formation of these compounds by sterilization were studied. Specimens of PU fabricated from different combinations of isocyanates and polyols were obtained from dialyzers. The molecular weight of the particular polyol was found to influence the production of MDA by sterilization. Sterilization also produced many unidentified compounds. MDA production was not always associated with the production of the other compounds. Compared with gamma-ray irradiation and ethylene oxide gas (EOG) sterilization, autoclave sterilization eluted more hydrophilic compounds. This phenomenon was significant for PUs produced from smaller-molecular-weight polyols. The combination of autoclave sterilization and a PU produced from a larger-molecular-weight polyol is recommended to minimize the production of potentially toxic compounds. Of the techniques studied, EOG sterilization produced the least amounts of MDA and the other compounds, but the residue of EOG is itself problematic. The risk posed by the amounts of MDA extracted was not significant, but the biological safety of the other compounds remains to be determined.

  8. Glass transition in thermosetting clay-nanocomposite polyurethanes

    Energy Technology Data Exchange (ETDEWEB)

    Corcione, C. Esposito [Dipartimento di Ingegneria dell' Innovazione, Universita del Salento, Via Monteroni 73100, Lecce (Italy)], E-mail: carola.corcione@unile.it; Maffezzoli, A. [Dipartimento di Ingegneria dell' Innovazione, Universita del Salento, Via Monteroni 73100, Lecce (Italy)

    2009-03-10

    In this work nanocomposite in a polyurethane (PU) matrix, using an organically modified montmorillonite (OMM), were studied. An amount of organoclay ranging from 2% up to 6% by volume was added to the polyol component of the resin before mixing with isocyanate. The basal distance of OMM before and after mixing with the polyol and after curing was characterized by X-ray diffraction. The glass transition temperature (T{sub g}) of PU nanocomposites, measured using differential scanning calorimeter, increases with increasing the volume fraction of OMM. On the other hand, the heat capacity increment, {delta}C{sub p}, decreases from that the unfilled PU to that of the sample with 5.7 vol.% of OMM. Therefore the rigid amorphous fraction of the PU nanocomposites increases with increasing volume fraction of OMM. Finally, a three-phase model similar to that applied to study semi-crystalline polymers, was used to analyze the intercalation of the PU chains between OMM lamellae. The definition of molecular cooperativity was discussed for these systems and the characteristic length of the cooperative region was determined, using Donth equation.

  9. Transport behavior of n-alkane penetrants into castor oil based polyurethane-polyester nonwoven fabric composites

    International Nuclear Information System (INIS)

    Satheesh Kumar, M.N.; Manjula, K.S.; Siddaramaiah

    2007-01-01

    Castor oil based polyurethane (PU)-polyester nonwoven fabric composites were fabricated by impregnating the polyester nonwoven fabric in a composition containing castor oil and diisocyanate. Composites were fabricated with two different isocyanates such as toluene-2,4-diisocyanate (TDI) and hexamethylene diisocyanate (HMDI). Transport behavior of n-alkane penetrants (pentane, hexane and heptane) into both PUs and PU-polyester nonwoven fabric composites were studied. Sorption studies were carried out at different temperatures. From the sorption results, the diffusion (D) and permeation (P) coefficients of penetrants have been calculated. Significant increase in the diffusion and permeation coefficients was observed with increase in the temperature of sorption experiments. Drastical reduction in diffusion and permeation coefficients was noticed in the composites compared to neat PUs. Attempts were made to estimate the empirical parameters like n, which suggests the mode of transport and K is a constant depends on the structural characteristics of the composite in addition to its interaction with penetrants. The temperature dependence of the transport coefficients has been used to estimate the activation energy parameter for diffusion (E D ) and permeation (E P ) processes from Arrhenius plots. Furthermore, the sorption results have been interpreted in terms of the thermodynamic parameters such as enthalpy (ΔH) and entropy (ΔS)

  10. Microencapsulation of Ethion by Interfacial Polymerization Utilizing Potassium Phthalimide-N-oxyl (PPINO) as a Promoter

    International Nuclear Information System (INIS)

    Moghbeli, M. R.; Abedi, V.; Dekamin, M. G.

    2011-01-01

    Poly urea microcapsules containing an active agent, i.e. ethion as pesticide, have been prepared by interfacial polymerization between 2, 4-toluene diisocyanate (TDI) and diethylenetriamine (DETA) in an oil-in-water (O/W) emulsion system. The effects of the nature of the emulsifier, the monomer weight ratio, and a novel promoter, i.e. potassium phthalimide-N-oxyl (PPINO), on the morphology, microstructure, and thermal stability of the microcapsules have been investigated. PPINO was used as a water-soluble promoter capable of dimerizing and trimerizing the isocyanate reactant in the interfacial polymerization. The transmission electron microscopy micrographs showed that the addition of the promoter had no significant effect on the microcapsule shell thickness. Increasing the amount of PPINO caused the degree of crystallinity of the polymer shell to decrease considerably. In addition, increasing the amount of promoter up to 2 wt % caused the thermal stability of the microcapsules to decrease, while using promoter beyond this level resulted in higher thermal stability.

  11. Detection of Aspergillus fumigatus mycotoxins: immunogen synthesis and immunoassay development.

    Science.gov (United States)

    Fox, M; Gray, G; Kavanagh, K; Lewis, C; Doyle, S

    2004-02-01

    Immunological detection of secreted low molecular weight toxins represents a potentially novel means of diagnosing infection by the fungus Aspergillus fumigatus. Two such metabolites, gliotoxin and helvolic acid, were selected and conjugated to thyroglobulin for antisera generation in rabbits. Gliotoxin was initially activated using N-[p-maleimidophenyl] isocyanate (PMPI) and subsequently conjugated to S-acetyl thioglycolic acid N-hydroxysuccinimide-activated thyroglobulin, whereas helvolic acid was activated with N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) in the presence of thyroglobulin prior to immunisation. To facilitate subsequent antisera evaluation, both toxins were similarly conjugated to bovine serum albumin (BSA). Matrix-Assisted Laser Desorption Ionisation-Time Of Flight (MALDI-TOF) mass spectrometry and SDS-PAGE analysis confirmed covalent attachment of toxins to BSA in the ratios of 15 and 2.4 mol per mol BSA for gliotoxin and helvolic acid, respectively. Resultant high titer antisera were capable of detecting both BSA-conjugated toxins (inhibitory concentration (IC)(50): 4-5 microg/ml). Free toxins were also detectable by competitive immunoassay, whereby 10 microg/ml free gliotoxin (30 microM) and helvolic acid (17 microM), respectively, inhibited antibody binding to cognate toxin-BSA previously immobilised on microwells. This work confirms that sensitive and specific antisera can be raised against fungal toxins and may have an application in diagnosing fungal infection.

  12. Preparation of Organic-Inorganic Hybrid Materials Based on MCM-41 and Its Applications

    Directory of Open Access Journals (Sweden)

    Sana M. Alahmadi

    2013-01-01

    Full Text Available This work reports the covalent attachment of three different calix[4]arenes (calix[4]arene (C4, p-sulfonatocalix[4]arene (C4S, and p-tert-butyl-calix[4]arene (PC4 to MCM-41, using a three-step modification process. 3-Chloropropyltrimethoxysilane (ClPTS was first attached to the mesoporous silica surface and subsequently converted to amides via the reaction with toluene diisocyanate (TDI. Finally, calix[4]arene derivatives attached to the isocyanate ending remained available on toluene di-iso-cyanate. Changes in the surface properties of the mesoporous silica caused by the chemical modification were monitored using the Fourier transform infrared spectroscopy (FTIR, thermal analysis (TGA, and elemental analysis. The FTIR spectra and TGA analysis verify that the calix[4]arene derivatives are covalently attached to the mesoporous silica. The preservation of the MCM-41 channel system was checked by the X-ray diffraction and nitrogen adsorption analysis. These materials were then used to evaluate the sorption properties of some organotins compounds (Tributyltin (TBT, Triphenyltin (TPT, and Dibutyltin (DBT.

  13. Preparation, characterization, and application of poly(vinyl alcohol)-graft-poly(ethylene glycol) resins: novel polymer matrices for solid-phase synthesis.

    Science.gov (United States)

    Luo, Juntao; Pardin, Christophe; Zhu, X X; Lubell, William D

    2007-01-01

    Spherical crosslinked poly(vinyl alcohol) (PVA) beads with good mechanical stability were prepared by reverse-suspension polymerization, using dimethyl sulfoxide (DMSO) as a cosolvent in an aqueous phase. Poly(ethylene glycol)s with varying chain lengths were grafted onto the PVA beads by anionic polymerization of ethylene oxide. The thermal behavior, morphology, and swelling were evaluated for each of the new polymer matrices. High loading and good swelling in water and organic solvents were characteristic of the PEG-grafted PVA beads. The polymer beads also exhibited good mechanical and chemical stability and were unaffected by treatment with 6 N HCl and with 6 N NaOH. The hydroxyl groups of the PVA-PEG beads were converted into aldehyde, carboxylic acid, and isocyanate functions to provide scavenger resins and were extended by way of a benzyl alcohol in a Wang linker. The transglutaminase substrates dipeptides (Z-Gln-Gly) and heptapeptides (Pro-Asn-Pro-Gln-Leu-Pro-Phe) were synthesized on PVA-PEG_5, PVA-PEG_20, and the Wang linker-derivatized PVA-PEG resins. The cleavage of the peptides from the resins using MeOH/NH3 mixture at different temperatures (0 degrees C and room temp) and 50% TFA/DCM provided, respectively, peptide methyl esters, amides, and acids in good yields and purity as assessed by LC-MS analysis.

  14. [Occupational asthma: Clinical and professional profile of the Tunisian asthmatic worker].

    Science.gov (United States)

    Toujani, S; Hedhli, A; Mjid, M; Ben Salah, N; Ouahchy, Y; Louzir, B; Daghfous, J; Mhiri, N; Cherif, J; Beji, M

    2016-08-01

    Asthma takes up a great importance in occupational diseases but remains underestimated as it is insufficiently diagnosed. We aimed to access the clinical and professional profile of the Tunisian asthmatic worker. It was a retrospective descriptive study in a professional pathology unit in a university hospital. All patients referred by their doctor for symptoms suggestive of occupational asthma, during a period from 2000 to 2008, were included. Forty-eight patients were selected from 172. The mean age was 40 years, with a male predominance (56 %). In 2/3 of the cases, it was the textile workers, food and chemical industry. The etiological agents incriminated were textile dust in 18.8 % of cases followed by isocyanates and flour. Typical episodes of wheezing dyspnea were present in 52 % and atopy in 54.2 % of workers. In 2 % of cases, symptoms disappeared and worsened in 18.8 %. The prognosis of OA depends on early end accurate diagnosis. The physician's role is to initiate the appropriate diagnostic approach, which must comply with the Tunisian conditions. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  15. Application Waste Sawdust as Mixed Polyurethane Insulation in Traditional Cold Storage of Fishing Vessel

    Directory of Open Access Journals (Sweden)

    Sutopo Purwono Fitri

    2017-03-01

    Full Text Available In the process of fishing it takes some supplies such as fishing equipment, instrumentation and storage of fish. The traditional fishermen of their fishing days fishing usually only bring ice cubes. Solid plastic polyurethane foam is a mixture solution of polyols and isocyanates, commonly used as an insulating material storage. From the observation waste generated being sawmill sawdust per spindle with diameter of 30 cm and a length of 1 m with 5 times sawmill, Saws 0.8 cm thick produced 0.0088 m³ / burnable logs only discarded. Therefore takes thermal conductivity test to review mixture of sawdust and polyurethane comparison with variations different dosing. Maximum disposals sawdust can be done is 40% of the total volume of material mixture, polyurethane and sawdust because composite material (sawdust-polyurethane can not be bond with good so easy slab separately from origin form. Thermal Conductivity insulating good and economical on disposals 40% wood flour (0.05252 W / m°C and is able to maintain a 2 kg of ice crystals melt up perfect on 34 hours. Operating profits economical from 4,8 m³insulation composite application with obtained Rp 4.486.000 compared with 100% Polyurethane Insulation Manufacture.

  16. Vapor space characterization of Waste Tank 241-U-106 (in situ): Results from samples collected on 8/25/94

    International Nuclear Information System (INIS)

    Ligotke, M.W.; Lucke, R.B.; Pool, K.H.

    1995-10-01

    This report describes inorganic and organic analyses results from in situ samples obtained from the headspace of the Hanford waste storage Tank 241-U-106 (referred to as Tank U-106). The results described here were obtained to support safety and toxicological evaluations. A summary of the results for inorganic and organic analytes is listed in Table 1. Detailed descriptions of the results appear in the text. Quantitative results were obtained for the inorganic compounds ammonia (NH 3 ), nitrogen dioxide (NO 2 ), nitric oxide (NO), and water (H 2 O). Sampling for hydrogen cyanide (HCN) and sulfur oxides (SO x ) was not performed. In addition, the authors looked for the 39 TO-14 compounds plus an additional 14 target analytes. Of these, six were observed above the 5-ppbv reporting cutoff. Ten organic tentatively identified compounds (TICs) were observed above the reporting cutoff of (ca.) 10 ppbv in two or more of the three samples collected and are reported with concentrations that are semiquantitative estimates based on internal standard response factors. The 10 organic analytes with the highest estimated concentrations are listed in Table 1 and account for approximately 89% of the total organic components in Tank U-106. Methyl isocyanate, a compound of possible concern in Tank U-106, was not detected. Tank U-106 is on the Organic Watch List

  17. Formation of the prebiotic molecule NH2CHO on astronomical amorphous solid water surfaces: accurate tunneling rate calculations.

    Science.gov (United States)

    Song, Lei; Kästner, Johannes

    2016-10-26

    Investigating how formamide forms in the interstellar medium is a hot topic in astrochemistry, which can contribute to our understanding of the origin of life on Earth. We have constructed a QM/MM model to simulate the hydrogenation of isocyanic acid on amorphous solid water surfaces to form formamide. The binding energy of HNCO on the ASW surface varies significantly between different binding sites, we found values between ∼0 and 100 kJ mol -1 . The barrier for the hydrogenation reaction is almost independent of the binding energy, though. We calculated tunneling rate constants of H + HNCO → NH 2 CO at temperatures down to 103 K combining QM/MM with instanton theory. Tunneling dominates the reaction at such low temperatures. The tunneling reaction is hardly accelerated by the amorphous solid water surface compared to the gas phase for this system, even though the activation energy of the surface reaction is lower than the one of the gas-phase reaction. Both the height and width of the barrier affect the tunneling rate in practice. Strong kinetic isotope effects were observed by comparing to rate constants of D + HNCO → NHDCO. At 103 K we found a KIE of 231 on the surface and 146 in the gas phase. Furthermore, we investigated the gas-phase reaction NH 2 + H 2 CO → NH 2 CHO + H and found it unlikely to occur at cryogenic temperatures. The data of our tunneling rate constants are expected to significantly influence astrochemical models.

  18. Bio-based polyurethane foams toward applications beyond thermal insulation

    International Nuclear Information System (INIS)

    Gama, Nuno V.; Soares, Belinda; Freire, Carmen S.R.; Silva, Rui; Neto, Carlos P.; Barros-Timmons, Ana; Ferreira, Artur

    2015-01-01

    Highlights: • Coffee grounds wastes were successfully liquefied yielding a bio-based polyol. • Coffee grounds derived foams formulations were optimized by tuning reagents’ contents. • The viscoelastic properties of these foams are promising to expand their applications. - Abstract: In this work the preparation of viscoelastic bio-based polyurethane foams (PUFs) using polyols obtained via acid liquefaction of coffee grounds wastes has been optimized. In a first stage, the effect of different ratios of isocyanate content to hydroxyl number (0.6, 0.7 and 0.8) and of three distinct percentages of catalyst (3%, 5% and 7%) on the extent of the polymerization reaction was studied by infrared spectroscopy. Next, different percentages of surfactant (14%, 16% and 18%) and blowing agent (12%, 14% and 16%) were used to assess their effect on the density, thermal conductivity and mechanical properties of the foams, including their recovery time. The mechanical properties of the ensuing foams proved to be very interesting due to their viscoelastic behavior. PUFs were also characterized by scanning electron microscopy (SEM) revealing a typical cellular structure and by thermogravimetric analysis (TGA) which proved that these materials are thermally stable up to 190 °C. These results suggest other potential applications for these materials beyond heat insulation in areas where damping properties can be an added value

  19. FY1998 report on the surveys and studies on developing next generation chemical process technologies; 1998 nendo jisedai kagaku process gijutsu kaihatsu ni kansuru chosa kenkyu hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    For further resource and energy conservation and environmental load reduction, development is necessary on innovative chemical reaction technologies. This paper describes surveys on next generation chemical processes. As non-halogen processes subject to development of new catalysts, new processes were investigated and searching experiments and discussions were given on isocyanate, propylene oxide, and phenol. Technological progress in the C1 chemistry was investigated. Problems in hydrocarbon compound oxidation, hydroxylation, and decomposition by utilizing microorganisms were put into order as application of environmentally friendly technologies. Marine biotechnical possibilities were surveyed. The surveys were given on new processes utilizing the phase transfer catalyst forming a third phase, manufacture of biodegradable plastics, and a novel reaction system combined with self-separation process using molecular assembly. Possibilities were searched on designing a truly simple production system of highly energy saving type. Such fundamental common technologies as structure analysis, property control and reaction engineering were investigated for methods to manufacture functional micro-powder chemical materials. Development was discussed on a system for technology assessment over whole product life cycle to structure a technology assessment basis. (NEDO)

  20. NCO-sP(EO-stat-PO Coatings on Gold Sensors—a QCM Study of Hemocompatibility

    Directory of Open Access Journals (Sweden)

    Frank K. Gehring

    2011-05-01

    Full Text Available The reliability of implantable blood sensors is often hampered by unspecific adsorption of plasma proteins and blood cells. This not only leads to a loss of sensor signal over time, but can also result in undesired host vs. graft reactions. Within this study we evaluated the hemocompatibility of isocyanate conjugated star shaped polytheylene oxide—polypropylene oxide co-polymers NCO-sP(EO-stat-PO when applied to gold surfaces as an auspicious coating material for gold sputtered blood contacting sensors. Quartz crystal microbalance (QCM sensors were coated with ultrathin NCO-sP(EO-stat-PO films and compared with uncoated gold sensors. Protein resistance was assessed by QCM measurements with fibrinogen solution and platelet poor plasma (PPP, followed by quantification of fibrinogen adsorption. Hemocompatibility was tested by incubation with human platelet rich plasma (PRP. Thrombin antithrombin-III complex (TAT, β-thromboglobulin (β-TG and platelet factor 4 (PF4 were used as coagulation activation markers. Furthermore, scanning electron microscopy (SEM was used to visualize platelet adhesion to the sensor surfaces. Compared to uncoated gold sensors, NCO-sP(EO-stat-PO coated sensors revealed significant better resistance against protein adsorption, lower TAT generation and a lower amount of adherent platelets. Moreover, coating with ultrathin NCO-sP(EO-stat-PO films creates a cell resistant hemocompatible surface on gold that increases the chance of prolonged sensor functionality and can easily be modified with specific receptor molecules.

  1. Beyond benzyl grignards: facile generation of benzyl carbanions from styrenes.

    Science.gov (United States)

    Grigg, R David; Rigoli, Jared W; Van Hoveln, Ryan; Neale, Samuel; Schomaker, Jennifer M

    2012-07-23

    Benzylic functionalization is a convenient approach towards the conversion of readily available aromatic hydrocarbon feedstocks into more useful molecules. However, the formation of carbanionic benzyl species from benzyl halides or similar precursors is far from trivial. An alternative approach is the direct reaction of a styrene with a suitable coupling partner, but these reactions often involve the use of precious-metal transition-metal catalysts. Herein, we report the facile and convenient generation of reactive benzyl anionic species from styrenes. A Cu(I)-catalyzed Markovnikov hydroboration of the styrenic double bond by using a bulky pinacol borane source is followed by treatment with KOtBu to facilitate a sterically induced cleavage of the C-B bond to produce a benzylic carbanion. Quenching this intermediate with a variety of electrophiles, including CO(2), CS(2), isocyanates, and isothiocyanates, promotes C-C bond formation at the benzylic carbon atom. The utility of this methodology was demonstrated in a three-step, two-pot synthesis of the nonsteroidal anti-inflammatory drug (±)-flurbiprofen. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Directing polyallylamine adsorption on microlens array patterned silicon for microarray fabrication.

    Science.gov (United States)

    Saini, Gaurav; Gates, Richard; Asplund, Matthew C; Blair, Steve; Attavar, Sachin; Linford, Matthew R

    2009-06-21

    The selective adsorption of reagents is often essential for bioarray and lab-on-a-chip type devices. As the starting point for a bioarray, alkyl monolayer terminated silicon shards were photopatterned in a few nanoseconds with thousands of wells (spots) using an optical element, a microlens array. Polyallylamine (PAAm), a primary amine containing polymer, adsorbed with little selectivity to the spots, i.e., silicon oxide, over the hydrophobic background. However, at appropriate concentrations, addition of a cationic surfactant to the PAAm deposition solution, cetyltrimethylammonium chloride, prevented the nonspecific adsorption of PAAm onto the hydrophobic monolayer, while directing it effectively to the active spots on the device. A nonionic surfactant was less effective in preventing the nonspecific adsorption of PAAm onto the hydrophobic monolayer. The localized reactions/interactions of adsorbed PAAm with four species that are useful for bioconjugate chemistry: glutaric anhydride, phenylenediisothiocyanate, biotin NHS ester, and an oligonucleotide (DNA) were shown in the spots of an array. The reactivity of PAAm was further demonstrated with an isocyanate. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) played an important role in confirming selective surface reactivity and adsorption. X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry, and wetting confirmed PAAm reactivity on planar substrates.

  3. A strategy to synthesize graphene-incorporated lignin polymer composite materials with uniform graphene dispersion and covalently bonded interface engineering

    Science.gov (United States)

    Wang, Mei; Duong, Le Dai; Ma, Yifei; Sun, Yan; Hong, Sung Yong; Kim, Ye Chan; Suhr, Jonghwan; Nam, Jae-Do

    2017-08-01

    Graphene-incorporated polymer composites have been demonstrated to have excellent mechanical and electrical properties. In the field of graphene-incorporated composite material synthesis, there are two main obstacles: Non-uniform dispersion of graphene filler in the matrix and weak interface bonding between the graphene filler and polymer matrix. To overcome these problems, we develop an in-situ polymerization strategy to synthesize uniformly dispersed and covalently bonded graphene/lignin composites. Graphene oxide (GO) was chemically modified by 4,4'-methylene diphenyl diisocyanate (MDI) to introduce isocyanate groups and form the urethane bonds with lignin macromonomers. Subsequential polycondensation reactions of lignin groups with caprolactone and sebacoyl chloride bring about a covalent network of modified GO and lignin-based polymers. The flexible and robust lignin polycaprolactone polycondensate/modified GO (Lig-GOm) composite membranes are achieved after vacuum filtration, which have tunable hydrophilicity and electrical resistance according to the contents of GOm. This research transforms lignin from an abundant biomass into film-state composite materials, paving a new way for the utilization of biomass wastes.

  4. Metal-Free Conversion of Carboxamides to Ureas Using Tertiary Amines and Iodosylmesitylene

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hoon; Chang, Suk Bok [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2010-03-15

    A new synthetic route has been developed for the preparation of ureas from the reaction of carboxamides with tertiary amines with the use of iodosylmesitylene as a stoichiometric oxidant. Although the reaction proceeds under the mild conditions to afford urea products in moderate yields, further optimization studies are required to improve the reaction efficiency and regioselectivity in the dealkylative pathway. Ureas are recognized as an important synthetic building unit, finding a wide range of applications in the preparation of agrochemicals, petrochemicals, and pharmaceuticals. In addition, hydrogen bond-mediated communication between ureas and certain types of compounds is an important structural motif in asymmetric catalysis, molecular recognition, and crystal engineering. Although numerous procedures have been developed for the urea synthesis, the most commonly employed strategy involves the reaction of amine precursors with phosgene, or its surrogates, isocyanates, or carbamates. Whereas these traditional methods are operative under conventional reaction conditions, they often lead to incomplete conversion. Additional drawback of these protocols is that unsymmetric ureas are difficult to prepare in many cases.

  5. Synthesis and Bioactivity of N-Benzoyl-N'-[5-(2'-substituted phenyl-2-furoyl] Semicarbazide Derivatives

    Directory of Open Access Journals (Sweden)

    Zining Cui

    2010-06-01

    Full Text Available In order to find novel chitin synthesis inhibitors (CSIs with good activity, benzoylphenylurea, a typical kind of CSIs, was chosen as the lead compound and 15 novel derivatives containing furan moieties were designed by converting the urea linkage of benzoylphenylureas into a semicarbazide and changing the aniline part into furoyl groups. The title compounds were synthesized by the reaction of substituted benzoyl isocyanates with 5-(substituted phenyl-2-furoyl hydrazine, and the structures were confirmed by IR, 1H-NMR, elemental analysis and single crystal X-ray diffraction analyses (compound E2. The bioassay results indicated that the title compounds exhibit good insecticidal activity, especially towards Plutella xylostella L., but had lower fungicidal activity. Inspiringly, the title compounds possessed obvious anticancer activity against human promyelocytic leukemic cell line (HL-60, and some of the title compounds also had activity against human hepatocellular carcinoma cell line (Bel-7402, human gastric carcinoma cell line (BGC-823, and human nasopharyngeal carcinoma cell line (KB. The results indicated that the linkage in the lead compounds was important to the bioactivity and spectra. The modification on the urea linkage is an effective strategy to discover new pesticide and drug candidates.

  6. Synthesis of hybrid polymers of beta-Cd and siloxanes

    International Nuclear Information System (INIS)

    Abbehausen, Camilla; Yoshida, Inez V.P.

    2009-01-01

    Hybrid polymers derived from siloxane and β-cyclodextrin (β-CD) were obtained from gamma-isocyanate-propyl-triethoxy-silane (IPTS) and β-CD. The resulting alkoxysilane was hydrolyzed generating glassy β-CD modified polysilsesquioxane. The alkoxysilane was also submitted to condensation with poly(dimethylsiloxane) with - Si(CH 3 -) 2 -OH end groups, giving rise to a polymeric network with β-CD at crosslinking nodes. These materials were characterized by infrared spectrum, 13 C and 29 Si nuclear magnetic resonance and X ray diffraction. The thermal behavior was analyzed by thermogravimetry. The capability of β-CD grafted in the siloxane polymers to form inclusion complexes was evaluated by the formation of β-CD-phenolphthalein complex, by UV-vis spectrum. The ability of water diffusion into β-CD-PSS film was evaluated by swollen measurement. β-CD-modified siloxanes were able to form films and their morphologies were evaluated by scanning electron microscopy. (author)

  7. Immunogenetic basis of environmental lung disease: Lessons from the berylliosis model

    International Nuclear Information System (INIS)

    Saltini, C.; Richeldi, L.; Amicosante, M.; Franchi, A.; Lombardi, G.

    1998-01-01

    The role of genetic factors has been hypothesized in the pathogenesis of a number of chronic inflammatory lung diseases. The genes of the major histocompatibility complex (MHC) locus on human chromosome 6 have been identified as important determinants in diseases caused both by inorganic and organic compounds such as beryllium, gold, acid anhydrides, isocyanates and grass pollens. Since many environmental factors are the determinants of the immunopathogenesis of asthma, pulmonary granulomatous disorders, hypersensitivity pneumonitis and fibrotic lung disorders, an understanding of the interaction between environmental factors is crucial to epidemiology, prevention and treatment of these disorders. Berylliosis is an environmental chronic inflammatory disorder of the lung caused by inhalation of beryllium dusts. A human leukocyte antigen class II marker (HLA-DP Glu69) has been found to be strongly associated with the disease. In in vitro studies, the gene has been shown to play a direct role in the immunopathogenesis of the disease. In human studies, the gene has been shown to confer increased susceptibility to beryllium in exposed workers, thus suggesting that HLA gene markers may be used as epidemiological probes to identify population groups at higher risk of environmental lung diseases, to identify environmental levels of lung immunotoxicants that would be safe for the entire population and the prevent disease risk associated with occupation, manufactured products and the environment. Studies on the associations between human leukocyte antigens and chronic inflammatory lung disorders are reviewed in the context of the berylliosis model. (au)

  8. Synthesis, Central Nervous System Activity and Structure-Activity Relationships of Novel 1-(1-Alkyl-4-aryl-4,5-dihydro-1H-imidazo-3-substituted Urea Derivatives

    Directory of Open Access Journals (Sweden)

    Elżbieta Szacoń

    2015-02-01

    Full Text Available A series of 10 novel urea derivatives has been synthesized and evaluated for their central nervous system activity. Compounds 3a–3h were prepared in the reaction between the respective 1-alkyl-4-aryl-4,5-dihydro-1H-imidazol-2-amines 1a and 1b and appropriate benzyl-, phenethyl-isocyanate or ethyl 4-isocyanatobenzoate and ethyl isocyanatoacetate 2 in dichloromethane. Derivatives 4c and 4g resulted from the conversion of 3c and 3g into the respective amides due to action of an aqueous ammonia solution. The results obtained in this study, based on literature data suggest a possible involvement of serotonin system and/or the opioid system in the effects of tested compounds, and especially in the effect of compound 3h. The best activity of compound 3h may be primarily attributed to its favourable ADMET properties, i.e., higher lipophilicity (related to lower polar surface area and greater molecular surface, volume and mass than for other compounds and good blood-brain permeation. This compound has also the greatest polarizability and ovality. The HOMO and LUMO energies do not seem to be directly related to activity.

