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Sample records for p-toluenesulfonyl isocyanate p-tosyl

  1. Stabilizing interface layer of LiNi0.5Co0.2Mn0.3O2 cathode materials under high voltage using p-toluenesulfonyl isocyanate as film forming additive

    Science.gov (United States)

    Dong, Peng; Wang, Ding; Yao, Yao; Li, Xue; Zhang, Yingjie; Ru, Juanjian; Ren, Ting

    2017-03-01

    p-Toluenesulfonyl isocyanate (PTSI) is introduced as electrolyte additive in a bid to enhance the electrochemical performances of LiNi0.5Co0.2Mn0.3O2 cathode materials under high voltage. A less resistive and stable film on the cathode surface derived from PTSI oxidation which taken place prior to the carbonate solvents is formed. As a result, the discharge capacity retention of Li/LiNi0.5Co0.2Mn0.3O2 cell is elevated from 71.4% to 86.2% after 100 cycles at room temperature, and from 32.3% to 54.5% after 100 cycles at 55 °C. In addition, the Li/LiNi0.5Co0.2Mn0.3O2 half cell with PTSI exhibits superior rate capability compared to that in baseline electrolyte. The improved performance is not only ascribed to the thin protective layer originated from PTSI decomposition which prevent the successive breakdown of the electrolyte on cathode surface, but it is also attributed to the sbnd Sdbnd O group in PTSI serves as the weak base site to restrain the reactivity of PF5, resulting in the suppression of LiF formation and HF generation.

  2. Amine-free approach toward N-toluenesulfonyl amidine construction: a phosphite-mediated Beckmann-like coupling of oximes and p-toluenesulfonyl azide.

    Science.gov (United States)

    Fleury, Lauren M; Wilson, Erin E; Vogt, Monika; Fan, Tiffany J; Oliver, Allen G; Ashfeld, Brandon L

    2013-10-25

    Atom hopping: A chlorophosphite-mediated Beckmann ligation of oximes and p-toluenesulfonyl azide gives access to N-sulfonyl phosphoramidines in good to excellent yields. The reaction proceeds under exceptionally mild conditions and constitutes a bioorthogonal approach toward amidines by avoiding the use of amines and transition-metal catalysts. dmp-ol=3,3-dimethylpropanediol.

  3. Study of TAMe (p-tosyl-L-arginine methyl ester) esterase activity of bovine plasma.

    Science.gov (United States)

    Claxton, J; Black, W D; Gentry, P A

    1978-07-01

    The TAMe (p-tosyl-L-arginine methyl ester) esterase activity of mature and immature bovine plasma was studied and compared with the activity of this enzyme in human plasma. Kaolin activation of 2 minutes was required to produce maximal activation in cattle, as compared with 1 minute activation in man. The kaolin-activated TAMe esterase values in bovine plasma were approximately one-half the values found in human plasma. The activity of this enzyme was statistically greater in immature than in mature cattle (P less than 0.05) at kaolin activation times of 1, 2, 15, and 20 minutes.

  4. 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

  5. Occupational allergic contact dermatitis caused by isocyanates.

    Science.gov (United States)

    Goossens, A; Detienne, T; Bruze, M

    2002-11-01

    Between 1978 and 2001, 22 patients were diagnosed with occupation-related allergic contact dermatitis from isocyanates and/or polyurethanes in our clinic. 13 had a positive reaction to the isocyanates, of whom 10 also reacted to diaminodiphenylmethane (MDA), which is used in the production or processing of isocyanates and polyurethanes; 9 reacted only to MDA. The object of the present study was to identify the trades and industries responsible for the development of contact allergy to these resins. Such patients must be patch tested with the isocyanates contacted at work, and account must be taken of positive reactions to MDA as a marker for isocyanate sensitivity.

  6. Synthesis and Crystal Structure of (2S,2 'S,4 'R)- 2-(1-Hydroxy- 1-ethylpropyl)- 1-[ (1'-p-tosyl-4 '-hydroxypyrrolidin-2'-yl)methyl]pyrrolidine

    Institute of Scientific and Technical Information of China (English)

    FU Yu-Qin; DING Li-Na; ZHANG Sheng-Hong; TAO Jing-Chao; ZHU Yu

    2006-01-01

    The title compound (2S,2'S,4'R)-2-(1hydroxy- 1 -ethylpropyl)- 1 -[(1'-p-tosyl-4'-hydroxypyrolidin-2'-yl)methyl]pyrrolidine synthesized by using (2S,4R)-4-hydroxy-L-proline and L-proline as the main materials was characterized through IR, 1H NMR, 13C NMR and HRMS spectra as well as single-crystal X-ray diffraction analysis. There is one equivalent ethanol involved in the crystal (C23H40N2O5S, Mr = 456.63). The crystal belongs to the triclinic system, space group P1, a = 6.5628(13), b = 8.4228(17), c = 11.957(2) (A), α = 80.54(3),β = 83.19(3), γ = 89.89(3)°, V=647.3(2) (A)3, Z = l, Dc = 1.171 g/cm3, λ(MoKα) = 0.71073 (A),μ = 0.158 mm-1, F(000) = 248, the final R = 0.0465 and wR = 0.1336 for 1769 observed reflections with I > 2σ(I). The adjacent molecules of compound 5 are linked through intermolecular hydrogen bonds formed by the secondary hydroxy group of one molecule with the tertiary hydroxy group of another one, and the molecular chains are further linked by ethanol through two kinds of hydrogen bonds with two molecules from different chains respectively to form a supramolecular structure.

  7. Nanoencapsulation of blocked isocyanates through aqueous emulsion polymerization

    Directory of Open Access Journals (Sweden)

    2008-05-01

    Full Text Available Blocked isocyanates were successfully encapsulated into polystyrene and hydroxyl and amine functionalized polymeric nanospheres via emulsion polymerization. The nanocapsules were characterized via Fourier transform infrared spectroscopy, differential scanning calorimetry and transmission electronic microscopy. The blocked isocyanates generated free isocyanate functionality upon thermal annealing of nanocapsules. This research establishes a novel encapsulating method for release and retention of free isocyanates in aqueous media. These nanocapsules can provide active isocyanates in coatings and adhesive applications, and represent a novel application of nanoencapsulated materials for controlled or delayed active material utilization.

  8. The antibody response to methyl isocyanate: experimental and clinical findings.

    OpenAIRE

    Karol, M H; Taskar, S; Gangal, S.; Rubanoff, B F; Kamat, S. R.

    1987-01-01

    As a result of the industrial accident in Bhopal, India (December 1984) in which thousands of people were exposed to methyl isocyanate (MIC), concern was raised for possible long-term health effects. The well-recognized immunologic consequences of exposure to other industrial isocyanates prompted investigation of an antibody response to MIC. Using procedures which had been developed in this laboratory to evaluate isocyanate immunotoxicity, animal studies were undertaken to develop and test re...

  9. Determination of isocyanic acid in air.

    Science.gov (United States)

    Karlsson, D; Dalene, M; Skarping, G; Marand, A

    2001-08-01

    A method is presented for the determination of isocyanic acid (ICA), HNCO, in air samples as a di-n-butylamine (DBA) derivative. The method is based on sampling in midget impinger flasks containing 10 ml of 0.01 mol l-1 DBA in toluene. Quantification was made using liquid chromatography (LC) and electrospray mass spectrometry (MS) monitoring positive ions. The instrumental detection limit for the LC-MS was 10 fmol of ICA-DBA. ICA was generated by thermal decomposition of urea. A standard solution containing the DBA derivatives of ICA was prepared by collecting the emitted ICA in an impinger flask containing DBA. ICA in the reference solution was characterised by LC and time-of-flight (TOF) MS and quantified by LC chemiluminescent nitrogen detection (LC-CLND). The instrumental detection limit for the LC-CLND was 1 ng of nitrogen. ICA was emitted during thermal degradation of PFU resins and polyurethane (PUR) lacquers, from car metal sheets. ICA was the most dominant isocyanate and in PUR coating up to 8% of the total weight was emitted as ICA and for PFU resins up to 14% was emitted as ICA. When air samples were collected in an iron foundry during casting in sand moulds with furan resins, concentrations of ICA in the range 50-700 micrograms m-3 were found in the working atmosphere.

  10. 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.

  11. Occupational exposure to selected isocyanates in Polish industry

    Directory of Open Access Journals (Sweden)

    Sławomir Brzeźnicki

    2015-06-01

    Full Text Available Background: Isocyanates constitute a group of highly reactive, low molecular weight chemicals used worldwide for polyurethane manufacturing. The occupational exposure to these compounds is a major cause of occupational asthma, thus it is very important to monitor their concentration in the workplace atmosphere. The aim of the study was to measure the concentration of 4,4’-methylenediphenyl diisocyanate (MDI; CAS 101-68-8, toluene-2,4-di-isocyanate (2,4-TDI; CAS 584-84-9, toluene-2,6-di-isocyanate (2,6-TDI; CAS 91-08-7 and hexamethylene di-isocyanate (HDI; CAS 822-06-0 in the work environment for evaluation of the occupational exposure to these compounds. Material and Methods: Determination of concentrations of selected isocyanates was carried out in 21 manufacturing plants, during different industrial processes. The collected air samples (personal samples were analyzed by means of the high-performance liquid chromatography (HPLC. Results: The presented results represent the 1st data on the occupational exposure to isocyanates in Poland. This set of data is generally indicative of concentrations of analyzed isocyanates that are low and do not exceed the maximum admissible concentration (MAC values in Poland. Elevated concentrations (above the MAC value were found only for the TDI in the course of manufacturing of polyurethane foam blocks. Conclusions: Results of many studies show that low concentrations of isocyanates (particularly of low volatility like for example MDI in the air cannot exclude the possibility of additional absorption of these compounds through skin. Taking into consideration all the uncertainties associated with the evaluation of the risk of exposure to isocyanates based solely on measurement of their levels in the air, it would seem that the simultaneous application of environmental and biological monitoring would only facilitate a reliable assessment of the occupational exposure risk. Med Pr 2015;66(3:291–301

  12. 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 po

  13. Characterization the Reaction of Isocyanate and Cellulose by XPS

    Institute of Scientific and Technical Information of China (English)

    GAOZhenhua; GUJiyou; LIZhiguo

    2004-01-01

    The X-ray photoelectron spectroscopy (XPS) technique was used to study the reaction of phenyl isocyanate and cellulose with different moisture contents (MC). The C1S XPS peak of cellulose is only one symmetrical contribution at 285.95 eV. While the C1S XPS peaks of N,N-dibenzylurea, the reaction resultant of phenyl isocyanate and water, have two contributions at 288.6±9.1 eV and 284.7±0.1 eV corresponding to the carbonyl group and phenyl ring group, respectively. Their area ratio is between 11.88 and 11,98 that is quite neat to the theoretical value of 12.0. With the moisture content (MC) of cellulose increased, the proportion of isocyanate reacted with water increased. When the MC reaches 9.78%, 92.98% of all consumed isocyanate will react with water. By spattering analysis, it reveals that the reaction resultants of benzyl isocyanate distribute mainly on the surface of cellulose.

  14. Laboratory study of methyl isocyanate ices under astrophysical conditions

    Science.gov (United States)

    Maté, B.; Molpeceres, G.; Timón, V.; Tanarro, I.; Escribano, R.; Guillemin, J. C.; Cernicharo, J.; Herrero, V. J.

    2017-10-01

    Methyl isocyanate has been recently detected in comet 67P/Churyumov-Gerasimenko (67P/CG) and in the interstellar medium. New physicochemical studies on this species are now necessary as tools for subsequent studies in astrophysics. In this work, infrared spectra of solid CH3NCO have been obtained at temperatures of relevance for astronomical environments. The spectra are dominated by a strong, characteristic multiplet feature at 2350-2250 cm-1, which can be attributed to the asymmetric stretching of the NCO group. A phase transition from amorphous to crystalline methyl isocyanate is observed at ˜90 K. The band strengths for the absorptions of CH3NCO in ice at 20 K have been measured. Deuterated methyl isocyanate is used to help with the spectral assignment. No X-ray structure has been reported for crystalline CH3NCO. Here we advance a tentative theoretical structure, based on density functional theory (DFT) calculations, derived taking the crystal of isocyanic acid as a starting point. A harmonic theoretical spectrum is then calculated for the proposed structure and compared with the experimental data. A mixed ice of H2O and CH3NCO was formed by simultaneous deposition of water and methyl isocyanate at 20 K. The absence of new spectral features indicates that methyl isocyanate and water do not react appreciably at 20 K, but form a stable mixture. The high CH3NCO/H2O ratio reported for comet 67P/CG, and the characteristic structure of the 2350-2250 cm-1 band, makes it a very good candidate for future astronomical searches.

  15. 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 oligom

  16. Isocyanate emissions from pyrolysis of mattresses containing polyurethane foam.

    Science.gov (United States)

    Garrido, María A; Gerecke, Andreas C; Heeb, Norbert; Font, Rafael; Conesa, Juan A

    2017-02-01

    This study examined the emissions of powerful asthmatic agents called isocyanates from small-scale pyrolysis experiments of two common foams employed in mattress production such as flexible polyurethane foam (FPUF) and viscoelastic memory foam (VMF). A nitrogen atmosphere and five different temperatures, 300, 350, 400, 450 and 850 °C, were selected to carry out the experiments in order to evaluate the worst possible conditions for thermal degradation. A similar trend for both materials was found. At lower temperatures, diisocyanates were the most important products whereas at 850 °C monoisocyanates, and mainly isocyanic acid released mainly from the thermal cracking of diisocyanates evolved directly from the polymer chains. The total yields of isocyanates were in the range of 1.43-11.95 mg/m(3) for FPUF at 300-850 °C and 0.05-6.13 mg/m(3) for VMF, 300-850 °C. This difference could be a consequence of the lower amount of isocyanates employed in the VMF production which was confirmed by the nitrogen content of the foams, 5.95% FPUF vs. 3.34% in VMF. Additionally, a qualitative search for so far unknown isocyanates was performed in samples from the pyrolysis of FPUF at 300, 400 and 850 °C. It was confirmed that six different aminoisocyanates at 300 °C were evolved, whereas at 400 and 850 °C only five of them were detected. The general trend observed was a decrease of the aminoisocyanate levels with increasing pyrolysis temperature.

  17. Potential energy surface of the photolysis of isocyanic acid HNCO

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The dissociation curves of the photolysis of the isocyanic acidHNCOHN+CO corresponding to the ground state (S0), the first triplet excited state (T1) and the first singlet excited state (S1) have been studied respectively at the UHF/6-311G** and CIS/6-311G** levels using ab initio method. The energy surface crossing points, S1/T1, T1/S0 and S1/S0, have been found and the characteristics of the energy minimum crossing point were given, based on which, the changes of the crossing points' geometries along the lower electronic energy surface and its end-result have been located according to the steepest descent principle. The computational result indicates that the photolysis of the isocyanic acid HNCOHN+CO has three competitive reaction channels ((A)-(C)), and from the kinetic piont of view, channel (A) is the most advantageous.

  18. The phosphinoboration of carbodiimides, isocyanates, isothiocyanates and CO2.

    Science.gov (United States)

    Geier, Stephen J; LaFortune, James H W; Zhu, Diya; Kosnik, Stephanie C; Macdonald, Charles L B; Stephan, Douglas W; Westcott, Stephen A

    2017-08-22

    The transition metal-free addition of phosphinoboronate ester Ph2PBpin (pin = 1,2-O2C2Me4) to heterocumulenes including carbodiimides, isocyanates, isothiocyanates and carbon dioxide has been investigated. The corresponding 1,2-addition products were readily prepared at room temperature without the need of a catalyst or added base. Addition of methanol to the compounds derived from addition of Ph2PBpin to carbodiimides, isocyanates, and isothiocyanates resulted in traditional hydrophosphination products. The methodology developed in this study provides a simple and elegant route for the generation of a wide range of functionalized phosphines. The phosphinoboronate ester Ph2PBpin also selectively and reversibly adds to CO2 at room temperature in a 1,2-manner.

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

    Science.gov (United States)

    Franklin, Gillian; Harari, Homero; Ahsan, Samavi; Bello, Dhimiter; Sterling, David A.; Nedrelow, Jonathan; Raynaud, Scott; Biswas, Swati; Liu, Youcheng

    2016-01-01

    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.

  20. Lymphocyte Gene Expression Characteristic of Immediate Airway Responses (IAR) and Methacholine (MCH) Hyperresponsiveness in Mice Sensitized and Challenged with Isocyanates

    Science.gov (United States)

    Exposure to isocyanates has been associated with occupational airway diseases, including asthma. Previously we reported on respiratory and immune responses following dermal sensitization and intranasal challenge of BALB/c mice with 6 different isocyanates. The purpose of this st...

  1. 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

  2. A new general pathway for synthesis of reference compounds of N-terminal valine-isocyanate adducts.

    Science.gov (United States)

    Davies, Ronnie; Rydberg, Per; Westberg, Emelie; Motwani, Hitesh V; Johnstone, Erik; Törnqvist, Margareta

    2010-03-15

    Adducts to Hb could be used as biomarkers to monitor exposure to isocyanates. Particularly useful is the measurement of carbamoylation of N-terminal valines in Hb, after detachment as hydantoins. The synthesis of references from the reactive isocyanates, especially diisocyanates, has been problematic due to side reactions and polymerization of the isocyanate starting material. A simpler, safer, and more general method for the synthesis of valine adducts of isocyanates has been developed using N-[(4-nitrophenyl)carbamate]valine methylamide (NPCVMA) as the key precursor to adducts of various mono- and diisocyanates of interest. By reacting NPCVMA with a range of isocyanate-related amines, carbamoylated valines are formed without the use of the reactive isocyanates. The carbamoylated products synthesized here were cyclized with good yields of the formed hydantoins. The carbamoylated derivative from phenyl isocyanate also showed quantitative yield in a test with cyclization under the conditions used in blood. This new pathway for the preparation of N-carbamoylated model compounds overcomes the above-mentioned problems in the synthesis and is a general and simplified approach, which could make such reference compounds of adducts to N-terminal valine from isocyanates accessible for biomonitoring purposes. The synthesized hydantoins corresponding to adducts from isocyanic acid, methyl isocyanate, phenyl isocyanate, and 2,6-toluene diisocyanate were characterized by LC-MS analysis. The background level of the hydantoin from isocyanic acid in human blood was analyzed with the LC-MS conditions developed.

  3. Liquid chromatographic determination of residual isocyanate monomers in plastics intended for food contact use.

    Science.gov (United States)

    Damant, A P; Jickells, S M; Castle, L

    1995-01-01

    A liquid chromatographic (LC) method was developed for the analysis of 10 isocyanates in polyurethane articles and laminates intended for food use. Residual isocyanates are extracted by dichloromethane with concurrent derivatization by 9-(methylaminomethyl)anthracene. The resultant derivatives are analyzed by reversed-phase LC with fluorescence detection. Separation of the isocyanates was studied and optimized. Quantitation uses 1-naphthyl isocyanate as internal standard and standard addition to the food package. Validation demonstrated the method to have good precision (+/- 2-5%) and recovery (83-95%) for samples spiked with isocyanates at 0.1 mg/kg. The limit of detection was 0.03 mg/kg. Analysis of 19 commercial polyurethane or laminate food packages demonstrated that the method was not prone to interferences. Residues of diphenylmethane-4,4'-diisocyanate were detected in 5 packages and ranged from 0.14 to 1.08 mg/kg.

  4. Thermal and Mechanical Properties of Sequential and Simultaneous Thiol-Ene-Isocyanate Networks

    Science.gov (United States)

    McNair, Olivia; Brent, Davis; Savin, Daniel

    2011-03-01

    Ternary networks containing having stoichiometrically balanced thiol /(ene+isocyanate) ranging from 0 to 20 mol% isocyanate were synthesized via sequential or simultaneous thiol/ene and thiol/isocyanate click reactions. The effects of cross-link density were studied using three thiols, GDMP (difunctional), 3T (trifunctional) and 4T (tetrafunctional) respectively. TEA catalyzes the isocyanate-thiol coupling and chain extension, while the photoinitiator DMPA initiates a radical thiol-ene crosslinking process. Real-time FTIR was used to study kinetics of both light and dark reactions utilizing thiol, ene and isocyanate peaks which appear independently. It was found that difunctional thiols and isocyanates reacted initially, forming chain extended prepolymers end-capped with thiol functionalities. Upon UV irradiation, thiol functionalized prepolymers reacted with TTT, a trifunctional ene, forming networks containing incorporated thiourethane linkages. Initial DSC results indicated higher Tgs for higher cross-linked networks; however, isocyanate content has significant effects on each system. Films were also be thermally characterized via DMA and mechanical properties measured using MTS.

  5. Thermolysis of Semicarbazones to the Corresponding Azines Through Reactive N-Substituted Isocyanate Intermediates

    Directory of Open Access Journals (Sweden)

    N. K. Chudgar

    2000-04-01

    Full Text Available Thermolysis of semicarbazones (I to azines (II occurs through reactive N-substituted isocyanate intermediates (Ia which can be converted in situ to carbamates and Nsubstituted ureas.

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

    Directory of Open Access Journals (Sweden)

    Chenggang Zhu

    2016-03-01

    Full Text Available 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%.

  7. 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%.

  8. 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

    2016-01-01

    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%. PMID:26999137

  9. Personnel Exposure to Airborne Isocyanates and Solvents During Shipboard Painting With 2-Pack Polyurethane Paints

    Science.gov (United States)

    2008-12-01

    contain low volatility isocyanate prepolymers in addition to small quantities of volatile isocyanate monomers [2,3]. The monomers may become airborne as...vapour whilst the non-volatile prepolymers and partially cured oligomers may form aerosols during spray painting and sanding of the painted surface...JL (1992) “ Prepolymers of hexamethylene diisocyanate as a cause of occupational asthma” J. Allergy Clinical Immunol. 91 850-61. 5. Redlich CA, Bello

  10. Imbalance of mitochondrial-nuclear cross talk in isocyanate mediated pulmonary endothelial cell dysfunction

    Directory of Open Access Journals (Sweden)

    Hariom Panwar

    2013-01-01

    Full Text Available Mechanistic investigations coupled with epidemiology, case-control, cohort and observational studies have increasingly linked isocyanate exposure (both chronic and acute with pulmonary morbidity and mortality. Though ascribed for impairment in endothelial cell function, molecular mechanisms of these significant adverse pulmonary outcomes remains poorly understood. As preliminary studies conducted in past have failed to demonstrate a cause-effect relationship between isocyanate toxicity and compromised pulmonary endothelial cell function, we hypothesized that direct exposure to isocyanate may disrupt endothelial structural lining, resulting in cellular damage. Based on this premise, we comprehensively evaluated the molecular repercussions of methyl isocyanate (MIC exposure on human pulmonary arterial endothelial cells (HPAE-26. We examined MIC-induced mitochondrial oxidative stress, pro-inflammatory cytokine response, oxidative DNA damage response and apoptotic index. Our results demonstrate that exposure to MIC, augment mitochondrial reactive oxygen species production, depletion in antioxidant defense enzymes, elevated pro-inflammatory cytokine response and induced endothelial cell apoptosis via affecting the balance of mitochondrial-nuclear cross talk. We herein delineate the first and direct molecular cascade of isocyanate-induced pulmonary endothelial cell dysfunction. The results of our study might portray a connective link between associated respiratory morbidities with isocyanate exposure, and indeed facilitate to discern the exposure-phenotype relationship in observed deficits of pulmonary endothelial cell function. Further, understanding of inter- and intra-cellular signaling pathways involved in isocyanate-induced endothelial damage would not only aid in biomarker identification but also provide potential new avenues to target specific therapeutic interventions.