  9. Hybrid Coatings Enriched with Tetraethoxysilane for Corrosion Mitigation of Hot-Dip Galvanized Steel in Chloride Contaminated Simulated Concrete Pore Solutions

    Science.gov (United States)

    Figueira, Rita B.; Callone, Emanuela; Silva, Carlos J. R.; Pereira, Elsa V.; Dirè, Sandra

    2017-01-01

    Hybrid sol-gel coatings, named U(X):TEOS, based on ureasilicate matrices (U(X)) enriched with tetraethoxysilane (TEOS), were synthesized. The influence of TEOS addition was studied on both the structure of the hybrid sol-gel films as well as on the electrochemical properties. The effect of TEOS on the structure of the hybrid sol-gel films was investigated by solid state Nuclear Magnetic Resonance. The dielectric properties of the different materials were investigated by electrochemical impedance spectroscopy. The corrosion behavior of the hybrid coatings on HDGS was studied in chloride-contaminated simulated concrete pore solutions (SCPS) by polarization resistance measurements. The roughness of the HDGS coated with hybrids was also characterized by atomic force microscopy. The structural characterization of the hybrid materials proved the effective reaction between Jeffamine® and 3-isocyanate propyltriethoxysilane (ICPTES) and indicated that the addition of TEOS does not seem to affect the organic structure or to increase the degree of condensation of the hybrid materials. Despite the apparent lack of influence on the hybrids architecture, the polarization resistance measurements confirmed that TEOS addition improves the corrosion resistance of the hybrid coatings (U(X):TEOS) in chloride-contaminated SCPS when compared to samples prepared without any TEOS (U(X)). This behavior could be related to the decrease in roughness of the hybrid coatings (due TEOS addition) and to the different metal coating interaction resulting from the increase of the inorganic component in the hybrid matrix. PMID:28772667

  10. Thermoanalytical studies of carbamazepine: hydration/dehydration, thermal decomposition, and solid phase transitions

    Directory of Open Access Journals (Sweden)

    Mônia Aparecida Lemos Pinto

    2014-12-01

    Full Text Available Carbamazepine (CBZ, a widely used anticonvulsant drug, can crystallize and exhibits four polymorphic forms and one dihydrate. Anhydrous CBZ can spontaneously absorb water and convert to the hydrate form whose different crystallinity leads to lower biological activity. The present study was concerned to the possibility of recovering the hydrated form by heating. The thermal behavior of spontaneously hydrated carbamazepine was investigated by TG/DTG-DTA and DSC in dynamic atmospheres of air and nitrogen, which revealed that the spontaneous hydration of this pharmaceutical resulted in a Form III hydrate with 1.5 water molecules. After dehydration, this anhydrous Form III converted to Form I, which melted and decomposed in a single event, releasing isocyanic acid, as shown by evolved gas analysis using TG-FTIR. Differential scanning calorimetry analyses revealed that Form III melted and crystallized as Form I, and that subsequent cooling cycles only generated Form I by crystallization. Solid state decomposition kinetic studies showed that there was no change in the substance after the elimination of water by heating to 120 °C. Activation energies of 98 ± 2 and 93 ± 2 kJ mol-1 were found for the hydrated and dried samples, respectively, and similar profiles of activation energy as a function of conversion factor were observed for these samples.

  11. [Synthetic Studies of Bioactive Heterocyclic Natural Products and Fused Heterocyclic Compounds Based on the Thermal Electrocyclic or Azaelectocyclic Reaction of 6π-Electron or Aza-6π-electron Systems].

    Science.gov (United States)

    Hibino, Satoshi

    2016-01-01

    Since 1979, synthetic studies of bioactive heterocyclic natural products and condensed heteroaromatic compounds based on the thermal electrocyclic reaction of 6π-electron or aza-6π-electron systems incorporating the double bond of the principal aromatic or heteroaromatic ring have been conducted by our research group. In this review, five types of electrocyclic and azaelectrocyclic reaction are described: 1) the synthesis of the carbazole alkaloids hyellazole and 6-chlorohyellazole through the electrocyclic reaction of 2,3-bisalkenylindoles; 2) synthetic studies of the pyridocarbazole alkaloids ellipticine and olivacine through the electrocyclic reactions of the indole-2,3- and pyridine-3,4-quinodimethane intermediates; 3) synthetic studies of polysubstituted carbazole alkaloids through the allene-mediated electrocyclic reactions involving the indole 2,3-bond; 4) synthetic studies of fused pyridine rings through the azaelectrocyclic reaction of the 1-aza-6π-electron system using the oxime or oxime ether; and 5) synthetic studies of fused pyridine rings through the azaelectrocyclic reaction of the 2-aza-6π-electron system using a carbodiimide or isocyanate.

  12. Producing Lignin-Based Polyols through Microwave-Assisted Liquefaction for Rigid Polyurethane Foam Production

    Directory of Open Access Journals (Sweden)

    Bai-Liang Xue

    2015-02-01

    Full Text Available Lignin-based polyols were synthesized through microwave-assisted liquefaction under different microwave heating times (5–30 min. The liquefaction reactions were carried out using polyethylene glycol (PEG-400/glycerol as liquefying solvents and 97 wt% sulfur acid as a catalyst at 140 °C. The polyols obtained were analyzed for their yield, composition and structural characteristics using gel permeation chromatography (GPC, Fourier transform infrared (FT-IR and nuclear magnetic resonance (NMR spectra. FT-IR and NMR spectra showed that the liquefying solvents reacted with the phenol hydroxyl groups of the lignin in the liquefied product. With increasing microwave heating time, the viscosity of polyols was slightly increased and their corresponding molecular weight (MW was gradually reduced. The optimal condition at the microwave heating time (5 min ensured a high liquefaction yield (97.47% and polyol with a suitable hydroxyl number (8.628 mmol/g. Polyurethane (PU foams were prepared by polyols and methylene diphenylene diisocyanate (MDI using the one-shot method. With the isocyanate/hydroxyl group ([NCO]/[OH] ratio increasing from 0.6 to 1.0, their mechanical properties were gradually increased. This study provided some insight into the microwave-assisted liquefied lignin polyols for the production of rigid PU foam.

  13. Attachment of inorganic moieties onto aliphatic polyurethanes

    Directory of Open Access Journals (Sweden)

    Eliane Ayres

    2007-06-01

    Full Text Available Polyurethanes have been used in a series of applications due basically to their versatility in terms of controlling the behavior by altering basically the type of reagents used. However, for more specific and advanced applications, such as in membranes, biomaterials and sensors, well-organized and defined chemical functionalities are necessary. In this work, inorganic functionalities were incorporated into aliphatic polyurethanes (PU having different macromolecular architectures. Polyurethanes were synthesized using a polyether diol and dicyclohexylmethane 4,4' diisocyanate (H12-MDI. Polyurethanes having carboxylic acid groups were also produced by introducing 2,2- bis (hydroxymethyl propionic acid in the polymerization process. Inorganic functionalities were inserted into polyurethanes by reacting isocyanate end capped chains with aminopropyltriethoxysilane followed by tetraethoxysilane. PU having carboxylic acid groups yielded transparent samples after the incorporation of inorganic entities, as an evidence of smaller and better dispersed inorganic entities in the polymer network. FTIR and swelling measurements showed that polyurethanes having carboxylic acid groups had inorganic domains less packed, condensed and cross-linked when compared to polyurethanes with no carboxylic acid groups. Results also suggested that the progressive incorporation of inorganic moieties in both types of polyurethanes occurred in regions previously activated with inorganic functionalities, instead of by the creation of new domains. The temperatures of thermal decomposition and glass transition were also shifted to higher temperatures when inorganic functionalities were incorporated into polyurethanes.

  14. Thioether-Bearing Hyperbranched Polyether Polyols with Methionine-Like Side-Chains: A Versatile Platform for Orthogonal Functionalization.

    Science.gov (United States)

    Seiwert, Jan; Herzberger, Jana; Leibig, Daniel; Frey, Holger

    2017-01-01

    The synthesis of thioether-bearing hyperbranched polyether polyols based on an AB/AB 2 type copolymerization (cyclic latent monomers) is introduced. The polymers are prepared by anionic ring-opening multibranching copolymerization of glycidol and 2-(methylthio)ethyl glycidyl ether (MTEGE), which is conveniently accessible in a single etherification step. Slow monomer addition provides control over molecular weights. Moderate dispersities (Đ = 1.48-1.85) are obtained, given the hyperbranched structure. In situ 1 H NMR copolymerization kinetics reveal reactivity ratios of r G = 3.7 and r MTEGE = 0.27. Using slow monomer addition, copolymer composition can be systematically varied, allowing for the adjustment of the hydroxyl/thioether ratio, the degree of branching (DB = 0.36-0.48), thermal properties, and cloud point temperatures in aqueous solution in the range of 29-75 °C. Thioether oxidation to sulfoxides enables to tailor the copolymers' solubility profile. Use of these copolymers as a versatile, multifunctional platform for orthogonal modification is highlighted. The methyl sulfide groups can be selectively alkoxylated, using propylene oxide, allyl glycidyl ether, or furfuryl glycidyl ether, resulting in functional hyperbranched polyelectrolytes. Reaction of the alcohol groups with benzyl isocyanate demonstrates successful orthogonal functionalization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Toxic pollutants emitted from thermal decomposition of phthalimide compounds

    Energy Technology Data Exchange (ETDEWEB)

    Chen Kai; Mackie, John C.; Wojtalewicz, Dominika; Kennedy, Eric M. [Process Safety and Environmental Protection Research Group, School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308 (Australia); Dlugogorski, Bogdan Z., E-mail: Bogdan.Dlugogorski@newcastle.edu.au [Process Safety and Environmental Protection Research Group, School of Engineering, University of Newcastle, Callaghan, New South Wales 2308 (Australia)

    2011-03-15

    Phthalimide (PI) and tetrahydrophthalimide (THPI) are two structurally similar compounds extensively used as intermediates for the synthesis of variety of industrial chemicals. This paper investigates the thermal decomposition of PI and THPI under oxygen rich to oxygen lean conditions, quantifying the production of toxicants and explaining their formation pathways. The experiments involved a plug flow reactor followed by silica cartridges, activated charcoal trap and a condenser, with the decomposition products identified and quantified by Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS) and micro gas chromatography ({mu}GC). The density functional theory (DFT) calculations served to obtain dissociation energies and reaction pathways, to elucidate the reaction mechanism. The oxidation of PI and THPI produced several toxic nitrogen-containing gases and volatile organic compounds, including hydrogen cyanide, isocyanic acid, nitrogen oxides, benzonitrile, maleimide and tentatively identified benzenemethanimine. The detection of dibenzo-p-dioxin (DD) and dibenzofuran (DF) suggests potential formation of the toxic persistent organic pollutants (POPs) in fires involving PI and THPI, in presence of a chlorine source. The oxidation of THPI produced 2-cyclohexen-1-one, a toxic unsaturated ketone. The results of the present study provide the data for quantitative risk assessments of emissions of toxicants in combustion processes involving PI and THPI.

  16. Formulation and properties of ADN/GAP propellants

    Energy Technology Data Exchange (ETDEWEB)

    Menke, Klaus; Heintz, Thomas; Schweikert, Wenka; Keicher, Thomas; Krause, Horst [Fraunhofer-Institut fuer Chemische Technologie ICT, Pfinztal (Germany)

    2009-06-15

    In this contribution two ways are described, how it is possible to achieve perfectly cured and processible propellants with prilled ADN, low amounts of HMX 5{mu}m mps and a binder system based on GAP diole and GAP triole oligomers with and without TMETN as a nitrate ester plasticizer. It was shown how it will be possible to suppress the strongly gas forming reaction between ADN and reactive isocyanates by a mixture of stabilizers. In this way it was possible to create minimum smoke ADN/HMX/GAP/TMETN propellants cured with the triisocyanate N100. In the second part an unconventional binder system based on the 1.3 dipolar cycloaddition reaction of azido groups with acetylene compounds forming 1,2,3-triazole heterocyclic rings has been applied for ADN/GAP and AP/GAP propellants. Together with small parts of HMX formulations with ADN/HMX/GAP and the corresponding AP/HMX/GAP exhibit high thermodynamic performance, are easily processible, and cure successfully at 60 C. Their basic properties consisting of burning behavior and mechanical properties, at ambient temperature, chemical stability, and sensitivity have been investigated and are compared to each other. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  17. Gas-chromatographic resolution of enantiomeric secondary alcohols. Stereoselective reductive metabolism of ketones in rabbit-liver cytosol.

    Science.gov (United States)

    Gal, J; DeVito, D; Harper, T W

    1981-01-01

    Chiral secondary alcohols were treated with (S)-(-)-1-phenylethyl isocyanate. For each racemic alcohol, the resulting diastereomeric urethane derivatives were resolved on flexible fused-silica capillary GLC columns with retention times of 15 min or less. Derivatization of individual enantiomers showed that the urethane derivatives of (R)-(-)-2-octanol, (R)-(+)-1-phenylethyl alcohol, and (S)-(+)-2,2,2-trifluoro-1-phenylethanol are eluted before the corresponding diastereomers. The procedure is simple and rapid, and is suitable for the determination of the enantiomeric composition of chiral alcohols extracted from biological media. A series of aliphatic alcohols, aryl alkyl carbinols, and arylalkyl alkyl carbinols were resolved with the procedure, and the degree of resolution varied from good to excellent. Eight achiral ketones were incubated, individually, with rabbit-liver 90,000 g supernatant fractions, and the enantiomeric composition of the alcohol metabolites was determined with the GLC procedure. The reductions proceeded with high stereoselectivity to give alcohol products of 90% or greater enantiomeric purity. The reduction of 2-octanone and acetophenone gave predominant alcohols of (S)-configuration, in agreement with the Baumann-Prelog rule. The configuration of the predominant alcohols arising in the reduction of the remainder of the ketones could not be firmly established, but the evidence suggests that they are also of the (S)-configuration. Fluorine or methyl substitution in the ortho position of acetophenone produced an increase in the stereoselectivity, and the alcohol produced from ortho-methylacetophenone was enantiomerically greater than 99% pure.

  18. The millimeter wave spectrum of methyl cyanate: a laboratory study and astronomical search in space ⋆,⋆⋆

    Science.gov (United States)

    Kolesniková, L.; Alonso, J. L.; Bermúdez, C.; Alonso, E. R.; Tercero, B.; Cernicharo, J.; Guillemin, J.-C.

    2016-01-01

    Aims The recent discovery of methyl isocyanate (CH3NCO) in Sgr B2(N) and Orion KL makes methyl cyanate (CH3OCN) a potential molecule in the interstellar medium. The aim of this work is to fulfill the first requirement for its unequivocal identification in space, i.e. the availability of transition frequencies with high accuracy. Methods The room-temperature rotational spectrum of methyl cyanate was recorded in the millimeter wave domain from 130 to 350 GHz. All rotational transitions revealed A-E splitting owing to methyl internal rotation and were globally analyzed using the ERHAM program. Results The data set for the ground torsional state of methyl cyanate exceeds 700 transitions within J″ = 10 – 35 and Ka″=0−13 and newly derived spectroscopic constants reproduce the spectrum close to the experimental uncertainty. Spectral features of methyl cyanate were then searched for in Orion KL, Sgr B2(N), B1-b, and TMC-1 molecular clouds. Upper limits to the column density of methyl cyanate are provided. PMID:27721514

  19. FY 1996 report meeting on the achievement of sending Japanese RITE researchers overseas; 1996 nendo RITE kokunai kenkyusha kaigai haken seika hokokukai

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-01

    In the report meeting, papers on the following were made public: 'Study of catalytic reaction removal technology and reaction mechanism of global warming substances such as N2O' given by Mr. A. Kushiyama sent to Swiss Federal Institute of Technology Zurich, Switzerland, and 'Study of proteins which are concerned with transport of biological membrane' given by Mr. M. Hara sent to Uppsala University, Sweden. In the former, examined were decomposition/oxidation reaction of tert-butyl compounds on various kinds of catalysts using a fixed bed normal pressure flow reactor equipped with FTIR, and selective reduction reaction of N{sub 2}O using these as reducing agent. As a result, it was found that under SCR reaction conditions, t-CNO is easily decomposed to tert-butyl amine through the isomerization to the correspondent tert-butyl isocyanate and further to isobutene and NH3 and also that isocyanato group of t-NCO and N2O easily react. In the latter, as to membrane proteins which play an important role in biological energy conversion system, especially proteins having transport activity such as electron, proton and amino acid, studied was appearance of the functions by solubilizing and separating the proteins, and restructuring them into liposome. (NEDO)

  20. Comparison of the internalization of targeted dendrimers and dendrimer-entrapped gold nanoparticles into cancer cells.

    Science.gov (United States)

    Shi, Xiangyang; Wang, Su He; Lee, Inhan; Shen, Mingwu; Baker, James R

    2009-11-01

    Dendrimer-based nanotechnology significantly advances the area of targeted cancer imaging and therapy. Herein, we compared the difference of surface acetylated fluorescein isocyanate (FI) and folic acid (FA) modified generation 5 (G5) poly(amidoamine) dendrimers (G5.NHAc-FI-FA), and dendrimer-entrapped gold nanoparticles with similar modifications ([(Au(0))(51.2)-G5.NHAc-FI-FA]) in terms of their specific internalization to FA receptor (FAR)-overexpressing cancer cells. Confocal microscopic studies show that both G5.NHAc-FI-FA and [(Au(0))(51.2-)G5.NHAc-FI-FA] exhibit similar internalization kinetics regardless of the existence of Au nanoparticles (NPs). Molecular dynamics simulation of the two different nanostructures reveals that the surface area and the FA moiety distribution from the center of the geometry are slightly different. This slight difference may not be recognized by the FARs on the cell membrane, consequently leading to similar internalization kinetics. This study underlines the fact that metal or inorganic NPs entrapped within dendrimers interact with cells in a similar way to that of dendrimers lacking host NPs. 2009 Wiley Periodicals, Inc.

  1. RX-08-HD, a low-viscosity, injection-moldable explosive for filling tortuous paths

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, D.M.; Jessop, E.S.; Swansiger, R.W.

    1997-10-01

    Cast cure, extrusion cast, and paste extrudable explosives have not been designed for transferring through long tortuous paths or into fine three dimensional shapes. To allow the crystalline explosive to flow a lubricating fluid is required. The energetic liquid ethane trinitrate (TMETN) was used as the lubricant to maximize the explosive energy. TMETN is a liquid nitrate ester which requires stabilization with conventional free radical stabilizers such as 2- nitrodiphenylamine, methyl-nitroanaline, or ethyl centrylite. Since these injection moldable explosives are expected to cure in place, a polyesterurethane binder based on polymeric isocyanate of hexamethylene diisocyanate and polycaprolactone polyols is dissolved in TMETN. The solubility of the polymer precursors in TMETN also reduces the energetic liquids sensitivity. The latent cure catalyst Dabco T-131 was used to minimize shrinkage associated with thermal expansion, reduce cost associated with oven cures, to give 4-6 hour potlife and overnight cure to handling strength. The product RX-08-HD is a new, low-viscosity, injection moldable explosive that can be extruded into complex, void-free shapes. Combined with appropriate design and other aspects of weaponization, RX-08-HD has produced outstanding results.

  2. Thermal Degradation and Damping Characteristic of UV Irradiated Biopolymer

    Directory of Open Access Journals (Sweden)

    Anika Zafiah M. Rus

    2015-01-01

    Full Text Available Biopolymer made from renewable material is one of the most important groups of polymer because of its versatility in application. In this study, biopolymers based on waste vegetable oil were synthesized and cross-link with commercial polymethane polyphenyl isocyanate (known as BF. The BF was compressed by using hot compression moulding technique at 90°C based on the evaporation of volatile matter, known as compress biopolymer (CB. Treatment with titanium dioxide (TiO2 was found to affect the physical property of compressed biopolymer composite (CBC. The characterization of thermal degradation, activation energy, morphology structure, density, vibration, and damping of CB were determined after UV irradiation exposure. This is to evaluate the photo- and thermal stability of the treated CB or CBC. The vibration and damping characteristic of CBC samples is significantly increased with the increasing of UV irradiation time, lowest thickness, and percentages of TiO2 loading at the frequency range of 15–25 Hz due to the potential of the sample to dissipate energy during the oscillation harmonic system. The damping property of CBC was improved markedly upon prolonged exposure to UV irradiation.

  3. Magnetically Bistable Nitrenes: Matrix Isolation of Furoylnitrenes in Both Singlet and Triplet States and Triplet 3-Furylnitrene.

    Science.gov (United States)

    Feng, Ruijuan; Lu, Yan; Deng, Guohai; Xu, Jian; Wu, Zhuang; Li, Hongmin; Liu, Qian; Kadowaki, Norito; Abe, Manabu; Zeng, Xiaoqing

    2018-01-10

    Two simple acylnitrenes, 2-furoylnitrene (2) and 3-furoylnitrene (6), were generated through 266 nm laser photolysis of the corresponding azides. Both are magnetically bistable in cryogenic matrices, as evidenced by the direct observation of the closed-shell singlet state with IR spectroscopy in solid Ne, Ar, Kr, Xe, and N 2 matrices (3-40 K) and the triplet state in toluene (10 K) with EPR spectroscopy ( 3 2: |D/hc| = 1.48 cm -1 and |E/hc| = 0.029 cm -1 ; 3 6: |D/hc| = 1.39 cm -1 and |E/hc|c = 0.039 cm -1 ). Subsequent visible-light and UV laser irradiations led to the formation of furyl isocyanates (3 and 7) and ring-opening product 3-cyanoacrolein (9-E and 9-Z), respectively, in which the elusive 3-furylnitrene ( 3 8) was also identified by IR and EPR spectroscopy (|D/hc| = 1.12 cm -1 and |E/hc| = 0.005 cm -1 ).

  4. The Impact of Post Harvest Agricultural Crop Residue Fires on Volatile Organic Compounds and Formation of Secondary Air Pollutants in the N.W. Indo-Gangetic Plain

    Science.gov (United States)

    Sinha, V.; Chandra, P.; Kumar, V.; Sarkar, C.

    2015-12-01

    The N.W. Indo-Gangetic Plain (IGP) is an agriculturally and demographically important region of the world. Every year during the post harvest months of April-May and October-November, large scale open burning of wheat straw and paddy straw occurs in the region impairing the regional air quality and resulting in air pollution episodes. Here, using online in-situ measurements from the IISER Mohali Atmospheric Chemistry Facility (Sinha et al., Atmos Chem Phys, 2014), which is located at a regionally representative suburban site in the agricultural state of Punjab, India, we investigated the effects of this activity on gas phase chemistry. The online data pertaining to the pre harvest and post harvest paddy residue fires in 2012, 2013 and 2014 were analyzed to understand the effect of this anthropogenic activity on atmospheric chemistry and regional air quality with respect to health relevant VOCs such as benzenoids and isocyanic acid and trace gases such as ozone and carbon monoxide. These compounds showed marked increases (factor of 2-3 times higher) in their concentrations which correlated with the biomass combustion tracers such as acetonitrile. Emissions from the paddy residue fires did not result in significant enhancement of ambient ozone in 2012 but instead sustained hourly daytime ozone concentrations at ~ 50 ppb during the late post monsoon season, despite decreases in solar radiation and temperature. Results of such massive perturbations to ambient chemical composition, reactivity and formation of secondary pollutants and its implications for human health will be presented in this paper.

  5. A survey of environmental and occupational work practices in the automotive refinishing industry of a developing country: Sonora, Mexico.

    Science.gov (United States)

    Velázquez, Luis; Bello, Dhimiter; Munguia, Nora; Zavala, Andrea; Marin, Amina; Moure-Eraso, Rafael

    2008-01-01

    The automotive repair and refinishing industry has been studied intensively in industrialized countries, in part due to use of hazardous chemicals such as isocyanates and solvents, but little is known about industry practices in the developing world. The main objective of this paper was to investigate environmental and occupational work practices of this industry in a developing region, Sonora, Mexico. An integrated survey approach maximizes the opportunity for identifying risks as well as reducing risks. This investigation included detailed workplace visits to 41 body shops and 6 paint suppliers, as well as a survey of shop owners and 24 workers. Information was collected on work practices, level of technology in the shops, use of personal protective equipment, consumption and handling of hazardous chemicals and waste, hazard communication, and environmental consciousness. Most shops had little capital, outdated technology for exposure control, poor working conditions, high potential for exposure to hazardous chemicals, and little awareness of environmental and occupational health and safety. We concluded that work practices in the Sonoran auto refinishing industry are unsustainable and may pose a health risk to workers and the environment.

  6. Network television news coverage of environmental risks

    International Nuclear Information System (INIS)

    Greenberg, M.R.; Sandman, P.M.; Sachsman, D.V.; Salomone, K.L.

    1989-01-01

    Despite the criticisms that surround television coverage of environmental risk, there have been relatively few attempts to measure what and whom television shows. Most research has focused analysis on a few weeks of coverage of major stories like the gas leak at Bhopal, the Three Mile Island nuclear accident, or the Mount St. Helen's eruption. To advance the research into television coverage of environmental risk, an analysis has been made of all environmental risk coverage by the network nightly news broadcasts for a period of more than two years. Researchers have analyzed all environmental risk coverage-564 stories in 26 months-presented on ABC, CBS, and NBC's evening news broadcasts from January 1984 through February 1986. The quantitative information from the 564 stories was balanced by a more qualitative analysis of the television coverage of two case studies-the dioxin contamination in Times Beach, Missouri, and the suspected methyl isocyanate emissions from the Union Carbide plant in Institute, West Virginia. Both qualitative and quantitative data contributed to the analysis of the role played by experts and environmental advocacy sources in coverage of environmental risk and to the suggestions for increasing that role

  7. Occupational allergic and irritant contact dermatitis in workers exposed to polyurethane foam

    Directory of Open Access Journals (Sweden)

    Marta Kieć-Świerczyńska

    2014-04-01

    Full Text Available Objectives: To evaluate sensitization to chemicals present in work environment after an outbreak of contact dermatitis in workers of vehicle equipment factory, exposed to polyurethane foam, based on 4,4'-diphenylmethane diisocyanate (MDI. Material and Methods: From among 300 employees, 21 individuals reporting work-related skin and/or respiratory tract symptoms underwent clinical examination, patch testing, skin prick tests, spirometry and MDI sIgE measurement in serum. Patch tests included isocyanates series, selected rubber additives, metals, fragrances, preservatives, and an antiadhesive agent. Results: Clinical examination revealed current eczema in the area of hands and/or forearms in 10 workers. Positive patch test reactions were found in 10 individuals, the most frequent to diaminodiphenylmethane and 4-phenylenediamine (7 persons. Reactions to an antiadhesive agent were assessed as irritant (5 workers. Except for sensitization to common aeroallergens, no significant abnormalities were found in the remaining tests. Occupational allergic contact dermatitis was diagnosed in 7 workers, irritant contact dermatitis in 10 and coexisiting allergic and irritant contact dermatitis in 3 workers. Conclusions: In workers manufacturing products from polyurethane foam, attention should be paid to the risk of developing contact dermatitis. Skin problems in our study group were attributable probably to insufficient protection of the skin.

  8. High Efficiency Robust Open Tubular Capillary Electrochromatography Column for the Separation of Peptides

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Faiz; Cheong, Won Jo [Inha University, Incheon (Korea, Republic of)

    2016-08-15

    In this study, the carefully designed tri-component copolymer layer was fabricated onto the inner surface of a pretreated silica capillary (52 cm effective length, 50 μm id). The initiator moieties were incorporated onto the capillary inner surface by reaction with 4-chloromehtylphenyl isocyanate followed by sodium diethyl dithiocarbamate. Next, RAFT copolymerization was held upon the initiator moieties and a thin polymer film was made. The observed peak capacity was, of course, lower than those of the state-of-the art gradient HPLC systems. The UPLC system operated in the long gradient elution mode with a long narrow column of sub-3 μm packed particles could achieve the impressive high peak capacity of ca. 1000. On the other hand, a system with a 20 cm column of 0.8 μm particles could achieve a peak capacity of 220 (comparable to our result) under a pressure of 20 000 psi in a gradient time of 20 min. It should be noted that the operational conditions of this study has been optimized to obtain the best column separation efficiency. It was also operated in the isocratic elution mode. A better peak capacity is expected if the operational conditions are tuned to the optimum peak capacity.

  9. The Effect of Reactives Diluents to the Physical Properties of Acrylated Palm Oil Based Polyurethane Coatings

    Directory of Open Access Journals (Sweden)

    Onn Munirah

    2016-01-01

    Full Text Available The development of polyurethane with hydroxyl access in a molecule leads to a new alternative of low toxicity green product. Palm oil is one of the major commodities in Malaysia. The potential of palm oil to be used as coatings raw material such as alkyd is limited due to low unsaturated side on fatty acid chains. To overcome this limitation, palm oil was modified through transesterification process to produce polyol. Acrylated isocyanate (urethane oligomer was then grafted onto polyol to produce polyurethane with vinylic ends. The polyurethane was formulated with different cross-linkers (reactive diluents and cured under UV radiation. The effect of three different diluents; monoacrylate, diacrylate and triacrylate on the properties of cured polymer were studied in this research. Fourier Transform Infrared (FTIR, Hydroxyl Value Titration, Gel Content, and Volatile Organic Compound (VOC were used for characterization. Physical testing performed were Pencil Hardness and Pull-Off Adhesion test. Novel palm oil-based polyurethane coatings have been found to have good properties with mono acrylate functionality.

  10. Proton transfer reaction time-of-flight mass spectrometry advancement in detection of hazardous substances

    International Nuclear Information System (INIS)

    Agarwal, B.

    2012-01-01

    Proton Transfer Reaction Mass Spectrometry (PTR-MS) is a mass spectrometric technique based on chemical ionization, which provides very rapid measurements (within seconds) of volatile organic compounds in air, usually without special sample preparation, and with a very low detection limit. The detection and study of product ion patterns of threat agents such as explosives and drugs and some major environmental pollutants (isocyanates and polychlorinated biphenyls (PCBs)) is explored in detail here using PTR-MS, specifically Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-TOF-MS). The proton transfer reaction (PTR) principle works on the detection of the compound in the vapor phase. For some compounds, which have extremely low vapor pressures, both sample and inlet line heating were needed. Generally, the protonated parent molecule (MH+) is found to be the dominant product ion, which therefore provides us with a higher level of confidence in the assignment of a trace compound. However, for several compounds, dissociative proton transfer can occur at various degrees resulting in other product ions. Analysis of other compounds, such as the presence of taggants and impurities were carried out, and in certain compounds unusual E/N anomalies were discovered (E/N is an instrumental set of parameters, where E is the electric field strength and N is the number density). Head space measurements above four different drinks (plain water, tea, red wine and white wine) spiked with four different 'date rape' drugs were also conducted. (author)

  11. Advances in environmental and occupational diseases 2004.

    Science.gov (United States)

    Frew, Anthony J

    2005-06-01

    2004 was another good year for publications on environmental and occupational disorders in our journal. The major focus is clearly on the environment and particularly on environmental risk factors for sensitization and asthma. There is a growing consensus that exposure to pets is good, provided there is enough of it. Low levels enhance sensitization, and higher levels protect against the consequences of that sensitization. Following on from previous work on cockroaches, we now see allergy to feral mice as an emergent problem--at least we now have the tools to study this properly. Emphasis seems to be swinging away from the outdoor environment as a cause of allergic disease and toward the indoor environment, which is, after all, where most of us spend most of our lives. New techniques for studying isocyanate allergy might kindle a revival of interest in the mechanisms of occupational asthma caused by low-molecular-weight compounds. But for all types of occupational allergy, prevention remains key, and it is good to see that comprehensive programs of allergen reduction can pay off in reduced rates of latex allergy in health care workers. Further work in the area of recombinant allergens is welcome but needs soon to be translated into new diagnostic and therapeutic strategies. This sector of allergy research remains vibrant, and the editors will continue to welcome outstanding contributions in this area.

  12. Construction of hydroxypropyl-{beta}-cyclodextrin copolymer nanoparticles and targeting delivery of paclitaxel

    Energy Technology Data Exchange (ETDEWEB)

    Miao Qinghua; Li Suping; Han Siyuan [National Center for Nanoscience and Technology of China, CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety (China); Wang Zhi, E-mail: wangzhi@jlu.edu.cn [Jilin University, Key Laboratory for Molecular Enzymology and Engineering, Ministry of Education (China); Wu Yan, E-mail: wuy@nanoctr.cn; Nie Guangjun, E-mail: niegj@nanoctr.cn [National Center for Nanoscience and Technology of China, CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety (China)

    2012-08-15

    A novel amphiphilic copolymer with p-maleimidophenyl isocyanate-hydroxypropyl-{beta}-cyclodextrin-polylactide-1, 2-dipalmitoyl-sn-glycero-3-phosphoethanolamine to generate copolymer nanoparticles (NPs) has been designed. In order to develop an active targeting system, integrin {alpha}{sub v}{beta}{sub 3}-specific targeting peptide cyclo(Arg-Gly-Asp-D-Phe-Cys), cRGD, was conjugated to the surface of NPs (NPs-RGD). These NPs were used to encapsulate anti-tumor drug, paclitaxel. The resulting NPs exhibited high drug-loading capacity and controlled drug release in vitro at acidic pH. In vitro cytotoxicity assay demonstrates that paclitaxel-loaded NPs-RGD significantly inhibited B16 tumor cell (high {alpha}{sub v}{beta}{sub 3}) proliferation relative to free paclitaxel and paclitaxel-loaded NPs at high concentrations. Paclitaxel-loaded NPs-RGD localized mainly in lysosomes in B16 cells as revealed by confocal microscopy. These results suggest a novel strategy for fabrication-functionalizing hydroxypropyl-{beta}-cyclodextrin copolymer nanoparticles for targeting delivery of paclitaxel to integrin {alpha}{sub v}{beta}{sub 3}-rich tumor cells. These nanocarriers can be readily extended to couple other bioactive molecules for active targeting and delivery of various chemotherapeutic drugs.

  13. Simultaneous analysis of pesticides from different chemical classes by using a derivatisation step and gas chromatography-mass spectrometry.

    Science.gov (United States)

    Raeppel, Caroline; Nief, Marie; Fabritius, Marie; Racault, Lucie; Appenzeller, Brice M; Millet, Maurice

    2011-11-04

    This work presents a new method to analyse simultaneously by GC-MS 31 pesticides from different chemical classes (2,4 D, 2,4 MCPA, alphacypermethrin, bifenthrin, bromoxynil, buprofezin, carbaryl, carbofuran, clopyralid, cyprodinil, deltamethrin dicamba, dichlobenil, dichlorprop, diflufenican, diuron, fenoxaprop, flazasulfuron, fluroxypyr, ioxynil, isoxaben, mecoprop-P, myclobutanil, oryzalin, oxadiazon, picloram, tau-fluvalinate tebuconazole, triclopyr, trifluralin and trinexapac-p-ethyl). This GC-MS method will be applied to the analysis of passive samplers (Tenax(®) tubes and SPME fiber) used for the evaluation of the indoor and outdoor atmospheric contamination by non-agricultural pesticides. The method involves a derivatisation step for thermo-labile or polar pesticides. Different agents were tested and MtBSTFA (N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide), a sylilation agent producing very specific fragments [M-57], was retained. However, diuron could not be derivatised and the isocyanate product was used for identification and quantification. Pesticides which did not need a derivatisation step were not affected by the presence of the derivatisation agent and they could easily be analysed in mixture with derivatised pesticides. The method can be coupled to a thermal-desorption unit or to SPME extraction for a multiresidue analysis of various pesticides in atmospheric samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Quality Assessment of Scarf Joints Considering the Acoustic Parameters: A Nondestructive Approach

    Directory of Open Access Journals (Sweden)

    Ali Yavari

    2015-07-01

    Full Text Available The present research studied the acoustic properties of 40 oak timber samples (Quercus castaneifolia: the acoustic coefficient (K and acoustic conversion efficiency (ACE in free vibration mode, using the free-free bar method with different planes of vibration, i.e., tangential (LT and radial (LR. These acoustic parameters were considered for both primary virgin wooden beams and modified beams carrying a single scarf joint in four different bonding angles (60°, 65°, 70°, and 75°, individually glued with two different adhesives (isocyanate and polyvinyl acetate. Comparing the acoustic properties of primary solid beams with scarf jointed beams of oak wood in LT and LR planes, the steeper joint angles of 70° and 75° did not result in any serious changes with polyvinyl acetate adhesive. Scarf-jointed beams with smaller joint angles (60° and 65° had significant effect on the acoustic properties relative to larger angles. Thus, beams having larger joint angles and beams glued using polyvinyl acetate may have enhanced acoustic properties.

  15. Strenght of the glue line of edge glued panels of Pinus taeda made with different adhesives

    Directory of Open Access Journals (Sweden)

    Merielen de Carvalho Lopes

    2013-12-01

    Full Text Available The study compares the strength of the glue line of edge glued panels of Pinus taeda made with different industrial adhesives. Three types of adhesives (poly(vinyl acetate (PVAc, emulsion polymer isocyanate (EPI and polyurethane (PU glued in two side gluing orientation (radial and tangential and analyzed after the conditioning tests (dry and wet were analyzed. The 360 specimens were prepared for determining the shear strength of edge glued panels of Pinus taeda, and these were tested in a universal testing machine called EMIC. The shear strength of the glue line at dry condition was lower in the tangential side for the three types of adhesives analyzed. The PU adhesive showed the highest values of shear strength in the applied conditions, differing from PVAc and EPI adhesive when tested on dry condition and did not differ from the others adhesives when tested on wet condition. The highest percentage of wood failure was observed after the shear strength test at dry condition to EPI adhesive glued in the radial side. And in the wet condition, the EPI adhesive and PU adhesive glued in tangential side showed higher mean values of wood failure. Thus, it was possible to conclude that the strength of the glue line of Pinus taeda wood was influenced by the type of adhesive and side gluing orientation, and showed differently behavior according to the condition of use (wet or dry.

  16. A new class of nitrosoureas. 4. Synthesis and antitumor activity of disaccharide derivatives of 3,3-disubstituted 1-(2-chloroethyl)-1-nitrosoureas.

    Science.gov (United States)

    Tsujihara, K; Ozeki, M; Morikawa, T; Kawamori, M; Akaike, Y; Arai, Y

    1982-04-01

    A series of 33 N-(2-chloroethyl)-N-nitrosocarbamoyl derivatives of N-substituted glycosylamines has been prepared and tested for antitumor activities. The compounds were obtained by reaction of glycosylamines with isocyanate, followed by nitrosation with N2O4. Structure-activity relationships of these trisubstituted nitrosoureas were investigated by varying the N-substituents and disaccharide groups and by comparing them with the corresponding disubstituted analogues. A large number of the nitrosoureas bearing a maltosyl group exhibited strong antitumor activities against leukemia L1210 and Ehrlich ascites carcinoma, and 60-day survivors against leukemia L1210 were found at the optimal dose for these derivatives. In contrast, the lactosyl and the melibiosyl derivatives were almost inactive. The most interesting compound in this series, the 3-isobutyl-3-maltosyl derivative (37), was tested against leukemia L1210 by single and multiple treatment. Its therapeutic ratio (96.3) obtained by multiple treatment is 3 times larger than that (31.5) obtained by single treatment, suggesting a possible clinical utility of 37 by multiple treatment. The favorable effect of a maltosyl moiety in this class of compounds is discussed.

  17. Value-added conversion of waste cooking oil and post-consumer PET bottles into biodiesel and polyurethane foams.

    Science.gov (United States)

    Dang, Yu; Luo, Xiaolan; Wang, Feng; Li, Yebo

    2016-06-01

    A sustainable process of value-added utilization of wastes including waste cooking oil (WCO) and post-consumer PET bottles for the production of biodiesel and polyurethane (PU) foams was developed. WCO collected from campus cafeteria was firstly converted into biodiesel, which can be used as vehicle fuel. Then crude glycerol (CG), a byproduct of the above biodiesel process, was incorporated into the glycolysis process of post-consumer PET bottles collected from campus to produce polyols. Thirdly, PU foams were synthesized through the reaction of the above produced polyols with isocyanate in the presence of catalysts and other additives. The characterization of the produced biodiesel demonstrated that its properties meet the specification of biodiesel standard. The effect of crude glycerol loading on the properties of polyols and PU foams were investigated. All the polyols showed satisfactory properties for the production of rigid PU foams which had performance comparable to those of some petroleum-based analogs. A mass balance and a cost analysis for the conversion of WCO and waste PET into biodiesel and PU foams were also discussed. This study demonstrated the potential of WCO and PET waste for the production of value-added products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Toxic pollutants emitted from thermal decomposition of phthalimide compounds

    International Nuclear Information System (INIS)

    Chen Kai; Mackie, John C.; Wojtalewicz, Dominika; Kennedy, Eric M.; Dlugogorski, Bogdan Z.

    2011-01-01

    Phthalimide (PI) and tetrahydrophthalimide (THPI) are two structurally similar compounds extensively used as intermediates for the synthesis of variety of industrial chemicals. This paper investigates the thermal decomposition of PI and THPI under oxygen rich to oxygen lean conditions, quantifying the production of toxicants and explaining their formation pathways. The experiments involved a plug flow reactor followed by silica cartridges, activated charcoal trap and a condenser, with the decomposition products identified and quantified by Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS) and micro gas chromatography (μGC). The density functional theory (DFT) calculations served to obtain dissociation energies and reaction pathways, to elucidate the reaction mechanism. The oxidation of PI and THPI produced several toxic nitrogen-containing gases and volatile organic compounds, including hydrogen cyanide, isocyanic acid, nitrogen oxides, benzonitrile, maleimide and tentatively identified benzenemethanimine. The detection of dibenzo-p-dioxin (DD) and dibenzofuran (DF) suggests potential formation of the toxic persistent organic pollutants (POPs) in fires involving PI and THPI, in presence of a chlorine source. The oxidation of THPI produced 2-cyclohexen-1-one, a toxic unsaturated ketone. The results of the present study provide the data for quantitative risk assessments of emissions of toxicants in combustion processes involving PI and THPI.

  19. Environmentally-Friendly Synthesis of Carbonate-Type Macrodiols and Preparation of Transparent Self-Healable Thermoplastic Polyurethanes

    Directory of Open Access Journals (Sweden)

    Seon-Mi Kim

    2017-11-01

    Full Text Available Carbonate-type macrodiols synthesized by base-catalyzed polycondensation of co-diols and dimethyl carbonate as an environmentally-friendly route were subsequently utilized for the preparation of transparent and self-healable thermoplastic polyurethanes (TPUs containing a carbonate-type soft segment. Three types of macrodiols, obtained from mono, dual and triple diol-monomers for target molecular weights of 1 and 1.5 kg mol−1, were analyzed by 1H NMR integration and the OH titration value. Colorless transparent macrodiols in a liquid state at a room temperature of 20 °C were obtained, except the macrodiol from mono 1,6-hexanediol. Before TPU synthesis, macrodiols require pH neutralization to prevent gelation. TPUs synthesized by a solution pre-polymer method with 4,4′-methylene(bisphenyl isocyanate and 1,4-butanediol as a chain extender exhibited moderate molecular weights, good transparencies and robust mechanical properties. Especially, the incorporation of 3-methyl-1,5-pentanediol within carbonate-type macrodiols enhanced the transparency of the resultant TPUs by decreasing the degree of microphase separation evidenced by ATR-FTIR and DSC. Interestingly, packing density of hard segments and the degree of microphase separation determined the self-healing efficiency of TPUs, which showed good performances in the case of sourced macrodiols from triple diol-monomers.

  20. Artifacts Generated During Azoalkane Peroxy Radical Oxidative Stress Testing of Pharmaceuticals Containing Primary and Secondary Amines.

    Science.gov (United States)

    Nefliu, Marcela; Zelesky, Todd; Jansen, Patrick; Sluggett, Gregory W; Foti, Christopher; Baertschi, Steven W; Harmon, Paul A

    2015-12-01

    We report artifactual degradation of pharmaceutical compounds containing primary and secondary amines during peroxy radical-mediated oxidative stress carried out using azoalkane initiators. Two degradation products were detected when model drug compounds dissolved in methanol/water were heated to 40°C with radical initiators such as 2,2'-azobis(2-methylpropionitrile) (AIBN). The primary artifact was identified as an α-aminonitrile generated from the reaction of the amine group of the model drug with formaldehyde and hydrogen cyanide, generated as byproducts of the stress reaction. A minor artifact was generated from the reaction between the amine group and isocyanic acid, also a byproduct of the stress reaction. We report the effects of pH, initiator/drug molar ratio, and type of azoalkane initiator on the formation of these artifacts. Mass spectrometry and nuclear magnetic resonance were used for structure elucidation, whereas mechanistic studies, including stable isotope labeling experiments, cyanide analysis, and experiments exploring the effects of butylated hydroxyanisole addition, were employed to support the degradation pathways. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  1. Direct Lactamization of Azido Amides via Staudinger-Type Reductive Cyclization

    International Nuclear Information System (INIS)

    Heo, In Jung; Lee, Su Jeong; Cho, Chang Woo

    2012-01-01

    The direct lactamization of 1,3- and 1,4-azido amides has been achieved using triphenylphosphine and water, affording various γ- and δ-lactams in good to excellent yields. The direct lactamization of the azido amides was performed via the Staudinger-type reductive cyclization in which the amide group acts as the electrophile for lactam synthesis. This lactamization provides a mild, functional group tolerant and efficient route for the synthesis of various γ- and δ-lactams found in natural products and pharmaceuticals. Further studies will be conducted to develop new synthetic routes for the synthesis of various lactams. The lactam ring system is one of the most ubiquitous structural motifs found in natural products and pharmaceuticals. Owing to the prevalence of lactams, their synthesis has attracted considerable attention. Lactams are usually prepared by the coupling of activated carboxylic acid derivatives with amines. Alternative routes include the Beckmann rearrangement of oximes, the Schmidt reaction of cyclic ketones and hydrazoic acid, the Kinugasa reaction of nitrones and terminal acetylenes, the Diels-Alder reaction of cyclopentadiene and chlorosulfonyl isocyanate, transition metal catalyzed lactamization of amino alcohols, and iodolactamization of amides and alkenes. In particular, the intramolecular Staudinger ligation of azides and activated carboxy acids, including esters, is well known as an environmentally friendly and mild protocol for lactam synthesis

  2. Synthesis and properties of radiation modified thermally cured castor oil based polyurethanes

    International Nuclear Information System (INIS)

    Mortley, Aba; Bonin, H.W.; Bui, V.T.

    2007-01-01

    Thermally cured polyurethanes were prepared from castor oil and hexamethylene diisocyanate (HMDI). Due to the long aliphatic chain of the castor oil component of polyurethane, thermal curing of castor oil based polyurethane (COPU) is limited by increasing polymer viscosity. To enhance further crosslinking, COPUs were exposed to doses up to 3.0 MGy produced by the mixed ionizing radiation field of a SLOWPOKE-2 research nuclear reactor. The physico-mechanical properties of castor oil based polyurethanes (COPU), unirradiated and irradiated, were characterized by mechanical tensile tests. A four-fold increase in modulus and tensile strength values from 0.930 to 4.365 MPa and 0.149 to 0.747 MPa, respectively, suggests improved physico-mechanical properties resulting from radiation. The changing areas of the carbonyl and the NH absorbance peaks and the disappearance of the isocyanate peak in the FTIR spectra as radiation progressed, indicates increased hydrogen bonding and intermolecular crosslinking, which is in agreement with the mechanical tests. Unchanging 13 C solid state NMR spectra imply limited sample degradation with increasing radiation

  3. Intrinsically radiopaque polyurethanes with chain extender 4,4'-isopropylidenebis [2-(2,6-diiodophenoxy)ethanol] for biomedical applications.

    Science.gov (United States)

    Dawlee, S; Jayabalan, M

    2015-05-01

    Radiopaque polyurethanes are used for medical applications as it allows post-operative assessment of the biomaterial devices using X-ray. Inherently, radiopaque polyurethanes based on polytetramethylene glycol (PTMG), polypropylene glycol, 4,4'-methylenebis(phenyl isocyanate), and a new iodinated chain extender 4,4'-isopropylidenebis[2-(2,6-diiodophenoxy)ethanol] with flexible spacers were synthesized and characterized. The iodinated polyurethanes were clear, optically transparent, and had high molecular weights. The polyurethanes also possessed excellent radiopacity and high thermal stability. The biocompatibility of the most promising iodinated polyurethane was evaluated both in vitro (cytotoxicity evaluation by direct contact and MTT assay, using L929 mouse fibroblast cells) and in vivo (toxicology studies in rabbits and subcutaneous implantation in rats). The material was nontoxic and well tolerated by the animals. Thus, these radiopaque and transparent polyurethanes are expected to have potential for various biomedical applications. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  4. Reduced Reactivity of Amines against Nucleophilic Substitution via Reversible Reaction with Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Fiaz S. Mohammed

    2015-12-01

    Full Text Available The reversible reaction of carbon dioxide (CO2 with primary amines to form alkyl-ammonium carbamates is demonstrated in this work to reduce amine reactivity against nucleophilic substitution reactions with benzophenone and phenyl isocyanate. The reversible formation of carbamates has been recently exploited for a number of unique applications including the formation of reversible ionic liquids and surfactants. For these applications, reduced reactivity of the carbamate is imperative, particularly for applications in reactions and separations. In this work, carbamate formation resulted in a 67% reduction in yield for urea synthesis and 55% reduction for imine synthesis. Furthermore, the amine reactivity can be recovered upon reversal of the carbamate reaction, demonstrating reversibility. The strong nucleophilic properties of amines often require protection/de-protection schemes during bi-functional coupling reactions. This typically requires three separate reaction steps to achieve a single transformation, which is the motivation behind Green Chemistry Principle #8: Reduce Derivatives. Based upon the reduced reactivity, there is potential to employ the reversible carbamate reaction as an alternative method for amine protection in the presence of competing reactions. For the context of this work, CO2 is envisioned as a green protecting agent to suppress formation of n-phenyl benzophenoneimine and various n-phenyl–n-alky ureas.

  5. Open tubular capillary column for the separation of cytochrome C tryptic digest in capillary electrochromatography.

    Science.gov (United States)

    Ali, Faiz; Cheong, Won Jo

    2015-10-01

    A silica capillary of 50 μm internal diameter and 500 mm length (416 mm effective length) was chemically modified with 4-(trifluoromethoxy) phenyl isocyanate in the presence of dibutyl tin dichloride as catalyst. Sodium diethyl dithiocarbamate was reacted with the terminal halogen of the bound ligand to incorporate the initiator moiety, and in situ polymerization was performed using a monomer mixture of styrene, N-phenylacrylamide, and methacrylic acid. The resultant open tubular capillary column immobilized with the copolymer layer was used for the separation of tryptic digest of cytochrome C in capillary electrochromatography. The sample was well eluted and separated into many components. The elution patterns of tryptic digest of cytochrome C were studied with respect to pH and water content in the mobile phase. This preliminary study demonstrates that open tubular capillary electrochromatography columns with a modified copolymer layer composed of proper nonpolar and polar units fabricated by reversible addition-fragmentation transfer polymerization can be useful as separation media for proteomic analysis. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Molding of strength testing samples using modern PDCPD material for purpose of automotive industry

    Science.gov (United States)

    Grabowski, L.; Baier, A.; Sobek, M.

    2017-08-01

    The casting of metal materials is widely known but the molding of composite polymer materials is not well-known method still. The initial choice of method for producing composite bodies was the method of casting of PDCPD material. For purpose of performing casting of polymer composite material, a special mold was made. Firstly, the 3D printed, using PLA material, mold was used. After several attempts of casting PDCPD many problems were encountered. The second step was to use mold milled from a firm and dense isocyanate foam. After several attempts research shown that this solution is more resistant to high-temperature peak, but this material is too fragile to use it several times. This solution also prevents mold from using external heating, which can be necessary for performing correct molding process. The last process was to use the aluminum mold, which is dedicated to PDCPD polymer composite, because of low adhesiveness. This solution leads to perform correct PDCPD polymer composite material injection. After performing casting operation every PDCPD testing samples were tested. These results were compared together. The result of performed work was to archive correct properties of injection of composite material. Research and results were described in detail in this paper.

  7. Sulfonated graphene oxide/nafion composite membrane for vanadium redox flow battery.

    Science.gov (United States)

    Kim, Byung Guk; Han, Tae Hee; Cho, Chang Gi

    2014-12-01

    Nafion is the most frequently used as the membrane material due to its good proton conductivity, and excellent chemical and mechanical stabilities. But it is known to have poor barrier property due to its well-developed water channels. In order to overcome this drawback, graphene oxide (GO) derivatives were introduced for Nafion composite membranes. Sulfonated graphene oxide (sGO) was prepared from GO. Both sGO and GO were treated each with phenyl isocyanate and transformed into corresponding isGO and iGO in order to promote miscibility with Nafion. Then composite membranes were obtained, and the adaptability as a membrane for vanadium redox flow battery (VRFB) was investigated in terms of proton conductivity and vanadium permeability. Compared to a pristine Nafion, proton conductivities of both isGO/Nafion and iGO/Nafion membranes showed less temperature sensitivity. Both membranes also showed quite lower vanadium permeability at room temperature. Selectivity of the membrane was the highest for isGO/Nafion and the lowest for the pristine Nafion.

  8. Glulam Properties of Fast-growing Species Using Mahogany Tannin Adhesive

    Directory of Open Access Journals (Sweden)

    Andi Sri Rahayu Diza Lestari

    2015-09-01

    Full Text Available Manufacturing glued laminated timber (glulam can help overcome the limited availability of large-sized timber, and the use of bio-adhesives may resolve environmental problems associated with synthetic adhesives containing high formaldehyde contents. Tannin adhesive is a bio-adhesive that can be used as alternative glue in the manufacture of glulam. The purpose of this study was to determine the physical and mechanical properties of glulam made with mahogany (Swietenia sp. tannin adhesive and wood from three fast-growing species, namely pine (Pinus merkusii, jabon (Anthocephalus cadamba, and sengon (Falcataria moluccana. Glulam (3 cm × 6 cm × 120 cm in thickness, width, and length, respectively was manufactured with three layers of lamina. The physical and mechanical properties of the glulams were tested based on relevant standards. The results showed that pine glulam fulfilled the standard for the modulus of rupture and modulus of elasticity, while sengon glulam met the standard for shear strength. In the delamination test, sengon glulam was resistant to immersion in cold water and hot water. All glulams had low formaldehyde emission levels and therefore fulfilled the standard requirements. The results showed that the tannin adhesive from mahogany bark was equal in quality to methylene diphenyl di-isocyanate for glulam manufacturing.

  9. Star-Branched Polymers (Star Polymers)

    KAUST Repository

    Hirao, Akira

    2015-09-01

    The synthesis of well-defined regular and asymmetric mixed arm (hereinafter miktoarm) star-branched polymers by the living anionic polymerization is reviewed in this chapter. In particular, much attention is being devoted to the synthetic development of miktoarm star polymers since 2000. At the present time, the almost all types of multiarmed and multicomponent miktoarm star polymers have become feasible by using recently developed iterative strategy. For example, the following well-defined stars have been successfully synthesized: 3-arm ABC, 4-arm ABCD, 5-arm ABCDE, 6-arm ABCDEF, 7-arm ABCDEFG, 6-arm ABC, 9-arm ABC, 12-arm ABC, 13-arm ABCD, 9-arm AB, 17-arm AB, 33-arm AB, 7-arm ABC, 15-arm ABCD, and 31-arm ABCDE miktoarm star polymers, most of which are quite new and difficult to synthesize by the end of the 1990s. Several new specialty functional star polymers composed of vinyl polymer segments and rigid rodlike poly(acetylene) arms, helical polypeptide, or helical poly(hexyl isocyanate) arms are introduced.

  10. Synthesis and mechanical properties of radiation-cured acrylo-urethane elastomers and their structural and morphological features

    International Nuclear Information System (INIS)

    Khamis, M.A.

    1984-01-01

    Polyacrylo-urethane elastomers were synthesized using a polyethylene adipate diol capped with toluene diisocyanate and hydroxyethylacrylate, to characterize the morphology of these elastomers and correlate their properties with both morphological and structural features. The one shot polymerization technique was used, where the prepolymer, the 2-hydroxyethylacrylate and the chain extender were mixed in the desired stoichiometric ratios and then reacted at various times and temperatures. The reaction progress was monitored by the isocyanate consumption. Acrylo-urethane mono-oligomers showed low elongation at break when compared with others in the literature at equivalent degrees of cross-linking in agreement with earlier work. It was postulated that the cause of low elongation was the high functionality of the cross-link in the polymerized network. Moisture-curing of the polymer films improved the mechanical properties of the partially reacted films, which was attributed to the formation of cross-linking by allophanate formation. Catalysts used (such as tertiary amines and metal catalysts) increase the rate so that even at lower temperatures the reaction is completed in a relatively short time, with no great influence on the film properties

  11. Atmospheric Photooxidation Products and Chemistry of Current-use Pesticides

    Science.gov (United States)

    Murschell, T.; Farmer, D.

    2017-12-01

    Pesticides are widely used in agricultural, commercial, and residential applications across the United States. Pesticides can volatilize off targets and travel long distances, with atmospheric lifetimes determined by both physical and chemical loss processes. In particular, oxidation by the hydroxyl radical (OH) can reduce the lifetime and thus atmospheric transport of pesticides, though the rates and oxidation products of atmospheric pesticide oxidation are poorly understood. Here, we investigate reactions of current-use pesticides with OH. MCPA, triclopyr, and fluroxypyr are herbicides that are often formulated together to target broadleaf weeds. We detect these species in the gas-phase using real-time high resolution chemical ionization mass spectrometry (CIMS) with both acetate and iodide reagent ions. We used an Oxidative Flow Reactor to explore OH radical oxidation and photolysis of these compounds, simulating up to 5 equivalent days of atmospheric aging by OH. Use of two ionization schemes allowed for the more complete representation of the OH radical oxidation of the three pesticides. The high resolution mass spectra allows us to deduce structures of the oxidation products and identify multi-generational chemistry. In addition, we observe nitrogen oxides, as well as isocyanic acid (HNCO), from some nitrogen-containing pesticides. We present yields of species of atmospheric importance, including NOx and halogen species and consider their impact on air quality following pesticide application.

  12. Allergy-related disorders in the construction industry.

    Science.gov (United States)

    Carino, Mauro; Romita, Paolo; Foti, Caterina

    2013-01-01

    Working conditions in the construction industry have improved in many industrialized countries, but heavy physical work with recurrent exposure to chemical agents, dust, and climatic influences still represents considerable risk for construction workers and may affect their health. The aim of this review is to analyze available data of the literature on allergy-related respiratory and skin disorders with emphasis on a preventive appraisal in order to produce statements and recommendations based on research evidence. The most common agents involved in the construction industry as a cause of occupational asthma (OA) in industrialized countries are isocyanates, wood dust, resins, glues, cobalt, and chromium. Allergic contact dermatitis (ACD) is an immunologic cell-mediated response to a sensitizing agent and the most common sensitizing agents associated with construction workers are epoxy resins, thiurams and thiazoles, and chromates. Medical surveillance must consider individual risk factors such as differences in individual susceptibility and sensitization to agents at workplace. Once work-related disorder is confirmed, adequate fitness for work should be assessed for the worker impaired by health condition. A reliable diagnosis of an index case is a sentinel event that may reveal risks for workers with similar exposure, leading to a revised risk assessment at the workplace that should reduce the risk and prevent further cases.

  13. Synthesis and Evaluation of New Phthalazine Urea and Thiourea Derivatives as Carbonic Anhydrase Inhibitors

    Directory of Open Access Journals (Sweden)

    Nurcan Berber

    2013-01-01

    Full Text Available A new series of phthalazine substituted urea and thiourea derivatives were synthesized, and their inhibitory effects on the activity of purified human carbonic anhydrases (hCAs I and II were evaluated. 2H-Indazolo[2,1-b]phthalazine-trione derivative (1 was prepared with 4-nitrobenzaldehyde, dimedone, and phthalhydrazide in the presence of TFA in DMF, and nitro group was reduced to amine derivative (2 with SnCl2·2H2O. The compound was reacted with isocyanates and isothiocyanates to get the final products (3a–p. The results showed that all the synthesized compounds inhibited the CA isoenzymes activity. 3a (IC50 = 6.40 µM for hCA I and 6.13 µM for hCA II has the most inhibitory effect. The synthesized compounds are very bulky to be able to bind near the zinc ion, and they much more probably bind as the coumarin derivatives.

  14. New mesostructured organosilica with chiral sugar derived structures: nice host for gold nanoparticles stabilisation.

    Science.gov (United States)

    Hérault, Damien; Cerveau, Geneviève; Corriu, Robert J P; Mehdi, Ahmad

    2011-01-14

    In this paper we describe the synthesis of functionalised mesoporous organosilicas containing a mannitol derivative in the framework. For this purpose, a bis-silylated precursor 3,4-Di-O-[3-(triethoxysilylpropyl)carbamate]-1,2:5,6-di-O-isopropylidene-D-mannitol was prepared by coupling of 1,2:5,6-di-O-isopropylidene-D-mannitol with 3-(triethoxysilylpropyl)isocyanate. The framework-functionalised materials were obtained in one step by the "direct synthesis" method which consists of a co-hydrolysis and polycondensation of a bis-silylated mannitol precursor with tetraethylorthosilicate (TEOS) in the presence of a non-ionic triblock co-polymer (P123) as structure-directing agent. Interestingly, deprotection of the 1,2,5,6 OH functional groups occurred during the material synthesis. The obtained solids were characterized by (13)C and (29)Si CP-MAS NMR, N(2) adsorption-desorption, powder X-ray diffraction, TEM and elemental analysis. We have shown that, the OH functional groups, which are released during the synthesis of the mesoporous silica, can be used for chelation of ions and stabilisation of nanoparticles. The subsequent growth of gold (0) nanoparticles in the wall has been investigated and evidenced.

  15. Development of polyisocyanurate pour foam formulation for space shuttle external tank thermal protection system

    Science.gov (United States)

    Harvey, James A.; Butler, John M.; Chartoff, Richard P.