  11. Accidental exposure to isocyanate fumes in a group of firemen.

    Science.gov (United States)

    Axford, A T; McKerrow, C B; Jones, A P; Le Quesne, P M

    1976-05-01

    A total of 35 firemen involved in fighting a fire in a factory in which polyurethane foam was made were exposed to fumes of toluene di-isocyanate from two large storage tanks which were damaged during the fire, resulting in massive spillage. Most of the men experienced symptoms during the fire or during the three weeks after it. The symptoms were mainly gastrointestinal, respiratory, or neurological. Altogether 15 men described gastrointestinal symptoms which subsided within two days of onset. Respiratory symptoms were described by 31 men and were most pronounced during the three days after the fire, thereafter tending to improve. The neurological findings are described separately. When the men were reviewed at six months there was a suggestion that some of them might have sustained long-term damage to the respiratory tract, and almost four years later 20 men had persistent respiratory symptoms. Serial measurements of ventilatory capacity revealed a marked decline in the first six months although this was not sustained.

  12. 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

  13. PREPARATION AND PROPERTIES OF STARCH-BASED BIOPOLYMERS MODIFIED WITH DIFUNCTIONAL ISOCYANATES

    Directory of Open Access Journals (Sweden)

    Ramzi Belhassen

    2011-02-01

    Full Text Available The present work reports on the preparation of thermoplastic starch (TPS modified in situ with a diisocyanate derivative. Evidence of the condensation reaction between the hydroxyl groups of starch and glycerol with the isocyanate function (NCO was confirmed by FTIR analysis. The evolution of the properties of the ensuing TPS, in term of mechanical properties, microstructure, and water sensitivity, was investigated using tensile mechanical, dynamic mechanical thermal analysis (DMTA, X-ray diffraction (XRD, and water uptake. The results showed that the addition of isocyanate did not affect the crystallinity of the TPS and slightly reduced the water uptake of the material. The evolution of the mechanical properties with ageing became less pronounced by the addition of the isocyanate as their amount exceeded 4 to 6wt%.

  14. Preparation and characterization of 3-(triethoxysilyl) propyl isocyanate self-assembled monolayer on surface of chip

    Institute of Scientific and Technical Information of China (English)

    XIE Yao; GENG LiNa; QU Feng; LUO AiQin; QU Feng; DENG YuLin

    2009-01-01

    Monolayer of 3-(triethoxysilyl) propyl isocyanate was prepared on the slide by self-assembled tech-nique. X-ray photoelectron spectroscopy (XPS) was employed to analyze the elementary composition of the film. Contact angle of distilled water was measured to characterize the surface state. It was shown that 3-(triethoxysilyl) propyl isocyanate had been successfully assembled on the slide. The in-crease of contact angle to 80 demonstrated that the hydrophobicity of the surface of chip was in-creased significantly. Moreover, further self-assembly of bovine serum albumin (BSA) on 3-(trietho-xysilyl) propyl isocyanate was also carried out with the advantages such as simple and convenient preparation. Therefore, the potential of broader applications in the modification of micro-channel in the μ-TAS system, the immobilization of protein or peptide and the surface modification of materials are all expectative.

  15. Room temperature polymerization of alkyl isocyanates catalyzed by rare earth Schiff base complexes

    Institute of Scientific and Technical Information of China (English)

    YANG XiongFa; NI XuFeng; SHEN ZhiQuan

    2009-01-01

    The polymerization of alkyl isocyanates catalyzed by rare earth chloride salen complexes/triisobutyl aluminum (Ln(H_2salen)_2Cl_3·2C_2H_7OH/Al(i-Bu)_3) at room temperature was investigated.The influences of ligand structure,catalyst composition,polymerization temperature,polymerization time,the concentration of catalyst and monomer,and the polymerization solvent on the polymerization of isocyanates were studied.It was found that under the polymerization conditions,examined La(H_2salen_A)_2Cl_3·2C_(2-)H_7OH/Al(i-Bu)_3 (H_2salen_A=N,N'-disalicylideneethylene diamine) is a fairly high efficient catalyst for the polymerization of n-hexyl isocyanate (n-HexNCO) to prepare high molecular weight poly(n-hexyl isocyanate) (PHNCO) with narrower molecular weight distribution at room temperature.PHNCO could be prepared with yield of 74.0%,number-average molecular weight (M_n) of 40.20×10~4 and MWD of 1.79 under the following optimum conditions:[Al]/[La]=30 (molar ratio),[n-HexNCO]/[La]=100 (molar ratio),[n-HexNCO]=3.43 mol/L polymerization at 20℃ for 12 h in toluene.In the same polymerization conditions,poly (n-octyl isocyanate) (PONCO) with yield of 67.3%,and poly(n-butyl isocyanate) (PBNCO) with yield of 45.5%,could be prepared respectively.The kinetics of the polymerization of n-HexNCO was also investigated and found to be first-order with respect to both monomer and catalyst concentrations.

  16. Ruthenium(II)-Catalyzed Regioselective Ortho Amidation of Imidazo Heterocycles with Isocyanates.

    Science.gov (United States)

    Shakoor, S M Abdul; Kumari, Santosh; Khullar, Sadhika; Mandal, Sanjay K; Kumar, Anil; Sakhuja, Rajeev

    2016-12-16

    Direct ortho amidation at the phenyl ring of 2-phenylimidazo heterocycles with aryl isocyanates has been achieved via a chelation-assisted cationic ruthenium(II) complex catalyzed mechanism. The methodology provides a straightforward, high-yielding regioselective approach toward the synthesis of an array of ortho-amidated phenylimidazo heterocycles without prior activation of C(sp(2))-H. This also reports the first method for coupling of aryl isocyanates with the imidazo[1,2-a]pyridine system via a pentacyclometalated intermediate. The methodology is found to be easily scalable and could be applied toward the selective ortho amidation of 2-heteroarylimidazo[1,2-a]pyridine frameworks.

  17. 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.

  18. The formation of poly(ester–urea) networks in the absence of isocyanate monomers

    NARCIS (Netherlands)

    Zimmermann, Jörg; Loontjens, Ton; Scholtens, B.J.R.; Mülhaupt, Rolf

    2004-01-01

    The polymerization of N,N' carbonylbis (caprolactam) (CBC) and polyol in the presence of alcoholate as catalyst produced cross-linked poly(ester–urea)s via ring opening addition reaction. In contrast to conventional synthetic routes, the use of non-toxic CBC eliminates the need for toxic isocyanate-

  19. Size-separated sampling and analysis of isocyanates in workplace aerosols. Part I. Denuder--cascade impactor sampler.

    Science.gov (United States)

    Dahlin, Jakob; Spanne, Mårten; Karlsson, Daniel; Dalene, Marianne; Skarping, Gunnar

    2008-07-01

    Isocyanates in the workplace atmosphere are typically present both in gas and particle phase. The health effects of exposure to isocyanates in gas phase and different particle size fractions are likely to be different due to their ability to reach different parts in the respiratory system. To reveal more details regarding the exposure to isocyanate aerosols, a denuder-impactor (DI) sampler for airborne isocyanates was designed. The sampler consists of a channel-plate denuder for collection of gaseous isocyanates, in series with three-cascade impactor stages with cut-off diameters (d(50)) of 2.5, 1.0 and 0.5 mum. An end filter was connected in series after the impactor for collection of particles smaller than 0.5 mum. The denuder, impactor plates and the end filter were impregnated with a mixture of di-n-butylamine (DBA) and acetic acid for derivatization of the isocyanates. During sampling, the reagent on the impactor plates and the end filter is continuously refreshed, due to the DBA release from the impregnated denuder plates. This secures efficient derivatization of all isocyanate particles. The airflow through the sampler was 5 l min(-1). After sampling, the samples containing the different size fractions were analyzed using liquid chromatography-mass spectrometry (LC-MS)/MS. The DBA impregnation was stable in the sampler for at least 1 week. After sampling, the DBA derivatives were stable for at least 3 weeks. Air sampling was performed in a test chamber (300 l). Isocyanate aerosols studied were thermal degradation products of different polyurethane polymers, spraying of isocyanate coating compounds and pure gas-phase isocyanates. Sampling with impinger flasks, containing DBA in toluene, with a glass fiber filter in series was used as a reference method. The DI sampler showed good compliance with the reference method, regarding total air levels. For the different aerosols studied, vast differences were revealed in the distribution of isocyanate in gas and

  20. Exposure to airborne isocyanates and other thermal degradation products at polyurethane-processing workplaces.

    Science.gov (United States)

    Henriks-Eckerman, Maj-Len; Välimaa, Jarmo; Rosenberg, Christina; Peltonen, Kimmo; Engström, Kerstin

    2002-10-01

    The thermal degradation products of polyurethanes (PURs) and exposure to isocyanates were studied by stationary and personal measurements in five different occupational environments. Isocyanates were collected on glass fibre filters impregnated with 1-(2-methoxyphenyl)piperazine (2MP) and in impingers containing n-dibutylamine (DBA) in toluene. connected to a glass fibre postfilter. The derivatives formed were analysed by liquid chromatography: 2MP derivatives with UV and electrochemical detection and DBA derivatives with mass spectrometric detection. The release of aldehydes and other volatile organic compounds into the air was also studied. In a comparison of the two sampling methods, the 2MP method yielded about 20% lower concentrations for 4,4'-methylenediphenyl diisocyanate (MDI) than did the DBA method. In car repair shops, the median concentration of diisocyanates (given as NCO groups) in the breathing zone was 1.1 microg NCO m(-3) during grinding and 0.3 microg NCO m(-3) during welding, with highest concentrations of 1.7 and 16 pg NCO m(-3), respectively. High concentrations of MDI, up to 25 and 19 microg NCO m(-3), respectively, were also measured in the breathing zone during welding of district heating pipes and turning of a PUR-coated metal cylinder. During installation of PUR-coated floor covering, small amounts of aliphatic diisocyanates were detected in the air. A small-molecular monoisocyanate, methyl isocyanate, and isocyanic acid were detected only during welding and turning operations. The diisocyanate concentrations were in general higher near the emission source than in the workers' breathing zone. A sampling strategy to evaluate the risk of exposure to isocyanates is presented.

  1. Cyclic tetramers of a five-membered palladacycle based on a head-to-tail-linked isocyanate dimer and their reactivity in cyclotrimerization of isocyanates.

    Science.gov (United States)

    Lee, Seon Gye; Choi, Keun-Young; Kim, Yong-Joo; Park, SuJin; Lee, Soon W

    2015-04-14

    Reactions of [Pd(styrene)(PR3)2], generated from trans-[PdEt2(PR3)2] and styrene, with 2 equiv. of benzyl isocyanate in THF at room-temperature afforded unusual cyclic Pd-tetramers of five-membered rings consisting of organic isocyanate dimers and palladium, [Pd(PR3){-C(O)N(R)C(O)N(R)-}]4 (PR3 = PMe3, ; PR3 = PMe2Ph, ). Additionally, a cyclic trimer, (RNCO)3, (R = benzyl) was produced as a catalytic product. Treatment of the cyclic tetramer () with 4 equiv. of chelated phosphine, such as (1,2-bis(diethylphosphino)ethane) (DEPE) or (1,2-bis(dimethylphosphino)ethane) (DMPE), readily caused conversion to a metallacyclic cis-form, [Pd{N(R)C(O)N(R)C(O)}(P ∼ P)] (P ∼ P = DEPE, ; P ∼ P = DMPE, ) in quantitative yields. In contrast, reactions of Pd(0)-PR3 with 2 equiv. of Ar-NCO (Ar = Ph, p-tolyl, p-ClC6H4) afforded metallacyclic complexes having a dimeric isocyanato moiety, cis-[Pd{C(O)N(Ar)-C(O)N(Ar)}(PR3)2] (PR3 = PMe3 Ar = C6H5, ; p-MeC6H4, ; p-Cl-C6H4, ; PR3 = PMe2Ph, Ar = p-Cl-C6H4, ). Treatment of the palladacyclic complex () with an equimolar amount of chelated phosphine such as DEPE readily caused conversion to a palladacyclic cis-form, [Pd{N(Ar)C(O)N(Ar)C(O)}(DEPE)], in quantitative yield. The catalytic cyclotrimerization of benzyl isocyanate to [Pd(styrene)(PMe3)2] was achieved by varying the molar ratio of R-NCO (R = benzyl). In addition, catalytic cyclotrimerization was performed from the five-membered palladacyclic complexes or the Pd(0)-PR3 complex with excess Ar-NCO.

  2. 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.

  3. Sensory and pulmonary irritation of methyl isocyanate in mice and pulmonary irritation and possible cyanidelike effects of methyl isocyanate in guinea pigs.

    OpenAIRE

    Alarie, Y.; Ferguson, J S; Stock, M. F.; Weyel, D A; Schaper, M.

    1987-01-01

    Methyl isocyanate (MIC) was evaluated for sensory and pulmonary irritation in mice. MIC was found to be both a potent sensory and pulmonary irritant in this species. From these results, a safe level of exposure for a period of 8 hr was estimated to be about 0.02 ppm for humans. Guinea pigs were also exposed to MIC for a single 3-hr exposure at a concentration of 37 ppm. During exposure to MIC, coughing was observed in all animals. Pulmonary function was evaluated immediately following exposur...

  4. Vibrational Spectra, Assignments and Ab initio/DFT Analysis for 2-Methyl-3-nitrophenyl isocyanate

    Science.gov (United States)

    Prasannakumar, Sushanti; Yenagi, Jayashree; Tonannavar, J.

    2008-11-01

    The FT-IR (4000-400 cm-1) and Raman (3200-100 cm-1) spectral measurements have been made for 2-Methyl-3-nitrophenyl isocyanate. Electronic energy, optimized geometry and harmonic vibrational spectra have been computed using ab initio and DFT methods, namely, at RHF/6-311G* and B3LYP/6-311G* levels of theory. The methyl, nitro and isocyanate vibrations observed in their characteristic regions, have been accurately computed by the B3LYP/6-311G* level. Computed low frequencies have been assigned to out-of-plane, wagging and torsional vibrations of these groups. A complete assignment of the observed as well as computed spectra has been proposed.

  5. 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

  6. Isocyanate exposure in bathtub refinishing: à propos a case of occupational asthma.

    Science.gov (United States)

    Seldén, Anders I; Andersson, Lennart; Barlas, Georgios; Westberg, Håkan

    2007-01-01

    Work-related asthma in a bathtub refinishing technician prompted measurements of isocyanate exposure in this operation. Very high levels of hexamethylene diisocyanate (HDI) oligomer, up to 8500 microg/m3 NCO, were found during top varnish spray-painting, whereas the levels of HDI monomer were substantially lower. The results suggest that only full-piece, self-contained respirators would suffice to protect technicians from serious pulmonary disease.

  7. Swelling and Creep of Isocyanate-Bonded Oriented-Particle Board

    OpenAIRE

    SEKINO, Noboru; Suzuki, Masaharu

    1984-01-01

    This paper reports swelling, bending strength, and creep of Isocyanate(ls)bonded oriented-particleboard(face: orlented, core: random), which is compared with Phenol-formaldehyde(PF) bonded and Urea-formaldehyde(UF) bonded oriented-particleboards.Test results are summarized as follows:1) The orientation of flakes greatly reduces linear expansion along the oriented dlreCtion, but the thickness swelling of oriented board is almost equal to that of random-orientedboard.2) ls-bonded particleboard...

  8. Isocyanate Exposure Assessment Combining Industrial Hygiene Methods with Biomonitoring for End Users of Orthopedic Casting Products

    OpenAIRE

    2013-01-01

    Previous studies have suggested a potential risk to healthcare workers applying isocyanate-containing casts, but the authors reached their conclusions based on immunological or clinical pulmonology test results alone. We designed a study to assess potential exposure to methylene diphenyl diisocyanate (MDI) among medical personnel applying orthopedic casts using two different application methods. Air, dermal, surface, and glove permeation sampling methods were combined with urinary biomonitori...

  9. Comprehensive mechanistic study of ion pair SN2 reactions of lithium isocyanate and methyl halides

    Science.gov (United States)

    Sun, Ying-Xin; Ren, Yi; Wong, Ning-Bew; Chu, San-Yan; Xue, Ying

    The anionic SN2 reactions NCO- + CH3X and ion pair SN2 reactions LiNCO + CH3X (X = F, Cl, Br, and I) at saturated carbon with inversion and retention mechanisms were investigated at the level of MP2/6-311+G(d,p). There are two possible reaction pathways in the anionic SN2 reactions, but eight in the ion pair SN2 reactions. Calculated results suggest that the previously reported T-shaped isomer of lithium isocyanate does not exist. All the retention pathways are not favorable based on the analysis of transition structures. Two possible competitive reaction pathways proceed via two six-member ring inversion transition structures. It is found that there are two steps in the most favorable pathway, in which less stable lithium cyanate should be formed through the isomerization of lithium isocyanate and nucleophilic site (N) subsequently attacks methyl halides from the backside. The thermodynamically and kinetically favorable methyl isocyanate is predicted as major product both in the gas phase anionic and the ion pair SN2 reactions. In addition, good correlations between the overall barriers relative to separated reactants, ?H?ovr , with geometrical looseness parameter %L? and the heterolytic cleavage energies of the C bond X and Li bond N (or Li bond O) bonds are observed for the anionic and ion pair SN2 reactions. The trend of variation of the overall barriers predicts the leaving ability of X increase in the order: F reactions of LiNCO + CH3X. The calculations in solution indicate that solvent effects will retard the rate of reactions and the predicted product, methyl isocyanate, is same as the one in the gas phase.

  10. Non-Isocyanate Polyurethane Soft Nanoparticles Obtained by Surfactant-Assisted Interfacial Polymerization.

    Science.gov (United States)

    Bossion, Amaury; Jones, Gavin O; Taton, Daniel; Mecerreyes, David; Hedrick, James L; Ong, Zhan Yuin; Yang, Yi Yan; Sardon, Haritz

    2017-02-28

    Polyurethanes (PUs) are considered ideal candidates for drug delivery applications due to their easy synthesis, excellent mechanical properties, and biodegradability. Unfortunately, methods for preparing well-defined PU nanoparticles required miniemulsion polymerization techniques with a nontrivial control of the polymerization conditions due to the inherent incompatibility of isocyanate-containing monomers and water. In this work, we report the preparation of soft PU nanoparticles in a one-pot process using interfacial polymerization that employs a non-isocyanate polymerization route that minimizes side reactions with water. Activated pentafluorophenyl dicarbonates were polymerized with diamines and/or triamines by interfacial polymerization in the presence of an anionic emulsifier, which afforded non-isocyanate polyurethane (NIPU) nanoparticles with sizes in the range of 200-300 nm. Notably, 5 wt % of emulsifier was required in combination with a trifunctional amine to achieve stable PU dispersions and avoid particle aggregation. The versatility of this polymerization process allows for incorporation of functional groups into the PU nanoparticles, such as carboxylic acids, which can encapsulate the chemotherapeutic doxorubicin through ionic interactions. Altogether, this waterborne synthetic method for functionalized NIPU soft nanoparticles holds great promise for the preparation of drug delivery nanocarriers.

  11. 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.

  12. Isocyanate-functional adhesives for biomedical applications. Biocompatibility and feasibility study for vascular closure applications.

    Science.gov (United States)

    Hadba, Ahmad R; Belcheva, Nadya; Jones, Fatima; Abuzaina, Ferass; Calabrese, Allison; Kapiamba, Mbiya; Skalla, Walter; Taylor, Jack L; Rodeheaver, George; Kennedy, John

    2011-10-01

    Biodegradable isocyanate-functional adhesives based on poly(ethylene glycol)-adipic acid esters were synthesized, characterized, and evaluated in vitro and in vivo. Two types of formulations, P2TT and P2MT, were developed by functionalization with 2,4-tolylene diisocyanate (TDI) or 4,4'-methylene-bis(phenyl isocyanate) (MDI), respectively, and branching with 1,1,1-trimethylolpropane (TMP). The biocompatibility of the synthesized adhesive formulations was evaluated as per ISO 10993. Cytotoxicity, systemic toxicity, pyrogenicity, genotoxicity (reverse mutation of Salmonella typhimurium and Escherichia coli), hemolysis, intracutaneous reactivity, and delayed-type hypersensitivity were evaluated. All formulations met the requirements of the conducted standard tests. The biological behavior and ability of the adhesive formulations to close an arteriotomy and withstand arterial pressure following partial approximation with a single suture were evaluated in a rat abdominal aorta model. Animals were evaluated at 1, 2, 3, and 4 weeks after surgery. Macroscopic and histopathologic evaluation of explanted arteries suggested that the P2TT formulation had better in vivo performance than the P2MT formulation. Additionally, the P2TT formulation resulted in less tissue reaction than P2MT formulation. To our knowledge, this is the first study demonstrating the potential of this new class of isocyanate-functional degradable adhesives for vascular applications. Copyright © 2011 Wiley Periodicals, Inc.