    1988-01-01

    Four commercially available polyisocyanurate polyurethane spray-foam insulation formulations are used to coat the external tank of the space shuttle. There are several problems associated with these formulations. For example, some do not perform well as pourable closeout/repair systems. Some do not perform well at cryogenic temperatures (poor adhesion to aluminum at liquid nitrogen temperatures). Their thermal stability at elevated temperatures is not adequate. A major defect in all the systems is the lack of detailed chemical information. The formulations are simply supplied to NASA and Martin Marietta, the primary contractor, as components; Part A (isocyanate) and Part B (poly(s) and additives). Because of the lack of chemical information the performance behavior data for the current system, NASA sought the development of a non-proprietary room temperature curable foam insulation. Requirements for the developed system were that it should exhibit equal or better thermal stability both at elevated and cryogenic temperatures with better adhesion to aluminum as compared to the current system. Several formulations were developed that met these requirements, i.e., thermal stability, good pourability, and good bonding to aluminum.

  16. Novel route of synthesis for cellulose fiber-based hybrid polyurethane

    Science.gov (United States)

    Ikhwan, F. H.; Ilmiati, S.; Kurnia Adi, H.; Arumsari, R.; Chalid, M.

    2017-07-01

    Polyurethanes, obtained by the reaction of a diisocyanate compound with bifunctional or multifunctional reagent such as diols or polyols, have been studied intensively and well developed. The wide range modifier such as chemical structures and molecular weight to build polyurethanes led to designs of materials that may easily meet the functional product demand and to the extraordinary spreading of these materials in market. Properties of the obtained polymer are related to the chemical structure of polyurethane backbone. A number polyurethanes prepared from biomass-based monomers have been reported. Cellulose fiber, as a biomass material is containing abundant hydroxyl, promising material as chain extender for building hybrid polyurethanes. In previous researches, cellulose fiber was used as filler in synthesis of polyurethane composites. This paper reported a novel route of hybrid polyurethane synthesis, which a cellulose fiber was used as chain extender. The experiment performed by reacting 4,4’-Methylenebis (cyclohexyl isocyanate) (HMDI) and polyethylene glycol with variation of molecular weight to obtained pre-polyurethane, continued by adding micro fiber cellulose (MFC) with variation of type and composition in the mixture. The experiment was evaluated by NMR, FTIR, SEM and STA measurement. NMR and FTIR confirmed the reaction of the hybrid polyurethane. STA showed hybrid polyurethane has good thermal stability. SEM showed good distribution and dispersion of sorghum-based MFC.

  17. Dispersiones acuosas de poliuretano bloqueado: una alternativa como agente curtiente Aqueous dispersions of blocked polyurethane: an alternative as tanning agents

    Directory of Open Access Journals (Sweden)

    José Luis Mata-Mata

    2008-06-01

    Full Text Available Se sintetizaron y se evaluaron como agentes curtientes de pieles vacunas dos tipos de agentes de reticulación base poliuretano bloqueado. Se presentan los resultados de la síntesis de dispersiones acuosas de poliuretano bloqueado (DPU’s, basadas en prepolímeros a partir de la reacción de los diisocianatos alifáticos H12MDI (4,4’ metilenbis-ciclohexilisocianato y HDI (hexametilendiisocianato con polioles base poliéter óxido de etileno de peso molecular 1 y 2 KDa, en una relación molar isocianato/oxhidrilo (NCO/OH de 4:1 y 6:1 a 100 °C por 2 y 4 horas. En una segunda reacción, los grupos isocianato (NCO libres del prepolímero se bloquearon con una solución acuosa de NaHSO3 ó Na2S2O5 al 40%p/p. Los prepolímeros se caracterizaron mediante espectroscopia IR y RMN de ¹H. El tanto por ciento de isocianato libre en el prepolímero, así como el bloqueo de dichos grupos, se determinaron por espectroscopía IR. La evaluación de la capacidad curtiente de las DPU’s se determinó de acuerdo a la estabilidad térmica de la piel (temperatura de desnaturalización, mediante Calorimetría Diferencial de Barrido (DSC y a la determinación del índice de reticulación de las DPU’s con la colágena de la piel mediante un ensayo con ninhidrina.Two types of crosslinking agents blocked polyurethanes were synthesized and evaluated as tanning agents of bovine skins. The results of the synthesis of aqueous dispersions of blocked polyurethane (DPU’s are presented. They were based on prepolymers from the reaction of the aliphatic diisocyanates H12MDI 4,4’-methylenebis(cyclohexyl isocyanate and HDI (hexamethylene diisocyanate with HO-polyols such as polyethylene oxide of molecular weight 1 and 2 kDa. The molar NCO/OH ratio was fixed in 4:1 or 6:1, at 100 °C and 2 or 4 hours for the reaction time. In a second reaction, the prepolymer containing terminal NCO groups were blocked by reaction with an aqueous NaHSO3 or Na2S2O5 solution to 40% w/w. The

  18. Shrinkage / stress reduction and mechanical properties improvement in restorative composites formulated with thio-urethane oligomers.

    Science.gov (United States)

    Bacchi, Atais; Yih, Jonathan A; Platta, Jacqueline; Knight, Joseph; Pfeifer, Carmem S

    2018-02-01

    Thio-urethane oligomers (TUs) have been shown to favorably modify methacrylate networks to reduce stress and significantly increase fracture toughness. Since those are very desirable features in dental applications, the objective of this work was to characterize restorative composites formulated with the addition of TUs. TUs were synthesized by combining thiols - pentaerythritol tetra-3-mercaptopropionate (PETMP) or trimethylol-tris-3-mercaptopropionate (TMP) - with isocyanates - 1,6-Hexanediol-diissocyante (HDDI) (aliphatic) or 1,3-bis(1-isocyanato-1-methylethyl)benzene (BDI) (aromatic) or dicyclohexylmethane 4,4'-Diisocyanate (HMDI) (cyclic), at 1:2 isocyanate:thiol, leaving pendant thiols. 20wt% TU were added to BisGMA-TEGDMA (70-30%). To this organic matrix, 70wt% silanated inorganic fillers were added. Near-IR was used to follow methacrylate conversion and rate of polymerization (Rp max ). Mechanical properties were evaluated in three-point bending (ISO 4049) for flexural strength/modulus (FS/FM) and toughness (T), and notched specimens (ASTM Standard E399-90) for fracture toughness (K IC ). Polymerization stress (PS) was measured on the Bioman. Volumetric shrinkage (VS) was measured with the bonded disk technique. Glass transition temperature (Tg) and heterogeneity of network were obtained with dynamic mechanical analysis. The addition of TUs led to an increase in mechanical properties (except for Tg and FS). Fracture toughness ranged from 1.6-1.94MPam 1/2 for TU-modified groups, an increase of 33-61% in relation to the control (1.21 ± 0.1MPam 1/2 ). Toughness showed a two-fold increase in relation to the control: from 0.91MPa to values ranging from 1.70-1.95MPa. Flexural modulus was statistically higher for the TU-modified groups. The Tg, as expected, decreased for all TU groups due to the greater flexibility imparted to the network (which also explains the increase in toughness and fracture toughness). Narrower tan-delta peaks suggest more homogeneous

  19. Radiosynthesis of [11C]SB-705498, a selective transient receptor potential Vanilloid 1 (TRPV1) receptor antagonist

    International Nuclear Information System (INIS)

    Dolle, F.; Bramoulle, Y.; Deverre, J.R.; Bottlaender, M.; Passchier, J.

    2011-01-01

    Complete text of publication follows: Objectives: The transient receptor potential vanilloid 1 (TRPV1) receptor, previously known as the vanilloid receptor 1 (VR1), is a non-selective cation channel activated by a range of noxious stimuli and highly expressed in nociceptive fibres. TRPV1 receptor is involved in pain and sensitisation associated with tissue injury and inflammation and therefore represents a pharmacological target of choice for the development of novel therapeutic agents for the treatment of chronic pain, migraine and gastrointestinal disorders. Among a novel series of pyrrolidinyl ureas recently discovered by GSK, SB-705498 (1, namely 1-(2-bromophenyl)-3-[(R)-1-(5- trifluoromethylpyridin-2-yl)pyrrolidin-3-yl]urea) has been identified as a potent, selective and orally bioavailable TRPV1 antagonist and considered for positron emission tomography studies. SB-705498 (1) has therefore been isotopically labelled with the short-lived positron-emitter carbon-11 (t1/2: 20.38 min) at its urea site using [ 11 C]phosgene in a one-pot two-step process, via the intermediate preparation of 2-bromophenyl [ 11 C]isocyanate. Methods: Carbon-11-labeling of SB-705498 comprises: (A) Trapping of [ 11 C]phosgene (radio-synthesized from cyclotron-produced [ 11 C]methane via [ 11 C]carbon tetrachloride using minor modifications of published processes) at room temperature for 1 to 2 minutes in 250 μL of acetonitrile containing 0.6 μmole of 2-bromoaniline (2) giving 2-bromophenyl [ 11 C]isocyanate ([ 11 C]-3), followed by (B) addition of an excess of chiral (R)-1-(5- trifluoromethylpyridin-2-yl)pyrrolidin-3-ylamine (4, 40 μmoles in 500 μL of acetonitrile) as the second amine and reaction at room temperature for an additional one minute giving the desired urea derivative ([ 11 C]SB-705498 ([ 11 C]-1)), (C) dilution of the crude reaction mixture with water (500 μL) containing 4% (v:v) of DEA, injection and purification on a semi-preparative Waters Symmetry R C18 HPLC

  20. Dermal, inhalation, and internal exposure to 1,6-HDI and its oligomers in car body repair shop workers and industrial spray painters.

    Science.gov (United States)

    Pronk, A; Yu, F; Vlaanderen, J; Tielemans, E; Preller, L; Bobeldijk, I; Deddens, J A; Latza, U; Baur, X; Heederik, D

    2006-09-01

    To study inhalation and dermal exposure to hexamethylene diisocyanate (HDI) and its oligomers as well as personal protection equipment (PPE) use during task performance in conjunction with urinary hexamethylene diamine (HDA) in car body repair shop workers and industrial spray painters. Personal task based inhalation samples (n = 95) were collected from six car body repair shops and five industrial painting companies using impingers with di-n-butylamine (DBA) in toluene. In parallel, dermal exposure was assessed using nitril rubber gloves. Gloves were submerged into DBA in toluene after sampling. Analysis for HDI and its oligomers was performed by LC-MS/MS. Urine samples were collected from 55 workers (n = 291) and analysed for HDA by GC-MS. Inhalation exposure was strongly associated with tasks during which aerosolisation occurs. Dermal exposure occurred during tasks that involve direct handling of paint. In car body repair shops associations were found between detectable dermal exposure and glove use (odds ratio (OR) 0.22, 95% confidence interval (CI) 0.09 to 0.57) and inhalation exposure level (OR 1.34, 95% CI 0.97 to 1.84 for a 10-fold increase). HDA in urine could be demonstrated in 36% and 10% of car body repair shop workers and industrial painting company workers respectively. In car body repair shops, the frequency of detectable HDA was significantly elevated at the end of the working day (OR 2.13, 95% CI 1.07 to 4.22 for 3-6 pm v 0-8 am). In both branches HDA was detected in urine of approximately 25% of the spray painters. In addition HDA was detected in urine of a large proportion of non-spray painters in car body repair shops. Although (spray) painting with lacquers containing isocyanate hardeners results in the highest external exposures to HDI and oligomers, workers that do not perform paint related tasks may also receive a considerable internal dose.

  1. [Cancer chemotherapy with special reference to pharmacokinetics of nitrosoureas].

    Science.gov (United States)

    Wakui, A

    1982-08-01

    This paper provides an overview of cancer chemotherapy with special reference to the pharmacokinetics of the nitrosoureas. At physiological PH, the chloroethylnitrosoureas can be decomposed into an isocyanate and 2-chloroethyl diazene hydroxide. Therefore, it is clear that they have both alkylation and carbamoylation actions. In addition to the spontaneous chemical dissociation, the nitrosoureas can be metabolized by liver microsomal enzymes to more polar hydroxylated products, and certain nitrosoureas can be denitrosated by these enzymes to the parent urea. Since the lipid-soluble nitrosoureas and some of the water-soluble nitrosoureas such as ACNU and MCNU demonstrated to cross the blood-brain barrier, they have been used in the treatment of primary brain tumors and tumors and tumors of metastatic origin. It has been demonstrated from the results of our study and other reports that the alkylation of DNA by ACNU progresses more slowly as compared with that of other alkylating agents. This is an important finding in relation to the appearance of delayed myelosuppression of the nitrosoureas and in the design of dose schedules of these agents. The major clinical emphasis has been directed towards the more active chloroethylnitrosoureas with reduced myelosuppression, and attempts are now made for this purpose. Unfortunately, the results of phase I and II trials of the newly developed nitrosoureas suggest that these agents produce delayed and cumulative bone marrow toxicity. Antitumor activity of the nitrosoureas is frequestly observed in chronic myelocytic leukemia, malignant lymphoma, brain tumors and small cell carcinoma of the lung, and less frequently in gastrointestinal carcinoma, multiple myeloma and malignant melanoma. In order to enhance clinical effects of the nitrosoureas, further investigation of the design in therapeutic schedules on the basis of their pharmacokinetic characteristics will be needed.

  2. Development of high performance lubricant through the compatibility of polyalphaolefin, polyurea and irradiated polytetrafluoroethylene; Graxa de poliureia: estudo da compatibilidade da poliureia, polialfaolefina e politetrafluoretileno irradiado para melhoria da lubricidade e estabilidade

    Energy Technology Data Exchange (ETDEWEB)

    Ratao, Natalia Torres

    2013-07-01

    Lubricants are gaseous, liquid, semi solid or solid (powder) materials those form a film between two parties preventing friction. High performance lubricants are designed to work under severe conditions of temperature, pressure, and contamination. The most used are liquids (oils) and semi solids (greases). Greases are applied where oils can drain or in inaccessible places and are divided generally into two classes, soap and no soap. The most used non soap grease is polyurea, obtained by the reaction between amine and isocyanate, has highly thixotropic, high dielectric strength and excellent anticorrosive property, so it is widely used for lubrication of electric motors and shipbuilding machinery. For a grease with high performance, in this study was used a synthetic lubricant fluid, polyalphaolefin, and was also employed solid lubricant additive polytetrafluoroethylene (PTFE) due its lowest coefficient of friction, is found commercially irradiated in air to obtain smaller particles and to produce oxygenated terminal groups those are more compatible with the metal surface. The tests conducted were comparatively between pure polyurea grease and with PTFE additive. The characterizations were made by infrared spectroscopy and elemental analysis of C, N and H and Free NCO index, proving the formation of four carbons polyurea (tetraurea). The functional analysis of drop point and oil separation showed high stability and compatibility between the polymers increased when PTFE was added. The excellent resistance of pure tetraurea grease to wear and extreme pressure were demonstrated by four-ball and practical bearings tests, characterizing this grease as a high performance lubricant, when compared to most used greases in the market. (author)

  3. The Effect of Plant Source on the Properties of Lignin-Based Polyurethanes

    Directory of Open Access Journals (Sweden)

    Jason M. Lang

    2018-02-01

    Full Text Available This work increases our understanding of the effect of plant source on the mechanical and morphological properties of lignin-based polyurethanes (PUs. Lignin is a polymer that is synthesized inside the plant cell wall and can be used as a polyol to synthesize PUs. The specific aromatic structure of the lignin is heavily reliant on the plant source from which it is extracted. These results show that the mechanical properties of lignin-based PUs differ based on lignin’s plant source. The morphology of lignin-based PUs was examined using atomic force microscopy and scanning electron microscopy and the mechanical properties of lignin-based PU samples were measured using dynamic mechanical analysis and shore hardness (Type A. The thermal analysis and morphology studies demonstrate that all PUs prepared form a multiphase morphology. In these PUs, better mixing was observed in the wheat straw lignin PU samples leading to higher moduli than in the hardwood lignin and softwood lignin PUs whose morphology was dominated by larger aggregates. Independent of the type of the lignin used, increasing the fraction of lignin increased the rigidity of PU. Among the different types of lignin studied, PU with wheat straw soda lignin exhibited storage moduli ~2-fold higher than those of PUs incorporating other lignins. This study also showed that during synthesis all hydroxyl groups in the lignin are not available to react with isocyanates, which alters the number of cross-links formed within the PU and impacts the mechanical properties of the material.

  4. Novel metallomesogenic polyurethanes: Synthesis, characterization and properties

    International Nuclear Information System (INIS)

    Senthilkumar, Natarajan; Narasimhaswamy, Tanneru; Kim, Il-Jin

    2012-01-01

    A series of tetradentate Schiff base metallomesogenic diols were synthesized from two simple dihydroxy benzenes. The metallomesogenic diol was constructed from three ring containing mesogen linked through ester and azomethine with terminal hydroxy group. This upon complexation with copper(II) formed metallomesogenic diol with varying terminal chain length. A series of metallomesogenic polyurethanes were synthesized using these metallomesogenic diols as chain extenders for the prepolymers based on polytetramethylene glycol (PTMG) of varying molecular weight (M n = 650, 2000) and 2,4-toluene diisocyanate (TDI), or 4,4′-methylene bis(phenyl isocyanate) (MDI). The molar ratio of metallomesogenic diol and PTMG were varied in the polyurethane to find their role in liquid crystalline and mechanical properties. Extensive characterization of all metallomesogenic compounds and intermediates were carried out by FT-IR, 1 H and 13 C NMR, EPR, VSM, Mass (EI and FAB) and UV–visible spectroscopy. Hot stage polarizing microscope and differential scanning calorimetry were used to ensure the phase characteristics such as nature of phase, melting and clearing temperatures and phase range. The appearance of enantiotropic smectic A phases indicated high molecular polarizability of the core due to the metal ion. - Highlights: ► Design and synthesis of metallomesogenic diols. ► Metallomesogenic polyurethanes were prepared using these diols as chain extenders. ► Liquid crystalline and mechanical properties were studied. ► A square pyramidal structure for the copper(II) complexes have been proposed. ► Polyurethanes exhibited enantiotropic smectic A phases.

  5. Biotransformation and Rearrangement of Laromustine.

    Science.gov (United States)

    Nassar, Alaa-Eldin F; Wisnewski, Adam V; King, Ivan

    2016-08-01

    This review highlights the recent research into the biotransformations and rearrangement of the sulfonylhydrazine-alkylating agent laromustine. Incubation of [(14)C]laromustine with rat, dog, monkey, and human liver microsomes produced eight radioactive components (C-1 to C-8). There was little difference in the metabolite profile among the species examined, partly because NADPH was not required for the formation of most components, which instead involved decomposition and/or hydrolysis. The exception was C-7, a hydroxylated metabolite, largely formed by CYP2B6 and CYP3A4/5. Liquid chromatography-multistage mass spectrometry (LC-MS(n)) studies determined that collision-induced dissociation, and not biotransformation or enzyme catalysis, produced the unique mass spectral rearrangement. Accurate mass measurements performed with a Fourier-transform ion cyclotron resonance mass spectrometer (FTICR-MS) significantly aided determination of the elemental compositions of the fragments and in the case of laromustine revealed the possibility of rearrangement. Further, collision-induced dissociation produced the loss of nitrogen (N2) and methylsulfonyl and methyl isocyanate moieties. The rearrangement, metabolite/decomposition products, and conjugation reactions were analyzed utilizing hydrogen-deuterium exchange, exact mass, (13)C-labeled laromustine, nuclear magnetic resonance spectroscopy (NMR), and LC-MS(n) experiments to assist with the assignments of these fragments and possible mechanistic rearrangement. Such techniques produced valuable insights into these functions: 1) Cytochrome P450 is involved in C-7 formation but plays little or no role in the conversion of [(14)C]laromustine to C-1 through C-6 and C-8; 2) the relative abundance of individual degradation/metabolite products was not species-dependent; and 3) laromustine produces several reactive intermediates that may produce the toxicities seen in the clinical trials. Copyright © 2016 by The American Society for

  6. Bronchial asthma and COPD due to irritants in the workplace - an evidence-based approach

    Directory of Open Access Journals (Sweden)

    Baur Xaver

    2012-09-01

    Full Text Available Abstract Background Respiratory irritants represent a major cause of occupational obstructive airway diseases. We provide an overview of the evidence related to irritative agents causing occupational asthma or occupational COPD. Methods We searched MEDLINE via PubMed. Reference lists of relevant reviews were also screened. The SIGN grading system was used to rate the quality of each study. The modified RCGP three-star system was used to grade the body of evidence for each irritant agent regarding its causative role in either occupational asthma or occupational COPD. Results A total of 474 relevant papers were identified, covering 188 individual agents, professions or work-sites. The focus of most of the studies and the predominant diagnosis was occupational asthma, whereas occupational COPD arose only incidentally. The highest level assigned using the SIGN grading was 2+ (well-conducted systematic review, cohort or case–control study with a low risk of confounding or bias. According to the modified RCGP three-star grading, the strongest evidence of association with an individual agent, profession or work-site (“**” was found for 17 agents or work-sites, including benzene-1,2,4-tricarboxylicacid-1,2-anhydride, chlorine, platinum salt, isocyanates, cement dust, grain dust, animal farming, environmental tobacco smoke, welding fumes or construction work. Phthalic anhydride, glutaraldehyde, sulphur dioxide, cotton dust, cleaning agents, potrooms, farming (various, foundries were found to be moderately associated with occupational asthma or occupational COPD (“*[+]”. Conclusion This study let us assume that irritant-induced occupational asthma and especially occupational COPD are considerably underreported. Defining the evidence of the many additional occupational irritants for causing airway disorders will be the subject of continued studies with implications for diagnostics and preventive measures.

  7. Oral epithelial cell reaction after exposure to Invisalign plastic material.

    Science.gov (United States)

    Premaraj, Thyagaseely; Simet, Samantha; Beatty, Mark; Premaraj, Sundaralingam

    2014-01-01

    Invisalign plastic aligners (Align Technology, Santa Clara, Calif) are used to correct malocclusions. The aligners wrap around the teeth and are in contact with gingival epithelium during treatment. The purpose of this study was to evaluate the cellular responses of oral epithelium exposed to Invisalign plastic in vitro. Oral epithelial cells were exposed to eluate obtained by soaking Invisalign plastic in either saline solution or artificial saliva for 2, 4, and 8 weeks. Cells grown in media containing saline solution or saliva served as controls. Morphologic changes were assessed by light microscopy. The 3-[4, 5-dimethythiazol- 2-yl]-2, 5-diphenyl tetrazolium bromide assay and flow cytometry were used to determine cell viability and membrane integrity, respectively. Cellular adhesion and micromotion of epithelial cells were measured in real time by electrical cell-substrate impedance sensing. Cells exposed to saline-solution eluate appeared rounded, were lifted from the culture plates, and demonstrated significantly increased metabolic inactivity or cell death (P <0.05). Saliva eluates did not induce significant changes in cell viability compared with untreated cells. Flow cytometry and electric cell-substrate impedance sensing showed that cells treated with saline-solution eluate exhibited compromised membrane integrity, and reduced cell-to-cell contact and mobility when compared with saliva-eluate treatment. Exposure to Invisalign plastic caused changes in viability, membrane permeability, and adhesion of epithelial cells in a saline-solution environment. Microleakage and hapten formation secondary to compromised epithelial integrity might lead to isocyanate allergy, which could be systemic or localized to gingiva. However, these results suggest that saliva might offer protection. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  8. Exploring rearrangements along the fragmentation pathways of diuron anion: A combined experimental and computational investigation

    Science.gov (United States)

    Kanawati, Basem; Harir, Mourad; Schmitt-Kopplin, Philippe

    2009-12-01

    Diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea), a common herbicide from phenyl urea class, was investigated by studying the formation of several negative ions [M-H]- in the gas phase and the fragmentation behaviour of the thermodynamically most probably formed isomeric anions upon linear ion acceleration/collision experiments. The collision induced dissociation experiments (CID) were carried out in a hexapole-quadrupole-hexapole hybrid system coupled to 12 T magnet with infinity ICR cell for high resolution measurements. Two distinctive main pathways were observed in the MS/MS spectrum. Sustained off-resonance irradiation (SORI) experiments inside the ICR cell reinforce the fragmentation channels obtained from linear ion acceleration experiments. The fragmentation pathways were also completely investigated by the use of B3LYP/6-311+G(2d,p)//B3LYP/6-31+G(d) level of theory. Elimination of dimethylamine takes place in a two-step process, by which two successive 1,3 proton shifts occur. The second 1,3 proton shift is concerted with the departure of dimethylamine. The driving force for the (CH3)2NH elimination is the formation of isocyanate group. The formed primary product ion can further decompose to release HCl through a new transition state. A stable new aromatic product ion is formed with 10[pi] electrons. Loss of C3H5NO neutral from another anionic isomer of the precursor ion was also observed and is characteristic for the amide terminal of the diamide functional group. A concerted mechanism is proposed, by which N-C bond breakage and cyclization of the eliminated neutral fragment C3H5NO takes place simultaneously to form 1-methyl-aziridin-2-one.

  9. Preparation and characterization of polyvinyl alcohol hydrogels crosslinked by biodegradable polyurethane for tissue engineering of cartilage

    International Nuclear Information System (INIS)

    Bonakdar, Shahin; Emami, Shahriar Hojjati; Shokrgozar, Mohammad Ali; Farhadi, Afshin; Ahmadi, Seyed Amir Hoshiar; Amanzadeh, Amir

    2010-01-01

    Polyurethane was prepared from hexamethylene diisocyanate (HMDI) and polycaprolactone diol (PCL) with stoichiometry ratio of two in a reactor to form prepolymer. Polyvinyl alcohol (PVA) at PVA/prepolymer ratios of 8, 4, 2 and 1 was crosslinked with the former degradable polyester polyurethane. Fourier transform infrared (FTIR) was employed to confirm polyurethane formation during the course of reactions. FTIR spectrum revealed bands at 1729-1733 cm -1 and 3347-3340 cm -1 which indicates carbonyl and NH of amine groups, respectively. Polyurethane formation was also confirmed by the absence of the isocyanate peaks (NCO) at 2270 cm -1 . Dynamic mechanical thermal analysis (DMTA) showed that by increasing prepolymer concentration glass transition temperature decreases from 26 deg. C for PVA to 19 deg. C for sample with PVA/prepolymer ratio of 4 and then it rises up to 31 deg. C. Water uptake measurements illustrated about four fold reduction in swelling ratio of PVA after crosslinking and the sample with equal amounts of PVA and PPU had water uptake of 100%, close to that of a natural cartilage and much less than PVA (425%). All samples had compressive modulus in the range of the articular cartilage (1.9-14.4 MPa). The morphology of the isolated cells on the samples was evaluated by scanning electron microscopy (SEM) and revealed cell attachment and proliferation. The cell viability (3-4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, MTT) and GAG expression (dimethylmethylene blue, DMMB) assays with human chondrocytes on the sample with PVA/prepolymer ratio of one showed about 14 and 33% increase in cell viability and GAG expression after 14 days of culture compare to the PVA, respectively.

  10. Mistura reativa de poliamida 6 e policarbonato: reatividade do copolímero formado "in situ" Polyamide 6 and polycarbonate reactive blends: reactivity of the copolymer formed "in situ"

    Directory of Open Access Journals (Sweden)

    Dilma A. Costa

    2004-01-01

    Full Text Available As misturas físicas de poliamida 6 (PA6 e policarbonato (PC processadas a 240 ºC, durante 10, 30 e 60 minutos formam um copolímero de PA6-PC. A alta temperatura e o longo tempo de processamento podem causar modificações nas propriedades dessas misturas e degradar o copolímero, originando grupos isocianato e subseqüentemente CO2 e grupos NH2 terminais. A quantidade de copolímero PA6-PC formado durante o processo de mistura é maior com o aumento da proporção de PC na mistura. As ligações uretânicas de polímeros termoplásticos exibem mais baixas estabilidades térmica e oxidativa, resultando no aumento da concentração de grupos terminais NH2. A reatividade dessas misturas foi investigada através do torque durante o processo de mistura, da titulação potenciométrica dos grupos NH2 terminais e por microscopia eletrônica de varredura.Polyamide 6 (PA6 and polycarbonate (PC blends processed at 240 °C, during 10, 30 and 60 minutes produced a copolymer of PA6-PC. The high temperature and long processing time can cause modifications on the properties of these blends and degradation of the copolymer. It can also form isocyanate groups and subsequently CO2 and NH2 "end groups". The amount of PA6-PC copolymer formed during the blending process was found to increase when the PC content is increased. The thermoplastic urethanes normally exhibit smaller thermal and oxidative stability, resulting in an increase in the concentration of NH2 terminal groups. The reactivity of the blends was investigated by monitoring the torque during the blending, potentiometer titration of NH2 terminal groups and scanning electronic microscopy (SEM.

  11. Entrecruzamiento en medio acuoso del biomaterial pericárdico bovino con un prepolímero de poliuretano Entrecruzamiento en medio acuoso del biomaterial pericárdico bovino con un prepolímero de poliuretano

    Directory of Open Access Journals (Sweden)

    Birzabith Mendoza-Novelo

    2012-02-01

    Full Text Available Animal tissues used in the manufacture of medical devices require chemical treatments to improve durability. A number of techniques have been proposed to preserve such collagenous biological tissues. This study reports a new strategy for the crosslinking of bovine pericardium with a blocked polyurethane prepolymer (PUP in aqueous medium. The decrease in amino group content (70 % and corresponding increase in shrinkage temperature (13 °C when native tissue was treated with PUP, indicate the participation of tissue-amines in the stabilization process. The resistance toward degradation by collagenase in PUP-treated tissue indicate a in vitro stability similar to the glutaraldehyde-crosslinked tissue. It can conclude that the isocyanate-blocked PUP is effective agent for the aqueous fixation of biological tissues of biomedical interest.Los tejidos animales destinados a la fabricación de dispositivos médicos requieren de tratamientos químicos para mejorar su durabilidad. Varias técnicas se han propuesto para preservar tales tejidos biológicos ricos en colágeno. En este estudio se reporta una nueva estrategia para entrecruzar pericardio bovino (PB con un prepolímero de poliuretano (PUP soluble en agua con grupos isocianato protegidos. La disminución del contenido de grupos amino libres (70 % y el correspondiente incremento de la temperatura de encogimiento (13 °C para PB tratado con PUP, indican la participación de los grupos amino del tejido en el proceso de estabilización. La resistencia a la digestión con colagenasa de PB tratado con PUP indican una estabilidad in vitro similar al tejido entrecruzado con glutaraldehído. Se puede concluir que el PUP bloqueado es un agente efectivo para la fijación en medio acuoso de tejidos biológicos de interés biomédico.