  13. Adsorption and hydrolysis of isocyanic acid on TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Piazzesi, Gaia; Kroecher, Oliver; Elsener, Martin; Wokaun, Alexander [Paul Scherrer Institute PSI, CH-5232 Villigen (Switzerland)

    2006-05-15

    The interaction of isocyanic acid (HNCO) with titania in the anatase modification has been investigated by means of DRIFT spectroscopy and TPD experiments. HNCO adsorbs dissociatively on TiO{sub 2} to yield isocyanate (NCO) groups, bound to Ti{sup 4+} sites, and hydroxyl (OH) groups. The stability of these NCO groups decreases with increasing temperatures, and at T>200{sup o}C they are very easily removed from the surface. In the presence of water, the hydrolysis of the NCO species to ammonia is also fostered by elevating the temperature. Moreover, HNCO adsorption on a sample previously exposed to ammonia revealed that competitive adsorption occurs on the surface. The catalytic activity of TiO{sub 2} for the hydrolyis of HNCO was investigated in a micro plug-flow reactor and correlated with the stability and reactivity of the isocyanate species found by DRIFT spectroscopy. The results are discussed in view of the role of the HNCO hydrolysis in the selective catalytic reduction (SCR) of diesel NO{sub x} emissions with urea (urea-SCR process). (author)

  14. The role of isocyanates in determining the viscoelastic properties of polyurethane

    Science.gov (United States)

    AqilahHamuzan, Hawa; Badri, Khairiah Haji

    2016-11-01

    Polyurethane (PU) has a unique structure that is dependent on the structure of the starting material used. This research focused on investigating the role of isocyanate groups (NCO) in the determination of the viscoelastic properties of the polymer. Monoester polyol was reacted with three different diisocyanates separately by prepolymerization method. The diisocyanates used were 2,4-diphenyl methane diisocyanate (MDI), toluene 2,4-diisocyanate (TDI) and isophoronediisocyanate (IPDI). Acetone was used as a solvent. IPDI, MDI and TDI were reacted with monoester polyol at ratios of 10:9, 10:10, 10:12 and 10:14 (polyol:diisocyanate). Then, the PU foams produced by the curing process were analyzed by Fourier Transform infrared spectroscopy (FTIR). The FTIR spectra showed the presence of the amide peak (-NH) and the absence of hydroxyl peak (-OH) indicated that the reaction between polyol and diisocyanate has occurred. However, the soxhlet extraction showed that only MDI-based PUs contain crosslinking bond. These cross-linking bond at the ratio of 10:10, 10:12 and 10:14 were 41.3 %,61.1 % and 74.1 % respectively. Thermal properties of the PU foams were determined by differential scanning calorimetry (DSC) and thermogravimetry (TGA) techniques. MDI-based PUs and TDI-based PUs show two values of Tg while IPDI-based PUs only show one Tg value. The tensile strains of PU foams decreased with increasing ratio of isocyanate. Meanwhile, PU foams with ratio of polyol to isocyanate at 10:12 showed the highest tensile stress and modulus compared to at 10:10 and 10:14.

  15. The Electrical Properties for Phenolic Isocyanate-Modified Bisphenol-Based Epoxy Resins Comprising Benzoate Group.

    Science.gov (United States)

    Lee, Eun Yong; Chae, Il Seok; Park, Dongkyung; Suh, Hongsuk; Kang, Sang Wook

    2016-03-01

    Epoxy resin has been required to have a low dielectric constant (D(k)), low dissipation factor (Df), low coefficient of thermal expansion (CTE), low water absorption, high mechanical, and high adhesion properties for various applications. A series of novel phenolic isocyanate-modified bisphenol-based epoxy resins comprising benzoate group were prepared for practical electronic packaging applications. The developed epoxy resins showed highly reduced dielectric constants (D(k)-3.00 at 1 GHz) and low dissipation values (Df-0.014 at 1 GHz) as well as enhanced thermal properties.

  16. Ultrathin coatings from isocyanate-terminated star PEG prepolymers: layer formation and characterization.

    Science.gov (United States)

    Groll, Juergen; Ameringer, Thomas; Spatz, Joachim P; Moeller, Martin

    2005-03-01

    In this study we present the preparation of thin and ultrathin coatings from six-arm star-shaped isocyanate-terminated prepolymers on amino-functionalized silicon wafers. The backbone of the stars is a statistical copolymer of ethylene oxide and propylene oxide in the ratio 80:20 (Star PEG). Film preparation by spin coating from aqueous THF resulted in a variety of film morphologies that are determined by the water content of the solvent. Water is indispensable for activation of the isocyanate-terminated stars in solution and for proper cross-linking of the coatings on the substrate. This cross-linking results in a dense network of PEG chains on the substrate linked via urea groups with a mesh size of the network that corresponds to the arm length of the stars. Layer thickness variations between 3 and 500 nm revealed a strong dependence of the contact angle with water on the layer thickness which is explained by the chemical composition of the coatings. Due to the high functionality of the star-shaped prepolymers, free amino groups remain in the films that were detected by fluorescence microscopy after reaction with 4-chloro-7-nitrobenzofurazan (NBF). To test the system for the ability to prevent unspecific interaction with proteins, adsorption of fluorescence-labeled avidin was examined with fluorescence microscopy. For layer thicknesses between 3 and 50 nm, no protein adsorption could be detected.

  17. Ultrathin coatings from isocyanate terminated star PEG prepolymers: patterning of proteins on the layers.

    Science.gov (United States)

    Groll, Juergen; Haubensak, Wulf; Ameringer, Thomas; Moeller, Martin

    2005-03-29

    This study presents the easy and fast patterning of low molecular weight molecules that act as binding partners for proteins on Star PEG coatings. These coatings are prepared from isocyanate terminated star shaped prepolymers and form a highly cross-linked network on the substrate in which the stars are connected via urea groups and free amino groups are present. Streptavidin has been patterned on these layers by microcontact printing (muCP) of an amino reactive biotin derivative and consecutive binding of streptavidin to the biotin. Patterns of Ni(2+)-nitriltriacetic acid (NTA) receptors have been prepared by printing amino functional NTA molecules in freshly prepared Star PEG layers that still contain amino reactive isocyanate groups. Complexation of the NTA groups with Ni(II) ions enabled the binding of His-tag enhanced green fluorescent protein (EGFP) in the desired pattern on the substrates. Since the unmodified Star PEG layers prevent unspecific protein adsorption, His-EGFP could selectively be bound to the sample by immersion into crude, nonpurified His-tag EGFP containing cell lysate.

  18. Well-defined biobased segmented polyureas synthesis via a TBD-catalyzed isocyanate-free route.

    Science.gov (United States)

    Tang, Donglin; Mulder, Dirk-Jan; Noordover, Bart A J; Koning, Cor E

    2011-09-01

    Via an isocyanate-free route, a series of segmented polyureas (PUs) were synthesized from (potentially) renewable resources. To the best of our knowledge, the present work shows for the first time that the organic superbase guanidine 1,5,7-triazabicyclododecene (TBD) which was originally developed as a catalyst for the ring-opening polymerization of lactones, lactides or cyclic carbonates, is also a promising catalyst for the transurethanization between dicarbamates and diamino-terminated poly(propylene glycol) (PPGda) providing PUs via an isocyanate-free strategy. The renewable segmented PUs contain monodisperse hard segments (HSs). This well-defined structure was verified by the DMTA plots of the PUs, showing a sharp glass transition, a sharp flow transition and a flat rubbery plateau. The flow and maximum use temperature (Tfl ) of the PUs increases with the increasing number of urea groups in the corresponding dicarbamates. In addition, at constant HS length, the length of the soft-segment (SS) can be changed to adjust the properties of the PU materials, enabling their application as adhesives, soft elastomers, or rigid plastics.

  19. Isocyanic acid in the atmosphere and its possible link to smoke-related health effects.

    Science.gov (United States)

    Roberts, James M; Veres, Patrick R; Cochran, Anthony K; Warneke, Carsten; Burling, Ian R; Yokelson, Robert J; Lerner, Brian; Gilman, Jessica B; Kuster, William C; Fall, Ray; de Gouw, Joost

    2011-05-31

    We measured isocyanic acid (HNCO) in laboratory biomass fires at levels up to 600 parts per billion by volume (ppbv), demonstrating that it has a significant source from pyrolysis/combustion of biomass. We also measured HNCO at mixing ratios up to 200 pptv (parts-per-trillion by volume) in ambient air in urban Los Angeles, CA, and in Boulder, CO, during the recent 2010 Fourmile Canyon fire. Further, our measurements of aqueous solubility show that HNCO is highly soluble, as it dissociates at physiological pH. Exposure levels > 1 ppbv provide a direct source of isocyanic acid and cyanate ion (NCO(-)) to humans at levels that have recognized health effects: atherosclerosis, cataracts, and rheumatoid arthritis, through the mechanism of protein carbamylation. In addition to the wildland fire and urban sources, we observed HNCO in tobacco smoke, HNCO has been reported from the low-temperature combustion of coal, and as a by-product of urea-selective catalytic reduction (SCR) systems that are being phased-in to control on-road diesel NO(x) emissions in the United States and the European Union. Given the current levels of exposure in populations that burn biomass or use tobacco, the expected growth in biomass burning emissions with warmer, drier regional climates, and planned increase in diesel SCR controls, it is imperative that we understand the extent and effects of this HNCO exposure.

  20. Di-Isocyanate Crosslinked Aerogels with 1, 6-Bis (Trimethoxysilyl) Hexane Incorporated in Silica Backbone

    Science.gov (United States)

    Vivod, Stephanie L.; Meador, Mary Ann B.; Nguyen, Baochau N.; Quade, Derek; Randall, Jason; Perry, Renee

    2008-01-01

    Silica aerogels are desirable materials for many applications that take advantage of their light weight and low thermal conductivity. Addition of a conformal polymer coating which bonds with the amine decorated surface of the silica network improves the strength of the aerogels by as much as 200 times. Even with vast improvement in strength they still tend to undergo brittle failure due to the rigid silica backbone. We hope to increase the flexibility and elastic recovery of the silica based aerogel by altering the silica back-bone by incorporation of more flexible hexane links. To this end, we investigated the use of 1,6-bis(trimethoxysilyl)hexane (BTMSH), a polysilsesquioxane precursor3, as an additional co-reactant to prepare silica gels which were subsequently cross-linked with di-isocyanate. Previously, this approach of adding flexibility by BTMSH incorporation was demonstrated with styrene cross-linked aerogels. In our study, we varied silane concentration, mol % of silicon from BTMSH and di-isocyanate concentration by weight percent to attempt to optimize both the flexibility and the strength of the aerogels.

  1. Synthesis and Characterization of A Polynuclear Yttrium Trifluoroethoxide and Its Activity for Oligomerization of Phenyl Isocyanate

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A polynuclear yttrium trifluoroethoxide was synthesized and its activity for the oligomerization of phenyl isocyanate was tested. Reaction of anhydrous YCl3 with CF3CH2ONa in a 1:3 molar ratio in THF at room temperature, after workup, gave complex 1 as colorless crystals. The composition of complex 1 is [Y(OCH2CF3)3]6ONa2(THF)12, which was identified by elemental analysis and 1H NMR. Further X-ray structure determination reveals that complex 1 is a polynuclear ion pair compound, [Y6(μ6-O)(OCH2CF3)18]2-[Na(THF)6]+2 (1). The crystal data of complex 1 are trigonal, P-3 space group, a=1.78440(14) nm, b=1.78440(14) nm, c=1.27395(12) nm, γ=120°, V=3.5129(5) nm3, Z=1, Dc=1.607 mg·m-3, μ=2.591 mm-1 (Mo Kα), F(000)=1710, R=0.067, wR=0.182. Preliminary results demonstrated that complex 1 is a highly effective catalyst for the oligomerization of phenyl isocyanate.

  2. Validation of transferability of DBA derivatization and LC-MS/MS determination method for isocyanates via an interlaboratory comparison

    NARCIS (Netherlands)

    Bobeldijk, I.; Karlsson, D.; Pronk, A.; Gonsalves, J.; Hekman, M.; Lagemaat, D. van de; Preller, L.; Heederik, D.; Skarping, G.

    2008-01-01

    An adapted method for the quantitative determination of isocyanates in air was implemented and validated in-house. The method was based on air sampling using an impinger flask containing di-n-butylamine (DBA) in toluene and a glass fibre filter in series. The DBA derivatives were determined using li

  3. Interfacial thiol-isocyanate reactions for functional nanocarriers: a facile route towards tunable morphologies and hydrophilic payload encapsulation.

    Science.gov (United States)

    Kuypers, Sören; Pramanik, Sumit Kumar; D'Olieslaeger, Lien; Reekmans, Gunter; Peters, Martijn; D'Haen, Jan; Vanderzande, Dirk; Junkers, Thomas; Adriaensens, Peter; Ethirajan, Anitha

    2015-11-11

    Functional nanocarriers were synthesized using an in situ inverse miniemulsion polymerization employing thiol-isocyanate reactions at the droplet interface to encapsulate hydrophilic payloads. The morphology of the nanocarriers is conveniently tunable by varying the reaction conditions and the dispersions are easily transferable to the aqueous phase.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cong Khanh Huynh; Trinh Vu Duc, E-mail: chuynh@hospvd.c [Institut Universitaire Romand de Sante au Travail (IST), 21 rue du Bugnon - CH-1011 Lausanne (Switzerland)

    2009-02-01

    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.

  5. Zinc catalyzed Guanylation reaction of Amines with Carbodiimides/ Isocyanate leading to Guanidines/Urea derivatives formation

    Indian Academy of Sciences (India)

    JAYEETA BHATTACHARJEE; MITALI SACHDEVA; INDRANI BANERJEE; TARUN K PANDA

    2016-06-01

    We report the highly chemo-selective catalytic addition of N–H bonds from various aromaticamines to carbodiimides and isocyanates using (Ar-BIAO)ZnCl2 complexes [Ar-BIAO = N-(aryl)iminoacenapthenone,Ar = 2,6-$Me_{2}C_{6}H_{3}$ (1), 2,4,6 $Me_{3}C_{6}H_{2}$ (2), $2,6-^{i}$ $Pr_{2}C_{6}_H{3} (3)] as the pre-catalyst to prepareguanidine and urea derivatives in 55-90% yield. The complex 3 showed higher catalytic activity than analogouscomplexes 1 and 2 under similar reaction conditions. The catalytic guanylation of N–H bonds with heterocumulenesdisplays a broad substrate scope. The amines having electron donating groups underwent higher conversionthan the amines having electron withdrawing groups to afford corresponding guanidine or urea derivatives.A possible mechanism involving penta-coordinated zinc transition state for the catalytic reaction is presented.

  6. Inhalation exposure system used for acute and repeated-dose methyl isocyanate exposures of laboratory animals.

    Science.gov (United States)

    Adkins, B; O'Connor, R W; Dement, J M

    1987-06-01

    Laboratory animals were exposed by inhalation for 2 hr/day (acute) or 6 hr/day (four consecutive days, repeated dose) to methyl isocyanate (MIC). Exposures were conducted in stainless steel and glass inhalation exposure chambers placed in stainless steel, wire mesh cages. MIC was delivered with nitrogen via stainless steel and Teflon supply lines. Chamber concentrations ranged from 0 to 60 ppm and were monitored continuously with infrared spectrophotometers to 1 ppm and at 2-hr intervals to 20 ppb with a high performance liquid chromatograph equipped with a fluorescence detector. Other operational parameters monitored on a continuous basis included chamber temperature (20-27 degrees C), relative humidity (31-64%), static (transmural) pressure (-0.3 in.), and flow (300-500 L/min). The computer-assistance system interfaced with the inhalation exposure laboratory is described in detail, including the analytical instrumentation calibration system used throughout this investigation.

  7. THE ROTATIONAL SPECTRUM OF THE UREA\\cdot\\cdot\\cdotISOCYANIC ACID COMPLEX

    Science.gov (United States)

    Mullaney, John C.; Medcraft, Chris; Walker, Nick; Legon, Anthony; Lewis-Borrell, Luke; Golding, Bernard T.

    2016-06-01

    A dimer of urea and isocyanic acid has been generated and observed in the gas phase. The complex was generated by laser vaporisation of a rod target containing urea and copper in a 1:1 ratio, then cooled in a supersonic expansion. Six isotopologues of the complex have been characterised using a chirped pulse Fourier-transform microwave spectrometer in the frequency range 6.5-18.5 GHz. The spectra have been fitted to the Hamiltonian for an asymmetric rotor using PGOPHER. Data obtained from the 13C and 15N isotopologues confirms that all nitrogen atoms are close to the a intertial axis while the carbon atoms are not. A tentative structure will be presented.

  8. 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.

  9. Phase Transition and Thermal Decomposition of Silver Isocyanate (AgNCO)

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, C.; Dinnebier, R; Jansen, M

    2009-01-01

    The thermal behavior of AgNCO (silver isocyanate) has been studied via thermal analysis, optical spectroscopy, X-ray powder diffraction and transmission electron microscopy. Upon quenching the high temperature polymorph (HT-AgNCO) to room temperature, a new modification has been obtained (q-AgNCO). Its crystal structure was solved from X-ray powder diffraction data and refined by the Rietveld method (Pmmn (no. 59), a = 3.579(3) A, b = 5.777(4) A, c = 5.807(2) A, V = 120.08(3) A3, Z = 2, T = 295 K). The structure consists of chains of Ag+ ions bridged by isocyanate units. HT-AgNCO exists between T = 135 C and the melting/decomposition point and exhibits virtually free rotation of the complex anions. According to preliminary single-crystal studies, HT-AgNCO (C2/m, a = 5.87 A, b = 3.51 A, c = 5.81 A, B = 105.953 degrees, Z = 2, T = 373 K) is structurally related to ?-NaN3. The crystal structures of both, HT-AgNCO and q-AgNCO have been compared with that of the room temperature modification (RT-AgNCO). The thermal behavior and the ionic conductivity of AgNCO are discussed with respect to the related compounds AgN3 and KSCN. Decomposition of AgNCO proceeds in distinct steps, as seen from TGA, and results in the formation of nanoparticles of elemental silver and an amorphous polymer consisting of C, N and O, only.

  10. A case of isocyanate-induced asthma possibly complicated by food allergy after peanut consumption: a case report

    Directory of Open Access Journals (Sweden)

    Xhixha Fatmira

    2008-11-01

    Full Text Available Abstract Background Isocyanates are extensively used in the manufacture of polyurethane foams, plastics, coatings or adhesives. They are a major cause of occupational asthma in a proportion of exposed workers. Recent findings in animal models have demonstrated that isocyanate-induced asthma does not always represent an IgE-mediated sensitization, but still a mixed profile of CD4+ Th1 and TH2, as well as a CD8+ immune response. Despite immunologic similarities between this pathology and IgE-mediated food allergies, this co-morbidity is rarely reported. Case presentation A 50-year old man employed as vehicle body painter, for 8 years complained about breathlessness, wheezing, sneezing, nasal obstruction and excessive production of mucus during the use of DuPont Refinish Centari Tintings – an acrylic enamel tint. Symptoms occurred 15–20 minutes after workplace exposure and usually persisted until evening, or at times, up to two consecutive days. The above mentioned symptoms were associated with a decrease of lung functions parameters. The use of inhaled adrenergic bronchio-dilatators and steroids relived the symptoms. In addition, three years ago he developed an anaphylactic reaction due to peanut consumption, experiencing urticaria, angioedema and airway obstruction. He was successfully treated in the hospital. Later, the subject exhibited labial itching, as well as orbital and perioral angioedema, 20 minutes after stationary performance of challenge test with peanuts. Evaluating the reported data, this process might be developed rather due to induction of a TH2 profile, because in both cases have occurred IgE-mediated symptoms. A less plausible mechanism could be the presence of isocyanates in peanuts due to a probable contamination by pesticides resulting in an allergic reaction after "consumption" of di-isocyanate as long as the isocyanate contamination of peanuts has not been proven. Conclusion Despite the lack of relevant laboratory

  11. Activation of dinitrogen-derived hafnium nitrides for nucleophilic N-C bond formation with a terminal isocyanate.

    Science.gov (United States)

    Semproni, Scott P; Chirik, Paul J

    2013-12-02

    Better by Hf: Anion coordination to a bridging hafnocene nitride complex, prepared from CO-induced N2 cleavage, increases the nucleophilicity of the nitrogen atom, thus promoting additional NC bond formation with a typically inert terminal isocyanate ligand. This cascade sequence allows synthesis of otherwise challenging mono-substituted ureas using N2 , CO, and an appropriate electrophile. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Biological effects of short-term, high-concentration exposure to methyl isocyanate. I. Study objectives and inhalation exposure design.

    OpenAIRE

    Dodd, D E; Frank, F R; Fowler, E H; Troup, C M; Milton, R M

    1987-01-01

    Early reports from India indicated that humans were dying within minutes to a few hours from exposure to methyl isocyanate (MIC). Attempts to explain the cause(s) of these rapid mortalities is where Union Carbide Corporation concentrated its post-Bhopal toxicologic investigations. The MIC studies involving rats and guinea pigs focused primarily on the consequences of acute pulmonary damage. All MIC inhalation exposures were acute, of short duration (mainly 15 min), and high in concentration (...

  13. Functional evidence of persistent airway obstruction in rats following a two-hour inhalation exposure to methyl isocyanate

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, M.A.; Fitzgerald, S.; Menache, M.G.; Costa, D.L.; Bucher, J.R.

    1987-06-01

    Pulmonary function was assessed in male, F344 rats 1,2,4,7 and 13 weeks after a single 2-hr exposure to 0, 3, 10, or 30 ppm methyl isocyanate. No significant changes were observed in the rats exposed to 3 ppm through 13 weeks. Diffusing capacity (DL/sub co/), quasistatic lung compliance, and homogeneity of ventilation, as determined by multibreath nitrogen washout, were depressed in the rats exposed to 10 and 30 ppm by 1 week after exposure. None of the rats exposed to 30 ppm survived beyond 1 week. By 13 weeks, dramatic increases in lung volumes were observed in the rats exposed to 10 ppm, while DL/sub co/ and lung compliance were only mildly affected. However, volume-specific DL/sub co/ and compliance were depressed in the rats exposed to 10 ppm, suggesting that lung hyperinflation or other compensatory means of increasing lung size occurred in response to the methyl isocyanate-induced lung lesion. This group also exhibited increased expiratory times during tidal breathing and severely impaired distribution of ventilated air. Collectively, these results suggest the development and likely progression of a severe, obstructive airway lesion with associated gas trapping, and the existence of a pronounced concentration-response relationship between 3 and 10 ppm methyl isocyanate exposures.

  14. Acid-promoted chemoselective introduction of amide functionality onto aromatic compounds mediated by an isocyanate cation generated from carbamate.

    Science.gov (United States)

    Sumita, Akinari; Kurouchi, Hiroaki; Otani, Yuko; Ohwada, Tomohiko

    2014-10-01

    Carbamates have been used as precursors of isocyanates, but heating in the presence of strong acids is required because cleavage of the C-O bond in carbamates is energy-demanding even in acid media. Direct amidation of aromatic compounds by isocyanate cations generated at room temperature from carbamoyl salicylates in trifluoromethanesulfonic acid (TfOH) was examined. Carbamates with ortho-salicylate as an ether group (carbamoyl salicylates) showed dramatically accelerated O-C bond dissociation in TfOH, which resulted in facile generation of the isocyanate cation. These chemoselective intermolecular aromatic amidation reactions proceeded even at room temperature and showed good compatibility with other electrophilic functionalities and high discrimination between N-monosubstituted carbamate and N,N-disubstituted carbamate. The reaction rates of secondary and tertiary amide formation were markedly different, and this difference was utilized to achieve successive (tandem) amidation reactions of molecules with an N-monosubstituted carbamate and an N,N-disubstituted carbamate with two kinds of aromatic compounds. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Protonation switching to the least-basic heteroatom of carbamate through cationic hydrogen bonding promotes the formation of isocyanate cations.