  12. Invention, design and performance of coconut agrowaste fiberboards for ecologically efficacious buildings

    Science.gov (United States)

    Lokko, Mae-ling Jovenes

    As global quantities of waste by-products from food production as well as the range of their applications increase, researchers are realizing critical opportunities to transform the burden of underutilized wastes into ecological profits. Within the tropical hot-humid region, where half the world's current and projected future population growth is concentrated, there is a dire demand for building materials to meet ambitious development schemes and rising housing deficits. However, the building sector has largely overlooked the potential of local agricultural wastes to serve as alternatives to energy-intensive, imported building technologies. Industrial ecologists have recently investigated the use of agrowaste biocomposites to replace conventional wood products that use harmful urea-formaldehyde, phenolic and isocyanate resins. Furthermore, developments in the performance of building material systems with respect to cost, energy, air quality management and construction innovation have evolved metrics about what constitutes material 'upcycling' within building life cycle. While these developments have largely been focused on technical and cost performance, much less attention has been paid to addressing deeply-seated social and cultural barriers to adoption that have sedimented over decades of importation. This dissertation evaluates the development coconut agricultural building material systems in four phases: (i) non-toxic, low-energy production of medium-high density boards (500-1200 kg/m3) from coconut fibers and emerging biobinders; (ii) characterization and evaluation of coconut agricultural building materials hygrothermal performance (iii) scaled-up design development of coconut modular building material systems and (iv) development of a value translation framework for the bottom-up distribution of value to stakeholders within the upcycling framework. This integrated design methodological approach is significant to develop ecological thinking around agrowaste

  13. A novel first aid stretcher for immobilization and transportation of spine injured patients.

    Science.gov (United States)

    Liu, Yan-Sheng; Feng, Ya-Ping; Xie, Jia-Xin; Luo, Zhuo-Jing; Shen, Cai-Hong; Niu, Fang; Zou, Jian; Tang, Shao-Feng; Hao, Jiang; Xu, Jia-Xiang; Xiao, Li-Ping; Xu, Xiao-Ming; Zhu, Hui

    2012-01-01

    Effective immobilization and transportation are vital to the life-saving acute medical care needed when treating critically injured people. However, the most common types of stretchers used today are wrought with problems that can lead to further medical complications, difficulty in employment and rescue, and ineffective transitions to hospital treatment. Here we report a novel first aid stretcher called the "emergency carpet", which solves these problems with a unique design for spine injured patients. Polyurethane composite material, obtained by a novel process of manually mixing isocyanate and additives, can be poured into a specially designed fabric bag and allowed to harden to form a rigid human-shaped stretcher. The effectiveness of the emergency carpet was examined in the pre-hospital management of victims with spinal fractures. Additionally, it was tested on flat ground and complex terrain as well as in the sea and air. We demonstrated that the emergency carpet can be assembled and solidified on the scene in 5 minutes, providing effective immobilization to the entire injured body. With the protection of the emergency carpet, none of the 20 patients, who were finally confirmed to have spinal column fracture or dislocation, had any neurological deterioration during transportation. Furthermore, the carpet can be handled and transported by multiple means under differing conditions, without compromising immobilization. Finally, the emergency carpet allows the critically injured patient to receive multiple examinations such as X-ray, CT, and MRI without being removed from the carpet. Our results demonstrate that the emergency carpet has ideal capabilities for immobilization, extrication, and transportation of the spine injured patients. Compared with other stretchers, it allows for better mobility, effective immobilization, remarkable conformity to the body, and various means for transportation. The emergency carpet is promising for its intrinsic advantages in

  14. The influence of polyol type on cell geometry and the thermal stability of polyurethane foams

    Directory of Open Access Journals (Sweden)

    Prendžov Slobodan J.

    2006-01-01

    Full Text Available The aim of this study was to examine the influence of substituting defined amounts of polyol Voranol 3322 by polyol Voranol CP 1055 on the cell geometry and thermal stability of the synthesized flexible polyurethane foams. The influence of the amount of antipyrene on the cell geometry and their thermal stability was also investigated. The following components were used in the synthesis of the polyurethanes: a mixture of two polyols (Voranol 3322 with the hydroxyl number 47 mg KOH/g, mean molecular mass 3400 and Voranol CP 1055 with the hydroxyl number 156 mg KOH/g, mean molecular mass 1000, toluene discarnate as the isocyanate component, a combination of an organic-metallic compound and a tertiary amine as catalysts, surfactant and water as the coreactant. The thermal stability was determined by thermogravimetric analysis (in a nitrogen atmosphere. The cell geometry was analyzed by optical microscopy. Examination of the cell geometry revealed different cell shapes. The form factor as an indicator of cell deviation from spherical shape increased (more round forms were observed with increasing amount of Voranol CP 1055. The TG examination showed that specimens with 6 and 8 g of Voranol 3322 substituted by Voranol CP 1055 completely degraded at 350 °C, while foams with 10 and 12 g of Voranol 3322 substituted by Voranol CP 1055 displayed lower mass loss at higher temperatures and had residual masses of 46 % and 43 % at 600°C respectively. The addition of antipyrene in an amount of 1% (based on the amount of polyol contributed to improved thermal stability, no visible color change of the specimen tested at 210°C for 40 minutes, and to rounder cell forms. Considering the obtained results it can be concluded that an increase in the amount of Voranol CP 1055 yielded more spherically shaped cells and better thermal stability of the synthesized flexible polyurethane foams. The addition of antipyrene improves the thermal stability and the cell geometry.

  15. Adhesion of nitrile rubber to UV-assisted surface chemical modified PET fabric, part II: Interfacial characterization of MDI grafted PET

    Energy Technology Data Exchange (ETDEWEB)

    Razavizadeh, Mahmoud; Jamshidi, Masoud, E-mail: mjamshidi@iust.ac.ir

    2016-08-30

    Highlights: • In this research UV-irradiated PET fabric was chemically modified. • The fabric at first carboxylated under UV irradiation using glutaric anhydride, then it was grafted using isocyanate (i.e. MDI). • The surface of the fabric was characterized before and after each treating satge. • The composite samples were prepared and tested for T-Peel test. The surfaces of the fabrics were surface characterized to understand. - Abstract: Fiber to rubber adhesion is an important subject in rubber industry. It is well known that surface treatment (i.e. physical, mechanical and chemical) is an effective method to improve interfacial bonding of fibers and/or fabrics to rubbers. UV irradiation is an effective method which has been used to increase fabric-rubber interfacial interactions. In this research UV assisted chemical modification of PET fabrics was used to increase PET to nitrile rubber (NBR) adhesion. Nitrile rubber is a perfect selection as fuel and oil resistant rubber. However it has weak bonding to PET fabric. For this purpose PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was grafted on carboxylated PET. The chemical composition of the fabric before and after surface treatment was investigated by X-ray photoelectron spectroscopy (XPS). The sectional morphology of the experimental PET fibers and the interface between rubber compound and PET fabric was studied using scanning electron microscope (SEM). The morphology and structure of the product were analyzed by an energy dispersive X-ray spectrometer (EDX). FTIR-ATR and H NMR analysis were used to assess surface modifications on the PET irradiated fabrics.

  16. Biomarkers on Europa: Unique signatures produced by radiolysis?

    Science.gov (United States)

    Carlson, R. W.; Hand, K. P.

    A promising habitat for life is Jupiter's moon Europa, with its likely ocean under a young, active surface. Europa orbits in the heart of Jupiter's powerful magnetosphere and suffers intense energetic particle bombardment, producing both good and bad aspects for astrobiology at Europa. Ionizing radiation can produce oxidants that could support a radiation-driven ecology as proposed by Chyba. On the other hand, biomolecular evidence for oceanic life that may be emplaced on the surface is rapidly altered by radiation, perhaps complicating astrobiological searches for evidence of life. We are studying the radiolytic degradation of molecular biomarkers in ice at Europa temperatures by studying both simple organics and more complex biomolecules, including microorganisms. High energy (1-100 keV) electron irradiation is employed and the products are analyzed using infrared spectroscopy, thermal desorption mass spectroscopy, and laser desorption/ionization mass spectroscopy. Hydrocarbon radiolysis yields carbon dioxide and methane which can escape the system and results in the net loss of carbon. Aliphatic molecules with C=O bonds are formed and thought to be mainly polymethylene oxides. When heated, they polymerize to form brown, high-molecular-weight refractory residues with linear, spherical, and ring- shaped macrostructures, typically many tens of micrometers in size. Laser desorption mass spectra of the residues are not overly complex and are different for each initial species. Radiolysis of microorganisms shows the destruction of amine, amide, methyl, and methylene groups, and production of carbon dioxide, carbon monoxide, nitriles, and isocyanates. Mass spectra of irradiated B. pumilus spores are different and surprisingly less complex than those of unirradiated spores. It is possible that unique, diagnostic biosignatures may exist in mass spectra of irradiated microorganisms.

  17. Adhesion of nitrile rubber to UV-assisted surface chemical modified PET fabric, part II: Interfacial characterization of MDI grafted PET

    International Nuclear Information System (INIS)

    Razavizadeh, Mahmoud; Jamshidi, Masoud

    2016-01-01

    Highlights: • In this research UV-irradiated PET fabric was chemically modified. • The fabric at first carboxylated under UV irradiation using glutaric anhydride, then it was grafted using isocyanate (i.e. MDI). • The surface of the fabric was characterized before and after each treating satge. • The composite samples were prepared and tested for T-Peel test. The surfaces of the fabrics were surface characterized to understand. - Abstract: Fiber to rubber adhesion is an important subject in rubber industry. It is well known that surface treatment (i.e. physical, mechanical and chemical) is an effective method to improve interfacial bonding of fibers and/or fabrics to rubbers. UV irradiation is an effective method which has been used to increase fabric-rubber interfacial interactions. In this research UV assisted chemical modification of PET fabrics was used to increase PET to nitrile rubber (NBR) adhesion. Nitrile rubber is a perfect selection as fuel and oil resistant rubber. However it has weak bonding to PET fabric. For this purpose PET fabric was carboxylated under UV irradiation and then methylenediphenyl diisocyanate (MDI) was grafted on carboxylated PET. The chemical composition of the fabric before and after surface treatment was investigated by X-ray photoelectron spectroscopy (XPS). The sectional morphology of the experimental PET fibers and the interface between rubber compound and PET fabric was studied using scanning electron microscope (SEM). The morphology and structure of the product were analyzed by an energy dispersive X-ray spectrometer (EDX). FTIR-ATR and H NMR analysis were used to assess surface modifications on the PET irradiated fabrics.

  18. Synthesis and study of nano-structured cellulose acetate based materials for energy applications; Synthese et etude de materiaux nanostructures a base d'acetate de cellulose pour applications energetiques

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, F

    2006-12-15

    Nano-structured materials have unique properties (high exchange areas, containment effect) because of their very low characteristic dimensions. The elaboration way set up in this PhD work consists in applying the classical processes for the preparation of aerogel-like materials (combining sol-gel synthesis and CO{sub 2} supercritical extraction) to cellulosic polymers. This work is divided in four parts: a literature review, the presentation and the study of the chemical synthesis that leads to cellulose acetate-based aerogel, the characterizations (chemical, structural and thermal) of the elaborated nano-materials, and finally the study of the first carbons that were obtained after pyrolysis of the organic matrix. The formulations and the sol-gel protocol lead to chemical gels by crosslinking cellulose acetate using a poly-functional iso-cyanate. The dry materials obtained after solvent extraction with supercritical CO{sub 2} are nano-structured and mainly meso-porous. Correlations between chemical synthesis parameters (reagent concentrations, crosslinking rate and degree of polymerisation) and porous properties (density, porosity, pore size distribution) were highlighted thanks to structural characterizations. An ultra-porous reference aerogel, with a density equals to 0,245 g.cm{sup -3} together with a meso-porous volume of 3,40 cm{sup 3}.g{sup -1} was elaborated. Once in granular shape, this material has a thermal conductivity of 0,029 W.m{sup -1}.K{sup -1}. In addition, carbon materials produced after pyrolysis of the organic matrix and after grinding are nano-structured and nano-porous, even if important structural modifications have occurred during the carbonization process. The elaborated materials are evaluated for applications in relation with energy such as thermal insulation (organic aerogels) but also for energy conversion and storage through electrochemical way (carbon aerogels). (author)

  19. Fabrication and characterization of silica aerogel as synthetic tissues for medical imaging phantoms

    Science.gov (United States)

    In, Eunji; Naguib, Hani

    2015-05-01

    Medical imaging plays an important role in the field of healthcare industry both in clinical settings and in research and development. It is used in prevention, early detection of disease, in choosing the optimal treatment, during surgical interventions and monitoring of the treatment effects. Despite much advancement in the last few decades, rapid change on its technology development and variety of imaging parameters that differ with the manufacturer restrict its further development. Imaging phantom is a calibrating medium that is scanned or imaged in the field of medical imaging to evaluate, analyze and tune the performance of various imaging devices. A phantom used to evaluate an imaging device should respond in a similar manner to how human tissue and organs would act in that specific imaging modality. There has been many research on the phantom materials; however, there has been no attempt to study on the material that mimics the structure of lung or fibrous tissue. So with the need for development of gel with such structure, we tried to mimic this structure with aerogel. Silica aerogels have unique properties that include low density (0.003g/cm) and mesoporosity (pore size 2-50nm), with a high thermal insulation value (0.005W/mK) and high surface area (500-1200m-2/g).] In this study, we cross-linked with di-isocyanate, which is a group in polyurethane to covalently bond the polymer to the surface of silica aerogel to enhance the mechanical properties. By formation of covalent bonds, the structure can be reinforced by widening the interparticle necks while minimally reducing porosity.

  20. Analytical determination of specific 4,4'-methylene diphenyl diisocyanate hemoglobin adducts in human blood.

    Science.gov (United States)

    Gries, Wolfgang; Leng, Gabriele

    2013-09-01

    4,4'-Methylene diphenyl diisocyanate (MDI) is one of the most important isocyanates in the industrial production of polyurethane and other MDI-based synthetics. Because of its high reactivity, it is known as a sensitizing agent, caused by protein adducts. Analysis of MDI is routinely done by determination of the nonspecific 4,4'-methylenedianiline as a marker for MDI exposure in urine and blood. Since several publications have reported specific adducts of MDI and albumin or hemoglobin, more information about their existence in humans is necessary. Specific adducts of MDI and hemoglobin were only reported in rats after high-dose MDI inhalation. The aim of this investigation was to detect the hemoglobin adduct 5-isopropyl-3-[4-(4-aminobenzyl)phenyl]hydantoin (ABP-Val-Hyd) in human blood for the first time. We found values up to 5.2 ng ABP-Val-Hyd/g globin (16 pmol/g) in blood samples of workers exposed to MDI. Because there was no information available about possible amounts of this specific MDI marker, the analytical method focused on optimal sensitivity and selectivity. Using gas chromatography-high-resolution mass spectrometry with negative chemical ionization, we achieved a detection limit of 0.02 ng ABP-Val-Hyd/g globin (0.062 pmol/g). The robustness of the method was confirmed by relative standard deviations between 3.0 and 9.8 %. Combined with a linear detection range up to 10 ng ABP-Val-Hyd/g globin (31 pmol/g), the enhanced precision parameter demonstrates that the method described is optimized for screening studies of the human population.

  1. pH-Responsive Shape Memory Poly(ethylene glycol)-Poly(ε-caprolactone)-based Polyurethane/Cellulose Nanocrystals Nanocomposite.

    Science.gov (United States)

    Li, Ying; Chen, Hongmei; Liu, Dian; Wang, Wenxi; Liu, Ye; Zhou, Shaobing

    2015-06-17

    In this study, we developed a pH-responsive shape-memory polymer nanocomposite by blending poly(ethylene glycol)-poly(ε-caprolactone)-based polyurethane (PECU) with functionalized cellulose nanocrystals (CNCs). CNCs were functionalized with pyridine moieties (CNC-C6H4NO2) through hydroxyl substitution of CNCs with pyridine-4-carbonyl chloride and with carboxyl groups (CNC-CO2H) via 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) mediated surface oxidation, respectively. At a high pH value, the CNC-C6H4NO2 had attractive interactions from the hydrogen bonding between pyridine groups and hydroxyl moieties; at a low pH value, the interactions reduced or disappeared due to the protonation of pyridine groups, which are a Lewis base. The CNC-CO2H responded to pH variation in an opposite manner. The hydrogen bonding interactions of both CNC-C6H4NO2 and CNC-CO2H can be readily disassociated by altering pH values, endowing the pH-responsiveness of CNCs. When these functionalized CNCs were added in PECU polymer matrix to form nanocomposite network which was confirmed with rheological measurements, the mechanical properties of PECU were not only obviously improved but also the pH-responsiveness of CNCs could be transferred to the nanocomposite network. The pH-sensitive CNC percolation network in polymer matrix served as the switch units of shape-memory polymers (SMPs). Furthermore, the modified CNC percolation network and polymer molecular chains also had strong hydrogen bonding interactions among hydroxyl, carboxyl, pyridine moieties, and isocyanate groups, which could be formed or destroyed through changing pH value. The shape memory function of the nanocomposite network was only dependent on the pH variation of the environment. Therefore, this pH-responsive shape-memory nancomposite could be potentially developed into a new smart polymer material.

  2. Modificação de fibra de carbono com PBLH e sua utilização em compósitos com resina epoxídica Hydroxyl-terminated polybutadiene-grafted carbon fiber in epoxy resin-based composites

    Directory of Open Access Journals (Sweden)

    Fábio L. Barcia

    1999-06-01

    Full Text Available Fibras de carbono contendo 1,4 e 2,1mmol/g de grupos carboxila e hidroxila fenólica, respectivamente, foram modificadas através de reação com TDI, resultando em fibras contendo 3,1 mmol/g de grupos isocianato. A introdução de grupos isocianato na superfície da fibra tornou possível a sua modificação com polibutadieno líquido hidroxilado. Fibras de carbono modificadas e não modificadas foram empregadas na preparação de compósitos com resina epoxídica, sendo observado um aumento considerável de resistência ao impacto em compósitos constituídos de fibras de carbono enxertadas com PBLH, devido, provavelmente, à natureza elastomérica da interface e à melhor adesão interfacial.Carbon fibers containing 1,4 e 2,1 mmol/g of carboxyl and phenolic hydroxyl groups, respectively, were modified through the reaction with TDI. The presence of isocyanate groups at the fiber surface made possible the fiber modification with hydroxyl terminated polybutadiene (HTPB. These modified and unmodified carbon fibers were employed in the preparation of epoxy resin-based composites. A substantial improvement in the impact properties was observed in the composites with HTPB-grafted carbon fibers when compared to unmodified carbon fibers. These results may be attributed to a higher interfacial adhesion promoted by reactions between the functional groups present at the modified carbon fiber surface and the epoxy matrix.

  3. Theoretical Investigation of OCN(-) Charge Transfer Complexes in Condensed Phase Media: Spectroscopic Properties in Amorphous Ice

    Science.gov (United States)

    Park, Jin-Young; Woon, David E.

    2004-01-01

    Density functional theory (DFT) calculations of cyanate (OCN(-)) charge-transfer complexes were performed to model the "XCN" feature observed in interstellar icy grain mantles. OCN(-) charge-transfer complexes were formed from precursor combinations of HNCO or HOCN with either NH3 or H2O. Three different solvation strategies for realistically modeling the ice matrix environment were explored, including (1) continuum solvation, (2) pure DFT cluster calculations, and (3) an ONIOM DFT/PM3 cluster calculation. The model complexes were evaluated by their ability to reproduce seven spectroscopic measurements associated with XCN: the band origin of the OCN(-) asymmetric stretching mode, shifts in that frequency due to isotopic substitutions of C, N, O, and H, plus two weak features. The continuum solvent field method produced results consistent with some of the experimental data but failed to account for other behavior due to its limited capacity to describe molecular interactions with solvent. DFT cluster calculations successfully reproduced the available spectroscopic measurements very well. In particular, the deuterium shift showed excellent agreement in complexes where OCN(-) was fully solvated. Detailed studies of representative complexes including from two to twelve water molecules allowed the exploration of various possible solvation structures and provided insights into solvation trends. Moreover, complexes arising from cyanic or isocyanic acid in pure water suggested an alternative mechanism for the formation of OCN(-) charge-transfer complexes without the need for a strong base such as NH3 to be present. An extended ONIOM (B3LYP/PM3) cluster calculation was also performed to assess the impact of a more realistic environment on HNCO dissociation in pure water.

  4. The inactivation of human CYP2E1 by phenethyl isothiocyanate, a naturally occurring chemopreventive agent, and its oxidative bioactivation.

    Science.gov (United States)

    Yoshigae, Yasushi; Sridar, Chitra; Kent, Ute M; Hollenberg, Paul F

    2013-04-01

    Phenethylisothiocyanate (PEITC), a naturally occurring isothiocyanate and potent cancer chemopreventive agent, works by multiple mechanisms, including the inhibition of cytochrome P450 (P450) enzymes, such as CYP2E1, that are involved in the bioactivation of carcinogens. PEITC has been reported to be a mechanism-based inactivator of some P450s. We describe here the possible mechanism for the inactivation of human CYP2E1 by PEITC, as well as the putative intermediate that might be involved in the bioactivation of PEITC. PEITC inactivated recombinant CYP2E1 with a partition ratio of 12, and the inactivation was not inhibited in the presence of glutathione (GSH) and not fully recovered by dialysis. The inactivation of CYP2E1 by PEITC is due to both heme destruction and protein modification, with the latter being the major pathway for inactivation. GSH-adducts of phenethyl isocyanate (PIC) and phenethylamine were detected during the metabolism by CYP2E1, indicating formation of PIC as a reactive intermediate following P450-catalyzed desulfurization of PEITC. Surprisingly, PIC bound covalently to CYP2E1 to form protein adducts but did not inactivate the enzyme. Liquid chromatography mass spectroscopy analysis of the inactivated CYP2E1 apo-protein suggests that a reactive sulfur atom generated during desulfurization of PEITC is involved in the inactivation of CYP2E1. Our data suggest that the metabolism of PEITC by CYP2E1 that results in the inactivation of CYP2E1 may occur by a mechanism similar to that observed with other sulfur-containing compounds, such as parathion. Digestion of the inactivated enzyme and analysis by SEQUEST showed that Cys 268 may be the residue modified by PIC.

  5. Improved lignin polyurethane properties with Lewis acid treatment.

    Science.gov (United States)

    Chung, Hoyong; Washburn, Newell R

    2012-06-27

    Chemical modification strategies to improve the mechanical properties of lignin-based polyurethanes are presented. We hypothesized that treatment of lignin with Lewis acids would increase the concentration of hydroxyl groups available to react with diisocyanate monomers. Under the conditions used, hydrogen bromide-catalyzed modification resulted in a 28% increase in hydroxyl group content. Associated increases in hydrophilicity of solvent-cast thin films were also recorded as evidenced by decreases in water contact angle. Polyurethanes were then prepared by first preparing a prepolymer based on mixtures of toluene-2,4-diisocyanate (TDI) and unmodified or modified lignin, then polymerization was completed through addition of polyethylene glycol (PEG), resulting in mass ratios of TDI:lignin:PEG of 43:17:40 in the compositions investigated here. The mixture of TDI and unmodified lignin resulted in a lignin powder at the bottom of the liquid, suggesting it did not react directly with TDI. However, a homogeneous solution resulted when TDI and the hydrogen bromide-treated lignin were mixed, suggesting demethylation indeed increased reactivity and resulted in better integration of lignin into the urethane network. Significant improvements in mechanical properties of modified lignin polyurethanes were observed, with a 6.5-fold increase in modulus, which were attributed to better integration of the modified lignin into the covalent polymer network due to the higher concentration of hydroxyl groups. This research indicates that chemical modification strategies can lead to significant improvements in the properties of lignin-based polymeric materials using a higher fraction of an inexpensive lignin monomer from renewable resources and a lower fraction an expensive, petroleum-derived isocyanate monomer to achieve the required material properties.

  6. A Robust Oil-in-Oil Emulsion for the Nonaqueous Encapsulation of Hydrophilic Payloads.

    Science.gov (United States)

    Lu, Xiaocun; Katz, Joshua S; Schmitt, Adam K; Moore, Jeffrey S

    2018-03-14

    Compartmentalized structures widely exist in cellular systems (organelles) and perform essential functions in smart composite materials (microcapsules, vasculatures, and micelles) to provide localized functionality and enhance materials' compatibility. An entirely water-free compartmentalization system is of significant value to the materials community as nonaqueous conditions are critical to packaging microcapsules with water-free hydrophilic payloads while avoiding energy-intensive drying steps. Few nonaqueous encapsulation techniques are known, especially when considering just the scalable processes that operate in batch mode. Herein, we report a robust oil-in-oil Pickering emulsion system that is compatible with nonaqueous interfacial reactions as required for encapsulation of hydrophilic payloads. A major conceptual advance of this work is the notion of the partitioning inhibitor-a chemical agent that greatly reduces the payload's distribution between the emulsion's two phases, thus providing appropriate conditions for emulsion-templated interfacial polymerization. As a specific example, an immiscible hydrocarbon-amine pair of liquids is emulsified by the incorporation of guanidinium chloride (GuHCl) as a partitioning inhibitor into the dispersed phase. Polyisobutylene (PIB) is added into the continuous phase as a viscosity modifier for suitable modification of interfacial polymerization kinetics. The combination of GuHCl and PIB is necessary to yield a robust emulsion with stable morphology for 3 weeks. Shell wall formation was accomplished by interfacial polymerization of isocyanates delivered through the continuous phase and polyamines from the droplet core. Diethylenetriamine (DETA)-loaded microcapsules were isolated in good yield, exhibiting high thermal and chemical stabilities with extended shelf-lives even when dispersed into a reactive epoxy resin. The polyamine phase is compatible with a variety of basic and hydrophilic actives, suggesting that this

  7. Molecular bio-dosimetry for carcinogenic risk assessment in survivors of Bhopal gas tragedy

    Directory of Open Access Journals (Sweden)

    Pradyumna Kumar Mishra

    2015-12-01

    Full Text Available December 2014 marked the 30th year anniversary of Bhopal gas tragedy. This sudden and accidental leakage of deadly poisonous methyl isocyanate (MIC gas instigated research efforts to understand the nature, severity of health damage and sufferings of 570 000 ailing survivors of this tragedy. In a decade-long period, our systematic laboratory investigations coupled with long-term molecular surveillance studies have comprehensively demonstrated that the risk of developing an environmental associated aberrant disease phenotype, including cancer, involves complex interplay of genomic and epigenetic reprogramming. These findings poised us to translate this knowledge into an investigative framework of “molecular biodosimetry” in a strictly selected cohort of MIC exposed individuals. A pragmatic cancer risk-assessment strategy pursued in concert with a large-scale epidemiological study might unfold molecular underpinnings of host-susceptibility and exposureresponse relationship. The challenges are enormous, but we postulate that the study will be necessary to establish a direct initiation-promotion paradigm of environmental carcinogenesis. Given that mitochondrial retrograde signaling-induced epigenetic reprogramming is apparently linked to neoplasticity, a cutting-edge tailored approach by an expert pool of biomedical researchers will be fundamental to drive these strategies from planning to execution. Validating the epigenomic signatures will hopefully result in the development of biomarkers to better protect human lives in an overburdened ecosystem, such as India, which is continuously challenged to meet population demands. Besides, delineating the mechanistic links between MIC exposure and cancer morbidity, our investigative strategy might help to formulate suitable regulatory policies and measures to reduce the overall burden of occupational and environmental carcinogenesis.

  8. Synthesis and study of nano-structured cellulose acetate based materials for energy applications

    International Nuclear Information System (INIS)

    Fischer, F.

    2006-12-01

    Nano-structured materials have unique properties (high exchange areas, containment effect) because of their very low characteristic dimensions. The elaboration way set up in this PhD work consists in applying the classical processes for the preparation of aerogel-like materials (combining sol-gel synthesis and CO 2 supercritical extraction) to cellulosic polymers. This work is divided in four parts: a literature review, the presentation and the study of the chemical synthesis that leads to cellulose acetate-based aerogel, the characterizations (chemical, structural and thermal) of the elaborated nano-materials, and finally the study of the first carbons that were obtained after pyrolysis of the organic matrix. The formulations and the sol-gel protocol lead to chemical gels by crosslinking cellulose acetate using a poly-functional iso-cyanate. The dry materials obtained after solvent extraction with supercritical CO 2 are nano-structured and mainly meso-porous. Correlations between chemical synthesis parameters (reagent concentrations, crosslinking rate and degree of polymerisation) and porous properties (density, porosity, pore size distribution) were highlighted thanks to structural characterizations. An ultra-porous reference aerogel, with a density equals to 0,245 g.cm -3 together with a meso-porous volume of 3,40 cm 3 .g -1 was elaborated. Once in granular shape, this material has a thermal conductivity of 0,029 W.m -1 .K -1 . In addition, carbon materials produced after pyrolysis of the organic matrix and after grinding are nano-structured and nano-porous, even if important structural modifications have occurred during the carbonization process. The elaborated materials are evaluated for applications in relation with energy such as thermal insulation (organic aerogels) but also for energy conversion and storage through electrochemical way (carbon aerogels). (author)

  9. Synthesis and biological activity of novel series of 4-methoxy, and 4,9-dimethoxy-5-substituted furo[2,3-g]-1,2,3-benzoxathiazine-7,7-dioxide derivatives.

    Science.gov (United States)

    El-Sawy, Eslam R; Ebaid, Manal S; Abo-Salem, Heba M; El-Hallouty, Salwa; Kassem, Emad M; Mandour, Adel H

    2014-05-01

    A novel series of 4-methoxy, and 4,9-dimethoxy-5-substituted furo[2,3-g]-1,2,3-benzoxathiazine-7,7-dioxide derivatives 3a,b, 10a-g and 11a-g were prepared in good yields via the reaction of 4-methoxy (1a) and 4,7-dimethoxy-5-acetyl-6-hydroxybenzofurans (1b) and their α,β-unsaturated keto derivatives 6a-g and 7a-g with chlorosulfonyl isocyanate (CSI). On the other hand, N-chlorosulfonyl carbamate derivatives 4a,b, 12a,b and 13a,b were prepared and allowed to react with piperidine to give the corresponding N-piperidinosulfonyl carbamate derivatives 5a,b, 14a,b and 15a,b, respectively. Sixteen new target compounds 3a,b, 10a-g, and 11a-g were tested for their DPPH radical-scavenging, and in vitro antiproliferative activity against A-549, MCF7 and HCT-116 cancer cell lines. Compounds 10a, 11c, 11e, and 11g showed moderate DPPH radical-scavenging activity compared to ascorbic acid at 100 μg/mL. 4,9-Dimethoxy-5-substituted styrylfuro[3,2-g]-1,2,3-benzoxathiazine-7,7-dioxides 11a, 11b, and 11c were found to be highly active against A-549 and HCT-116 cancer cell lines with IC50 values ranging from 0.02 to 0.08 μmol/mL compared to doxorubicin with IC50 = 0.04 and 0.06 μmol/mL, respectively.

  10. The formation of urea in space. I. Ion-molecule, neutral-neutral, and radical gas-phase reactions

    Science.gov (United States)

    Brigiano, Flavio Siro; Jeanvoine, Yannick; Largo, Antonio; Spezia, Riccardo

    2018-02-01

    Context. Many organic molecules have been observed in the interstellar medium thanks to advances in radioastronomy, and very recently the presence of urea was also suggested. While those molecules were observed, it is not clear what the mechanisms responsible to their formation are. In fact, if gas-phase reactions are responsible, they should occur through barrierless mechanisms (or with very low barriers). In the past, mechanisms for the formation of different organic molecules were studied, providing only in a few cases energetic conditions favorable to a synthesis at very low temperature. A particularly intriguing class of such molecules are those containing one N-C-O peptide bond, which could be a building block for the formation of biological molecules. Urea is a particular case because two nitrogen atoms are linked to the C-O moiety. Thus, motivated also by the recent tentative observation of urea, we have considered the synthetic pathways responsible to its formation. Aims: We have studied the possibility of forming urea in the gas phase via different kinds of bi-molecular reactions: ion-molecule, neutral, and radical. In particular we have focused on the activation energy of these reactions in order to find possible reactants that could be responsible for to barrierless (or very low energy) pathways. Methods: We have used very accurate, highly correlated quantum chemistry calculations to locate and characterize the reaction pathways in terms of minima and transition states connecting reactants to products. Results: Most of the reactions considered have an activation energy that is too high; but the ion-molecule reaction between NH2OHNH2OH2+ and formamide is not too high. These reactants could be responsible not only for the formation of urea but also of isocyanic acid, which is an organic molecule also observed in the interstellar medium.

  11. Thio-urethane oligomers improve the properties of light-cured resin cements.

    Science.gov (United States)

    Bacchi, Ataís; Consani, Rafael L; Martim, Gedalias C; Pfeifer, Carmem S

    2015-05-01

    Thio-urethanes were synthesized by combining 1,6-hexanediol-diissocyante (aliphatic) with pentaerythritol tetra-3-mercaptopropionate (PETMP) or 1,3-bis(1-isocyanato-1-methylethyl)benzene (aromatic) with trimethylol-tris-3-mercaptopropionate (TMP), at 1:2 isocyanate:thiol, leaving pendant thiols. Oligomers were added at 10-30 phr to BisGMA-UDMA-TEGDMA (5:3:2, BUT). 25 wt% silanated inorganic fillers were added. Commercial cement (Relyx Veneer, 3M-ESPE) was also evaluated with 10-20 phr of aromatic oligomer. Near-IR was used to follow methacrylate conversion (DC) and rate of polymerization (Rpmax). Mechanical properties were evaluated in three-point bending (ISO 4049) for flexural strength/modulus (FS/FM, and toughness), and notched specimens (ASTM Standard E399-90) for fracture toughness (KIC). Polymerization stress (PS) was measured on the Bioman. Volumetric shrinkage (VS, %) was measured with the bonded disk technique. Results were analyzed with ANOVA/Tukey's test (α=5%). In general terms, for BUT cements, conversion and mechanical properties in flexure increased for selected groups with the addition of thio-urethane oligomers. The aromatic versions resulted in greater FS/FM than aliphatic. Fracture toughness increased by two-fold in the experimental groups (from 1.17 ± 0.36 MPam(1/2) to around 3.23 ± 0.22 MPam(1/2)). Rpmax decreased with the addition of thio-urethanes, though the vitrification point was not statistically different from the control. VS and PS decreased with both oligomers. For the commercial cement, 20 phr of oligomer increased DC, vitrification, reduced Rpmax and also significantly increased KIC, and reduced PS and FM. Thio-urethane oligomers were shown to favorably modify conventional dimethacrylate networks. Significant reductions in polymerization stress were achieved at the same time conversion and fracture toughness increased. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  12. Characterization of methacrylate-based composites containing thio-urethane oligomers.

    Science.gov (United States)

    Bacchi, Atais; Nelson, Morgan; Pfeifer, Carmem S

    2016-02-01

    To evaluate the ability of thio-urethane oligomers to improve the properties of restorative composite resins. Oligomers were synthesized by combining 1,6-hexanediol-diissocyante (aliphatic) with pentaerythritol tetra-3-mercaptopropionate (PETMP) or 1,3-bis(1-isocyanato-1-methylethyl)benzene (aromatic) with trimethylol-tris-3-mercaptopropionate (TMP), at 1:2 isocyanate:thiol, leaving pendant thiols. Oligomers were added at 0-20 wt% to BisGMA-TEGDMA (70-30 wt%). Silanated inorganic fillers were added (70 wt%). Materials were photoactivated at 800 mW/cm(2) filtered to 320-500 nm. Near-IR was used to follow degree of methacrylate conversion (DC). Mechanical properties were evaluated in three-point bending with 2 mm × 2 mm × 25 mm bars for flexural strength/modulus and toughness (FS/E, and T) according to ISO 4049, and 2 mm × 5 mm × 25 mm notched specimens for fracture toughness (KIC). Polymerization stress (PS) was measured on the Bioman. Results were analyzed with ANOVA/Tukey's test (α=5%). Significant increase in DC was observed in thio-urethane-containing materials especially for the group with 20 wt% of aliphatic version. Materials composed by oligomers also promoted higher FS, E, and KIC in comparison to controls irrespective of thio-urethane type. A significant increase in toughness was detected by ANOVA, but not distinguished in the groups. The PS was significantly reduced by the presence of thio-urethane for almost all groups. The use of thio-urethane oligomer to compose methacrylate-based restorative composite promote increase in DC, FS, E and KIC while significant reduces PS. A simple additive was shown to reduce stress while increasing convrersion and mechanical properties, mainly fracture toughness. This has he potential of increasing the service life of dental composites, without changing current operatory procedures. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  13. Cosmic ray processing of N2-containing interstellar ice analogues at dark cloud conditions

    Science.gov (United States)

    Fedoseev, G.; Scirè, C.; Baratta, G. A.; Palumbo, M. E.

    2018-04-01

    N2 is believed to lock considerable part of nitrogen elemental budget and, therefore, to be one of the most abundant ice constituent in cold dark clouds. This laboratory-based research utilizes high energetic processing of N2 containing interstellar ice analogues using 200 keV H+ and He+ ions that mimics cosmic ray processing of the interstellar icy grains. It aims to investigate the formation of (iso)cyanates and cyanides in the ice mantles at the conditions typical for cold dark clouds and prestellar cores. Investigation of cosmic ray processing as a chemical trigger mechanism is explained by the high stability of N2 molecules that are chemically inert in most of the atom- and radical-addition reactions and cannot be efficiently dissociated by cosmic ray induced UV-field. Two sets of experiments are performed to closer address solid-state chemistry occurring in two distinct layers of the ice formed at different stages of dark cloud evolution, i.e. `H2O-rich' and `CO-rich' ice layers. Formation of HNCO and OCN- is discussed in all of the performed experiments. Corresponding kinetic curves for HNCO and OCN- are obtained. Furthermore, a feature around 2092 cm-1 assigned to the contributions of 13CO, CN-, and HCN is analysed. The kinetic curves for the combined HCN/CN- abundance are derived. In turn, normalized formation yields are evaluated by interpolation of the obtained results to the low irradiation doses relevant to dark cloud stage. The obtained values can be used to interpret future observations towards cold dark clouds using James Webb Space Telescope.

  14. Mechanical Properties of Renewable Polymer with Thermoplastics Endurance to Ultraviolet irradiation Exposure

    Directory of Open Access Journals (Sweden)

    Salim Nurul Syamimi M.

    2016-01-01

    Full Text Available At present the disposal of waste tyre rubber (WTR has become a major waste management problem in the world. Therefore in this study, polymer blended based on Polyethylene which is Low Density Polyethylene (LDPE or High Density Polyethylene (HDPE, with Renewable Polymer (RP and waste tyre rubber (WTR is prepared via injection molding. Blended polymer such as LDPE/RP/WTR and HDPE/RP/WTR is known as LRT and HRT respectively. The preparation of polymer blend steps start with the preparation of RP. The RP is prepared by crosslinking the renewable monomer with Polymethane Polyphenyl Isocyanate (MDI at composition ratio of 1:0.5. The second steps involved by adding 10 gm of liquid RP prepared earlier on with fixed amount of LDPE and HDPE of 100 gm. Then the blended LDPE/RP or HDPE/RP namely as LR or HR respectively is further added with WTR with different percentages ratio of 5 %, 10 % and 15 %. The manually blended polymer mixture and filler is then melt mixing using injection moulding to fabricate the tensile specimen for mechanical tensile test and physical determination such as density, distribution of WTR in polymer blend and surface fracture morphology using scanning electron microscope. The samples were then exposed to UV irradiation exposure in UV Accelerated Weathering for 500, 1000, 1500, 2000, 2500 and 3000 hours to evaluate the photostability of the polymer blends. The optimum amount of WTR ratio composition is at 5 % for both LRT and HRT blends which indicate the stability of polymer blends towards UV irradiation exposure at 1000 hours.

  15. A hydrogel-based versatile screening platform for specific biomolecular recognition in a well plate format.

    Science.gov (United States)

    Beer, Meike V; Rech, Claudia; Diederichs, Sylvia; Hahn, Kathrin; Bruellhoff, Kristina; Möller, Martin; Elling, Lothar; Groll, Jürgen

    2012-04-01

    Precise determination of biomolecular interactions in high throughput crucially depends on a surface coating technique that allows immobilization of a variety of interaction partners in a non-interacting environment. We present a one-step hydrogel coating system based on isocyanate functional six-arm poly(ethylene oxide)-based star polymers for commercially available 96-well microtiter plates that combines a straightforward and robust coating application with versatile bio-functionalization. This system generates resistance to unspecific protein adsorption and cell adhesion, as demonstrated with fluorescently labeled bovine serum albumin and primary human dermal fibroblasts (HDF), and high specificity for the assessment of biomolecular recognition processes when ligands are immobilized on this surface. One particular advantage is the wide range of biomolecules that can be immobilized and convert the per se inert coating into a specifically interacting surface. We here demonstrate the immobilization and quantification of a broad range of biochemically important ligands, such as peptide sequences GRGDS and GRGDSK-biotin, the broadly applicable coupler molecule biocytin, the protein fibronectin, and the carbohydrates N-acetylglucosamine and N-acetyllactosamine. A simplified protocol for an enzyme-linked immunosorbent assay was established for the detection and quantification of ligands on the coating surface. Cell adhesion on the peptide and protein-modified surfaces was assessed using HDF. All coatings were applied using a one-step preparation technique, including bioactivation, which makes the system suitable for high-throughput screening in a format that is compatible with the most routinely used testing systems.

  16. Development of high performance lubricant through the compatibility of polyalphaolefin, polyurea and irradiated polytetrafluoroethylene

    International Nuclear Information System (INIS)

    Ratao, Natalia Torres

    2013-01-01

    Lubricants are gaseous, liquid, semi solid or solid (powder) materials those form a film between two parties preventing friction. High performance lubricants are designed to work under severe conditions of temperature, pressure, and contamination. The most used are liquids (oils) and semi solids (greases). Greases are applied where oils can drain or in inaccessible places and are divided generally into two classes, soap and no soap. The most used non soap grease is polyurea, obtained by the reaction between amine and isocyanate, has highly thixotropic, high dielectric strength and excellent anticorrosive property, so it is widely used for lubrication of electric motors and shipbuilding machinery. For a grease with high performance, in this study was used a synthetic lubricant fluid, polyalphaolefin, and was also employed solid lubricant additive polytetrafluoroethylene (PTFE) due its lowest coefficient of friction, is found commercially irradiated in air to obtain smaller particles and to produce oxygenated terminal groups those are more compatible with the metal surface. The tests conducted were comparatively between pure polyurea grease and with PTFE additive. The characterizations were made by infrared spectroscopy and elemental analysis of C, N and H and Free NCO index, proving the formation of four carbons polyurea (tetraurea). The functional analysis of drop point and oil separation showed high stability and compatibility between the polymers increased when PTFE was added. The excellent resistance of pure tetraurea grease to wear and extreme pressure were demonstrated by four-ball and practical bearings tests, characterizing this grease as a high performance lubricant, when compared to most used greases in the market. (author)

  17. Effect of silica nanoparticles on polyurethane foaming process and foam properties

    International Nuclear Information System (INIS)

    Francés, A B; Bañón, M V Navarro

    2014-01-01

    Flexible polyurethane foams (FPUF) are commonly used as cushioning material in upholstered products made on several industrial sectors: furniture, automotive seating, bedding, etc. Polyurethane is a high molecular weight polymer based on the reaction between a hydroxyl group (polyol) and isocyanate. The density, flowability, compressive, tensile or shearing strength, the thermal and dimensional stability, combustibility, and other properties can be adjusted by the addition of several additives. Nanomaterials offer a wide range of possibilities to obtain nanocomposites with specific properties. The combination of FPUF with silica nanoparticles could develop nanocomposite materials with unique properties: improved mechanical and thermal properties, gas permeability, and fire retardancy. However, as silica particles are at least partially surface-terminated with Si-OH groups, it was suspected that the silica could interfere in the reaction of poyurethane formation.The objective of this study was to investigate the enhancement of thermal and mechanical properties of FPUF by the incorporation of different types of silica and determining the influence thereof during the foaming process. Flexible polyurethane foams with different loading mass fraction of silica nanoparticles (0-1% wt) and different types of silica (non treated and modified silica) were synthesized. PU/SiO 2 nanocomposites were characterized by FTIR spectroscopy, TGA, and measurements of apparent density, resilience and determination of compression set. Addition of silica nanoparticles influences negatively in the density and compression set of the foams. However, resilience and thermal stability of the foams are improved. Silica nanoparticles do not affect to the chemical structure of the foams although they interfere in the blowing reaction

  18. Mining the human tissue proteome for protein citrullination.

    Science.gov (United States)

    Lee, Chien-Yun; Wang, Dongxue; Wilhelm, Mathias; Zolg, Daniel Paul; Schmidt, Tobias; Schnatbaum, Karsten; Reimer, Ulf; Pontén, Fredrik; Uhlén, Mathias; Hahne, Hannes; Kuster, Bernhard

    2018-04-02

    Citrullination is a post-translational modification of arginine catalyzed by five peptidylarginine deiminases (PADs) in humans. The loss of a positive charge may cause structural or functional alterations and while the modification has been linked to several diseases including rheumatoid arthritis and cancer, its physiological or pathophysiological roles remain largely unclear. In part this is owing to limitations in available methodology able to robustly enrich, detect and localize the modification. As a result, only few citrullination sites have been identified on human proteins with high confidence. In this study, we mined data from mass spectrometry-based deep proteomic profiling of 30 human tissues to identify citrullination sites on endogenous proteins. Database searching of ~70 million tandem mass spectra yielded ~13,000 candidate spectra which were further triaged by spectrum quality metrics and the detection of the specific neutral loss of isocyanic acid from citrullinated peptides to reduce false positives. Because citrullination is easily confused with deamidation, we synthetized ~2,200 citrullinated and 1,300 deamidated peptides to build a library of reference spectra. This led to the validation of 375 citrullination sites on 209 human proteins. Further analysis showed that >80% of the identified modifications sites were new and for 56% of the proteins, citrullination was detected for the first time. Sequence motif analysis revealed a strong preference for Asp and Gly, residues around the citrullination site. Interestingly, while the modification was detected in 26 human tissues with the highest levels found in brain and lung, citrullination levels did not correlate well with protein expression of the PAD enzymes. Even though the current work represents the largest survey of protein citrullination to date, the modification was mostly detected on high abundant proteins arguing that the development of specific enrichment methods would be required in order

  19. Radiation 2006. In association with the Polymer Division, Royal Australian Chemical Institute. Incorporating the 21st AINSE Radiation Chemistry Conference and the 18th Radiation Biology Conference, conference handbook

    International Nuclear Information System (INIS)

    Barner, L.; Davis, T. P.; Stenzel, M. H.; Barner-Kowollik, C.

    2006-01-01

    Full text: The reversible addition fragmentation chain transfer (RAFT) process is a controlled/'living' free radical polymerisation process that was invented in Australia by the Commonwealth Scientific and Industrial Research Organisation (CSRIO) group led by Ezio Rizzardo. RAFT polymerisation has proven to be a powerful tool for the synthesis of polymers with predetermined molecular weight and low polydispersity. The RAFT process is capable of effecting living free radical polymerisation control over a great variety of monomers (eg (meth)acrylates, styrenes, acrylamides, vinyl acetate). The RAFT technique uses thiocarbonylthio compounds to mediate the polymerisation via a reversible chain transfer process. This leads to the establishment of an equilibrium under which all the propagating chains have approximately the same chain length at the same instant of time. The RAFT agent typically possesses a thiocarbonylthio group (S=C-S) with substituents R (radical leaving group) and Z (activating/stabilising group), which govern the reaction kinetics and the degree of structural control. In 2001, we reported the synthesis of RAFT agents (phenyl dithio acetates) that can be applied at low/ambient temperatures in the polymerization of alkyl acrylates and styrene. Low/ambient temperature RAFT agents allow the application of γ-radiation as source of initiation. The combination of γ-radiation and ambient temperature RAFT agents allows performing living polymerization at ambient temperature up to high conversions. This technique also opens the possibility to graft narrow polydisperse polymers from existing polymer surfaces. We have applied RAFT polymerization in conjunction with γ-radiation to graft various monomers (e.g. styrene, m-isopropenyl-α,α ' -dimethylbenzyl isocyanate (TMI), N,N ' -dimethyl acrylamide) from solid polypropylene phases that can be used for applications in combinatorial chemistry (eg peptide synthesis and scavenger reactions)

  20. Rapid hemostatic and mild polyurethane-urea foam wound dressing for promoting wound healing

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiangyu; Niu, Yuqing [College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060 (China); Nanshan District Key lab for Biopolymers and Safety Evaluation, Shenzhen 518060 (China); Shenzhen Key Laboratory of Polymer Science and Technology, Shenzhen 518060 (China); Guangdong Research Center for Interfacial Engineering of Functional Materials, Shenzhen 518060 (China); Chen, Kevin C. [Multidisciplinary Research Center, Shantou University, Shantou, Guangdong 515063 (China); Chen, Shiguo, E-mail: csg@szu.edu.cn [College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060 (China); Nanshan District Key lab for Biopolymers and Safety Evaluation, Shenzhen 518060 (China); Shenzhen Key Laboratory of Polymer Science and Technology, Shenzhen 518060 (China); Guangdong Research Center for Interfacial Engineering of Functional Materials, Shenzhen 518060 (China)

    2017-02-01

    A novel rapid hemostatic and mild polyurethane-urea foam (PUUF) wound dressing was prepared by the particle leaching method and vacuum freeze-drying method using 4, 4-Methylenebis(cyclohexyl isocyanate), 4,4-diaminodicyclohexylmethane and poly (ethylene glycol) as raw materials. And X-ray diffraction (XRD), tensile test, differential scanning calorimetry (DSC) and thermogravimetry (TG) were used to its crystallinity, stress and strain behavior, and thermal properties, respectively. Platelet adhesion, fibrinogen adhesion and blood clotting were performed to evaluate its hemostatic effect. And H&E staining and Masson Trichrome staining were used to its wound healing efficacy. The results revealed the pore size of PUUF is 50–130 μm, and its porosity is 71.01%. Porous PUUF exhibited good water uptake that was benefit to adsorb abundant wound exudates to build a regional moist environment beneficial for wound healing. The PUUF wound dressing exhibit better blood coagulation effect than commercial polyurethane dressing (CaduMedi). Though both PUUF and CaduMedi facilitated wound healing generating full re-epithelialization within 13 days, PUUF was milder and lead to more slight inflammatory response than CaduMedi. In addition, PUUF wound dressing exhibited lower cytotoxicity than CaduMedi against NIH3T3 cells. Overall, porous PUUF represents a novel mild wound dressing with excellent water uptake, hemostatic effect and low toxicity, and it can promote wound healing and enhance re-epithelialization. - Highlights: • Rapid hemostatic and mild PUUF wound dressing was fabricated. • Low-toxic PUUF exhibited good water uptake that could build a regional moist environment beneficial for wound healing. • PUUF could promote wound healing and enhance re-epithelialization.

  1. Studies on the effect of virtual crosslinking on the hydrolytic stability of novel aliphatic polyurethane ureas for blood contact applications.

    Science.gov (United States)

    Thomas, V; Jayabalan, M

    2001-07-01

    The effect of virtual crosslinking on the hydrolytic stability of completely aliphatic novel poly(urethane ureas), HFL9-PU1 (hard-segment content 57.5%) and HFL13-PU2 (hard-segment content 67.9%) based on 4,4'-methylene bis(cyclohexyl isocyanate) (H(12)MDI)-hydroxy-terminated polybutadiene-1,6-hexamethylene diamine, was studied. Fourier transform infrared-attenuated total reflectance and wide-angle X-ray diffraction studies revealed hydrogen-bonding interaction and microphase separation and formation of crystallites by short- and long-range ordering in hard-segment domains. Three-dimensional networks from hydrogen bonding in the present polymers lead to virtually crosslinking and insolubility. These polymers were noncytotoxic to L929 fibroblast cells. The hemolytic potential is below the accepted limit. The studies on in vitro biostability in Ringer's solution, phosphate buffered saline, and papain enzyme revealed no weight loss. The infrared spectral studies revealed changes in the surface, especially on HFL9-PU1 aged in Ringer's solution and phosphate buffered saline, and no changes when aged in papain. The marginal changes noticed in tensile properties were attributed to the changes in degree of hydrogen bonding and associated rearrangement of molecular structure in the bulk. The results revealed that the lesser the crosslinking in virgin polymer, the higher the crosslinking in aged polymer and vice versa. Increased crosslinking during aging provided increased tensile properties in the aged polymer over the virgin polymer and vice versa. For comparison, an aliphatic polyetherurethane urea (HFL16-PU3) was also synthesized using poly(oxy tetra methylene glycol) in addition to the above reactants. Though both HFL9-PU1 and HFL16-PU3 contained the same hard-segment content, the aged sample of the latter showed decreased tensile properties with increased crosslinking during aging in contrast to the former. This was attributed to less microphase separation in the

  2. The effect of virtual cross linking on the oxidative stability and lipid uptake of aliphatic poly(urethane urea).

    Science.gov (United States)

    Thomas, Vinoy; Jayabalan, Muthu

    2002-01-01

    In vitro oxidative degradation and lipid sorption of aliphatic, low elastic modulus and virtually cross-linked poly(urethane urea)s based on 4,4' methylene bis(cyclohexyl isocyanate), hydroxy terminated poly butadiene and hexamethylene diamine were evaluated. The aged samples revealed no weight loss in the oxidation medium. The IR spectral analyses revealed the stability of unsaturated double bonds at 964 cm(-1) (characteristic for polybutadiene soft segment) with no change in peak intensity. The poly(tetramethylene glycol) (PTMG)-added poly(ether urethane urea) polymer also revealed no disappearance of IR peaks for ether and unsaturated double bonds in samples aged in vitro oxidation medium. All the polymers have shown increase in weight due to lipid up take in lipid-rich medium (palm oil) but it was rather low in Dulbecco's modified eagle medium (DMEM) cholesterol. The slight change in mechanical properties of the present polymers in oxidation and DMEM is due to the rearrangement of molecular structure with virtual cross links of hydrogen bonding (physical cross linking) without degradation and plasticization effect of lipid. The influence of these media on the rearrangement of virtual cross links has been observed. Higher the virtual cross-link density, lesser is the loss of tensile properties of poly(urethane urea)s in the oxidation medium and vice versa. On the other hand, higher the virtual cross-link density of poly(urethane urea), higher is the loss of ultimate tensile strength and stress at 100% strain and vice versa in DMEM medium.

  3. Work-Related Asthma in Korea - Findings from the Korea Work-Related Asthma Surveillance (KOWAS) program, 2004-2009.

    Science.gov (United States)

    Kwon, Soon-Chan; Song, Jaechul; Kim, Yong-Kyu; Calvert, Geoffrey M

    2015-01-01

    To determine the incidence and epidemiological characteristics of work-related asthma in Korea. During 2004-2009, the Korea Work-Related Asthma Surveillance (KOWAS) program collected data on new cases of work-related asthma from occupational physicians, allergy and chest physicians, regional surveillance systems, and workers' compensation schemes. The incidence was calculated on the basis of industry, occupation, sex, age, and region. In addition, the distribution of causal agents was determined. During the study period, 236 cases of work-related asthma were reported, with 77 cases from more than 1 source. A total of 22.0% (n=52) were reported by occupational physicians, 52.5% (n=124) by allergy and chest physicians, 24.2% (n=57) by regional surveillance systems, and 43.2% (n=102) by workers' compensation schemes. The overall average annual incidence was 3.31 cases/million workers, with a rate of 3.78/million among men and 2.58/million among women. The highest incidence was observed in the 50-59-year age group (7.74/million), in the Gyeonggi/Incheon suburb of Seoul (8.50/million), in the furniture and other instrument manufacturing industries (67.62/million), and among craft and related trades workers (17.75/million). The most common causal agents were isocyanates (46.6%), flour/grain (8.5%), metal (5.9%), reactive dyes (5.1%), and solvents (4.2%). The incidence of work-related asthma in Korea was relatively low, and varied according to industry, occupation, gender, age, and region. Data provided by workers' compensation schemes and physician reports have been useful for determining the incidence and causes of work-related asthma.

  4. Assessing the impact of national level interventions on workplace respiratory disease in the UK: part 2--regulatory activity by the Health and Safety Executive.

    Science.gov (United States)

    Stocks, S J; McNamee, R; Turner, S; Carder, M; Agius, R M

    2013-07-01

    To investigate whether interventions implemented by the UK Health and Safety Executive addressing exposure to isocyanate-based spray paints in motor vehicle repair (MVR), flour dust in craft bakeries, rosin-based solder flux fume (RBSFF) in the electronics industry, metalworking fluids and wood dust coincided with a decline in incidence of work-related short latency respiratory disease (SLRD) or asthma in the target groups. Changes in the incidence of SLRD reported to a UK-based surveillance scheme were compared using a longitudinal, negative binomial regression model with β distributed random effects. An interrupted time series design was used and comparisons according to inclusion or exclusion in the target group were made by including a statistical interactions expressed as a ratio of incidence rate ratios (RIRRs) in the model. The incidence of SLRD attributed to flour dust significantly increased relative to all other agents (RIRR: 1.10; 95% CI 1.06 to 1.16) whereas SLRD attributed to RBSFF significantly declined relative to all other agents (0.94; 0.90 to 0.99). No significant changes in the incidence of SLRD attributed to wood dust (1.03; 0.91 to 1.16) or spray paints (1.03; 0.95 to 1.11) relative to all other agents were observed. A higher proportion of reports originated from the industries targeted by the intervention for RBSFF (65/107; 61%) than spray painting (27/93; 27%) or wood dust (16/42; 38%). These data support a beneficial effect of interventions to reduce exposure to RBSFF but an increase in SLRD attributed to flour dust may indicate increased exposure or increased awareness of the problem.

  5. Diisocyanate emission from a paint product: a preliminary analysis.

    Science.gov (United States)

    Jarand, Curtis W; Akapo, Samuel O; Swenson, Lonie J; Kelman, Bruce J

    2002-07-01

    Exposure of workers to diisocyanates in the polyurethane foam manufacturing industry is well documented. However, very little quantitative data have been published on exposure to diisocyanates from the use of paints and coatings. The purpose of this study was to evaluate emission of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate (2,6-TDI), and isophorone diisocyanate from a commercially available two-stage concrete coating and sealant. A laboratory model of an outdoor deck coating process was developed and diisocyanate concentrations determined by derivatization with 1-(2-methoxyphenol)-piperazine and subsequent high performance liquid chromatographic analysis with UV detection. The detection limit for 2,4-toluene diisocyanate and 2,6-toluene diisocyanate urea derivatives was 0.6 microg TDI/gm wet product, and 0.54 microg IPDI/gm wet product for the isophorone diisocyanate urea derivative. No 2,4-toluene diisocyanate or isophorone diisocyanate was detected in the mixed product. A maximum mean 2,6-TDI emission rate of 0.32 microg of 2,6-TDI/gram of wet product applied/hour was observed for the 1-hour sampling time, 0.38 microg of 2,6-TDI/gram of wet product applied/hour was observed for the 5-hour sampling time, and 0.02 micrpg of 2,6-TDI/gram of wet product applied/hour was observed for the 15-hour sampling time. The decrease in rate of 2,6-TDI emission over the 15-hour period indicates that emission of 2,6-TDI is virtually complete after 5 hours. These emission rates should allow industrial hygienists to calculate exposures to isocyanates emitted from at least one curing sealant.

  6. A novel first aid stretcher for immobilization and transportation of spine injured patients.

    Directory of Open Access Journals (Sweden)

    Yan-Sheng Liu

    Full Text Available Effective immobilization and transportation are vital to the life-saving acute medical care needed when treating critically injured people. However, the most common types of stretchers used today are wrought with problems that can lead to further medical complications, difficulty in employment and rescue, and ineffective transitions to hospital treatment. Here we report a novel first aid stretcher called the "emergency carpet", which solves these problems with a unique design for spine injured patients. Polyurethane composite material, obtained by a novel process of manually mixing isocyanate and additives, can be poured into a specially designed fabric bag and allowed to harden to form a rigid human-shaped stretcher. The effectiveness of the emergency carpet was examined in the pre-hospital management of victims with spinal fractures. Additionally, it was tested on flat ground and complex terrain as well as in the sea and air. We demonstrated that the emergency carpet can be assembled and solidified on the scene in 5 minutes, providing effective immobilization to the entire injured body. With the protection of the emergency carpet, none of the 20 patients, who were finally confirmed to have spinal column fracture or dislocation, had any neurological deterioration during transportation. Furthermore, the carpet can be handled and transported by multiple means under differing conditions, without compromising immobilization. Finally, the emergency carpet allows the critically injured patient to receive multiple examinations such as X-ray, CT, and MRI without being removed from the carpet. Our results demonstrate that the emergency carpet has ideal capabilities for immobilization, extrication, and transportation of the spine injured patients. Compared with other stretchers, it allows for better mobility, effective immobilization, remarkable conformity to the body, and various means for transportation. The emergency carpet is promising for its

  7. Protective Skins for Aerogel Monoliths

    Science.gov (United States)

    Leventis, Nicholas; Johnston, James C.; Kuczmarski, Maria A.; Meador, Ann B.