    Science.gov (United States)

    Kurouchi, Hiroaki; Sumita, Akinari; Otani, Yuko; Ohwada, Tomohiko

    2014-07-07

    We found that phenethylcarbamates that bear ortho-salicylate as an ether group (carbamoyl salicylates) dramatically accelerate OC bond dissociation in strong acid to facilitate generation of isocyanate cation (N-protonated isocyanates), which undergo subsequent intramolecular aromatic electrophilic cyclization to give dihydroisoquinolones. To generate isocyanate cations from carbamates in acidic media as electrophiles for aromatic substitution, protonation at the ether oxygen, the least basic heteroatom, is essential to promote CO bond cleavage. However, the carbonyl oxygen of carbamates, the most basic site, is protonated exclusively in strong acids. We found that the protonation site can be shifted to an alternative basic atom by linking methyl salicylate to the ether oxygen of carbamate. The methyl ester oxygen ortho to the phenolic (ether) oxygen of salicylate is as basic as the carbamate carbonyl oxygen, and we found that monoprotonation at the methyl ester oxygen in strong acid resulted in the formation of an intramolecular cationic hydrogen bond (>CO(+) H⋅⋅⋅Ocarbamate afforded a rather stable dication, which did not readily undergo CO bond dissociation. This is an unprecedented and unknown case in which the monocation has greater reactivity than the dication. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Organic-rich hybrid O/I systems based on isocyanate chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Cuney, S. [INSA, Villeurbanne (France). Lab. des Materiaux Macromoleculaires]|[BSN, Givors (France); Gerard, J.F.; Pascault, J.P.Vigier, G. [INSA, Villeurbanne (France)

    1996-12-31

    The isocyanate chemistry has been used to prepare, without adding any solvent, organic-rich hybrid O/I systems, {alpha}-{omega} hydroxy-terminated prepolymers (soft segments, denoted SS) can be end-capped with {gamma}-isocyanato propyl triethoxy silane ({gamma}-IPS), or previously reacted with a diisocyanate (DI) and then end-capped with {gamma}-amino propyl triethoxy silane ({gamma}-APS), or with {gamma}-amino propyl methyl diethoxy silane ({gamma}-APMDES). With this second pathway, a double distribution of molecules is present. The aim of this work is to investigate the morphologies and structural properties of different organic-rich hybrid organic/inorganic materials. Two types of {alpha}-{Omega} hydroxy prepolymers have been used: hydrogenated polybutadiene, HPBD, and polycaprolactone, PCL. The inorganic phase is obtained through the hydrolysis and condensation of the silane groups under acidic conditions and with [H{sub 2}O]/Si = 3. The nanometric silica-rich particles in the final morphologies, after a post-cure at 150 C, were also studied by means of SAXS measurements. Viscoelastic measurements show one or two main relaxation peaks depending on the phase separation process during reaction and the polarity of the initial SS. However for full crosslinked SS/{gamma}-IPS hybrid networks, the relaxed modulus does not depend on SS nature and it is well described by the affine network theory.

  17. Isocyanate-Functionalized Chitin and Chitosan as Gelling Agents of Castor Oil

    Directory of Open Access Journals (Sweden)

    José M. Franco

    2013-06-01

    Full Text Available 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.

  18. Structure-property-glass transition relationships in non-isocyanate polyurethanes investigated by dynamic nanoindentation

    Science.gov (United States)

    Weyand, Stephan; Blattmann, Hannes; Schimpf, Vitalij; Mülhaupt, Rolf; Schwaiger, Ruth

    2016-07-01

    Newly developed green-chemistry approaches towards the synthesis of non-isocyanate polyurethane (NIPU) systems represent a promising alternative to polyurethanes (PU) eliminating the need for harmful ingredients. A series of NIPU systems were studied using different nanoindentation techniques in order to understand the influence of molecular parameters on the mechanical behavior. Nanoindentation revealed a unique characteristic feature of those materials, i.e. stiffening with increasing deformation. It is argued that the origin of this observed stiffening is a consequence of the thermodynamic state of the polymer network, the molecular characteristics of the chemical building blocks and resulting anisotropic elastic response of the network structure. Flat-punch nanoindentation was applied in order to characterize the constitutive viscoelastic nature of the materials. The complex modulus shows distinct changes as a function of the NIPU network topology illustrating the influence of the chemical building blocks. The reproducibility of the data indicates that the materials are homogeneous over the volumes sampled by nanoindentation. Our study demonstrates that nanoindentation is very well-suited to investigate the molecular characteristics of NIPU materials that cannot be quantified in conventional experiments. Moreover, the technique provides insight into the functional significance of complex molecular architectures thereby supporting the development of NIPU materials with tailored properties.

  19. Isocyanate exposure assessment combining industrial hygiene methods with biomonitoring for end users of orthopedic casting products.

    Science.gov (United States)

    Pearson, Ronald L; Logan, Perry W; Kore, Anita M; Strom, Constance M; Brosseau, Lisa M; Kingston, Richard L

    2013-07-01

    Previous studies have suggested a potential risk to healthcare workers applying isocyanate-containing casts, but the authors reached their conclusions based on immunological or clinical pulmonology test results alone. We designed a study to assess potential exposure to methylene diphenyl diisocyanate (MDI) among medical personnel applying orthopedic casts using two different application methods. Air, dermal, surface, and glove permeation sampling methods were combined with urinary biomonitoring to assess the overall risk of occupational asthma to workers handling these materials. No MDI was detected in any of the personal and area air samples obtained. No glove permeation of MDI was detected. A small proportion of surface (3/45) and dermal wipe (1/60) samples were positive for MDI, but were all from inexperienced technicians. Urinary metabolites of MDI [methylenedianiline (MDA)] were detected in three of six study participants prior to both a 'dry' and 'wet' application method, five of six after the dry method, and three of six after the wet method. All MDA results were below levels noted in worker or general populations. Our conclusion is that the risk of MDI exposure is small, but unquantifiable. Because there is some potential risk of dermal exposure, medical personnel are instructed to wear a minimum of 5-mil-thick (5 mil = 0.005 inches) nitrile gloves and avoid contact to unprotected skin. This could include gauntlets, long sleeves, and/or a laboratory coat.

  20. 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.

  1. 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.

  2. 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.

  3. Study on the Synthetic Technology of Isocyanate Prepolymer%异氰酸酯预聚体合成工艺的研究

    Institute of Scientific and Technical Information of China (English)

    张文瑾; 王颖倩; 苏雨; 岳智帅; 廖有为

    2016-01-01

    采用H12MDI和IPDI为异氰酸酯单体,聚四氢呋喃为聚醚多元醇,醋酸丁酯为溶剂,配制成异氰酸酯预聚体。讨论了反应原材料、反应温度以及溶剂含水量对反应过程和异氰酸酯预聚体性能的影响。分析了原材料配比与异氰酸酯基含量(—NCO%)和体系黏度的关系,最终确定了异氰酸酯预聚体的最佳合成工艺条件。%An isocyanate prepolymer was prepared by using the H12MDI and IPDI as isocyanate monomers, polytetrahydrofuran as polyether polyol and butyl acetate as solvent. The influences of reaction raw materials, reaction temperature and water content of solvent on the reaction process and properties of isocyanate prepolymer were discussed. The relationship among the ratio of raw materials,isocyanate group content and system viscosity was analyzed,and finally the optimum synthetic conditions of isocyanate prepolymer were determined.

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

    Science.gov (United States)

    Jathar, Shantanu H.; Heppding, Christopher; Link, Michael F.; Farmer, Delphine K.; Akherati, Ali; Kleeman, Michael J.; de Gouw, Joost A.; Veres, Patrick R.; Roberts, James M.

    2017-07-01

    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 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 burning) and wintertime

  5. Biological effects of short-term, high-concentration exposure to methyl isocyanate. II. Blood chemistry and hematologic evaluations.

    OpenAIRE

    Troup, C M; Dodd, D E; Fowler, E H; Frank, F R

    1987-01-01

    Human, rat, and guinea pig packed erythrocytes exposed to 100, 500, or 1000 ppm of methyl isocyanate (MIC) vapor in vitro showed a concentration-related inhibition of cholinesterase (ChE) activity. Rat and guinea pig packed erythrocytes showed an almost complete inhibition of ChE activity at 2000 ppm. In vitro exposures of human and guinea pig blood to 1000 or 2000 ppm of MIC vapor resulted in qualitative alterations in the electrophoretic mobility of hemoglobin (Hb) as measured by citrated a...

  6. Investigation Of The Hydrolysis Of Isocyanic Acid In Urea SCR: Catalyst Screening And Low-Temperature Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Piazzesi, G.; Elsener, M.; Kroecher, O.; Wokaun, A.

    2005-03-01

    Several oxide catalysts were tested for the hydrolysis of isocyanic acid under typical diesel exhaust conditions. Among the tested catalysts, TiO{sub 2} and ZrO{sub 2} have been shown to be the most active catalysts. The kinetics of the HNCO hydrolysis over TiO{sub 2} at low temperatures was studied and reaction orders and the activation energy were determined. The effect of NO{sub 2} on the catalytic activity of TiO{sub 2} was also investigated, revealing that, at low temperatures, the formation of ammonium nitrate inhibits the reaction. (author)

  7. Metathesis of carbon dioxide and phenyl isocyanate catalysed by group(IV) metal alkoxides: An experimental and computational study

    Indian Academy of Sciences (India)

    Akshai Kumar; Ashoka G Samuelson

    2011-01-01

    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. The intermediate metallacycle extrudes a new heterocumulene, different from the two that have inserted leading to metathesis. As the reaction is reversible, catalytic metathesis is feasible. In stoichiometric reactions heterocumulene insertion, metathesis and metathesis cum insertion products are observed. However, catalytic amounts of the metal alkoxide primarily led to metathesis products. It is shown that zirconium alkoxides promote catalytic metathesis (isocyanates, carbon dioxide) more efficiently than the corresponding titanium alkoxide. The difference in the metathetic activity of these alkoxides has been explained by a computational study using model complexes Ti(OMe)4 (1bTi) and Zr(OMe)4 (1bZr). The computation was carried out at the B3LYP/LANL2DZ level of theory.

  8. Tris-[8]annulenyl Isocyanurate Trianion Triradical and Hexa-anion from the Alkali Metal Reduction of [8]Annulenyl Isocyanate.

    Science.gov (United States)

    Peters, Steven J; Klen, Joseph R

    2015-06-05

    The solution phase alkali metal reduction of [8]annulenyl isocyanate (C8H7NCO) yields an EPR spectrum, which reveals electron couplings to seven protons and only one nitrogen. Although this strongly suggested that the C8H7NCO anion radical was generated, experiments on the oxidized product reveal the actual reduced species to be tris-[8]annulenyl isocyanurate. Unlike the previously studied phenyl isocyanurate anion radical, the unpaired electron(s) is now localized within an [8]annulenyl moiety. Further exposure to metal results in the formation of an equilibrium mixture of trianion triradical and trianion radical species. The cyclotrimerization to form the isocyanurate is proposed to be driven by a reactive C8H7NCO dianion, which is produced from the large equilibrium disproportionation of the anion radical. Exhaustive reduction of the tris-[8]annulenyl isocyanurate with potassium in THF generates the first-ever observed hexa-anion of an isocyanurate. NMR analysis reveals that the polarity of the carbonyl bonds within this hexa-anion is augmented and is caused by the close proximity of K(+) ions, which are tightly ion paired to the three [8]annulenyl dianion rings. These preliminary studies on the reduction of C8H7NCO suggest that polymeric materials (e.g., polyisocyanates) made from this isocyanate might exhibit unique properties.

  9. 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

  10. Ferrocenoyl piperazide as derivatizing agent for the analysis of isocyanates and related compounds using liquid chromatography/electrochemistry/mass spectrometry (LC/EC/MS)

    NARCIS (Netherlands)

    Seiwert, Bettina; Henneken, Hartmut; Karst, Uwe

    2004-01-01

    Ferrocenoyl piperazide is introduced as a new pre-column derivatizing agent for the analysis of various isocyanates in air samples using reversed-phase liquid chromatographic separation, electrochemical oxidation/ionization, and mass spectrometry. The nonpolar derivatives can be separated well using

  11. Ferrocenoyl piperazide as derivatizing agent for the analysis of isocyanates and related compounds using liquid chromatography/electrochemistry/mass spectrometry (LC/EC/MS)

    NARCIS (Netherlands)

    Seiwert, Bettina; Seiwert, B.; Henneken, H.; Karst, U.

    2004-01-01

    Ferrocenoyl piperazide is introduced as a new pre-column derivatizing agent for the analysis of various isocyanates in air samples using reversed-phase liquid chromatographic separation, electrochemical oxidation/ionization, and mass spectrometry. The nonpolar derivatives can be separated well using

  12. Respiratory tract changes in guinea pigs, rats, and mice following a single six-hour exposure to methyl isocyanate vapor.

    OpenAIRE

    Fowler, E H; Dodd, D E

    1987-01-01

    Groups of male and female Fischer 344 rats, B6C3F1 mice, and Hartley guinea pigs were exposed once for 6 hr to mean concentrations of 10.5, 5.4, 2.4, 1.0, or 0 (control) ppm of methyl isocyanate (MIC) vapor. Rats and mice were also exposed to 20.4 ppm of MIC. The majority of deaths occurred during postexposure days 1 through 3. The 6-hr LC50 values (with 95% confidence limits) were 6.1 (4.6 to 8.2) ppm for rats, 12.2 (8.4 to 17.5) ppm for mice, and 5.4 (4.4 to 6.7) ppm for guinea pigs. Notabl...

  13. A multi-dimensional microcanonical Monte Carlo study of S0→T1 intersystem crossing of isocyanic acid

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    A general formula for the multi-dimensional Monte Carlo microcanonical nonadiabatic rate constant expressed in configuration space is applied to calculate the rate of intersystem crossing(ISC) between the ground(S0) and first excited triplet(T1) states for isocyanic acid.One-,two-and three-dimensional potential energy surfaces are constructed by coupled-cluster single-double CCSD calculations,which are used for Monte Carlo sampling.The calculated S0→T1 ISC rate is in good agreement with experimental findings,which gives us a reason to believe that the multi-dimensional Monte Carlo microcanonical nonadiabatic rate theory is a very effective method for calculating nonadiabatic transition rate of a polyatomic molecule.

  14. A multi-dimensional microcanonical Monte Carlo study of S_0→T_1 intersystem crossing of isocyanic acid

    Institute of Scientific and Technical Information of China (English)

    ZHANG Feng; FANG WeiHai; LUO Yi; LIU RuoZhuang

    2009-01-01

    A general formula for the multi-dimensional Monte Carlo microcanonical nonadiabatic rate constant expressed in configuration space is applied to calculate the rate of intersystem crossing (ISC) between the ground (S_0) and first excited triplet (T_1) states for isocyanic acid.One-,two-and three-dimensional potential energy surfaces are constructed by coupled-cluster single-double CCSD calculations,which are used for Monte Carlo sampling.The calculated S_0→T_1 ISC rate is in good agreement with experimental findings,which gives us a reason to believe that the multi-dimensional Monte Carlo microcanonical nonadiabatic rate theory is a very effective method for calculating nonadiabatic transition rate of a polyatomic molecule.

  15. Effect of dosage of expandable graphite, dimethyl methylphosphonate, triethanolamine, and isocyanate on fluidity, mechanical, and flame retardant properties of polyurethane materials in coal reinforcement

    Institute of Scientific and Technical Information of China (English)

    Hu Xiangming; Wang Deming; Cheng Weimin

    2016-01-01

    In this study, orthogonal experiments were conducted to investigate the influence of expandable graphite (EG), dimethyl methylphosphonate (DMMP), triethanolamine (TEA), and isocyanate content on the com-pressive and bonding strengths, oxygen index, and fluidity of rigid polyurethane foam (RPUF). The results revealed that EG significantly increased the oxygen index of RPUF, enlarged the diameter of foam cells, and decreased the cell-closed content in foam;thus, leading to a pressure drop in RPUF. However, exces-sive EG was capable of reducing the fluidity of polyurethane slurry. TEA exhibited significant influence on the compressive strength of RPUF, which dropped initially, and then increased. DMMP had a remarkable effect on the flame retardant property and compressive strength of RPUF. Compressive strength of RPUF initially displayed an increase followed by a decrease with increasing dosage of DMMP, and achieved the maximum value at DMMP dosage of 4%. DMMP could effectively reduce the diameter of RPUF cells lead-ing to an increase in the percentage of close area in foam. DMMP displayed the flame-retardation effects mainly in the gas phase leading to a significant enhancement in the oxygen index of RPUF. Moreover, the compressive strength and bonding strength of RPUF decrease significantly with the increase of isocyanate content due to the increased blowing efficiency by the CO2. The oxygen index and flowing length of foam increased with the increase in isocyanate dosage.

  16. Structural and spectroscopic characterization of methyl isocyanate, methyl cyanate, methyl fulminate, and acetonitrile N-oxide using highly correlated ab initio methods

    Science.gov (United States)

    Dalbouha, S.; Senent, M. L.; Komiha, N.; Domínguez-Gómez, R.

    2016-09-01

    Various astrophysical relevant molecules obeying the empirical formula C2H3NO are characterized using explicitly correlated coupled cluster methods (CCSD(T)-F12). Rotational and rovibrational parameters are provided for four isomers: methyl isocyanate (CH3NCO), methyl cyanate (CH3OCN), methyl fulminate (CH3ONC), and acetonitrile N-oxide (CH3CNO). A CH3CON transition state is inspected. A variational procedure is employed to explore the far infrared region because some species present non-rigidity. Second order perturbation theory is used for the determination of anharmonic frequencies, rovibrational constants, and to predict Fermi resonances. Three species, methyl cyanate, methyl fulminate, and CH3CON, show a unique methyl torsion hindered by energy barriers. In methyl isocyanate, the methyl group barrier is so low that the internal top can be considered a free rotor. On the other hand, acetonitrile N-oxide presents a linear skeleton, C3v symmetry, and free internal rotation. Its equilibrium geometry depends strongly on electron correlation. The remaining isomers present a bend skeleton. Divergences between theoretical rotational constants and previous parameters fitted from observed lines for methyl isocyanate are discussed on the basis of the relevant rovibrational interaction and the quasi-linearity of the molecular skeleton.

  17. Increased micronucleus frequency in peripheral blood lymphocytes contributes to cancer risk in the methyl isocyanate-affected population of Bhopal.

    Science.gov (United States)

    Senthilkumar, Chinnu Sugavanam; Akhter, Sameena; Malla, Tahir Mohiuddin; Sah, Nand Kishore; Ganesh, Narayanan

    2015-01-01

    The Bhopal gas tragedy involving methyl isocyanate (MIC) is one of the most horrific industrial accidents in recent decades. We investigated the genotoxic effects of MIC in long-term survivors and their offspring born after the 1984 occurrence. There are a few cytogenetic reports showing genetic damage in the MIC-exposed survivors, but there is no information about the associated cancer risk. The same is true about offspring. For the first time, we here assessed the micronucleus (MN) frequency using cytokinesis-blocked micronucleus (CBMN) assay to predict cancer risk in the MIC-affected population of Bhopal. A total of 92 healthy volunteers (46 MIC- affected and 46 controls) from Bhopal and various regions of India were studied taking gender and age into consideration. Binucleated lymphocytes with micronuclei (BNMN), total number of micronuclei in lymphocytes (MNL), and nuclear division index (NDI) frequencies and their relationship to age, gender and several lifestyle variabilities (smoking, alcohol consumption and tobacco-chewing) were investigated. Our observations showed relatively higher BNMN and MNL (Pexposure to MIC. Briefly, the observed cytogenetic damage to the MIC-affected could contribute to cancer risk, especially in the EF and FOE.

  18. Polyurethane-Keratin Membranes: Structural Changes by Isocyanate and pH, and the Repercussion on Cr(VI Removal

    Directory of Open Access Journals (Sweden)

    María D. Manrique-Juárez

    2013-01-01

    Full Text Available Keratin has the capacity to interact with metal ions. In order to take advantage of this potential, a novel membrane with polyurethane and keratin has been developed and studied for removal of Cr(VI from aqueous solution. Physicochemical and morphological properties of these hybrid membranes were studied, varying synthesis parameters such as the type of isocyanate and pH in keratin solution. The effects of using diphenyl-methane-diisocyanate or toluene-diisocyanate and modifying the pH in keratin solutions were evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy, and dynamical mechanical analysis. Results show that pH has a strong influence on morphology and on Cr(VI removal efficiency. When pH in keratin solution is low (2.5, the protein separates from water, and a more closed cell in the membrane is obtained affecting its mechanical properties. The removal efficiency of Cr(VI was also assessed at different pH values of chromium solutions. These results show that when pH of the Cr solution is acidic (at 1.5, the Cr(VI removal percentages increase significantly, reaching up to a 58%. Thus this paper demonstrates the successful combination of synthetic and natural polymers depending on the process parameters to be applied in the critical purpose of remediation of Cr(VI contamination.

  19. Interstellar Detection of Methyl Isocyanate CH$_3$NCO in Sgr B2(N): A Link from Molecular Clouds to Comets

    CERN Document Server

    Halfen, DeWayne T; Ziurys, Lucy M

    2015-01-01

    A new interstellar molecule, CH$_3$NCO (methyl isocyanate), has been detected using the 12 m telescope of the Arizona Radio Observatory (ARO). CH$_3$NCO was identified in spectra covering 48 GHz (68-116 GHz) in the 3 mm segment of a broadband survey of Sgr B2(N). Thirty very favorable rotational lines (K$_a$ = 0 and K$_a$ = 1 only; E$_u$ < 60 K) originating in five consecutive transitions (J = 8 $\\rightarrow$ 7, 9 $\\rightarrow$ 8, 10 $\\rightarrow$ 9, 11 $\\rightarrow$ 10, and 12 $\\rightarrow$ 11) in both the A and E internal rotation species are present in this frequency range. Emission was observed at all of the predicted frequencies, with seventeen lines appearing as distinct, uncontaminated spectral features, clearly showing the classic a-type, asymmetric top pattern, with T$_R$* ~ 20-70 mK. The CH$_3$NCO spectra also appear to exhibit two velocities components near V$_{LSR}$ ~ 62 and 73 km s$^{-1}$, both with $\\Delta$V$_{1/2}$ ~ 10 km s$^{-1}$ - typical of molecules such as CH$_2$CHCN, HNCO, and HCOOCH$...

  20. Biological effects of short-term, high-concentration exposure to methyl isocyanate. I. Study objectives and inhalation exposure design

    Energy Technology Data Exchange (ETDEWEB)

    Dodd, D.E.; Frank, F.R.; Fowler, E.H.; Troup, C.M.; Milton, R.M.

    1987-06-01

    Early reports from India indicated that humans were dying within minutes to a few hours from exposure to methyl isocyanate (MIC). Attempts to explain the cause(s) of these rapid mortalities is where Union Carbide Corporation concentrated its post-Bhopal toxicologic investigations. The MIC studies involving rats and guinea pigs focused primarily on the consequences of acute pulmonary damage. All MIC inhalation exposures were acute, of short duration (mainly 15 min), and high in concentration. MIC vapors were statically generated in a double chamber exposure design. Precautionary measures taken during exposures are discussed. Guinea pigs were more susceptible than rats to MIC exposure-related early mortality. A greater than one order of magnitude difference was observed between an MIC concentration that caused no early mortality in rats (3506 ppm) and an MIC concentration that caused partial (6%) early mortality in guinea pigs (225 ppm) for exposures of 10 to 15 min duration. For both species, the most noteworthy clinical signs during exposure were lacrimation, blepharospasm, and mouth breathing. Fifteen minute LC/sub 50/ tests with 14-day postexposure follow-up were conducted, and the LC/sub 50/ (95% confidence limit) values were 171 (114-256) ppm for rats and 112 (61-204) ppm for guinea pigs. Target exposure concentrations for the toxicologic investigations of MIC-induced early mortality were established. A short summary of pertinent results of Union Carbide Corporation's post-Bhopal toxicologic investigations is presented.

  1. In silico interaction of methyl isocyanate with immune protein responsible for Mycobacterium tuberculosis infection using molecular docking.

    Science.gov (United States)

    Shrivastava, Rahul; Yasir, Mohammad; Tripathi, Manish; Singh, Pushpendra

    2016-01-01

    This article reports in silico analysis of methyl isocyanate (MIC) on different key immune proteins against Mycobacterium tuberculosis. The analysis shows that MIC is released in the Bhopal gas tragedy in 1984, which is highly toxic and extremely hazardous to human health. In this study, we have selected immune proteins to perform molecular docking with the help of Autodock 4.0. Results show that the CD40 ligand and alpha5beta1 integrin have higher inhibition compared to plasminogen activator urokinase, human glutathione synthetase, mitogen-activated protein kinase (P38 MAPK 14), surfactant protein-B, -D (SP-D), and pulmonary SP-D. MIC interacted with His-125, Try-146 residue of CD40 ligand and Ala-149, and Arg-152 residue of alpha5beta1 integrin and affects the proteins functioning by binding on their active sites. These inhibitory conformations were energetically and statistically favored and supported the evidence from wet laboratory experiments reported in the literature. We can conclude that MIC directly or indirectly affects these proteins, which shows that survivals of the disaster suffer from the diseases like tuberculosis infection and lung cancer.

  2. 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.

  3. A New Methodology for Assessing Macromolecular Click Reactions and Its Application to Amine--Tertiary Isocyanate Coupling for Polymer Ligation.

    Science.gov (United States)

    Gody, Guillaume; Roberts, Derrick A; Maschmeyer, Thomas; Perrier, Sébastien

    2016-03-30

    Click reactions have provided access to an array of remarkably complex polymer architectures. However, the term "click" is often applied inaccurately to polymer ligation reactions that fail to respect the criteria that typify a true "click" reaction. With the purpose of providing a universal way to benchmark polymer-polymer coupling efficiency at equimolarity and thus evaluate the fulfilment of click criteria, we report a simple one-pot methodology involving the homodicoupling of α-end-functionalized polymers using a small-molecule bifunctional linker. A combination of SEC analysis and chromatogram deconvolution enables straightforward quantification of the coupling efficiency. We subsequently employ this methodology to evaluate an overlooked candidate for the click reaction family: the addition of primary amines to α-tertiary isocyanates (α-(t)NCO). Using our bifunctional linker coupling strategy, we show that the amine-(t)NCO reaction fulfills the criteria for a polymer-polymer click reaction, achieving rapid, chemoselective, and quantitative coupling at room temperature without generating any byproducts. We demonstrate that amine-(t)NCO coupling is faster and more efficient than the more common amine-tertiary active ester coupling under equivalent conditions. Additionally, we show that the α-(t)NCO end group is unprecedentedly stable in aqueous media. Thus, we propose that the amine-(t)NCO ligation is a powerful new click reaction for efficient macromolecular coupling.

  4. 封端异氰酸酯的制备及其解封研究%Synthesis of blocked isocyanate and study of unblocking reaction

    Institute of Scientific and Technical Information of China (English)

    李建明; 王小妹; 陈为都

    2011-01-01

    The isocyanate terminated prepolymer was blocked with methyl ethyl ketoximel (MEKO),the effect of different blocking percentage on the prepolymer viscosity was studied. The unblocking reaction was characterized by TGA,DSC and TG-IR.Experiment results showed that when the NCO% is less than 0.1% the blocked isocyanate has good stability for overed year. The H1 NMR. analysis showed that the prepolymer was successfully blocked and the unblocking temperature was 105 ℃.The blocked isocyanate was used in PET/VMCPP laminating when mixing with polyether amine,the PET/VMCPP laminate was activate at 110 ℃ for 1 hour,and the peeling strength reached 2.0 N/15mm.%用甲乙酮肟(MEKO)对端NCO预聚体进行封端,考查了不同的封端率对端NCO预聚体黏度的影响.用TGA、DSC、TG-IR等对封端聚氨酯解封过程进行研究.实验结果表明,当封端聚氨酯中残余NCO%低于0.1%时,贮存期可达1年以上.H'NMR分析表明,端异氰酸酯封闭成功.MEKO封端的聚氧酯在105℃解封,与聚醚胺混合后用于PET/VMCPP覆膜,其复合膜在110℃时活化固化1h,T-剥离强度达2.0N/15mm.

  5. p-Tolyl isocyanate derivatization for analysis of CWC-related polar degradation products by mass spectrometry.

    Science.gov (United States)

    Karthikraj, R; Sridhar, L; Murty, M R V S; Raju, N P; Vairamani, M; Prabhakar, S

    2014-08-01

    Most of the precursors and/or degradation products related to the Chemical Weapons Convention (CWC) are polar. Identification of these molecules in environmental samples provides clues regarding the alleged usage and/or synthesis of the parent toxic chemicals. Such polar compounds need to be derivatized in order to analyze them by gas chromatography-mass spectrometry (GC-MS). In this study, we developed a new derivatizing reagent, para-tolyl isocyanate (PTI), for derivatization of polar CWC-related compounds. The PTI reagent selectively derivatizes the -OH and/or-SH functional groups with high efficiency, but does not react with carboxylic acid (-COOH) or phosphonic acid (-(O)P(OH)2) groups. The PTI derivatives of dialkyl aminoethanols, dialkyl aminoethanol-N-oxides, and 3-quinuclidinol were successfully eluted through GC, and their electron ionization (EI) mass spectra were distinct and provided the structure information by which the isomeric compounds can be easily distinguished. We also calculated the GC-retention index values that can be used for further confirmation of the target compounds. All the studied PTI derivatives can be analyzed by EI-MS with direct insertion probe and/or by direct electrospray ionization mass spectrometry (ESI-MS) together with the MS-MS data; both sets of data provide full structure information. The PTI reagent was found to be better in some respects than the conventional bistrimethylsilyl trifluoroacetamide (BSTFA), a trimethyl silylating reagent. The PTI reagent is commercially available, and the PTI derivatives are highly stable for months and are not sensitive to moisture. The applicability of the PTI derivatization for trace-level determination of the target CWC-related polar compounds in environmental matrices and in human plasma samples is also evaluated.

  6. Respiratory tract changes in guinea pigs, rats, and mice following a single six-hour exposure to methyl isocyanate vapor

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, E.H.; Dodd, D.E.

    1987-06-01

    Groups of male and female Fischer 344 rats, B6C3F1 mice, and Hartley guinea pigs were exposed once for 6 hr to mean concentrations of 10.5, 5.4, 2.4, 1.0, or 0 (control) ppm of methyl isocyanate (MIC) vapor. Rats and mice were also exposed to 20.4 ppm of MIC. The majority of deaths occurred during postexposure days 1 through 3. The 6-hr LC/sub 50/ values were 6.1 ppm for rats, 12.2 ppm for mice, and 5.4 ppm for guinea pigs. Notable clinical observations during and immediately following MIC exposure were lacrimation, perinasal/perioral wetness, respiratory difficulty (e.g., mouth breathing), decreased activity, ataxia, and hypothermia. Body weight losses were common in all species following MIC exposures of 2.4 ppm or greater. Microscopic lesions included acute necrosis of the epithelial lining throughout the respiratory tract in animals that died shortly after exposure, coupled with congestion, edema, and inflammation. A microscopic lesion that appeared unique to guinea pigs was bronchiolitis obliterans. Additional microscopic lesions observed in some animals that died or were sacrificed at the end of the study (postexposure day 14) consisted of squamous metaplasia of respiratory epithelium in the nasal cavity, which extended into the larynx, trachea, and in some cases, the bronchi. In addition, epithelial regeneration throughout the tract and submucosal fibroplasia in the trachea, bronchi, and bronchioles were observed, the latter lesion being primarily confined to rodents. Only in guinea pigs were there lesions in the 1.0 ppm group attributed to MIC exposure. In conclusion, guinea pigs were more sensitive to the MIC vapor than were rats, which were in turn more sensitive than mice.

  7. Biological effects of short-term, high-concentration exposure to methyl isocyanate. IV. Influence on the oxygen-binding properties of guinea pig blood.

    OpenAIRE

    Maginniss, L A; Szewczak, J M; Troup, C M

    1987-01-01

    Whole blood oxygen equilibrium curves (O2 ECs), blood buffer lines, and several hematologic properties were determined for adult guinea pigs exposed to 700 ppm methyl isocyanate (MIC) for 15 min. MIC inhalation effected a significant reduction of blood O2 affinity; the half-saturation pressure (P50) at 38 degrees C increased from the control (untreated) level of 22.8 +/- 0.1 mm Hg to values ranging from 28.5 to 43.7 mm Hg for experimental animals. MIC exposure had no apparent influence on O2 ...

  8. Aberrant signature patterns of ATM, γ-H2AX and p53 proteins in the patients exposed to methyl isocyanate diagnosed with gallbladder cancer

    Directory of Open Access Journals (Sweden)

    SURESH K. JATAWA

    2014-08-01

    Full Text Available Cancer of gallbladder is a hidden phenomenon and highly malignant with underprivileged diagnosis and poor survival. Study of cancer patterns amongst victims of Bhopal gas tragedy exposed to methyl isocyanate revealed higher incidence of gallbladder cancer that necessitated a more objective elucidation of the disease at its molecular level. Tissues of 92 cases of gallbladder cancer patients were taken in the study (31 men and 61 women, age range 16–85 years, mean age 45.8±1.50 years. Mutations of ATM, γ-H2AX and p53 were predominantly seen in the methyl isocyanate exposed cohort diagnosed with adenocarcinoma, with 61.4% (43/70, 54.3% (38/70 and 73% (51/70 respectively, involving infiltration into the papillary and mucinous region/cell types of the gallbladder. Out of these, the expression frequency of all the above three genes was higher in moderately differentiated adenocarcinoma in comparison to poorly and well-differentiated ones. The results of the present study support the hypothesis that ATM and p53 mutations provide fundamental genetic signatures influencing tumor behavior across patient subsets and invasiveness of the disease, while γ-H2AX is apparently an ordinary pathway involved in the genesis of tumors.

  9. Advances of Research on the Nonphosgenated Process for Isocyanates%异氰酸酯的非光气工艺

    Institute of Scientific and Technical Information of China (English)

    任天瑞; 汪永生; 李鹏鸽

    2003-01-01

      Isocyanates are important chemicals, widely used in medical and agricultural fields, and they are mostly produced by phosgenation, which, however, has severe environmental disadvantages. This paper reviews non-phosgenation methods for synthesis of isocyanates, including oxidative carbonization, reductive carbonization, CO2 method, dimethylcarbonate method and amide pyrolysis, which are considered as green processes.%  异氰酸酯是一类重要的化合物,在医药和农药等领域有广泛的用途。这类化合物常用的生产工艺是光气法,该工艺路线存在严重的环境缺陷。本文介绍和评价了近年来几种异氰酸酯的非光气合成方法及研究进展,其中两步氧化羰化法、还原羰化法,CO2法和碳酸二甲酯法是较有工业化前景的方法。

  10. 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

  11. Durability of Aqueous Polymer Isocyanate Wood Adhesive%水性异氰酸酯木材胶黏剂耐久性研究

    Institute of Scientific and Technical Information of China (English)

    王淑敏; 时君友

    2015-01-01

    通过红外、热重和压剪强度分析,对水性异氰酸酯( API)木材胶黏剂在加速老化处理1~7个周期( A1~A7)和湿热老化处理1~7个周期( H1~H7)的耐久性进行了研究。红外分析表明:未处理的API胶膜( S)含有大量的异氰酸酯基团,A1~A7的API胶膜中异氰酸酯基团全部消失,H1~H3的API胶膜中仍有异氰酸酯吸收峰存在,但强度减弱, H4~H7的异氰酸酯基团消失。热重分析结果表明:A1~A4胶膜的初期热稳定性优于H1~H4,5~7个周期热稳定性几乎相同。在相同质量损失下,加速老化处理API胶膜更稳定, A1~A7降解活化能不完全相同,即降解速度不同;而H1~H7胶膜的活化能几乎相同。2种处理方法胶合制品的压剪强度随时间延长逐渐降低,加速老化处理到第3个周期压剪强度仅为5.32MPa,湿热老化处理到第5个周期压剪强度降为6.92 MPa,均达不到国家标准。%The durability of aqueous polymer isocyanate ( API) wood adhesive was studied under accelerated aging process for 1-7 cycles (A1-A7) and hydrothermal aging for 1 -7 cycles (H1 -H7) by using Fourier transform infrared spectroscopy ( FT-IR) , thermogravimetric analysis( TGA) , and compressive shear strength analysis. FT-IR analysis showed that the untreated API film( S) contained a considerable amount of isocyanate group, whereas the isocyanate groups of API films for A1 -A7 disappeared. Absorption peaks of isocyanate group of API films for H1 - H3 still existed, but the intensity weakened. The isocyanate groups of API films for H4 -H7 also disappeared. TGA analysis showed that thermal stabilities of A1 -A4 in the initial stage were superior to those of H1-H4, but they were almost the same in the 5-7 cycles. Under the same weight loss, the API films with accelerated aging process were more stable, and the degradation activation energies of A1 -A7 were not exactly the same, namely, the degradation rates were different. However, the activation energies of H1

  12. An evaluation of the respiratory health status of automotive spray-painters exposed to paints containing hexamethylene di-isocyanates in the greater Durban area.

    Science.gov (United States)

    Randolph, B W; Lalloo, U G; Gouws, E; Colvin, M S

    1997-03-01

    A survey of automotive spray-painting establishments was undertaken to evaluate the respiratory health status of spray-painters exposed to paints containing hexamethylene di-isocyanates (HDIs). This was a cross-sectional study. Spray-painting establishments in the Durban municipal area. Spray-painters from a random sample of 40 (25%) of the registered spray-painting establishments were studied. Responses to an Interviewer-administered standardised respiratory health questionnaire and a cross-shift spirometric lung function test were obtained for each spray-painter, questionnaires assessing the firm's compliance with the spray-painting safety requirements were also obtained. The mean cross-shift decrease in forced expiratory volume in 1 second (FEV1) was 130.5 ml (SD 203.19) (P = 0.0002). The lung function data indicated that of the 40 spray-painters examined, 10 (25%) showed clinically significant cross-shift decreases in FEV1, viz, decreases > 250 ml. Only 2 subjects had a diagnosis of asthma. Chronic respiratory symptoms of cough, wheeze and wheeze with breathlessness were similar to those noted in community-based studies. A high proportion had eye irritation (55%) and dermatitis of the hand (32%). The potential determinants of FEV1 were examined in a multiple linear regression analysis and only the isocyanate concentration levels approached statistical significance (P = 0.082), suggesting that other factors such as duration of exposure, spray-paint 'bounce-back' phenomenon, and 'healthy worker' effect may be more important. ('Bounce back' refers to the phenomenon whereby some of the mist from the spray-gun, after striking the surface being painted, is deflected back into the operator's breathing zone in the form of fine droplets or aerosols.) Forty per cent of the 40 spray booths had ventilation standards substantially below that specified in current South African legislation. Only 21 (55%) spray-painters were provided with the regulation respiratory protective

  13. Gas-grain Modeling of Isocyanic Acid (HNCO), Cyanic Acid (HOCN), Fulminic Acid (HCNO), and Isofulminic Acid (HONC) in Assorted Interstellar Environments

    Science.gov (United States)

    Quan, Donghui; Herbst, Eric; Osamura, Yoshihiro; Roueff, Evelyne

    2010-12-01

    Isocyanic acid (HNCO) is a well-known interstellar molecule. Evidence also exists for the presence of two of its metastable isomers in the interstellar medium: HCNO (fulminic acid) and HOCN (cyanic acid). Fulminic acid has been detected toward cold and lukewarm sources, while cyanic acid has been detected both in these sources and in warm sources in the Galactic Center. Gas-phase models can reproduce the abundances of the isomers in cold sources, but overproduce HCNO in the Galactic Center. Here we present a detailed study of a gas-grain model that contains these three isomers, plus a fourth isomer, isofulminic acid (HONC), for four types of sources: hot cores, the warm envelopes of hot cores, lukewarm corinos, and cold cores. The current model is partially able to rationalize the abundances of HNCO, HOCN, and HCNO in cold and warm sources. Predictions for HONC in all environments are also made.

  14. Improved thermal stability of poly(vinyl chloride) by nanoscale layered double hydroxide particles grafted with toluene-2,4-di-isocyanate

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jun [Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Chen Guangming, E-mail: chengm@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Yang Jiping, E-mail: jyang@buaa.edu.cn [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Ding Liping [Beijing National Laboratory for Molecular Sciences (BNLMS), Center for Physiochemical Analysis and Measurement (CPAM), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2009-12-15

    A novel interlamellar surface modification of layered double hydroxides (LDHs) via covalent bonding by toluene-2,4-di-isocyanate (TDI) has been successfully obtained, and poly(vinyl chloride) (PVC)/TDI-modified LDH nanocomposites have been prepared via solution intercalation process. After the interlamellar modification, TDI was grafted to the surface hydroxyl groups of LDHs with nitrate, dodecyl sulfate or stearate anion as counterion anion. The structures of the TDI-modified LDHs and the nanocomposites were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectra, and transmission electron microscopy (TEM) techniques. The enhanced thermal stability of PVC/TDI-modified LDH nanocomposites was confirmed by means of conventional Congo Red test and dynamic thermogravimetric analysis (TGA). In addition, the thermal degradation mechanism was briefly discussed on the basis of the above experimental results.

  15. Facile synthesis of 1,3,4-benzotriazepines and 1-arylamide-1H-indazoles via palladium-catalyzed cyclization of aryl isocyanates and aryl hydrazones under microwave irradiation.

    Science.gov (United States)

    Dong, Chune; Xie, Lingli; Mou, Xiaohong; Zhong, Yashan; Su, Wei

    2010-11-07

    A strategy involving palladium-catalyzed cyclization of halo-phenyl hydrazones and aryl isocyanates provides a convenient approach to the synthesis of 1,3,4-benzotriazepines (4) or 1-arylamide-1H-indazoles (5) in good isolated yields. Microwave irradiation was found to afford high reaction efficiency, while the choice of halophenyl hydrazone had an effect on the pathway of the reaction.

  16. Bioactivation of a dihydropyrazole-1-carboxylic acid-(4-chlorophenyl amide) scaffold to a putative p-chlorophenyl isocyanate in rat liver microsomes and in vivo in rats.

    Science.gov (United States)

    Chen, Hao; Zhang, Yanhua; Edmunds, Jeremy; Bigge, Christopher; Mutlib, Abdul

    2008-05-01

    Compound I (4,5-dihydropyrazole-1,5-dicarboxylic acid-1-[(4-chlorophenyl)-amide] 5-[(2-oxo-2 H-[1,3']bipyridinyl-6'-yl)-amide] was found to undergo metabolic activation in rat liver microsomes in the presence of NADPH. A reactive intermediate, postulated to be p-chlorophenyl isocyanate (CPIC), was trapped by GSH in vitro and characterized by liquid chromatography tandem mass spectrometry (LC/MS/MS). Subsequently, the structure of the GSH conjugate was confirmed by a comparison with a synthetic standard. The GSH conjugate was also found in the bile of rats that received an oral dose (10 mg/kg) of compound I. Further analyses of rat bile and urine using online electrochemical derivatization coupled to LC/MS demonstrated the presence of p-chlorophenyl aniline (CPA), a hydrolytic product of the intermediate isocyanate. This provided further evidence for the potential existence of CPIC. Approximately 7% of the dose was accounted by the products of CPIC, which included the GSH conjugate and CPA excreted in bile and urine. Multiple rat cytochrome P450 enzymes, including P450 1A, P450 2C, and P450 3A, appeared to be responsible for the activation of compound I to CPIC. The activation kinetics of compound I to CPIC in male rat liver microsomes exhibited a biphasic profile, indicative of at least two contributing P450 enzymes. One enzyme showed a small value of K m at 42 microM and a low V max of 66 pmol min (-1) mg (-1), while the other exhibited a large value of K m at 148 microM and a high V max of 1200 pmol min (-1) mg (-1). The formation of a putative CPIC intermediate, a carbamoylating species known to be capable of covalent binding to macromolecules, suggests a potential liability associated with the compound, particularly the dihydropyrazole-1-carboxylic acid-(4-chlorophenyl amide) scaffold, which appears to be responsible for the generation of CPIC. The mechanism of bioactivation to the putative CPIC is postulated to involve an initial P450-mediated hydroxylation of

  17. 异氰酸酯改性纳米粒子的制备方法与应用%The Preparation and Applications of Isocyanates Modified Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    颜爱军; 王雅丽; 李会宁; 曹德榕

    2014-01-01

    综述了异氰酸酯改性纳米粒子的制备方法、分散稳定性及其接枝聚合物形成纳米复合材料的性能特征。概括了经接枝改性后形成的有机/无机杂化纳米复合材料在涂料、生物医疗等领域广泛的应用前景和研究价值,提出了今后纳米复合材料研究的重点和方向。%The preparation methods, advantages, dispersing stability and the performance characteristics of nanocomposites formed by isocyanates modified nanoparticles were reviewed. The organic/inorganic hybrid nano-composite prepared by grafting and modification were proposed,their widespread application prospect and research value in coatings,biomedical and other fields were also summarized,furthermore,the future research orientation and focus of nanocomposites were proposed.

  18. Research progress in preparation of polyimide via isocyanate method%异氰酸酯法制备聚酰亚胺的研究进展

    Institute of Scientific and Technical Information of China (English)

    周成飞

    2015-01-01

    Polyimide is an extremely important high temperature resistant polymer with excellent heat resist-ance and oxidation resistance, and also has excellent physical and mechanical properties, flame retardant proper-ties, dielectric properties, insulation and radiation resistance. In this paper, the preparation of polyimide using iso-cyanate method was summarized, and the applications of the polyimide in foams, nanocomposites, aerogels, aero-gels and membranes were introduced in detail.%聚酰亚胺是一种极其重要的耐高温聚合物,具有优异的耐热性和抗热氧化性能,同时还具有优异的物理机械性能、阻燃性能、介电性能、绝缘性能及耐辐射性能。笔者介绍了利用异氰酸酯来制备聚酰亚胺的方法,并详细介绍了用该法制备聚酰亚胺在泡沫材料、纳米复合材料、气凝胶、膜材料等方面的应用。

  19. Biological effects of short-term, high-concentration exposure to methyl isocyanate. III. Influence on gas exchange in the guinea pig lung

    Energy Technology Data Exchange (ETDEWEB)

    Fedde, M.R.; Dodd, D.E.; Troup, C.M.; Fowler, E.H.