    2007-01-01

    A method of imparting relatively hard protective outer skins to aerogel monoliths has been developed. Even more than aerogel beads, aerogel monoliths are attractive as thermal-insulation materials, but the commercial utilization of aerogel monoliths in thermal-insulation panels has been inhibited by their fragility and the consequent difficulty of handling them. Therefore, there is a need to afford sufficient protection to aerogel monoliths to facilitate handling, without compromising the attractive bulk properties (low density, high porosity, low thermal conductivity, high surface area, and low permittivity) of aerogel materials. The present method was devised to satisfy this need. The essence of the present method is to coat an aerogel monolith with an outer polymeric skin, by painting or spraying. Apparently, the reason spraying and painting were not attempted until now is that it is well known in the aerogel industry that aerogels collapse in contact with liquids. In the present method, one prevents such collapse through the proper choice of coating liquid and process conditions: In particular, one uses a viscous polymer precursor liquid and (a) carefully controls the amount of liquid applied and/or (b) causes the liquid to become cured to the desired hard polymeric layer rapidly enough that there is not sufficient time for the liquid to percolate into the aerogel bulk. The method has been demonstrated by use of isocyanates, which, upon exposure to atmospheric moisture, become cured to polyurethane/polyurea-type coats. The method has also been demonstrated by use of commercial epoxy resins. The method could also be implemented by use of a variety of other resins, including polyimide precursors (for forming high-temperature-resistant protective skins) or perfluorinated monomers (for forming coats that impart hydrophobicity and some increase in strength).

  8. Enhancing the water stability of Al-MIL-101-NH2 via postsynthetic modification.

    Science.gov (United States)

    Wittmann, Thomas; Siegel, Renée; Reimer, Nele; Milius, Wolfgang; Stock, Norbert; Senker, Jürgen

    2015-01-02

    The resistance of metal-organic frameworks towards water is a very critical issue concerning their practical use. Recently, it was shown for microporous MOFs that the water stability could be increased by introducing hydrophobic pendant groups. Here, we demonstrate a remarkable stabilisation of the mesoporous MOF Al-MIL-101-NH2 by postsynthetic modification with phenyl isocyanate. In this process 86 % of the amino groups were converted into phenylurea units. As a consequence, the long-term stability of Al-MIL-101-URPh in liquid water could be extended beyond a week. In water saturated atmospheres Al-MIL-101-URPh decomposed at least 12-times slower than the unfunctionalised analogue. To study the underlying processes both materials were characterised by Ar, N2 and H2 O sorption measurements, powder X-ray diffraction, thermogravimetric and chemical analysis as well as solid-state NMR and IR spectroscopy. Postsynthetic modification decreased the BET equivalent surface area from 3363 to 1555 m(2)  g(-1) for Al-MIL-101-URPh and reduced the mean diameters of the mesopores by 0.6 nm without degrading the structure significantly and reducing thermal stability. In spite of similar water uptake capacities, the relative humidity-dependent uptake of Al-MIL-101-URPh is slowed and occurs at higher relative humidity values. In combination with (1) H-(27) Al D-HMQC NMR spectroscopy experiments this favours a shielding mechanism of the Al clusters by the pendant phenyl groups and rules out pore blocking. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Preparation and characterization of polyvinyl alcohol hydrogels crosslinked by biodegradable polyurethane for tissue engineering of cartilage

    Energy Technology Data Exchange (ETDEWEB)

    Bonakdar, Shahin [Biomedical Engineering Department, Amirkabir University of Technology, Tehran, 15875-4413 (Iran, Islamic Republic of); Emami, Shahriar Hojjati, E-mail: shahriar16@yahoo.com [Biomedical Engineering Department, Amirkabir University of Technology, Tehran, 15875-4413 (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran, 13164 (Iran, Islamic Republic of); Farhadi, Afshin [Tehran Azad University of Medical Science, Amiralmomenin Hospital (Iran, Islamic Republic of); Ahmadi, Seyed Amir Hoshiar [Biomedical Engineering Department, Amirkabir University of Technology, Tehran, 15875-4413 (Iran, Islamic Republic of); Amanzadeh, Amir [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran, 13164 (Iran, Islamic Republic of)

    2010-05-10

    Polyurethane was prepared from hexamethylene diisocyanate (HMDI) and polycaprolactone diol (PCL) with stoichiometry ratio of two in a reactor to form prepolymer. Polyvinyl alcohol (PVA) at PVA/prepolymer ratios of 8, 4, 2 and 1 was crosslinked with the former degradable polyester polyurethane. Fourier transform infrared (FTIR) was employed to confirm polyurethane formation during the course of reactions. FTIR spectrum revealed bands at 1729-1733 cm{sup -1} and 3347-3340 cm{sup -1} which indicates carbonyl and NH of amine groups, respectively. Polyurethane formation was also confirmed by the absence of the isocyanate peaks (NCO) at 2270 cm{sup -1}. Dynamic mechanical thermal analysis (DMTA) showed that by increasing prepolymer concentration glass transition temperature decreases from 26 deg. C for PVA to 19 deg. C for sample with PVA/prepolymer ratio of 4 and then it rises up to 31 deg. C. Water uptake measurements illustrated about four fold reduction in swelling ratio of PVA after crosslinking and the sample with equal amounts of PVA and PPU had water uptake of 100%, close to that of a natural cartilage and much less than PVA (425%). All samples had compressive modulus in the range of the articular cartilage (1.9-14.4 MPa). The morphology of the isolated cells on the samples was evaluated by scanning electron microscopy (SEM) and revealed cell attachment and proliferation. The cell viability (3-4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, MTT) and GAG expression (dimethylmethylene blue, DMMB) assays with human chondrocytes on the sample with PVA/prepolymer ratio of one showed about 14 and 33% increase in cell viability and GAG expression after 14 days of culture compare to the PVA, respectively.

  10. Degradation of carbendazim in water via photo-Fenton in Raceway Pond Reactor: assessment of acute toxicity and transformation products.

    Science.gov (United States)

    da Costa, Elizângela Pinheiro; Bottrel, Sue Ellen C; Starling, Maria Clara V M; Leão, Mônica M D; Amorim, Camila Costa

    2018-05-08

    This study aimed at investigating the degradation of fungicide carbendazim (CBZ) via photo-Fenton reactions in artificially and solar irradiated photoreactors at laboratory scale and in a semi-pilot scale Raceway Pond Reactor (RPR), respectively. Acute toxicity was monitored by assessing the sensibility of bioluminescent bacteria (Aliivibrio fischeri) to samples taken during reactions. In addition, by-products formed during solar photo-Fenton were identified by liquid chromatography coupled to mass spectrometry (UFLC-MS). For tests performed in lab-scale, two artificial irradiation sources were compared (UV λ > 254nm and UV-Vis λ > 320nm ). A complete design of experiments was performed in the semi-pilot scale RPR in order to optimize reaction conditions (Fe 2+ and H 2 O 2 concentrations, and water depth). Efficient degradation of carbendazim (> 96%) and toxicity removal were achieved via artificially irradiated photo-Fenton under both irradiation sources. Control experiments (UV photolysis and UV-Vis peroxidation) were also efficient but led to increased acute toxicity. In addition, H 2 O 2 /UV λ > 254nm required longer reaction time (60 minutes) when compared to the photo-Fenton process (less than 1 min). While Fenton's reagent achieved high CBZ and acute toxicity removal, its efficiency demands higher concentration of reagents in comparison to irradiated processes. Solar photo-Fenton removed carbendazim within 15 min of reaction (96%, 0.75 kJ L -1 ), and monocarbomethoxyguanidine, benzimidazole isocyanate, and 2-aminobenzimidazole were identified as transformation products. Results suggest that both solar photo-Fenton and artificially irradiated systems are promising routes for carbendazim degradation.

  11. Bulk gold catalyzed oxidation reactions of amines and isocyanides and iron porphyrin catalyzed N-H and O-H bond insertion/cyclization reactions of diamines and aminoalcohols

    Energy Technology Data Exchange (ETDEWEB)

    Klobukowski, Erik [Iowa State Univ., Ames, IA (United States)

    2011-01-01

    This work involves two projects. The first project entails the study of bulk gold as a catalyst in oxidation reactions of isocyanides and amines. The main goal of this project was to study the activation and reactions of molecules at metal surfaces in order to assess how organometallic principles for homogeneous processes apply to heterogeneous catalysis. Since previous work had used oxygen as an oxidant in bulk gold catalyzed reactions, the generality of gold catalysis with other oxidants was examined. Amine N-oxides were chosen for study, due to their properties and use in the oxidation of carbonyl ligands in organometallic complexes. When amine N-oxides were used as an oxidant in the reaction of isocyanides with amines, the system was able to produce ureas from a variety of isocyanides, amines, and amine N-oxides. In addition, the rate was found to generally increase as the amine N-oxide concentration increased, and decrease with increased concentrations of the amine. Mechanistic studies revealed that the reaction likely involves transfer of an oxygen atom from the amine N-oxide to the adsorbed isocyanide to generate an isocyanate intermediate. Subsequent nucleophilic attack by the amine yields the urea. This is in contrast to the bulk gold-catalyzed reaction mechanism of isocyanides with amines and oxygen. Formation of urea in this case was proposed to proceed through a diaminocarbene intermediate. Moreover, formation of the proposed isocyanate intermediate is consistent with the reactions of metal carbonyl ligands, which are isoelectronic to isocyanides. Nucleophilic attack at coordinated CO by amine N-oxides produces CO{sub 2} and is analogous to the production of an isocyanate in this gold system. When the bulk gold-catalyzed oxidative dehydrogenation of amines was examined with amine N-oxides, the same products were afforded as when O{sub 2} was used as the oxidant. When the two types of oxidants were directly compared using the same reaction system and

  12. Dermal, inhalation, and internal exposure to 1,6‐HDI and its oligomers in car body repair shop workers and industrial spray painters

    Science.gov (United States)

    Pronk, A; Yu, F; Vlaanderen, J; Tielemans, E; Preller, L; Bobeldijk, I; Deddens, J A; Latza, U; Baur, X; Heederik, D

    2006-01-01

    Objectives To study inhalation and dermal exposure to hexamethylene diisocyanate (HDI) and its oligomers as well as personal protection equipment (PPE) use during task performance in conjunction with urinary hexamethylene diamine (HDA) in car body repair shop workers and industrial spray painters. Methods Personal task based inhalation samples (n = 95) were collected from six car body repair shops and five industrial painting companies using impingers with di‐n‐butylamine (DBA) in toluene. In parallel, dermal exposure was assessed using nitril rubber gloves. Gloves were submerged into DBA in toluene after sampling. Analysis for HDI and its oligomers was performed by LC‐MS/MS. Urine samples were collected from 55 workers (n = 291) and analysed for HDA by GC‐MS. Results Inhalation exposure was strongly associated with tasks during which aerosolisation occurs. Dermal exposure occurred during tasks that involve direct handling of paint. In car body repair shops associations were found between detectable dermal exposure and glove use (odds ratio (OR) 0.22, 95% confidence interval (CI) 0.09 to 0.57) and inhalation exposure level (OR 1.34, 95% CI 0.97 to 1.84 for a 10‐fold increase). HDA in urine could be demonstrated in 36% and 10% of car body repair shop workers and industrial painting company workers respectively. In car body repair shops, the frequency of detectable HDA was significantly elevated at the end of the working day (OR 2.13, 95% CI 1.07 to 4.22 for 3–6 pm v 0–8 am). In both branches HDA was detected in urine of ∼25% of the spray painters. In addition HDA was detected in urine of a large proportion of non‐spray painters in car body repair shops. Conclusion Although (spray) painting with lacquers containing isocyanate hardeners results in the highest external exposures to HDI and oligomers, workers that do not perform paint related tasks may also receive a considerable internal dose. PMID:16728504

  13. Synthesis and characterization of conditioned carbon with iron nanoparticles for the arsenic removal in aqueous phase

    International Nuclear Information System (INIS)

    Flores C, D. O.

    2012-01-01

    Using pineapple husks conditioned with carboxymethylcellulose, hexamine and ferric nitrate, a carbonaceous material was obtained with nanoparticles of Fe (C Fe), which was characterized and tested for arsenic removal in the aqueous phase. The microscopic study showed spheres 4 microns and filaments 100 nm wide, so as iron particles whose diameter decreases to an average of 38.81 nm, when pyrolysis time was increased to 180 min. their distribution in the carbonaceous matrix is homogeneous. According to energy dispersive X-ray spectroscopy, C Fe contains C (82.29%), O (7.23%), K (0.68%), Ca (3.77%) and Fe (6.25%) and its diffraction pattern shows the characteristic peak of Fe (0), which is not observed in the coal without iron. By neutron activation analysis were quantified Al, Br, Ce, Co, Cr, Cs, Eu, Hf, K, Mg, Mn, Na, Rb, Sb, Sc and Zn, they can be involved in the process of sorption of As (v) forming surface active sites. For C Fe and C B characterized by Fourier transform infrared spectrometry, groups C-H, C=O, C=C, -Nh, NH 2 , isocyanate and isonitrile were found, the last two were formed by the present hexamine. X-ray photoelectron spectroscopy showed energy states of C 1 and O 1 in pineapple shell washed, shell conditioned with iron, C Fe at different times and the pyrolysis coal without iron (C B). The material C Fe 180 presented a specific area of 167 m 2 /g and 7.12 ± 1 sites/nm 2 isoelectric point while pH i = 11.1 C B is 98.80 m 2 /g specific area and 1.5 ± 1 sites/nm 2 and pH i = 10.6, being favorable to the sorption process. The highest removal of As(v) for both materials was at ph = 2, fitting the kinetic data to pseudo-second order model. The isotherms as a function of concentration were adjusted to Freundlich model indicating multilayer chemisorption at specific sites of a heterogeneous medium. Characterization by scanning electron microscopy after the sample sorption Fe nanoparticles remain in the carbonaceous matrix being not affected by the

  14. Degradation Mechanism of Poly(Ether-Urethane) Estane Induced by High Energy Radiation (III) : Radiolytic Gases and Water Soluble Products

    International Nuclear Information System (INIS)

    Dannoux, A.

    2006-01-01

    Within the framework of nuclear waste management, there is interest in the prediction of long-term behaviour of organic materials subjected to high energy radiation. Once organic waste has been stored, gases and low molecular products might be generated from materials irradiated by radionuclides. Long-term behaviour of organic material in nuclear waste has several common concerns with radiation ageing of polymers. But a more detailed description of the chemical evolution is needed for nuclear waste management. In a first approach, an extensive work on radiation ageing is used to identify the different processes encountered during the degradation of a polyurethane, including oxidation dose rate-effects and influence of dose on the oxidation mechanism. In a second approach, a study is performed to identify and quantify gases and possible production of water soluble chemical complexing agents which might enhance radionuclides migration away from the repository. In this work, we present results concerning the production of radiolytic gases and the formation of water soluble oligomers reached with leaching tests Films were made from a poly(ether-urethane) synthesized from methylene bis(p-phenyl isocyanate) (MDI) and poly(tetramethylene glycol) (PTMG) with 1,4 butanediol (BD) and were irradiated by high-energy electron beam to cover a wide doses range and by γ rays to determine the formation/consumption yields of gases. They were measured by mass spectrometry and gas-chromatography/mass spectrometry (GC/MS). The migration of water soluble oligomers in water was reached by measuring the weight loss versus leaching time. The identification of oligomers was performed by using a mass spectrometry with an electrospray ionisation interface (ESI-MS-MS). The analysis of radiolytic gases indicates the formation of H 2 , CO 2 and CO with respective radiolytic yields of 1, 0.5 and 0.3 molecule/100 eV. The consumption of O 2 is evaluated to 6 molecules/100 eV. For absorbed doses

  15. Synthesis and characterization of cycloaliphatic hydrophilic polyurethanes, modified with L-ascorbic acid, as materials for soft tissue regeneration

    International Nuclear Information System (INIS)

    Kucinska-Lipka, J.; Gubanska, I.; Strankowski, M.; Cieśliński, H.; Filipowicz, N.; Janik, H.

    2017-01-01

    In this paper we described synthesis and characteristic of obtained hydrophilic polyurethanes (PURs) modified with ascorbic acid (commonly known as vitamin C). Such materials may find an application in the biomedical field, for example in the regenerative medicine of soft tissues, according to ascorbic acid wide influence on tissue regeneration Flora (2009), Szymańska-Pasternak et al. (2011), Taikarimi and Ibrahim (2011), Myrvik and Volk (1954), Li et al. (2001), Cursino et al. (2005) . Hydrophilic PURs were obtained with the use of amorphous α,ω-dihydroxy(ethylene-butylene adipate) (dHEBA) polyol, 1,4-butanediol (BDO) chain extender and aliphatic 4,4′-methylenebis(cyclohexyl isocyanate) (HMDI). HMDI was chosen as a nontoxic diisocyanate, suitable for biomedical PUR synthesis. Modification with L-ascorbic acid (AA) was performed to improve obtained PUR materials biocompatibility. Chemical structure of obtained PURs was provided and confirmed by Fourier transform infrared spectroscopy (FTIR) and Proton nuclear magnetic resonance spectroscopy ( 1 HNMR). Differential scanning calorimetry (DSC) was used to indicate the influence of ascorbic acid modification on such parameters as glass transition temperature, melting temperature and melting enthalpies of obtained materials. To determine how these materials may potentially behave, after implementation in tissue, degradation behavior of obtained PURs in various chemical environments, which were represented by canola oil, saline solution, distilled water and phosphate buffered saline (PBS) was estimated. The influence of AA on hydrophilic-hydrophobic character of obtained PURs was established by contact angle study. This experiment revealed that ascorbic acid significantly improves hydrophilicity of obtained PUR materials and the same cause that they are more suitable candidates for biomedical applications. Good hemocompatibility characteristic of studied PUR materials was confirmed by the hemocompatibility test with

  16. Tools and drugs for uracil nucleotide-activated P2Y receptors.

    Science.gov (United States)

    Rafehi, Muhammad; Müller, Christa E

    2018-04-13

    P2Y receptors (P2YRs) are a family of G protein-coupled receptors activated by extracellular nucleotides. Physiological P2YR agonists include purine and pyrimidine nucleoside di- and triphosphates, such as ATP, ADP, UTP, UDP, nucleotide sugars, and dinucleotides. Eight subtypes exist, P2Y 1 , P2Y 2 , P2Y 4 , P2Y 6 , P2Y 11 , P2Y 12 , P2Y 13 , and P2Y 14 , which represent current or potential future drug targets. Here we provide a comprehensive overview of ligands for the subgroup of the P2YR family that is activated by uracil nucleotides: P2Y 2 (UTP, also ATP and dinucleotides), P2Y 4 (UTP), P2Y 6 (UDP), and P2Y 14 (UDP, UDP-glucose, UDP-galactose). The physiological agonists are metabolically unstable due to their fast hydrolysis by ectonucleotidases. A number of agonists with increased potency, subtype-selectivity and/or enzymatic stability have been developed in recent years. Useful P2Y 2 R agonists include MRS2698 (6-01, highly selective) and PSB-1114 (6-05, increased metabolic stability). A potent and selective P2Y 2 R antagonist is AR-C118925 (10-01). For studies of the P2Y 4 R, MRS4062 (3-15) may be used as a selective agonist, while PSB-16133 (10-06) represents a selective antagonist. Several potent P2Y 6 R agonists have been developed including 5-methoxyuridine 5'-O-((R p )α-boranodiphosphate) (6-12), PSB-0474 (3-11), and MRS2693 (3-26). The isocyanate MRS2578 (10-08) is used as a selective P2Y 6 R antagonist, although its reactivity and low water-solubility are limiting. With MRS2905 (6-08), a potent and metabolically stable P2Y 14 R agonist is available, while PPTN (10-14) represents a potent and selective P2Y 14 R antagonist. The radioligand [ 3 H]UDP can be used to label P2Y 14 Rs. In addition, several fluorescent probes have been developed. Uracil nucleotide-activated P2YRs show great potential as drug targets, especially in inflammation, cancer, cardiovascular and neurodegenerative diseases. Copyright © 2018. Published by Elsevier Inc.

  17. Physicochemical and biological properties of a novel injectable polyurethane system for root canal filling

    Directory of Open Access Journals (Sweden)

    Wang J

    2015-01-01

    Full Text Available Jian Wang,1 Yi Zuo,1 Minghui Zhao,1 Jiaxing Jiang,1 Yi Man,2 Jun Wu,3 Yunjiu Hu,3 Changlei Liu,4 Yubao Li,1 Jidong Li11Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu, Sichuan, People’s Republic of China; 2College of Stomatology, Sichuan University, Chengdu, Sichuan, People’s Republic of China; 3Department of Orthopedics, Chongqing Medical University, Chongqing, People’s Republic of China; 4College of Chemistry, Sichuan University, Chengdu, Sichuan, People’s Republic of ChinaAbstract: A root canal sealer with antibacterial activity can be efficacious in preventing reinfection that results from residual microorganisms and/or the leakage of microorganisms. In the present study, a series of injectable, self-curing polyurethane (PU-based antibacterial sealers with different concentrations of silver phosphate (Ag3PO4 were fabricated. Subsequently, their physicochemical properties, antibacterial abilities, and preliminary cytocompatibilities were evaluated. The results indicated that the fabricated PU-based sealers can achieve a high conversion rate in a short amount of time. More than 95% of the isocyanate group of PU sealers with 3 wt% (PU3 and 5 wt% (PU5 concentrations of Ag3PO4 were included in the curing reaction after 7 hours. With the exception of those for film thickness for PU5, the results of setting time, film thickness, and solubility were able to meet the requirements of the International Organization for Standardization. The antibacterial tests showed that PU3 and PU5 exhibit stronger antimicrobial effects than that achieved with 1 wt% Ag3PO4 (PU1 and AH Plus (positive control against Streptococcus mutans. The cytocompatibility evaluation revealed that the PU1 and PU3 sealers possess good cytocompatibility and low cytotoxicity. These results demonstrate that the PU3 sealer offers good physicochemical and antimicrobial properties along with cytocompatibility, which may hold great

  18. Síntesis y caracterización de adhesivos reposicionables de poliuretano dispersos en agua, obtenidos a partir de aceite de castor maleinizado Synthesis and characterization of pressure-sensitive adhesives of waterborne polyurethane from maleinizated castor oil

    Directory of Open Access Journals (Sweden)

    Paula Mazo

    2010-06-01

    Full Text Available El presente trabajo se centró en la producción de dispersiones acuosas de poliuretano empleando el método de emulsificación por inversión de fases. Para la síntesis fueron empleados dos polioles: uno comercial tipo poliéster y el otro es aceite de castor maleinizado (MACO; dos diisocianatos, uno aromático Toluen diisocianato (TDI y otro alifático Hexametilen diisocianato (HDI, siendo poco comunes para esta aplicación. Como emulsificante interno se empleó ácido cítrico el cual es muy económico y de fácil adquisición. Como factores se evaluaron la cantidad de ácido cítrico y la relación molar de grupos isocianato a hidroxilos (NCO/OH, generando un diseño de experimentos factorial 3² y minimizando el contenido de sólidos sedimentados. Mediante la metodología de superficie de respuesta, se obtuvo una ecuación polinomial cuadrática por un análisis de regresión múltiple. Los poliuretanos formados fueron evaluados en cuanto a sus propiedades adhesivas y mecánicas (pegajosidad tack, pegajosidad en cinta loop tack, cohesión hold, pelado peel, lo que permitió clasificar el adhesivo como reposicionable, para emplearlo en etiquetas.This work focused on the production of aqueous dispersions of polyurethane using the emulsification method by phase inversion. For the synthesis two polyols were employed, viz. a commercial polyester and Maleinizated Castor Oil (MACO, with two diisocyanates: one aromatic, toluene diisocyanate (TDI and another aliphatic, hexamethylene diisocyanate (HDI, which are not common for this application. Citric acid was used as internal emulsifier which is inexpensive and readily available. The parameters were the amount of citric acid and the mole ratio of isocyanate groups to hydroxyl (NCO/OH, generating a 3² factorial design, with minimization of the sedimented solids. The surface methodology was used to obtain a quadratic polynomial equation by multiple regression analysis. Polyurethanes synthesized were

  19. Synthesis and evaluation of polymeric bioadhesive based on polyurethane

    International Nuclear Information System (INIS)

    Sheikh, N.

    2001-01-01

    Surgeons have always sought to suture or unite tissues in a variety of methods. The most common way, suturing by the use of different materials such as cotton, stainless steel, silk, nylon and various absorbable sutures mainly catgut, poly glycolic acid (Dexon), has been bound as the best method. However, suturing and stapling have been reported to have some disadvantages such as foreign body reaction, sinus and granuloma formation. As a result of these numerous drawbacks, efforts have been made by scientists to obtain another method of getting tissue to adhere and heal. Gluing has been found to be the best alternative surgeons, the most important of which is cyanoacrylate. However, in spite of the high importance in surgery, currently available glues have shown few weaknesses that should be improved for clinical uses. For example, foreign body granulation reaction followed by infection, local allergenic effects, headache, irritation and sometimes lack of toughness by the cured adhesive as well as generation of toxic materials during the curing process of the glue, have been mentioned to be associated with presently used glues. As a bioadhesive, we have designed and prepared a urethane-based prepolymer composed of free end group isocyanate with controlled viscosity suitable for surgical purposes. The main objective of this work has been removal of chemical catalyst or initiator necessary for the curing of the prepolymer. For this purpose, we have explored a special type of protein, which can cure the synthesized prepolymer with a rate suitable for surgical purposes. Effects of polymerization parameters upon the molecular structure and viscosity have been studied. Wetting and spreading behavior of the prepolymer together with its surface tension have also been investigated and optimized. The surface behavior and physico-mechanical properties of the cured films of the prepolymer were characterized. Biocompatibility of the cured films has been evaluated by the cell

  20. Chemical segregation in hot cores with disk candidates. An investigation with ALMA

    Science.gov (United States)

    Allen, V.; van der Tak, F. F. S.; Sánchez-Monge, Á.; Cesaroni, R.; Beltrán, M. T.

    2017-07-01

    find co-spatial emission of isocyanic acid (HNCO) and formamide (NH2CHO) in both sources indicating a strong chemical link between the two species. Conclusions: The chemical segregation between N-bearing organic species and others in G35.20 suggests the presence of multiple protostars surrounded by a disk or torus.

  1. Evaluación de la resistencia al cizallamiento por compresión y falla en madera de uniones encoladas en maderas nacionales e importadas

    Directory of Open Access Journals (Sweden)

    Sebastián Quagliotti

    2011-05-01

    values under dry conditions. Another relevant conclusion is that the samples of E. grandis bonded with isocyanate shown the highest values of the Ratio wet/dry shear after water immersion treatments, as well as a lower fall in the percentage of wood failure, compared with the otherspecies under study.

  2. Physical and electrical properties of trimetallic nitride template endohedral metallofullerenes and their polymer nanocomposites

    Science.gov (United States)

    Ahmed, Hanaa Mohammed

    The main objective of this study was characterization of pure metallic nitride fullerene, MNF, and MNF containing polymers to evaluate these materials as suitable devices for tunable applications. Polymer-fullerene nanocomposites consisting of linear polyurethane (PU) segments crosslinked via polyhydroxylated fullerenes (C60 and Sc3N C 80, a metallic nitride fullerene) were prepared and characterized for their mechanical and dielectric properties using dynamic mechanical analysis (DMA) and broadband dielectric spectroscopic techniques. Polyhydroxylated fullerenes C60(OH)29 and Sc3N C80(OH) 18 were synthesized in a high yield through a solid-state high sheer ball-milling procedure and were characterized using a verity of techniques, such as FT-R, mass spectroscopy (MS) and thermal gravimetric analysis (TGA), to elucidate their structures. A difunctional isocyanate-terminated prepolymer was prepared from the reaction of poly(tetramethylene oxide) glycol (PTMO, ˜2000 g/mol) and methylene bis(4-isocyanatobenzene) (MDI) followed by the addition of the crosslinking fullerene agent. Fullerene-polymer networks [C60 -PU and Sc3N C80-PU] having high gel fractions and good mechanical properties and thermal stabilities were produced. Dynamic mechanical analyses of (C60 or Sc3N C80)-PU networks indicated a glass transition temperature, Tg, of -50°C with a sub-Tg relaxation due to local chain motions. Broadband dielectric spectroscopic analyses of the nanoparticles prior to incorporation into the networks revealed one relaxation and large epsilon' values in hydroxylated C60 relative to unfunctionalized C60. The analogous hydroxylated Sc3N C80 exhibited two relaxations, and the extra relaxation may be due to reorientations of cage-encapsulated Sc 3N clusters. Permittivity values (epsilon') for Sc3N C 80-PU were found to be higher than the corresponding values for C 60-PU, likely because of the rotationally mobile dipoles. For temperature voltage characteristics of the fullerene

  3. Astrobiological Aspects of Radiation Chemistry in Europa's Icy Regolith

    Science.gov (United States)

    Carlson, R. W.; Hand, K. P.

    2006-05-01

    addition, polymerization produces brown, high-molecular weight residues with complex mass spectra. Radiolysis of microorganisms shows the loss of amine, amide, methyl, and methylene groups, and production of carbon dioxide, carbon monoxide, nitriles, and isocyanates. Work is continuing to establish useful biosignatures that may persist in the complex mass spectra of irradiated microorganisms.