    1987-06-01

    The influence of methyl isocyanate (MIC) inhalation on the gas exchange function of the lungs in guinea pigs was studied by measuring arterial blood gases, pH, and tracheal pressure during constant-volume, artificial ventilation with air or 100% O/sub 2/ at 40 and 120 min after exposure. A 15 min exposure to MIC at concentrations of 240 to 628 ppm caused a marked reduction in PaO/sub 2/ and pH/sub a/ and an elevated tracheal pressure during artificial ventilation. The low PaO/sub 2/ was only slightly elevated when the animals were ventilated with 100% O/sub 2/. Although the dry-wet lung weight ratio was reduced at the highest exposure concentration, the effect was not severe and no significant increase in lung water was found at the lower concentrations. MIC inhalation caused severe pulmonary blood shunting and ventilation/perfusion imbalance. This, in turn, led to hypoxemia, metabolic acidosis, and tissue hypoxia, which could produce death. The pulmonary gas exchange deficit likely resulted from bronchial and bronchiolar obstruction caused by sloughed epithelium and other debris from intra- and extrapulmonary airways.

  20. 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.

  1. Activation of electrophilicity of stable Y-delocalized carbamate cations in intramolecular aromatic substitution reaction: evidence for formation of diprotonated carbamates leading to generation of isocyanates.

    Science.gov (United States)

    Kurouchi, Hiroaki; Kawamoto, Kyoko; Sugimoto, Hiromichi; Nakamura, Satoshi; Otani, Yuko; Ohwada, Tomohiko

    2012-10-19

    Although cations with three heteroatoms, such as monoprotonated guanidine and urea, are stabilized by Y-shaped conjugation and such Y-conjugated cations are sufficiently basic to be further protonated (or protosolvated) to dications in strongly acid media, only O-monoprotonated species have been detected in the case of carbamates even in magic acid. We found that the trifluoromethanesulfonic acid-catalyzed cyclization of arylethylcarbamates proceeds to afford dihydroisoquinolones in high yield. In strong acids, methyl carbamates are fully O-monoprotonated, and these monocations do not undergo cyclization even under heating. But, as the acidity of the reaction medium is further increased, the cyclization reaction of methyl phenethylcarbamates starts to proceed as a first-order reaction, with a linear relationship between rate and acidity. The sign and magnitude of the entropy of activation ΔS(‡) were found to be similar to those of other A(Ac)1 reactions. These results strongly support the idea that further protonation of the O-protonated carbamates is involved in the cyclization, but the concentration of the dications is very low and suggests that the rate-determining step is dissociation of methanol from the diprotonated carbamate to generate protonated isocyanate, which reacts with the aromatic ring. Therefore, O-protonated carbamates are weak bases in sharp contrast to other Y-shaped monocations.

  2. In vivo skin decontamination of methylene bisphenyl isocyanate (MDI): soap and water ineffective compared to polypropylene glycol, polyglycol-based cleanser, and corn oil.

    Science.gov (United States)

    Wester, R C; Hui, X; Landry, T; Maibach, H I

    1999-03-01

    In the home and workplace, decontamination of a chemical from skin is traditionally done with a soap-and-water wash, although some workplaces may have emergency showers. It has been assumed that these procedures are effective, yet workplace illness and even death occur from chemical contamination. Water, or soap and water, may not be the most effective means of skin decontamination, particularly for fat-soluble materials. This study was undertaken to help determine whether there are more effective means of removing methylene bisphenyl isocyanate (MDI), a potent contact sensitizer, from the skin. MDI is an industrial chemical for which skin decontamination, using traditional soap and water and nontraditional polypropylene glycol, a polyglycol-based cleanser (PG-C), and corn oil were all tried in vivo on the rhesus monkey, over 8 h. Water, alone and with soap (5% and 50% soap), were partially effective in the first h after exposure, removing 51-69% of the applied dose. However, decontamination fell to 40-52% at 4 h and 29-46% by 8 h. Thus, the majority of MDI was not removed by the traditional soap-and-water wash; skin tape stripping after washing confirmed that MDI was still on the skin. In contrast, polypropylene glycol, PG-C, and corn oil all removed 68-86% of the MDI in the first h, 74-79% at 4 h, and 72-86% at 8 h. Statistically, polypropylene glycol, PG-C, and corn oil were all better (p soap and water at 4 and 8 h after dose application. These results indicate that a traditional soap-and-water wash and the emergency water shower are relatively ineffective at removing MDI from the skin. More effective decontamination procedures, as shown here, are available. These procedures are consistent with the partial miscibility of MDI in corn oil and polyglycols.

  3. On improving of filter paper water resistance with water based blocked isocyanate%用封端型水性聚氨酯固化剂提高滤纸耐水性的研究

    Institute of Scientific and Technical Information of China (English)

    俞佳; 贺江平; 白蕊

    2012-01-01

    采用甲苯二异氰酸酯( TDI)、聚丙二醇-400( PPG -400)为原料,丙酮为溶剂,亚硫酸氢钠为封端剂,借助外乳化法,合成了一种封端型水性聚氨酯固化剂.将这种固化剂与一定比例的淀粉糊化液混合后,对汽车工业用滤纸进行耐水性能整理.实验结果表明,在一定温度下封端型水性聚氨酯固化剂解封出异氰酸酯基与吸附在滤纸上的淀粉及滤纸自身的羟基反应生成氨基甲酸酯,能够有效地提高滤纸的耐水性;同时也赋予滤纸良好的硬挺度、强度、透气性.合成成本低廉、方法简单.%Using toluene disocyanate (TDI) and polypropylene glycol-400 (PPG-400) as the raw materials and sodium bisulfite as the blocking agent,the water-soluble blocked isocyanate was prepared in acetone by external emulsion method.The mixture of the blocked isocyanate and starch paste in proper proportion was used to carry out the water resistance finishing of the filter paper used in auto industry.The results showed that at a certain temperature the blocked isocyanate deblocked to release the isocyanate groups which were able to react with the hydroxyl groups of starch adsorped on the filter paper and paper itself and form the urethane linkages, which can effectively increase the water resistance of filter paper and give the filter paper with a good stiffness,strength,permeability.Further more,this synthetic method was simple and cost-effective.

  4. 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.

  5. Feasibility of ultra-performance liquid chromatography-ion mobility-time-of-flight mass spectrometry in analyzing oxysterols.

    Science.gov (United States)

    Kylli, Petri; Hankemeier, Thomas; Kostiainen, Risto

    2017-03-03

    Oxysterols are oxygenated cholesterols that are important in many cell functions and they may also be indicative of certain diseases. The purpose of this work was to study the feasibility of ultra-performance liquid chromatography-ion mobility-time-of-flight mass spectrometry (UPLC-IM-TOFMS) using traveling wave cell in analyzing oxysterols and especially their isomers in biological samples. Oxysterols were analyzed as their p-toluenesulfonyl isocyanate derivatives, which improved the separation of isomeric oxysterols by ion mobility and ionization efficiency in the electrospray ionization step. The UPLC-IM-TOFMS method was shown to be fast and to provide good quantitative performance. The feasibility of the method was demonstrated in the analyses of oxysterols in fibroblast cell samples.

  6. Improvement of the Test Method of Isocyanate Group Content in Polyurethane Prepolymer%聚氨酯合成革浆料预聚过程NCO测定方法的改进

    Institute of Scientific and Technical Information of China (English)

    陈建福; 黄慧珍; 林洵

    2012-01-01

    The dimethylformamide-dibutylamine method for testing isocyanate group content in polyurethane prepolymer is developed.The results indicated that the new test method was similar to the traditional method in the accuracy,but had the higher precision.This new method is accurate,simple and effective,and reduces the test cost.%以二甲基甲酰胺作溶剂,采用二正丁胺滴定法测定聚氨酯合成革预聚体中的异氰酸酯基含量,发现用二甲基甲酰胺—二正丁胺法测定值与传统方法相比准确度相差不大,但精确度较高,本方法精确、简便,有效降低了实验成本。

  7. 端胺基非异氰酸酯预聚体嵌段共聚聚醚型聚氨酯%Prepolymers of Amino-terminal Non-isocyanate Block Copolymerized with Polyether-based Polyurethane

    Institute of Scientific and Technical Information of China (English)

    宋赫; 邓新华; 孙元

    2012-01-01

    Modified polyether polyurethane and its film were prepared from prepolymer of amino- terminal non-isocyanate polyurethane and prepolymer of polyether-based polyurethane via block copolymerization. Synthesis condition of non-isocyanate prepolymer was analyzed; The impact of film-forming temperature and value of NCO and NH2 ratio on mechanical properties of membrane were investigated; Mechanical properties of different polyurethane materials were compared; Degree of phase separation was studied using differential scanning calorimetry(DSC). It showed that carbamate group was introduced into the amino-terminal non-isocyanate prepolymer; The best film-forming temperature was 140 ℃; When NCO/NH2 of prepolymer was 1/0. 9, the best performance was obtained, tensile strength of 25.1 MPa, modulus of 100% elongation of 5 MPa. Compared with regular polyurethane, polyurethane block with amino-terminal non-isocyanate polyurethane prepolymer had higher mechanical properties; DSC curves showed two different glass transition temperatures indicating phase separation.%用端胺基非异氰酸酯基聚氨酯预聚体与聚醚型聚氨酯预聚体嵌段共聚制备了改性聚醚型聚氨酯及其膜,分析了端胺基非异氰酸酯基聚氨酯预聚体,考查了聚醚型聚氨脂树脂成膜温度和预聚体的NCO/NH2配比对膜力学性能的影响,同时对比了聚氨酯材料的力学性能,采用差示扫描量热法(DSC)研究了相分离程度。结果表明,合成的端胺基非异氰酸酯基聚氨酯预聚体中成功地引入了氨基甲酸酯基团;最佳成膜温度为140℃;当预聚体的NCO/NH2=1/0.9(摩尔比,下同)时膜的性能最好,拉伸强度为25.1MPa,伸长100%模量为5MPa;与普通聚氨酯相比,端胺基非异氰酸酯基聚氨酯预聚体嵌段的聚氨酯力学性能更高;DSC曲线显示其有2个不同的玻璃化转变温度,相分离明昂。

  8. 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.

  9. Extrinsic Allergic Alveolitis Induced by Suction Isocyanate:A Case Report and Literature Review%吸入异氰酸酯致外源性变应性肺泡炎报告并文献复习

    Institute of Scientific and Technical Information of China (English)

    孙晋渊; 韩锋锋; 黄雁西; 管雯斌; 李惠民; 郭雪君

    2014-01-01

    目的:探讨外源性变应性肺泡炎( extrinsic allergic alveolitis,EAA)的临床特点及诊疗思路。方法回顾分析1例吸入异氰酸酯所致 EAA的诊治经过,并复习相关文献。结果患者表现为反复咳嗽、发热及活动后气促。外院胸部高分辨率 CT( HRCT)检查示双肺弥漫性间质病变,诊断为间质性肺炎,予相应治疗病情无好转。入我科后追问病史,发现有异氰酸酯吸入史。支气管肺泡灌洗液( BALF)细胞分类淋巴细胞增多。转胸外科行右下肺楔形切除术,术后病理检查确诊 EAA。予甲泼尼龙治疗14个月,临床症状及胸部 HRCT 表现均得到明显改善。结论胸部HRCT检查对 EAA的诊断和鉴别诊断有较大价值,肺活组织病理检查是其确诊手段。随着工业发展,临床医师应警惕吸入异氰酸酯等小分子化合物所致 EAA。%Objective To explore the clinical features and treatment of extrinsic allergic alveolitis( EAA). Methods The diagnosis and treatment of one patient with EAA induced by isocyanate suction was reviewed,and the relevant literature was also reviewed. Results The patient suffered chronic cough,fever and accelerated breathing after activities. In other hos-pitals,the chest high-resolution computed tomography( HRCT)showed diffuse interstitial substance pathological changes in hibateral pulmones,and the patient was diagnosed as having interstitial pneumonia,but the patient′s condition did not improve after corresponding treatment. In our department,the patient was found to have a history of isocyanate suction after history en-quiry. Lymphocytosis was found after bronchoalveolar lavage fluid(BALF)cell classification. After the thoracic surgery,right pulmonary wedge resection was performed,and then the diagnosis of EAA was confirmed by postoperative pathological exami-nation. The patient′s manifestations and chest HRCT symptoms significantly improved after methylprednisolone

  10. Optimal designing of phosgene recovery system for 3-chloro-4-methyl phenyl isocyanate process units%3-氯-4-甲基苯基异氰酸酯装置光气回收系统优化设计

    Institute of Scientific and Technical Information of China (English)

    毕荣山; 李明

    2014-01-01

    传统冷凝回收3-氯-4-甲基苯基异氰酸酯(CMPI)生产装置尾气的方法具有以下不足:不能保证光气完全回收,而一旦光气进入尾气破坏系统,不仅会增加产品的成本,而且还会降低系统安全性、增加碱液消耗和废水排放;文献中研究的甲苯二异氰酸酯装置的尾气回收系统,由于反应条件的不同,不能适用于常压CMPI装置。本文以年产2000 t CMPI常压反应装置为例,对其光气回收系统进行了模拟分析和优化设计,确定了满足工艺要求的最佳理论塔板数为12,最佳吸收剂甲苯用量为780 kg/h。对常压装置与高压装置光气回收系统进行了比较,认为常压装置的光气回收系统需要更多的吸收剂用量,但是不需要在塔中增加中间冷却器,并给出了理论上的解释。考虑异氰酸酯生产工艺的共性,本文研究结论可以推广应用于其他类似异氰酸酯装置。%The traditional method of phosgene recovery for 3-chloro-4-methyl phenyl isocyanate (CMPI) equipments has following disadvantages:The phosgene cannot be recovered completely. Once the phosgene goes to the off-gas,there would be some bad consequence such as:the security of system is decrease;the security of system,the cost of production,the consumption of sodium hydroxide and the discharge of waste water are increase. The research in references which studied the phosgene recovery for producing toluene diisocyanate cannot be used in CMPI system for the difference of reactive conditions. An equipment of 2000 t/a for producing CMPI was taken for example,the phosgene recovery system was simulated and optimally designed:Under the condition of meeting the technological requirements,the number of theoretical plates was identified as 12 and the optimal feeding rate was defined as 780 kg/h. We as compared the phosgene recovery systems of normal pressure reactive system and that of high pressure. The results showed that

  11. Synthesis and anticorrosive properties of waterborne isocyanate functionalized graphene/polyurethane nanocomposite emulsion%水性异氰酸酯改性石墨烯/聚氨酯复合乳液防腐性能研究∗

    Institute of Scientific and Technical Information of China (English)

    朱科; 李小瑞; 李菁熠; 费贵强; 王佼

    2016-01-01

    通过逐步聚合反应将异氰酸酯功能化石墨烯(IGN)接枝到水性聚氨酯(WPU)链段中,制备得到水性异氰酸酯改性石墨烯/聚氨酯纳米复合乳液(IGN/WPU).通过傅里叶变换红外的光谱(红外光谱)、原子力显微镜(AFM)、扫描电镜(SEM)对氧化石墨烯(GO)、IGN、WPU 及 IGN/WPU 复合材料的结构进行表征,并研究了IGN含量对复合乳液作为金属防腐涂层性能的影响.结果表明,随IGN含量增加,涂层硬度提高,水蒸气透过率下降,防腐效率增大.当m(IGN)=1%(质量分数)时,涂层硬度达到了2H,水蒸气透过率降低到51.98 g/m2. h,与空白样相比防腐效率提高了94.70%.%Waterborne isocyanate functionalized graphene/polyurethane nanocomposite emulsion has been pre-pared through step by step polymerization reaction,which isocyanate functionalization of graphene is grafted to the water-borne polyurethane chain section.Fourier transform infared spectrometer (FT-IR),atomic force mi-croscope (AFM)and scanning electron microscope (SEM)were used to characterize the structures of GO,IGN, WPU and IGN/WPU;the effect of IGN content on the properties of composite emulsion as metal anti-corrosion coating was systematically studied.The results show that hardness,barrier property to vapor and anticorrosive efficiency of the composite coating increases as IGN content is increasing.When m(IGN)=1wt%,the coating hardness up to 2 h,water vapor transmittance decreased to 51.98 g/(m2 .h),anticorrosive efficiency increased by 94.70% compared with blank sample.

  12. 异氰酸酯指数对蓖麻油聚氨酯胶粘剂性能的影响%Influence of Isocyanate Index on the Properties of Castor Oil Based Polyurethane Adhesive

    Institute of Scientific and Technical Information of China (English)

    贾金荣; 黄志雄; 秦岩; 王富忠; 张慧

    2012-01-01

    A solventless castor oil based polyurethane adhesive was prepared by TDI and castor oil.The structure, damping property and morphology were investigated by FT-IR, DMA and SEM.The influence of isocyanate index (nNCO/nOH) on the damping and adhesion mechanical property and morphology were also examined.The results showed that the adhesive exhibited excellent damping property, the glass transition temperature, damping temperature range and maximum loss factor were - 18.4 ℃,48.3 ℃ and 1.262 when nNCO/nOH was 1.4 in prepolymer. The adhesive with nNCO/nOH 1.6 showed the optimal mechanical property.%以甲苯-2,4-二异氰酸酯(TDI)及蓖麻油为原料制备了一种无溶剂蓖麻油聚氨酯胶粘剂,用FT-IR、DMA及SEM分析了胶粘剂结构、阻尼性能及断口形貌,考察了异氰酸酯指数(nNco/noH)对胶粘剂阻尼、粘接的力学性能及断面形貌的影响.结果表明,当预聚体中nNCO/nOH为1.4时,该胶粘剂阻尼性能优异,玻璃化转变温度Tg为-18.4℃,阻尼温域为48.3℃,(tanδ)max为1.262;胶粘剂的力学性能在nNCO/noH为1.6时达到最佳.

  13. Postpolymerization modification of a hydroxy monolith precursor. Part I. Epoxy alkane and octadecyl isocyanate modified poly (hydroxyethyl methacrylate-co-pentaerythritol triacrylate) monolithic capillary columns for reversed-phase capillary electrochromatography.

    Science.gov (United States)

    Khadka, Shantipriya; El Rassi, Ziad

    2016-12-01

    A novel precursor monolithic capillary column referred to as "hydroxy monolith" or OHM was prepared by the in situ copolymerization of hydroxyethylmethacrylate (HEMA) with pentaerythritol triacrylate (PETA) yielding the neutral poly(HEMA-co-PETA) monolith. The neutral precursor OHM capillary thus obtained was subjected to postpolymerization modifications of the hydroxyl functional groups present on its surface with 1,2-epoxyalkanes catalyzed by boron trifluoride (BF3 ) ultimately providing Epoxy OHM C-m capillary column at varying alkyl chain lengths where m = 8, 12, 14, and 16 for RP-CEC. Also, the same precursor OHM was grafted with octadecyl isocyanate yielding Isocyanato OHM C-18 column to provide an insight into the effect of the nature of the linkage to the surface hydroxyl groups of the OHM precursor. While the epoxide reaction leaves on the surface of the OHM precursor hydroxy-ether linkages, the isocyanato reaction leaves carbamate linkages on the same surface of the OHM precursor. This study revealed that changing the alkyl chain length resulted in changing the column phase ratio (ϕ) and also the solute distribution constant (K). While increasing the surface alkyl chain length increased steeply the solute hydrophobic selectivity, i.e. methylene group selectivity, the nature of the ligand linkage produced different retention for the same solutes and affected the selectivity of slightly polar solutes. The various monoliths proved very useful for RP-CEC of different small solutes at varying polarity over a wide range of mobile phase composition. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. 全生物基非异氰酸酯聚氨酯的制备与性能%Preparation and properties of all-bio-based non-isocyanate polyurethane

    Institute of Scientific and Technical Information of China (English)

    王朝; 张星; 陈佳佳; 母雅丹; 黄兆辉; 周舟; 张立群

    2012-01-01

    Carbonated soybean oil ( CSBO) was prepared by catalytic addition reaction of epoxidized soybean oil and carbon dioxide, then the all-bio-based non-isocyanate polyurethane (NIPU) prepolymers were synthesized with CSBO and 1,10-decanediamine using a ring-opening method. The optimum reaction conditions were investigated, the NIPU elastomer was prepared by directly tabletting according to the conditions, and the properties of NIPU elastomer were studied. The results showed that the best reaction temperature was 120℃ and the best mole ratio of carbonic ester group to amine group was about l:l. The glass transition temperature of NIPU elastomer was about -5℃ and tensile strength was 1. 8 MPa.%通过环氧大豆油与二氧化碳催化加成反应制得五元环碳酸酯,然后与1,10-癸二胺进行开环反应制备了全生物基非异氰酸酯聚氨酯( NIPU)预聚物,考察了预聚反应条件,并根据该条件直接压片制得NIPU弹性体,研究了NIPU弹性体的性能.结果表明,预聚反应最适宜条件为温度120℃、五元环碳酸酯官能团与胺基的摩尔比约1∶1;NIPU弹性体的玻璃化转变温度为-5℃,拉伸强度为1.8 MPa.

  15. 新型非免疫活性的FKBP12配基N308促神经生长和神经损伤保护作用的体外评价%Evaluation of a novel non-immunosuppressive FKBP12 ligand,(3R)-4-(p-Toluenesulfonyl)-1,4-thiazane-3-carboxylic acid-L-Leucine ethyl ester(N308), on neuroregenerative and neuroprotective effects in vitro

    Institute of Scientific and Technical Information of China (English)

    刘洪英; 苏翠玲; 聂爱华; 李松; 王莉莉

    2011-01-01

    Aim To evaluate the neuronregenerative and neuroprotective effects of a novel non-immunosup-pressive FKBP12 ligand, N308, in vitro. Methods Growth of chick embryo dorsal root ganglion ( DRG ) was used to test the neurite growth effects of N308. The neuroprotective effects of N308 were observed by primary culture of midbrain dopaminergic neurons and cerebral cortex neurocytes models damaged by 6-OHDA and Na2S2O4 respectively. Results N308 displayed promoting neurite outgrowth effect in chick embryo DRG culture in vitro in concentration-dependent man-ner from 10 to 1 000 pmol ? L *and the maximal effect was 100 pmol ? L"1. N308 could prevent the midbrain dopaminergic neurons and cerebral cortex neurocytes from 6-OHDA and hypoxia respectively, increase the number of TH positive cells ( P < 0. 05 ) and the survival rate of cortex neurocytes( P < 0. 05 ) . Conclusion N308 definitely has protective and promoting growth effect on nerve cells in vitro.%目的 评价新型非免疫抑制的FKBP12 配基N308在体外促神经生长和神经损伤的保护作用.方法 采用鸡胚背根神经生长实验评价N308体外促神经生长作用;在原代培养的大鼠中脑多巴胺神经元损伤和大脑皮层神经细胞缺氧损伤的模型上观察N308的保护作用.结果 N308能够协同神经生长因子(NGF)对鸡胚背根神经节的神经纤维生长,具有明确的促进作用,在10~1000 pmol·L-1浓度范围内表现出良好的剂量依赖关系.在0.3~30 nmol·L-1 浓度范围内N308明显提高缺氧诱导的大脑皮层神经细胞的存活率;0.5 μmol·L-1 N308对6-OHDA诱导的大鼠中脑多巴胺神经元细胞损伤具有明确的保护作用,使细胞突起明显增长.结论 N308在体外具有明确的促神经生长及神经损伤的保护作用.

  16. 异氰酸酯作业工人职业性支气管哮喘患病情况及其危险因素研究%The prevalence and risk factors of occupational asthma in workers exposed to isocyanate

    Institute of Scientific and Technical Information of China (English)

    安晓琴; 蒋轶文; 孔灵菲; 章敏华

    2013-01-01

    Objective To investigate the prevalence of occupational asthma,airway inflammation and analyze the risk factors for workers exposed to isocyanates.Methods A cross-sectional study was applied.Totally 429 isocyanates exposed workers were surveyed and the prevalence of occupational asthma and airway inflammation situation were examined by questionnaire,physical examination and laboratory tests.Multivariate logistic regression was applied to analyze the possible risk factors of isocyanate-induced occupational asthma.Results (1) A total of 366 patients with complete data were included in the study,and finally 11 cases were diagnosed as isocyanate-induced occupational asthma with a prevalence of 3.0%.(2) Neutrophil percentage in the induced sputum of occupational asthma increased significantly [42.00% (34.00%-55.00%) before work and 59.00% (51.00%-70.00%) after work (Z =-2.940.P < 0.05)].(3) Length of service (OR =3.096,P =0.025) and rhinitis (OR =1.901,P =0.008) were independent dangerous factors,and protective measures (OR =0.074,P =0.015) was protective factors to isocyanateinduced occupational asthma.Conclusions Neutrophilic inflammation can be triggered by isocyanate exposure.Regular health examinations,effective protective measures can reduce the prevalence of isocyanateinduced occupational asthma.%目的 研究异氰酸酯作业工人职业性支气管哮喘患病情况及相关危险因素.方法 采用横断面研究,选2011年3-6月某企业发泡车间429名异氰酸酯暴露工人为研究对象,通过问卷调查、体检、实验室检查调查职业性支气管哮喘患病率,检测受试者诱导痰中炎性细胞计数,多因素logistic回归分析其可能的危险因素.结果 (1)共有366名资料完整者纳入本研究,最终11例诊断为异氰酸酯职业性支气管哮喘,患病率为3.0%.(2)异氰酸酯职业性支气管哮喘工人诱导痰中中性粒细胞计数明显增加[上班前为42.00 (34.00,55.00)%,上班后为59

  17. 非异氰酸酯路线由微藻油与CO2合成聚氨酯%Microalgae oil-based polyurethane prepared from microalgae oil and CO2 via the non-isocyanate route

    Institute of Scientific and Technical Information of China (English)

    徐文杰; 单玉华; 鲁墨弘; 李明时

    2013-01-01

    通过非异氰酸酯合成微藻油基聚氨酯(MOPU).以微藻油(MAO)为原料,经甲酸催化、双氧水环氧化合成环氧化藻油(EMAO),接着与CO2在四丁基溴化铵和碘化钾催化下反应制备碳酯化微藻油(CMAO),再与二元胺反应得到MOPU.用1H-NMR和FT-IR对化合物结构进行表征,用DSC和TG对固化反应进行分析.考察了反应温度与时间、CO2压力以及催化剂质量分数对合成反应的影响,使92.65%的EMAO碳酯化为CMAO.胺类固化生成MOPU的活性顺序是:乙二胺(EDA)>丁二胺(BDA)>异佛尔酮二胺(IPDA).%Through the non-isocyanate route,microalgae oil-based polyurethane (MOPU) is prepared by expoxidation of microalgae oil with hydrogen peroxide catalyzed by formic acid to form epoxidized microalgae oil (EMAO),followed by carbonation of EMAO with CO2 catalyzed by tetra-butylammonium bromide and potassium iodide to form carbonated microalgae oil (CMAO),and then by curing CMAO with diamine.The structures of synthesized compounds are characterized by 1H-NMR and FT-IR.The curing reactions with aliphatic amines are monitored by DSC and TG analysis.The influence of reaction temperature and time,CO2 pressure,and catalyst dosage is investigated.The conversion of EMAO into CMAO is 92.65%.The active order of MOPU formation with diamine curing agents is:ethylene diamine (EDA) > butanediamine (BDA) > isophorone diamine (IPDA).

  18. 亲水性封闭型芳香族异氰酸酯交联剂的合成及性能研究%Synthesis and Performance Research of Waterborne Blocked Aromatic Isocyanate Crosslinking Agent

    Institute of Scientific and Technical Information of China (English)

    邱峻; 韦军; 王宝总; 郑小娟

    2011-01-01

    以4,4 '-二苯基甲烷二异氰酸酯(MDI)和三羟甲基丙烷(TMP)为原料,在催化剂作用下反应制得NCO封端的预聚物,再以2,2-二羟甲基丙酸(DMPA)和聚醚二元醇(PEG)对预聚物进行扩链,最后以3,5-二甲基吡唑(DMP)来封闭活性的NCO基团得到亲水性封闭型芳香族异氰酸酯交联剂,并用红外光谱表征了交联剂的结构.讨论了加料工艺对聚合反应影响,以及nDMPA/nPEG对交联剂性能的影响.研究表明,将TMP连续缓慢加入MDI体系有利于聚合反应的控制,当DMPA与PEG的摩尔比在2:1时,交联剂的综合性能较好.%The NCO-terminated prepolymer was prepared by the reaction of 4,4'-diphenyl-methane-diisocya-nate (MDI) and trimethylolpropane (TMP), which was further reacted with 2,2-dimethylolpropionic acid (DM-PA) and polyether glycol (PEG) to obtain chain-extending intermediate. The active NCO groups of the intermediate were blocked by 3,5-dimethylpyrazole (DMP) to achieve hydrophilic blocked aromatic isocyanate crosslinking agent. FT-IR spectra confirmed the active NCO groups were successfully blocked. The effect of feeding process on the control of polymerization and the molar ration of DMPA and PEG on the properties of crosslinking agent were discussed, respectively. The results indicated that dropping TMP continuously and slowly into MDI system favored the control of polymerization, and the crosslinking agent had better comprehensive properties while the molar ration of DMPA and PEG was kept at 2:1.

  19. 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.

  20. Lanthanide Complexes for Oligomerization of Phenyl Isocyanate

    Institute of Scientific and Technical Information of China (English)

    DENG,Ming-Yu; YAO,Ying-Ming; ZHOU,Yu-Fang; ZHANG,Li-Fen; SHEN,Qi

    2003-01-01

    A series of lanthanide complexes including (Ind)3Sm(THF)(1),[(MeCp)2Sm(μ-SPh)(THF)]2(2),[(MeCp)2Y(μ-O-i-Pr)]2(3),(MeCp)3Sm·THF(4),Sm(SPh)3(hmpa)3(5),[(MeCp)2Y-(μ-OCH2CF3)2(6)and (CF3CH2O)3Y(THF)3(7) were synthesized and they have good activity for the oligomerization of phenylisocyanate.Among them 5 shows the highest activity.The conversion is as high as 96.2%,with 1/2500 of the molar ratio of cat./PhNCO.The main components in oligomer were characterized to be a cycdlodimer and a cyclotrimer.The ratio of cyclodimer to cyclotrimer depends on the lanthanide complexes used.7 gave 85.2%cyclotrimer with 1/300 of the molar ratio of cat./PhNCO at 40℃ for 0.5h,while 5 gave 77.6% cyclodimer with 1/300 of the molar ratio of cat./PhNCO at 40℃ for 4h.

  1. Bitumen modification by reactive isocyanate prepolymers

    OpenAIRE

    Martín Alfonso, María José

    2014-01-01

    Los materiales bituminosos presentan una serie de propiedades, tales como ductilidad, adhesividad, resistencia al efecto de los factores ambientales y químicos, etc. Estas características permiten su utilización en el desarrollo de diversas aplicaciones que incluyen desde su uso en construcción de pavimentos hasta la utilización como impermeabilizantes en la industria de recubrimientos. La eficacia de los betunes ha sido mejorada mediante la modificación física con aditivos poliméricos. Es...

  2. Blocked Isocyanate Functionalized Graphene and Its Polyurethane Composite Materials%封闭异氰酸酯功能化石墨烯及其聚氨酯复合材料

    Institute of Scientific and Technical Information of China (English)

    李晓萱; 梁娟; 伍胜利; 王忠娟

    2014-01-01

    The semi-enclosed toluene diisocyanate( b-TDI) was prepaned by the reaction of methyl ethyl ketone oxime( MEKO) and toluene diisocyanate( TDI) ,then,graphene oxide was treated in N,N-dimethyformamide in use of the b-TDI and finally the functionalized graphene( bi-G) whose surface contained blocked isocyanate groups was obtained with hydrazine. Secondly,the above bi-G was added to the polyurethane prepolymer in water to prepare the polyurethane/graphene dispersion,and the polyurethane prepolymer was maked by PBA2000 and IPDI,et al. The X-Ray Diffraction ( XRD ) , the transmission electron microscope ( TEM ) and the thermal gravimetric analyzer ( TG ) were used to characterized the specialities of the composites. The analysis showed that the graphite was successfully oxided to graphene oxide and modified by b-TDI to obtain bi-G after reduction. The bi-G disperation was found dis-persed in the aqueous polyurethane micelles stably. Meanwhile,the TG analysis showed that the composite�s thermal stability had significantly improved, espectionly after heat treatment, the polyuerthane/graphene composite�s heat performance was more prominent.%将甲乙酮肟( MEKO)与甲苯二异氰酸酯( TDI)进行反应,制备了半封闭TDI( b-TDI)单体,利用该b-TDI单体对氧化石墨( GO)进行处理,最后用水合肼还原得到表面含封闭NCO基团的功能化石墨烯(bi-G);将bi-G添加到由聚己二酸丁二醇酯(PBA2000)与异佛尔酮二异氰酸酯(IPDI)等制备的水性聚氨酯( WPU )预聚体中,加水分散后得到bi-G/WPU分散液。并采用红外光谱仪( FT-IR)、X射线衍射仪( XRD)、透射电镜( TEM)和热重分析( TG)对产物进行表征。结果表明,石墨成功地被氧化成氧化石墨烯,并且实现了异氰酸酯的改性,同时也表明,改性后的氧化石墨烯被充分地还原;bi-G被稳定分散到WPU胶束中;bi-G的引入明显改善了聚氨酯材料的

  3. Study on Synthesis and Stability of the Waterborne Blocked Isocyanate Emulsion%水性封闭异氰酸酯乳液的合成及稳定性研究

    Institute of Scientific and Technical Information of China (English)

    李阿峰; 樊国栋; 李会宁; 陈华; 赵琪

    2013-01-01

    Waterborne blocked isocyanate emulsion (WBI) was synthesized with toluene 2, 4 -diisocya-nate (TDI) , trimethylolpropane (TMP) , dimethylol propionic acid (DMPA) as the reaetants and 2 -meth-ylimidazole ( 2 - MI) as blocked agents and triethylamine as nentralizer. The influence of neutralizer and Ze-ta potential on stability of WBI emulsion was studied. The hydrolyte resistance and temperature dependence of emulsion and unblocking temperature of WBI and properties of two - component polyurethane film were discussed. The results showed that when triethylamine (TEA) was used as neutralizer, the emulsion provid-ed good stability and storage stability due to the small particle size. When the neutralization was up to 100% , the stability of emulsion was the best. With the increase of DMPA, the stability of the emulsion was improved. The Zeta potential and particle sized were less influenced by temperature. Suitable mole fraction of DMPA is 20%~25%. The unblocking temperature was 125. 6℃ to 137. 8℃ by DSC test. The WBI could be used as curing agent to provide better water resistance, alcohol resistance, hardness and impact proverties of coatings.%采用甲苯二异氰酸酯(TDI)、三羟甲基丙烷(TMP)、二羟甲基丙酸(DMPA)为原料,2-甲基咪唑为封闭剂,三乙胺为中和剂制备了水分散封闭异氰酸酯(WBI)乳液,考察了中和剂和Zeta电位(ξ-电位)对WBI乳液稳定性的影响,探讨了乳液耐电解质能力及其温敏特性对其解封温度及双组分聚氨酯漆膜性能的影响.实验结果表明:用三乙胺作为中和剂时,乳液粒径较小,稳定性及贮存稳定性均较好,最佳中和度为100%.随DMPA用量的增加,乳液的ξ电位绝对值增大,乳液粒径减小、耐电解质能力增强,乳液的稳定性提高.乳液的Zeta电位及粒径受温度影响较小,说明乳液较为稳定.DMPA用量为20% ~ 25%(摩尔分数)较适宜.差示扫描量热法(DSC)分析表征其解封温度为125.6 ~ 138.1

  4. 异氰酸酯基偶联剂改性PAN基碳纤维增强聚三唑复合材料的研究%Modification of PAN-based carbon fiber reinforced polytriazole composites with isocyanate-containing coupling agent

    Institute of Scientific and Technical Information of China (English)

    葛雅琨; 扈艳红; 杜磊; 沈程; 王寒; 李智鹏; 葛宇

    2013-01-01

    采用异氰酸酯基偶联剂(A1)对聚丙烯腈(PAN)基碳纤维表面进行处理,制备了碳纤维增强聚三唑(PTA)复合材料;考察了偶联剂A1改性PAN基碳纤维的工艺;对比了溶剂丙酮中水分的影响.结果表明:工业丙酮为溶剂时,加入偶联剂A1缩短了PTA树脂胶液贮存期,需现配现用;偶联剂A1处理PAN基碳纤维,预处理法使T700碳纤维布/增强复合材料剪切强度提高39.2%,迁移法提高9.5%,相比用分析纯丙酮为溶剂的体系,改性效果降低;偶联剂A1在PAN基碳纤维表面生成脲类等极性化合物,增强了与树脂基体的氢键吸附,改善了复合材料的界面粘结,但工业丙酮中的水分消耗了偶联剂的作用基团,过量的杂质削弱了偶联剂与纤维的化学作用.%A carbon fiber reinforced polytriazole (PTA) composite was prepared by modifiying the surface of polyacrylonitrile (PAN)-based carbon fiber with a coupling agent (A1) containing isocyanate group.The modification process of PAN-based carbon fiber with coupling agent A1 was investigated.The impact of the moisture content in acetone solvent was contrasted.The results showed that the addition of coupling agent A1 shortened the shelf life of PTA resin while using industrial acetone as a solvent,which should be formulated immediately before application; and the shearing strength of T700 carbon fiber cloth reinforced PTA composite can be increased by 39.2% by pretreatment method and 9.5% by migration method when the PAN-based carbon fiber was treated with coupling agent A1,which contributed the lower modification effect than analytically pure acetone; isocyanate group in coupling agent A1 reacted with active sites on PAN-based carbon fiber surface and formed polar ureas groups which enhanced the hydrogen bonding adsorption on resin matrix and improved the interfacial adhesion of the composite,but the excess water in industrial acetone preferentially reacted with isocyanate group and the produced

  5. 单组分封闭异氰酸酯胶束/聚乙烯醇复合胶粘剂的制备及性能%Preparation and characterization of one-component blocked isocyanate micelle/PVA composite adhesive

    Institute of Scientific and Technical Information of China (English)

    邬洪川; 李志国; 白龙; 朱丽滨; 顾继友

    2015-01-01

    采用甲苯二异氰酸酯 TDI 、聚乙二醇(PEG)、二羟甲基丙酸(DMPA)以及封闭剂甲乙酮肟(MEKO)等为主要原料以及聚乙烯醇为复合组分制备了单组分封闭异氰酸酯胶束/聚乙烯醇 BIP/PVA 复合胶粘剂。系统研究了在加热条件下封闭胶束解封闭交联固化反应。考查了封闭异氰酸酯预聚胶束(BIP)对复合乳液稳定性,强度以及耐水性的影响。研究结果表明,复合胶粘剂的固化温度在120~125℃。随着BIP含量增加,复合胶粘剂强度和耐水性提高,但稳定性逐渐下降,当w BIP =15%时,可制得常温(20~30℃)存放3个月以上,干强度超过3.04 MPa,湿强度可达1.29 MPa的单组分BIP/PVA胶粘剂。()()()%The one-component blocked isocyanate micelle/PVA emulsions were prepared from toluene diisocyanate (TDI), polyethylene glycol (PEG), dimethylol propionic acid (DMPA), methyl ethyl ketone oxime (MEKO) as the blocking agent and polyvinyl alcohol (PVA) as the composite component. The deblocking and subsequent crosslinking reaction of the blocked emulsions was systematically researched. Furthermore, the effects of blocked isocyanate pre-polymer micelles (BIP) on the stability, water resistance and strength of the emulsions were investigated. The results showed that this composite adhesive was cured at between 120~125℃. With increasing BIP content, the strength and water-resistance of the composite adhesive was improved but its stability was gradually decreased. When the BIP content was 15 wt%, the storage time was over three months under the room temperature (20~30℃), and both the wet and dry strength reached 1.29 MPa and over 3.04 MPa,respectively..

  6. Enantioseparation of Salbutamol on the 3,4-Dichlorophenyl Isocyanate Vancomycin Chiral Stationary Phase%沙丁胺醇在3,4-二氯苯基异氰酸酯万古霉素手性柱上的对映体分离

    Institute of Scientific and Technical Information of China (English)

    于萍; 苏蕾; 刘光; 李丽

    2013-01-01

    Objective To establish a self-made chiral column for enantiomeric separation of salbutamol. Methods We used different concentrations of acid,alkali additives in the polar phase flow for enantiomers separation of salbutamol by using 3, 4-dichlorophenyl isocyanate vancomycin chiral column, and discussed the chiral recognition mechanism. Results The ratio of acid to alkali additive in the mobile phase was 0.01%:0.01% (V/V), the flow rate was 1ml/min, the column temperature was 25℃, and the best separation of enantiomers of salbutamol was obtained,the selective factor was 1.16, the separation degree reached 1.41. Conclusion Self-made 3, 4-two chlorophenyl isocyanate vancomycin chiral column is effective for salbutamol separation, and it can be as a reference for developing other similar chiral stationary phase.%目的:建立一种在自制手性柱上对沙丁胺醇进行了对映体分离的方法.方法利用极性流动相中不同浓度的酸、碱添加剂在自制的3,4-二氯苯基异氰酸酯万古霉素手性柱对沙丁胺醇对映体分离的研究,初步探讨了手性识别机理.结果流动相中酸、碱添加剂的比例为0.01%:0.01%(V/V),流速为1 mL/min,柱温为25℃时,沙丁胺醇获得了最好的对映体分离,选择因子为1.16,分离度达到1.41.结论自制的3,4-二氯苯基异氰酸酯万古霉素手性柱对沙丁胺醇有一定的分离效果,可以此为参考,开发其他类似的手性固定相.

  7. Isocyanate-Free Elastomers as Replacements for Isocyanate-Cured Polyurethanes (Briefing Charts)

    Science.gov (United States)

    2015-08-20

    position of vinyl groups on polymer chain • Initial investigation with nonanedithiol cure produces elastomeric material • Thiol-terminated polyethylene...Low Tg • High elongation to break • Compatibility with high solids loading • Approach • Nucleobase binding • Thiolene “click” chemistry...distribution is unlimited. 4 Nucleobase Binding • DNA is biologically ubiquitous therefore no current environmental regulation and likely no

  8. Observation of an unusually facile fragmentation pathway of gas-phase peptide ions: a study on the gas-phase fragmentation mechanism and energetics of tryptic peptides modified with 4-sulfophenyl isothiocyanate (SPITC) and 4-chlorosulfophenyl isocyanate (SPC) and their 18-crown-6 complexes.

    Science.gov (United States)

    Shin, Joong-Won; Lee, Yong Ho; Hwang, Sungu; Lee, Sang-Won

    2007-03-01

    Various peptide modifications have been explored recently to facilitate the acquisition of sequence information. N-terminal sulfonation is an interesting modification because it allows unambiguous de novo sequencing of peptides, especially in conjunction with MALDI-PSD-TOF analysis; such modified peptide ions undergo fragmentation at energies lower than those required conventionally for unmodified peptide ions. In this study, we systematically investigated the fragmentation mechanisms of N-terminal sulfonated peptide ions prepared using two different N-terminal sulfonation reagents: 4-sulfophenyl isothiocyanate (SPITC) and 4-chlorosulfophenyl isocyanate (SPC). Collision-induced dissociation (CID) of the SPC-modified peptide ions produced a set of y-series ions that were more evenly distributed relative to those observed for the SPITC-modified peptides; y(n-1) ion peaks were consistently and significantly larger than the signals of the other y-ions. We experimentally investigated the differences between the dissociation energies of the SPITC- and SPC-modified peptide ions by comparing the MS/MS spectra of the complexes formed between the crown ether 18-crown-6 (CE) and the modified peptides. Upon CID, the complexes formed between 18-crown-6 ether and the protonated amino groups of C-terminal lysine residues underwent either peptide backbone fragmentation or complex dissociation. Although the crown ether complexes of the unmodified ([M + CE + 2H]2+) and SPC-modified ([M* + CE + 2H]2+) peptides underwent predominantly noncovalent complex dissociation upon CID, the low-energy dissociations of the crown ether complexes of the SPITC-modified peptides ([M' + CE + 2H]2+) unexpectedly resulted in peptide backbone fragmentations, along with a degree of complex dissociation. We performed quantum mechanical calculations to address the energetics of fragmentations observed for the modified peptides. Copyright 2007 John Wiley & Sons, Ltd.

  9. Non-Isocyanate Polymer Design and Coating Development

    Science.gov (United States)

    2012-09-11

    Allen - Manager of Coating Operations 3 Problem Statement ● 1.2 million gallons of Chemical Agent Resistant Coating (CARC) purchased in 2011  Up...Approach ● Project Management Principles  Frequent sample exchanges to ensure reproducibility and maintain program focus  Monthly team meetings...Maintenance Center (MDMC) Albany and a representative from that organization is included in the projet team. • Final field use will require introducing a

  10. Zein-based polymers formed by modifications with isocyanates

    Science.gov (United States)

    Zein is a prolamine protein found in corn and a promising industrial bioplastic. However, for zein to reach its full commercial potential, research must find ways to overcome two main problems: its relatively high cost and its poor resistance to water. In this work, we have modified zein with severa...

  11. Facile Conversion of Alcohols to Olefins by Tosylation and Subsequent SiO2- promoted β-elimination

    Institute of Scientific and Technical Information of China (English)

    RUAN Xiaohong; SONG Gaopeng; ZHANG Yichun; LI Yingxia

    2007-01-01

    A convenient and effective procedure was developed for the conversion of alcohol to olefin by tosylation and subsequent β-elimination promoted by silica gel in this study. Treatment of the alcohols with p-toluenesulfonyl chloride in pyridine at 0℃ affords tosylates which undergo β-elimination with silica gel in dichloromethane or chloroform at room temperature, yielding olefinswith high productivity.