  4. Synthesis and characterization of cycloaliphatic hydrophilic polyurethanes, modified with L-ascorbic acid, as materials for soft tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Kucinska-Lipka, J., E-mail: juskucin@pg.gda.pl [Gdank University of Technology, Faculty of Chemistry, Department of Polymer Technology, Narutowicza St. 11/12, 80-233 Gdansk (Poland); Gubanska, I.; Strankowski, M. [Gdank University of Technology, Faculty of Chemistry, Department of Polymer Technology, Narutowicza St. 11/12, 80-233 Gdansk (Poland); Cieśliński, H.; Filipowicz, N. [Gdansk University of Technology, Faculty of Chemistry, Department of Microbiology, Narutowicza St. 11/12, 80-233 Gdansk (Poland); Janik, H. [Gdank University of Technology, Faculty of Chemistry, Department of Polymer Technology, Narutowicza St. 11/12, 80-233 Gdansk (Poland)

    2017-06-01

    In this paper we described synthesis and characteristic of obtained hydrophilic polyurethanes (PURs) modified with ascorbic acid (commonly known as vitamin C). Such materials may find an application in the biomedical field, for example in the regenerative medicine of soft tissues, according to ascorbic acid wide influence on tissue regeneration Flora (2009), Szymańska-Pasternak et al. (2011), Taikarimi and Ibrahim (2011), Myrvik and Volk (1954), Li et al. (2001), Cursino et al. (2005) . Hydrophilic PURs were obtained with the use of amorphous α,ω-dihydroxy(ethylene-butylene adipate) (dHEBA) polyol, 1,4-butanediol (BDO) chain extender and aliphatic 4,4′-methylenebis(cyclohexyl isocyanate) (HMDI). HMDI was chosen as a nontoxic diisocyanate, suitable for biomedical PUR synthesis. Modification with L-ascorbic acid (AA) was performed to improve obtained PUR materials biocompatibility. Chemical structure of obtained PURs was provided and confirmed by Fourier transform infrared spectroscopy (FTIR) and Proton nuclear magnetic resonance spectroscopy ({sup 1}HNMR). Differential scanning calorimetry (DSC) was used to indicate the influence of ascorbic acid modification on such parameters as glass transition temperature, melting temperature and melting enthalpies of obtained materials. To determine how these materials may potentially behave, after implementation in tissue, degradation behavior of obtained PURs in various chemical environments, which were represented by canola oil, saline solution, distilled water and phosphate buffered saline (PBS) was estimated. The influence of AA on hydrophilic-hydrophobic character of obtained PURs was established by contact angle study. This experiment revealed that ascorbic acid significantly improves hydrophilicity of obtained PUR materials and the same cause that they are more suitable candidates for biomedical applications. Good hemocompatibility characteristic of studied PUR materials was confirmed by the hemocompatibility test

  5. Resin cements formulated with thio-urethanes can strengthen porcelain and increase bond strength to ceramics.

    Science.gov (United States)

    Bacchi, Atais; Spazzin, Aloisio Oro; de Oliveira, Gabriel Rodrigues; Pfeifer, Carmem; Cesar, Paulo Francisco

    2018-06-01

    The use of thio-urethane oligomers has been shown to significantly improve the mechanical properties of resin cements (RCs). The aim of this study was to use thio-urethane-modified RC to potentially reinforce the porcelain-RC structure and to improve the bond strength to zirconia and lithium disilicate. Six oligomers were synthesized by combining thiols - pentaerythritol tetra-3-mercaptopropionate (PETMP, P) or trimethylol-tris-3-mercaptopropionate (TMP, T) - with di-functional isocyanates - 1,6-Hexanediol-diissocyante (HDDI) (aliphatic, AL) or 1,3-bis(1-isocyanato-1-methylethyl)benzene (BDI) (aromatic, AR) or Dicyclohexylmethane 4,4'-Diisocyanate (HMDI) (cyclic, CC). Thio-urethanes (20 wt%) were added to a BisGMA/UDMA/TEGDMA organic matrix. Filler was introduced at 60 wt%. The microshear bond strength (μSBS), Weibull modulus (m), and failure pattern of RCs bonded to zirconia (ZR) and lithium disilicate (LD) ceramics was evaluated. Biaxial flexural test and fractographic analysis of porcelain discs bonded to RCs were also performed. The biaxial flexural strength (σ bf ) and m were calculated in the tensile surfaces of porcelain and RC structures (Z = 0 and Z = -t 2 , respectively). The μSBS was improved with RCs formulated with oligomers P_AL or T_AL bonded to LD and P_AL, P_AR or T_CC bonded to zirconia in comparison to controls. Mixed failures predominated in all groups. σ bf had superior values at Z = 0 with RCs formulated with oligomers P_AL, P_AR, T_AL, or T_CC in comparison to control; σ bf increased with all RCs composed by thio-urethanes at Z = -t 2 . Fractographic analysis revealed all fracture origins at Z = 0. The use of specific thio-urethane oligomers as components of RCs increased both the biaxial flexural strength of the porcelain-RC structure and the μSBS to LD and ZR. The current investigation suggests that it is possible to reinforce the porcelain-RC pair and obtain higher bond strength to LD and ZR with RCs

  6. Thio-urethanes improve properties of dual-cured composite cements.

    Science.gov (United States)

    Bacchi, A; Dobson, A; Ferracane, J L; Consani, R; Pfeifer, C S

    2014-12-01

    This study aims at modifying dual-cure composite cements by adding thio-urethane oligomers to improve mechanical properties, especially fracture toughness, and reduce polymerization stress. Thiol-functionalized oligomers were synthesized by combining 1,3-bis(1-isocyanato-1-methylethyl)benzene with trimethylol-tris-3-mercaptopropionate, at 1:2 isocyanate:thiol. Oligomer was added at 0, 10 or 20 wt% to BisGMA-UDMA-TEGDMA (5:3:2, with 25 wt% silanated inorganic fillers) or to one commercial composite cement (Relyx Ultimate, 3M Espe). Near-IR was used to measure methacrylate conversion after photoactivation (700 mW/cm(2) × 60s) and after 72 h. Flexural strength and modulus, toughness, and fracture toughness were evaluated in three-point bending. Polymerization stress was measured with the Bioman. The microtensile bond strength of an indirect composite and a glass ceramic to dentin was also evaluated. Results were analyzed with analysis of variance and Tukey's test (α = 0.05). For BisGMA-UDMA-TEGDMA cements, conversion values were not affected by the addition of thio-urethanes. Flexural strength/modulus increased significantly for both oligomer concentrations, with a 3-fold increase in toughness at 20 wt%. Fracture toughness increased over 2-fold for the thio-urethane modified groups. Contraction stress was reduced by 40% to 50% with the addition of thio-urethanes. The addition of thio-urethane to the commercial cement led to similar flexural strength, toughness, and conversion at 72h compared to the control. Flexural modulus decreased for the 20 wt% group, due to the dilution of the overall filler volume, which also led to decreased stress. However, fracture toughness increased by up to 50%. The microtensile bond strength increased for the experimental composite cement with 20 wt% thio-urethane bonding for both an indirect composite and a glass ceramic. Novel dual-cured composite cements containing thio-urethanes showed increased toughness, fracture toughness and

  7. Numerical simulation of urea based selective non-catalytic reduction deNOx process for industrial applications

    International Nuclear Information System (INIS)

    Baleta, Jakov; Mikulčić, Hrvoje; Vujanović, Milan; Petranović, Zvonimir; Duić, Neven

    2016-01-01

    Highlights: • SNCR is a simple method for the NOx reduction from large industrial facilities. • Capabilities of the developed mathematical framework for SNCR simulation were shown. • Model was used on the geometry of experimental reactor and municipal incinerator. • Results indicate suitability of the developed model for real industrial cases. - Abstract: Industrial processes emit large amounts of diverse pollutants into the atmosphere, among which NOx takes a significant portion. Selective non-catalytic reduction (SNCR) is a relatively simple method for the NOx reduction in large industrial facilities such as power plants, cement plants and waste incinerator plants. It consists of injecting the urea-water solution in the hot flue gas stream and its reaction with the NOx. During this process flue gas enthalpy is used for the urea-water droplet heating and for the evaporation of water content. After water evaporates, thermolysis of urea occurs, during which ammonia, a known NO_x reductant, and isocyanic acid are generated. In order to cope with the ever stringent environmental norms, equipment manufacturers need to develop energy efficient products that are at the same time benign to environment. This is becoming increasingly complicated and costly, and one way to reduce production costs together with the maintaining the same competitiveness level is to employ computational fluid dynamics (CFD) as a tool, in a process today commonly known under the term “virtual prototyping”. The aim of this paper is to show capabilities of the developed mathematical framework implemented in the commercial CFD code AVL FIRE®, to simulate physical processes of all relevant phenomena occurring during the SNCR process. First, mathematical models for description of SNCR process are presented and afterwards, models are used on the 3D geometry of an industrial reactor and a real industrial case to predict SNCR efficiency, temperature and velocity field. Influence of the main

  8. Synthesis, structure, spectroscopy and redox energetics of a series of uranium(4) mixed-ligand metallocene complexes

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, R.K.; Scott, B.L.; Morris, D.E.; Kiplinger, J.L. [Los Alamos National Laboratory, Los Alamos, NM (United States)

    2010-06-15

    A series of uranium(IV) mixed-ligand amide-halide/pseudo-halide complexes (C{sub 5}Me{sub 5}){sub 2}U[N(SiMe{sub 3}){sub 2}](X) (X = F (1), Cl (2), Br (3), I (4), N{sub 3} (5), NCO (6)), (C{sub 5}Me{sub 5}){sub 2}U(NPh{sub 2})(X) (X = Cl (7), N{sub 3} (8)), and (C{sub 5}Me{sub 5}){sub 2}U[N(Ph)(SiMe{sub 3})](X) (X Cl (9), N{sub 3} (10)) have been prepared by one electron oxidation of the corresponding uranium(III) amide precursors using either copper halides, silver iso-cyanate, or triphenylphosphine gold(I)azide. Agostic U---H-C interactions and {eta}{sub 3}-(N,C,C') coordination are observed for these complexes in both the solid-state and solution. There is a linear correlation between the chemical shift values of the C{sub 5}Me{sub 5} ligand protons in the {sup 1}H NMR spectra and the U(IV)/U(III) reduction potentials of the (C{sub 5}Me{sub 5}){sub 2}U[N(SiMe{sub 3}){sub 2}](X) complexes, suggesting that there is a common origin, that is overall {sigma}-/{pi}-donation from the ancillary (X) ligand to the metal, contributing to both observables. Optical spectroscopy of the series of complexes 1-6 is dominated by the (C{sub 5}Me{sub 5}){sub 2}U[N(SiMe{sub 3}){sub 2}] core, with small variations derived from the identity of the halide/pseudo-halide. The considerable {pi}-donating ability of the fluoride ligand is reflected in both the electrochemistry and UV-visible-NIR spectroscopic behavior of the fluoride complex (C{sub 5}Me{sub 5}){sub 2}U[N(SiMe{sub 3}){sub 2}](F) (1). The syntheses of the new trivalent uranium amide complex, (C{sub 5}Me{sub 5}){sub 2}U[N(Ph)(SiMe{sub 3})](THF), and the two new weakly-coordinating electrolytes, [Pr{sub 4}N][B{l_brace}3,5-(CF{sub 3}){sub 2}C{sub 6}H{sub 3{r_brace}4}] and [Pr{sub 4}N][B(C{sub 6}F{sub 5}){sub 4}], are also reported. (authors)

  9. Exposure to organophosphate flame retardants in spray polyurethane foam applicators: Role of dermal exposure.

    Science.gov (United States)

    Bello, Anila; Carignan, Courtney C; Xue, Yalong; Stapleton, Heather M; Bello, Dhimiter

    2018-04-01

    Spray polyurethane foam (SPF) is a highly effective thermal insulation material that has seen considerable market growth in the past decade. Organophosphate flame retardants (PFRs) are added to SPF formulations to meet fire code requirements. A common flame retardant used in SPF formulations is tris 1-chloro 2-propyl phosphate (TCIPP), a suspected endocrine disruptor. Exposure monitoring efforts during SPF applications have focused primarily on the isocyanate component, a potent respiratory and dermal sensitizer. However, to our knowledge, there is no monitoring data for TCIPP. To characterize occupational exposures to TCIPP and other flame retardants during SPF insulation. Workers at four SPF insulation sites and one foam removal site (total n = 14) were recruited as part of this pilot study. Personal inhalation exposure to TCIPP was monitored with a CIP-10MI inhalable sampler and potential dermal exposure was assessed through the use of a glove dosimeter. Biomarkers of TCIPP and three other PFRs were measured in urine collected from workers pre-and post-shift. Linear mixed effect models were used to analyze associations of urinary biomarkers with inhalation and dermal exposures and paired t-tests were used to examine the difference on the means of urinary biomarkers pre-and post-shift. Chemical analysis of all species was performed with liquid chromatography-electrospray ionization tandem mass spectrometry. Geometric mean (GM) concentrations of TCIPP in personal air monitors and glove dosimeters collected from SPF applicators, 294.7 μg/m 3 and 18.8 mg/pair respectively. Overall, GM concentrations of the two TCIPP urinary biomarkers BCIPP and BCIPHIPP and (6.2 and 88.8 μg/mL) were 26-35 times higher than reported in the general population. Post-shift levels of TCIPP biomarkers were higher than pre-shift even though workers at insulation sites wore supplied air respirators, gloves and coveralls. The urinary biomarkers for the other PFRs were not

  10. Anticorrosive organic/inorganic hybrid coatings

    Science.gov (United States)

    Gao, Tongzhai

    evaluated by electrochemical impedance spectroscopy (EIS) and the results showed that 10 wt% pigmentation improved the corrosion resistance of the entire coating system. The effect of pigmentation on epoxide/polysiloxane hybrid coatings was also investigated. The epoxide was successfully modified using 3-(triethoxysilyl) propyl isocyanate (TEOSPI) as indicated by FTIR and NMR. Good dispersion of the pigment particles was achieved as revealed by the SEM images. The tensile modulus, tensile strength, pencil hardness and thermal stability of the hybrid coatings were improved while the flexibility and pull-off adhesion were deteriorated when increasing PVC.

  11. Synthesis and characterization of conditioned carbon with iron nanoparticles for the arsenic removal in aqueous phase; Sintesis y caracterizacion de carbon acondicionado con nanoparticulas de hierro para la remocion de arsenico en fase acuosa

    Energy Technology Data Exchange (ETDEWEB)

    Flores C, D. O.

    2012-07-01

    Using pineapple husks conditioned with carboxymethylcellulose, hexamine and ferric nitrate, a carbonaceous material was obtained with nanoparticles of Fe (C Fe), which was characterized and tested for arsenic removal in the aqueous phase. The microscopic study showed spheres 4 microns and filaments 100 nm wide, so as iron particles whose diameter decreases to an average of 38.81 nm, when pyrolysis time was increased to 180 min. their distribution in the carbonaceous matrix is homogeneous. According to energy dispersive X-ray spectroscopy, C Fe contains C (82.29%), O (7.23%), K (0.68%), Ca (3.77%) and Fe (6.25%) and its diffraction pattern shows the characteristic peak of Fe (0), which is not observed in the coal without iron. By neutron activation analysis were quantified Al, Br, Ce, Co, Cr, Cs, Eu, Hf, K, Mg, Mn, Na, Rb, Sb, Sc and Zn, they can be involved in the process of sorption of As (v) forming surface active sites. For C Fe and C B characterized by Fourier transform infrared spectrometry, groups C-H, C=O, C=C, -Nh, NH{sub 2}, isocyanate and isonitrile were found, the last two were formed by the present hexamine. X-ray photoelectron spectroscopy showed energy states of C 1 and O 1 in pineapple shell washed, shell conditioned with iron, C Fe at different times and the pyrolysis coal without iron (C B). The material C Fe 180 presented a specific area of 167 m{sup 2}/g and 7.12 {+-} 1 sites/nm{sup 2} isoelectric point while pH{sub i} = 11.1 C B is 98.80 m{sup 2}/g specific area and 1.5 {+-} 1 sites/nm{sup 2} and pH{sub i} = 10.6, being favorable to the sorption process. The highest removal of As(v) for both materials was at ph = 2, fitting the kinetic data to pseudo-second order model. The isotherms as a function of concentration were adjusted to Freundlich model indicating multilayer chemisorption at specific sites of a heterogeneous medium. Characterization by scanning electron microscopy after the sample sorption Fe nanoparticles remain in the carbonaceous

  12. Occupational diseases in the automotive industry in Czechia - Geographic and medical context.

    Science.gov (United States)

    Jarolímek, Jan; Urban, Pavel; Pavlínek, Petr; Dzurova, Dagmar

    2017-05-08

    The automotive industry represents the most important industrial sector in Czechia. The objective of this study has been to analyze the occurrence of occupational diseases (OD) in the automotive industry during the period from 2001 till 2014. Data on OD cases was retrieved from the National Registry of OD. Further, we conducted a survey in automotive companies with focus on occupational health services and positions of the companies in global production networks (GPNs). An analysis of OD distribution in the automotive industry was performed (age, gender, company size and its role in GPNs, regional distribution of studied companies, and regional unemployment rate), and was accompanied by assessment of the quality and range of occupational health services. Employees older than 40 years old have nearly 2.5 times higher probability of OD occurrence as compared with employees younger than 40 years old (odds ratio (OR) = 2.41, 95% confidence interval (CI): 2.05-2.85). Occupational diseases occurrence probability was 3 times higher for women than for men (OR = 3.01, 95% CI: 2.55-3.55). Occupational diseases incidence rates increased with the size of the company (0 OD/10 000 employees in micro enterprises to 57 OD/10 000 employees in large enterprises). A particularly steep rise in OD incidents in the automotive industry was observed in the Plzeň Region between 2001 and 2011. An association between OD incidents and the unemployment rate was not statistically confirmed. A statistically significant increase in OD incidents dependent on company size may be arguably attributed to a higher quality of occupational medical services in bigger companies, which ensures better detection and diagnosis of OD. In the Plzeň Region, the rapid increase in OD incidents was mainly caused by a change in the production process of automobile textiles in one factory due to the introduction of a glue containing isocyanates, which are potent allergising agents. This led to an increase in

  13. The prevalence of occupational dermatitis in the UK printing industry.

    Science.gov (United States)

    Livesley, E J; Rushton, L; English, J S; Williams, H C

    2002-07-01

    To quantify occupational ill health resulting from dermatitis in the UK printing industry and to explore links with particular processes and activities. Approximately 2600 members of the Graphical, Paper and Media Union living in Nottinghamshire were sent a self completion questionnaire. A sample of respondents, both those who reported current skin problems and those who did not, were invited for a short dermatological examination. The overall response rate was 62%. A total of 1189 respondents were directly involved in the printing industry and categorised according to work in pre-press (25%), printing (46%), or finishing (42%) processes. A total of 490 respondents (41%) self reported having a skin complaint at some time. Prevalence was highest in males (43%) and those working in printing (49%), in particular those who cleaned rollers and cylinders or who came into contact with substances containing isocyanates on a daily basis. The most commonly affected areas reported were the fingers and webs between the fingers. Twenty six per cent of the 490 reported a current problem on the hand. Reported symptoms included itching (61%), rash (58%), and dry skin (56%). Although certain printing industry substances were thought by respondents to aggravate their condition, constant washing and friction was most often cited. Reported use of protective equipment and cleansing products was generally high, particularly by printers. Clinical examination confirmed the high self reported prevalence and also identified a substantial proportion of mild cases which were not reported. The overall prevalence of occupationally related skin complaints is estimated to be 40%. A much higher prevalence of dermatitis has been identified than from routine surveillance schemes. The use of good quality records from unions with high membership facilitated access to workers across a range of company sites and printing processes. Validation of self reported symptoms through clinical examination was

  14. Polyurea-Based Aerogel Monoliths and Composites

    Science.gov (United States)

    Lee, Je Kyun

    2012-01-01

    to their lower content of hydrogen element. The invention involves mixing at least one isocyanate resin in solvent along with a specific amount of at least one polyamine hardener. The hardener is selected from a group of polyoxyalkyleneamines, amine-based polyols, or a mixture thereof. Mixing is performed in the presence of a catalyst and reinforcing inorganic and/or organic materials, and the system is then subjected to gelation, aging, and supercritical drying. The aerogels will offer exceptional flexibility, excellent thermal and physical properties, and good hydrophobicity. The rubbery polyurea-based aerogels are very flexible with no dust and hydrophobic organics that demonstrated the following ranges of typical properties: densities of 0.08 to 0.293 g/cu cm, shrinkage factor (raerogel/rtarget) = 1.6 to 2.84, and thermal conductivity values of 15.2 to 20.3 mW/m K.

  15. Recycling of polyurethanes from laboratory to industry, a journey towards the sustainability.

    Science.gov (United States)

    Simón, D; Borreguero, A M; de Lucas, A; Rodríguez, J F

    2018-06-01

    . Moreover, this review also describes the most recent studies employing crude glycerol (biodiesel subproduct) as an economic, sustainable and environmental friendly cleavage agent, which should lead the way to the industrial implantation of split-phase glycolysis in a near future, providing high quality recovered products, susceptible of replacing raw ones in the synthesis of new PU specialties. What is more, this review intends that any reader could know and understand the reactions involved in the polyurethane chemistry and recycling, the main polyurethanes types and the fundamentals of the recycling strategies in order to comprehend what are the advantages and drawbacks of each recycling process as starting point for looking for new advantageous alternatives from an environmental, technical and economic point of view. Broader context. This paper reviews the main advances in the polyurethane (PU) recycling field, from laboratory and academia processes to pilot plant and industrial scale ones, including the most relevant patents in the subject. Opposite to other common used plastics, PUs are not polymerization but condensation polymers, synthesized from polyols and isocyanates. The wide diversity of polyols and isocyanates allows the synthesis of numerous different compounds covering a huge range of applications. As a direct consequence of their commercial success, an increasing quantity of PU waste is being disposed by landfilling in the last decades. Such waste comprises not only post-consumer products but also scrap from slabstock manufacturing, which can reach the 10% of the total foam production. However, the massive enforcement of the environmental laws is pointing out a new route in the polymer waste removal sector based in the polymer recycling, and this fact has placed the research in waste treatment as one of the most prolific topics nowadays. In fact, polymer recycling processes have experienced a growing attention from the research and industrial worlds as a

  16. Stereoselective determination of unchanged and glucuroconjugated eliprodil, a new anti-ischaemic drug, in human plasma and urine by precolumn derivatization and column-switching high-performance liquid chromatography with fluorescence detection.

    Science.gov (United States)

    Malavasi, B; Ripamonti, M; Rouchouse, A; Ascalone, V

    1996-04-05

    An HPLC method was developed and validated for the determination in human plasma and urine of the enantiomers of eliprodil, (+/-)-alpha-(4-chlorophenyl)-4[(4-fluorophenyl) methyl]piperidine-1-ethanol hydrochloride, a new anti-ischaemic agent administered as a racemate. Both enantiomers are present in human plasma in unchanged and glucuroconjugated form, whereas only the glucuroconjugated form is excreted into urine; as a consequence, such metabolites in human plasma and urine should be submitted to enzymatic deconjugation with beta-glucuronidase (Escherichia coli) before being extracted. The general method involves a liquid-liquid extraction of eliprodil and internal standard from alkalinized plasma or urine with n-hexane, evaporation of the organic phase and derivatization with (S)-(+)-naphthylethyl isocyanate to give carbamate diastereoisomeric derivatives of (S)-(+)- and (R)-(-)-eliprodil and internal standard; after evaporation of the derivatizing mixture and dissolution of the residue in a small volume of phosphate buffer-acetonitrile (60:40, v/v), an aliquot is injected into a column-switching HPLC system. The derivatized sample extract is purified on a precolumn filled with C8-bonded silica material, which is flushed with acetonitrile-water, then diastereoisomers of eliprodil and the internal standard are automatically transferred by the mobile phase to the analytical column. The analytical column is a C8 type, specially deactivated for basic compounds, the mobile phase is 0.025 M phosphate buffer (pH 2.6)-methanol-acetonitrile (42:2:56) at a flow-rate of 1.2 ml min-1 and fluorimetric detector operating at lambda ex = 275 nm and lambda em = 336 nm is used. The retention times, under these conditions, are about 16 and 17 min for (S)-(+)- and (R)-(-)-eliprodil diastereoisomers, respectively, and about 19 min for the first-eluted diastereoisomer of the internal standard. During the analysis time, the precolumn, reset in a different path from that of the

  17. Design and Application of Nanogel-Based Polymer Networks

    Science.gov (United States)

    Dailing, Eric Alan

    Crosslinked polymer networks have wide application in biomaterials, from soft hydrogel scaffolds for cell culture and tissue engineering to glassy, high modulus dental restoratives. Composite materials formed with nanogels as a means for tuning network structure on the nanoscale have been reported, but no investigation into nanogels as the primary network component has been explored to this point. This thesis was dedicated to studying network formation from the direct polymerization of nanogels and investigating applications for these unique materials. Covalently crosslinked polymer networks were synthesized from polymerizable nanogels without the use of reactive small monomers or oligomers. Network properties were controlled by the chemical and physical properties of the nanogel, allowing for materials to be designed from nanostructured macromolecular precursors. Nanogels were synthesized from a thermally initiated solution free radical polymerization of a monomethacrylate, a dimethacrylate, and a thiol-based chain transfer agent. Monomers with a range of hydrophilic and hydrophobic character were copolymerized, and polymerizable groups were introduced through an alcohol-isocyanate click reaction. Nanogels were dispersible in water up to 75 wt%, including nanogels that contained a relatively high fraction of a conventionally water-insoluble component. Nanogels with molecular weights that ranged from 10's to 100's of kDa and hydrodynamic radii between 4 and 10 nm were obtained. Macroscopic crosslinked polymer networks were synthesized from the photopolymerization of methacrylate-functionalized nanogels in inert solvent, which was typically water. The nanogel composition and internal branching density affected both covalent and non-covalent interparticle interactions, which dictated the final mechanical properties of the networks. Nanogels with progressively disparate hydrophilic and hydrophobic character were synthesized to explore the potential for creating

  18. Extraction and Identification of Secondary Metabolites Produced by Trichoderma atroviridae (6022 and Evaluating of their Antifungal Effects

    Directory of Open Access Journals (Sweden)

    M. Shahiri Tabarestani

    2017-08-01

    Full Text Available Introduction: Fungi release wide spectrum of secondary metabolites that belong to several chemical groups with different biochemical origins. These materials produce as intermediate and end products of diverse metabolic pathways. The profile of the secondary metabolites for a known species or strain will vary depending on the substrate, the duration of incubation, the type of nutrients, temperature and other environmental parameters. Trichoderma spp. are well-known producers of secondary metabolites with different biological activities. The secondary metabolites with antibiotic activity can be classified into two main types. Low molecular weight and volatile metabolites which are involved in complex Trichoderma plant-pathogen interactions. They belong to various structure classes such as alcohols, ketones, alkanes, furans, simple aromatic compounds, isocyanate compounds, volatile terpenes, some polyketides, butenolides, and pyrones. All of them are relatively nonpolar compounds with a significant vapor pressure. These volatile organic compounds (VOCs in the soil environment could be traveled over distance and affect the physiology of the pathogens. They also enhance growth and systemic resistance in plants. These VOCs have been evaluated for T. atroviride, T. harzianum, T. viride, T. longibrachiatum, T. pseudokoningii and T. aureoviride. High molecular weight metabolites (like peptaibols are polar metabolites which act directly by contact between Trichoderma species and competitor organisms. Due to potent separation and highly sensitive detection, gas chromatography-mass spectrometry (GC-MS is the main method for detection of the fungal VOCs. Mass spectrometric detection offers the possibility to identify individual volatiles from complex mixtures. Structure characterization and confirmation of identity are usually achieved by comparison of mass spectra with library spectra and the determination of chromatographic retention indices. Due to the

  19. An Efficient Synthesis of Nitriles from Aldoximes Using Diethyl Phosphorocyanidate under Mild Conditions

    International Nuclear Information System (INIS)

    Lee, Kieseung; An, Hyeonseong; Hwang, Chanyeon

    2012-01-01

    Nitriles are valuable intermediates in organic synthesis not only because they serve as the appropriate precursors to various functional groups, but also because they are widely used as the key intermediates for pharmaceuticals, agrochemicals and various N-heterocyclic compounds. The cyano group itself is also frequently found in many biologically important molecules. Therefore, a variety of synthetic routes to nitriles from diverse chemical precursors have been developed. Among these routes, nitrile synthesis from aldoximes using an appropriate dehydrating agent has been a general and clean method. For this purpose, numerous reagents such as chlorosulfonyl isocyanate, di-2-pyridyl sulfite, Burgess reagent, [RuCl 2 (p-cymene)] 2 /MS, 4A, BOP, Pd(OAc) 2 /PPh 3 , Cu(OAc) 2 /ultrasound have been developed. These reagents, however, may have limitations in some respects such as harsh reaction conditions, use of expensive or less readily available reagents, low yields, and lack of generality. Therefore, there is still a need to develop mild and general method for this conversion. Diethyl phosphorocyanidate (DEPC) was initially introduced as an efficient peptide coupling reagent, and has been utilized for useful organic reactions. Previously, we reported that 2-chloro-1-methylpyridinium iodide is an efficient and mild reagent for the dehydration of aldoximes to nitriles under mild conditions. In continuation of our interest in developing mild method for the conversion of aldoximes to nitriles, we herein wish to report the first application of DEPC to the efficient synthesis of nitriles from aldoximes under mild conditions (Scheme 1). In order to obtain the information regarding the optimum reaction conditions, 4-pyridine aldoxime (1a) was reacted with DEPC without base, and in presence of various base in CH 2 Cl 2 at rt for a prolonged reaction time (20 h) (Table 1). CH 2 CI 2 was chosen as reaction medium in this reaction due to the good solubility for both 1 and 3 in CH

  20. An Efficient Synthesis of Nitriles from Aldoximes Using Diethyl Phosphorocyanidate under Mild Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kieseung; An, Hyeonseong; Hwang, Chanyeon [Woosuk Univ.,Wanju (Korea, Republic of)

    2012-10-15

    Nitriles are valuable intermediates in organic synthesis not only because they serve as the appropriate precursors to various functional groups, but also because they are widely used as the key intermediates for pharmaceuticals, agrochemicals and various N-heterocyclic compounds. The cyano group itself is also frequently found in many biologically important molecules. Therefore, a variety of synthetic routes to nitriles from diverse chemical precursors have been developed. Among these routes, nitrile synthesis from aldoximes using an appropriate dehydrating agent has been a general and clean method. For this purpose, numerous reagents such as chlorosulfonyl isocyanate, di-2-pyridyl sulfite, Burgess reagent, [RuCl{sub 2}(p-cymene)]{sub 2}/MS, 4A, BOP, Pd(OAc){sub 2}/PPh{sub 3}, Cu(OAc){sub 2}/ultrasound have been developed. These reagents, however, may have limitations in some respects such as harsh reaction conditions, use of expensive or less readily available reagents, low yields, and lack of generality. Therefore, there is still a need to develop mild and general method for this conversion. Diethyl phosphorocyanidate (DEPC) was initially introduced as an efficient peptide coupling reagent, and has been utilized for useful organic reactions. Previously, we reported that 2-chloro-1-methylpyridinium iodide is an efficient and mild reagent for the dehydration of aldoximes to nitriles under mild conditions. In continuation of our interest in developing mild method for the conversion of aldoximes to nitriles, we herein wish to report the first application of DEPC to the efficient synthesis of nitriles from aldoximes under mild conditions (Scheme 1). In order to obtain the information regarding the optimum reaction conditions, 4-pyridine aldoxime (1a) was reacted with DEPC without base, and in presence of various base in CH{sub 2}Cl{sub 2} at rt for a prolonged reaction time (20 h) (Table 1). CH{sub 2}CI{sub 2} was chosen as reaction medium in this reaction due to the