  12. 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.

  13. Disparate Behavior of Carbonyl and Thiocarbonyl Compounds: Acyl Chlorides vs Thiocarbonyl Chlorides and Isocyanates vs Isothiocyanates

    Science.gov (United States)

    Wiberg, Kenneth B.; Wang, Yi-gui; Miller, Scott J.; Puchlopek, Angela L.A.; Bailey, William F.; Fair, Justin D.

    2009-01-01

    The reaction of benzoyl chloride with methanol catalyzed by pyridine is 9 times more rapid than is the same reaction with thiobenzoyl chloride. The difference in reactivity, as well as the dealkylation reactions that occur when the reaction of thiobenzoyl chloride is catalyzed by bases such as Et3N, can be understood in terms of the charge distributions in the intermediate acylammonium ions. The reaction of PhNCO with ethanol occurs at a much higher rate (4.8 × 104) than that of PhNCS, corresponding to a difference in activation free energies for the additions of 6 kcal/mol. Transition states for each of these reactions were located, and each involves two alcohol molecules in a hydrogen bonded six-membered ring arrangement. Information concerning differences in reactivity was derived from analysis of Hirshfeld atomic charge distributions and calculated hydrogenolysis reaction energies. PMID:19371054

  14. Isocyanate-terminated Polyethers Toughened Epoxy Resin: Chemical Modification, Thermal Properties, and Mechanical Strength

    Institute of Scientific and Technical Information of China (English)

    CAI Haopeng; WANG Jun; WANG Xiang; XU Renxin

    2007-01-01

    The toughening of the diglycidyl ether of bisphenol A epoxy resin with isocyanateterminated polyethers (ITPE) was investigated. The progress of the reaction and the structural changes during modification process were studied using FTIR spectroscopy. The studies support the proposition that TDI (tolylene diisocyanate) acts as a coupling agent between the epoxy and polyethers, forming a urethane linkage with the former and the latter, respectively. Me THPA-cured ER/ITPs blends were characterized using dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). It is indicated the glass transition temperature (Tg) of systems was lower than the Tg of pure epoxy resin and overfull ITPE separated from the modified epoxy resin and formed another phase at an ITPE-content of more than 10wt%. The thermal stability was decreased by the introduction of ITPE. The impact strength and the flexural strength of the cured modifiedepoxy increased with increasing the ITPE content and a maximum plateau value of about 24.03 kJ/m2 and 130.56 MPa was measured in 10wt% ITPE. From scanning electron microscopy (SEM) studies of the fractrue surfaces of ER/ITPE systems, the nature of the micromechanisms responsible for the increases in toughness of the systems was identified.

  15. 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.

    of Bhopal, Puntius ticto was found to be the most susceptible to MIC-poisoning. There is a change in the values of pH, ammonia-nitrogen and urea-nitrogen concentrations in the Lower Lake water. The cholinesterase activities of different tissues of various...

  16. Penetration and performance of isocyanate wood binders on selected wood species

    Directory of Open Access Journals (Sweden)

    Gruver, T. M., and

    2006-11-01

    Full Text Available The penetration and performance of polymeric diphenylmethane diisocyanate (pMDI wood binder was investigated according to three factors: substrate species (aspen, yellow-poplar, or southern yellow pine; anatomical bonding plane (radial or tangential; and moisture content (0%, 5%, or 12%. Compression shear block tests and fluorescence microscopy were used to examine bond performance and resin penetration. Statistically, each of the aforementioned factors impacted results. As moisture content increased, observed bond strengths and wood failure increased. Bond formation did not occur when the substrates were equilibrated to 0% moisture content, except for the radial bonding surfaces of pine, which did adhere. At 5 and 12% moisture contents, tangential bonding surfaces out-performed radial bonding surfaces. In terms of resin penetration, moisture content was clearly the most important variable. Little penetration was observed at 0% moisture content, while extensive resin penetration was observed at elevated moisture contents. Pine was the only wood species to exhibit resin flow through radial cells, possibly explaining the enhanced resin penetration depths observed in pine samples.

  17. Detection of methyl isocyanate (CH3NCO) in a solar-type protostar

    Science.gov (United States)

    Martín-Doménech, R.; Rivilla, V. M.; Jiménez-Serra, I.; Quénard, D.; Testi, L.; Martín-Pintado, J.

    2017-08-01

    We report the detection of the pre-biotic molecule CH3NCO in a solar-type protostar, IRAS16293-2422 B. A significant abundance of this species on the surface of the comet 67P/Churyumov-Gerasimenko has been proposed, and it has recently been detected in hot cores around high-mass protostars. We observed IRAS16293-2422 B with the Atacama Large Millimeter Array in the 90 to 265 GHz range, and detected eight unblended transitions of CH3NCO. From our Local Thermodynamic Equilibrium analysis, we derived an excitation temperature of 110 ± 19 K and a column density of (4.0 ± 0.3) × 1015 cm-2, which results in an abundance of ≤(1.4 ± 0.1) × 10-10 with respect to molecular hydrogen. This implies a CH3NCO/HNCO and CH3NCO/NH2CHO column density ratios of ∼0.08. Our modelling of the chemistry of CH3NCO suggests that both ice surface and gas phase formation reactions of this molecule are needed to explain the observations.

  18. Rheology and thermal degradation of isocyanate-functionalized methyl cellulose-based oleogels.

    Science.gov (United States)

    Gallego, R; Arteaga, J F; Valencia, C; Franco, J M

    2013-10-15

    The -NCO-functionalization of methyl cellulose with HMDI and its application to chemically gel the castor oil is explored in this work by analyzing the influence of functionalization degree on the rheological and thermogravimetric behavior of resulting chemical oleogels. With this aim, different methyl cellulose chemical modifications were achieved by limiting the proportion of HMDI and, subsequently, oleogels were obtained by dispersing these polymers in castor oil and promoting the reaction between those biopolymers and the hydroxyl groups located in the ricinoleic fatty acid chain. -NCO-functionalized methyl cellulose-based oleogels were characterized from themogravimetric and rheological points of view. Suitable thermal resistance and rheological characteristics were found in order to propose these oleogels as promising bio-based alternatives to traditional lubricating greases based on non-renewable resources. In general, -NCO-functionalized methyl cellulose thermally decomposed in three main steps whereas resulting oleogels thermal decomposition takes place in one main single stage which comprises the thermal degradation of both the polymer and the castor oil. Temperature range for thermal degradation is broadened when using highly -NCO-functionalized methyl cellulose. A cross-linked viscoelastic gel was obtained with methyl cellulose functionalized in a relatively low degree (around 6% -NCO molar content). The rheological properties of highly functionalized methyl cellulose-based oleogels evolve during several months of aging, but mainly during the first week, due to the progress of the reaction between -NCO functional groups and castor oil -OH groups. SAOS functions analyzed and oleogel relative elasticity increase with the functionalization degree. Oleogel linear viscoelastic response is also extremely dependent on NCO-functionalized methyl cellulose concentration.

  19. Bitumen modification with a low-molecular-weight reactive isocyanate-terminated polymer

    Energy Technology Data Exchange (ETDEWEB)

    F.J. Navarro; P. Partal; M. Garcia-Morales; F.J. Martinez-Boza; C. Gallegos [Universidad de Huelva, Huelva (Spain). Departamento de Ingenieria Quimica, Facultad de Ciencias Experimentales

    2007-10-15

    A low-molecular-weight polyethyleneglycol functionalized with a polymeric MDI (4,4'-diphenylmethane diisocynate) was used as a modifying agent for a 60/70 penetration grade bitumen. The rheological properties of the resulting modified binder, at both low and intermediate temperatures, before and after curing at room temperature were studied and compared with those corresponding to a SBS modified bitumen. The analysis showed that the addition of a small quantity of this reactive polymer leads to enhanced rheological properties mainly at high in-service temperature (50{sup o}C). However, modification was found to be rather slow during binder curing at room temperature. Moreover, storage stability analysis showed that phase separation did not take place after bitumen storage at 163{sup o}C, though storage at high temperature affects the modification capability of the reactive polymer. Atomic force microscopy measurements showed that the reactive polymer addition leads to asphaltene-rich regions with lower thermal susceptibility, which are present even at high temperature, yielding an improved bitumen viscosity in this range of in-service temperatures. 38 refs., 7 figs., 2 tabs.

  20. Chemical, Physical, and Mechanical Characterization of Isocyanate Cross-linked Amine-Modified Silica Aerogels

    Science.gov (United States)

    Katti, Atul; Shimpi, Nilesh; Roy, Samit; Lu, Hongbing; Fabrizio, Eve F.; Dass, Amala; Capadona, Lynn A.; Leventis, Nicholas

    2006-01-01

    We describe a new mechanically strong lightweight porous composite material obtained by encapsulating the skeletal framework of amine-modified silica aerogels with polyurea. The conformal polymer coating preserves the mesoporous structure of the underlying silica framework and the thermal conductivity remains low at 0.041 plus or minus 0.001 W m(sup -1 K(sup -1). The potential of the new cross-linked silica aerogels for load-carrying applications was determined through characterization of their mechanical behavior under compression, three-point bending, and dynamic mechanical analysis (DMA). A primary glass transition temperature of 130 C was identified through DMA. At room temperature, results indicate a hyperfoam behavior where in compression cross-linked aerogels are linearly elastic under small strains (less than 4%) and then exhibit yield behavior (until 40% strain), followed by densification and inelastic hardening. At room temperature the compressive Young's modulus and the Poisson's ratio were determined to be 129 plus or minus 8 MPa and 0.18, respectively, while the strain at ultimate failure is 77% and the average specific compressive stress at ultimate failure is 3.89 x 10(exp 5) N m kg(sup -1). The specific flexural strength is 2.16 x 10(exp 4) N m kg(sup -1). Effects on the compressive behavior of strain rate and low temperature were also evaluated.

  1. 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.

  2. A discussion on producing agro-residue composites with isocyanate resins

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    With the urgent shortage of forest resource in China, using agro-residues as raw materials of composite become increasingly important. Agro-residue is the most potential fiber resource, which is helpful to sustainable development of composite industries in China. Based on a great deal of researches, this paper summarized and discussed some problems in using agro-residues as raw materials of composites, including raw material preparation, hot-pressing, bonding technology, preventing composite from going moldy. It is proposed that to manufacture the composite of rice straws or wheat straws, the isocayante resin is a suitable adhesive, and the appropriate technologies, bonding, and treatment measures are also needed.

  3. Syntese af amino/hydroxypyrrolidines og -piperidiner fra kulhydratderivater

    DEFF Research Database (Denmark)

    Godskesen, Michael Anders

    -methyl-D-xylitol, hydrotosylate with lithium aluminium hydride.The epoxide in methyl 2,3-anhydro-5-O-p-toluenesulfonyl-beta-D-ribofuranoside was opened by diethyl aluminium cyanide with formation of methyl 3-C-cyano-5-O-p-toluenesulfonyl-beta-D-xylofuranoside. Hydrogenation of the nitrile function with palladium on carbon led...... by methyliodide. The 5-Bromo functionality was then substituted by azid, which was hydrogenated in presence of palladium on carbon. The amino-lactones rearranged to the corresponding lactams, that could be reduced to 1,2,5-trideoxy-1,5-imino-2-C-methyl-D-arabinitol, hydrotosylate and 1,2,5-trideoxy-1,5-imino-2-C...

  4. Effect of pMDI isocyanate additive on mechanical and thermal properties of Kenaf fibre reinforced thermoplastic polyurethane composites

    Indian Academy of Sciences (India)

    Y A El-Shekeil; S M Sapuan; K Abdan; E S Zainudin; O M Al-Shuja’a

    2012-12-01

    The effect of polymeric methylene diphenyl diisocyanate (pMDI) on mechanical and thermal properties of Kenaf fibre (KF) reinforced thermoplastic polyurethane (TPU) composites was studied. Various percentages viz. 2%, 4% and 6%, were studied. The composites were characterized by using tensile testing, thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FTIR). It was noticed that the addition of pMDI 2%, 4%and 6% did not induce a better tensile nor thermal properties.

  5. The ALMA-PILS survey: First detections of deuterated formamide and deuterated isocyanic acid in the interstellar medium

    CERN Document Server

    Coutens, A; van der Wiel, M H D; Müller, H S P; Lykke, J M; Bjerkeli, P; Bourke, T L; Calcutt, H; Drozdovskaya, M N; Favre, C; Fayolle, E C; Garrod, R T; Jacobsen, S K; Ligterink, N F W; Öberg, K I; Persson, M V; van Dishoeck, E F; Wampfler, S F

    2016-01-01

    Formamide (NH$_2$CHO) has previously been detected in several star-forming regions and is thought to be a precursor for different prebiotic molecules. Its formation mechanism is still debated, however. Observations of formamide, related species and their isopotologues may provide useful clues to the chemical pathways leading to their formation. The Protostellar Interferometric Line Survey (PILS) represents an unbiased high angular resolution and sensitivity spectral survey of the low-mass protostellar binary IRAS 16293-2422 with the Atacama Large Millimeter/submillimeter Array (ALMA). We detect for the first time the three singly deuterated forms of NH$_2$CHO (NH$_2$CDO, cis- and trans-NHDCHO) as well as DNCO towards the component B of this binary source. The images reveal that the different isotopologues all are present in the same region. Based on the observations of the $^{13}$C isotopologues of formamide and a standard $^{12}$C/$^{13}$C ratio, the deuterium fractionation is found to be similar for the thr...

  6. 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.

  7. 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.

  8. 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.

  9. General, robust, and stereocomplementary preparation of alpha,beta-disubstituted alpha,beta-unsaturated esters.

    Science.gov (United States)

    Nakatsuji, Hidefumi; Nishikado, Hiroshi; Ueno, Kanako; Tanabe, Yoo

    2009-10-01

    An (E)- and (Z)-stereocomplementary preparative method for alpha,beta-disubstituted alpha,beta-unsaturated esters is performed via three general and robust reaction sequences: (i) Ti-Claisen condensation (formylation) of esters to give alpha-formyl esters (12 examples, 60-99%), (ii) (E)- and (Z)-stereocomplementary enol p-toluenesulfonylation (tosylation) using TsCl-N-methylimidazole (NMI)-Et(3)N and LiOH (24 examples, 82-99%), and (iii) stereoretentive Suzuki-Miyaura cross-coupling (18 examples, 64-96%).

  10. Synthesis of New Thiazine and Thiosemicarbazone Derivatives from D-Xylose

    Institute of Scientific and Technical Information of China (English)

    Xiao Ming JI; He Ping SUN; Hai Wei XU; Hong Min LIU

    2006-01-01

    1,2-O-Isopropylidene-5-O-p-toluenesulfonyl-α-D-erythro-pentofuranos-3-ulose 1 was treated with thiourea and aminothiourea to give a D-ribose derivative 2 bearing a 2-amino 1,3-thiazine ring and a thiosemicarbazone derivative 5, respectively. 2 was acylated with Ac2O and propandioic acid to afford two acylation derivatives 3 and 4, respectively. Reduction of 5with NaBH4 in methanol produced a hydrothiosemicarbazone derivative 6. The absolute configuration of 2 was confirmed by X-ray crystallographic analysis. The structures of all products were elucidated by IR, NMR and HRMS spectra.

  11. Crystallization and preliminary X-ray diffraction analysis of FKBP12 complexed with a new neurotrophic ligand

    Institute of Scientific and Technical Information of China (English)

    LI Pengyun; WANG Liwei; WU Beili; SHU Cuiling; NIE Aihua; SHEN Beifen; LI Song; RAO Zihe

    2003-01-01

    A novel neurotrophic ligand, (3R)-4-(p-toluenesulfonyl)-1,4-thiazane-3-carboxylic acid-L-phenylalanine ethyl ester, has been complexed with the FK506 binding protein of 12 kD (FKBP12) and crystallized using the hanging-drop vapor-diffusion method in 0.1 mol/L Hepes Na (pH6.5) solution containing 15%~27% PEG10000. Crystals belong to the P21 space group, with unit cell parameters of a=42.0, b=30.4, c=42.4A , β=110.7°. The crystals diffract to a 1.8A resolution limit.

  12. In vivo toxicity study of N-1-sulfonylcytosine derivatives and their mechanisms of action in cervical carcinoma cell line.

    Science.gov (United States)

    Kašnar-Šamprec, Jelena; Ratkaj, Ivana; Mišković, Katarina; Pavlak, Marina; Baus-Lončar, Mirela; Kraljević Pavelić, Sandra; Glavaš-Obrovac, Ljubica; Žinić, Biserka

    2012-06-01

    New N-1-sulfonylpyrimidines showed potent growth inhibitory activity against human and mouse tumour cells of different origin. 1-(p-toluenesulfonyl)cytosine (TsC) and 1-(p-toluenesulfonyl)cytosine hydrochloride (TsC × HCl) inhibited the growth of human cervical carcinoma cells (HeLa), and had no significant cytotoxic effects on normal human foreskin fibroblasts (BJ). TsC and TsC × HCl interfered with the HeLa cell cycle progression bringing about the accumulation of G1 phase cells and the induction of apoptosis. Antiproliferative effects of TsC and TsC × HCl were additionally confirmed by investigating de novo synthesis of RNA, DNA and proteins in HeLa cells. Monitoring gene expression using DNA Chip Analysis and quantitative PCR showed that TsC × HCl affects the expression of several cell-cycle regulating genes implying that cell cycle arrest and DNA damage-induced apoptosis might account for the observed cellular effects. In vivo experiments revealed low toxicity of TsC × HCl, as demonstrated by unaltered haematological and metabolic blood parameters. In conclusion, potent antitumour efficacy and low toxicity of new compounds in comparison with the common chemotherapy drug 5-FU make them promising anticancer agents. Additional pre-clinical and clinical studies are warranted to illuminate the mode of action of these newly synthesized compounds in vivo, which would lay the groundwork for their further optimization.

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

    Energy Technology Data Exchange (ETDEWEB)

    Razavizadeh, Mahmoud; Jamshidi, Masoud, E-mail: mjamshidi@iust.ac.ir

    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.

  14. CPD

    African Journals Online (AJOL)

    (e.g. isocyanate may block beta-2 adrenergic ... Isocyanates (e.g. toluene diisocyanate, diphenylmethane, ... Dyes (e. g. anthraquinone, caimine, paraphenyl diamine, henna .... 2,4 mg salbutamol sulphate equivalem to 2 mg salblmtampl.

  15. Insensitive explosive composition and method of fracturing rock using an extrudable form of the composition

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Lloyd L.

    2015-07-28

    Insensitive explosive compositions were prepared by reacting di-isocyanate and/or poly-isocyanate monomers with an explosive diamine monomer. Prior to a final cure, the compositions are extrudable. The di-isocyanate monomers tend to produce tough, rubbery materials while polyfunctional monomers (i.e. having more than two isocyanate groups) tend to form rigid products. The extrudable form of the composition may be used in a variety of applications including rock fracturing.

  16. Formation of substituted oxa- and azarhodacyclobutanes.

    Science.gov (United States)

    Dauth, Alexander; Rigling, Carla; Tsoung, Jennifer; Love, Jennifer A

    2013-12-01

    The preparation of substituted oxa- and azarhodacyclobutanes is reported. After exchange of ethylene with a variety of unsymmetrically and symmetrically substituted alkenes, the corresponding rhodium-olefin complexes were oxidized with H2O2 and PhINTs (Ts=p-toluenesulfonyl) to yield the substituted oxa- and azarhodacyclobutanes, respectively. Oxarhodacyclobutanes could be prepared with excellent selectivity for incorporation of the oxygen atom on the more substituted carbon atom of the alkene. At the same time, azarhodacyclobutanes showed good-to-excellent selectivity for heteroatom incorporation on the less substituted carbon. Furthermore, it was shown that steric modifications of the ancillary ligand have a significant influence on the selectivity of Rh-olefin complex formation as well as formation of the substituted azametallacycles.

  17. 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.

  18. An easy stereoselective access to beta,gamma-aziridino alpha-amino ester derivatives via mannich reaction of benzophenone imines of glycine esters with N-sulfonyl alpha-chloroaldimines.

    Science.gov (United States)

    Kiss, Loránd; Mangelinckx, Sven; Sillanpää, Reijo; Fülöp, Ferenc; De Kimpe, Norbert

    2007-09-14

    Mannich-type addition of benzophenone imine glycinates across newly synthesized N-(p-toluenesulfonyl) alpha-chloroaldimines afforded gamma-chloro-alpha,beta-diamino ester derivatives with moderate diastereoselectivity as separable mixtures of anti and syn diastereomers. The gamma-chloro-alpha,beta-diamino esters were efficiently cyclized under basic conditions to the corresponding beta,gamma-aziridino alpha-amino ester derivatives, representing a new class of conformationally constrained heterocyclic alpha,beta-diamino acid derivatives. The relative configuration of the aziridines was determined via X-ray diffraction analysis. Mechanisms and intermediate transition states to explain the stereochemical outcome of the Mannich reaction with different substrates or under different conditions are proposed. The synthetic importance of the beta,gamma-aziridino alpha-amino ester derivatives is demonstrated by their conversion into the corresponding Boc-protected derivatives and ring opening reactions to alpha,beta-diamino esters and a gamma-amino alpha,beta-unsaturated amino ester.

  19. Solvent-induced chirality control in the enantioseparation of 1-phenylethylamine via diastereomeric salt formation.

    Science.gov (United States)

    Kodama, Koichi; Kimura, Yuria; Shitara, Hiroaki; Yasutake, Mikio; Sakurai, Rumiko; Hirose, Takuji

    2011-04-01

    Solvent-induced chirality control in the enantioseparation of 1-phenylethylamine 1 by N-(p-toluenesulfonyl)-(S)-phenylalanine 2 via diastereomeric salt formation was studied. (S)-1·(S)-2 was preferentially crystallized as a less-soluble salt from aqueous alcohol, while (R)-1·(S)-2 salt was mainly obtained by addition of solvents with a six-membered ring such as dioxane, cyclohexane, tetrahydropyran, and cyclohexene to 2-propanol. Further investigations were carried out from the viewpoints of molecular structures, optical rotation measurement, and X-ray crystallographic analyses. Crystallographic analyses have revealed that incorporation of the six-membered ring solvent molecule in (R)-1·(S)-2 without hydrogen bonds changed the molecular conformation of (S)-2 to stabilize the salt, which changed the selectivity of 1 in the enantioseparation.

  20. Method of neutralizing the corrosive surface of amine-cured epoxy resins

    Science.gov (United States)

    Lee, S. Y. (Inventor)

    1982-01-01

    The corrosive alkaline surface layer of an epoxy resin product formed by the curing of the epoxy with an aliphatic amine is eliminated by first applying a non-solvent to remove most or all of the free unreacted amine and then applying a layer of a chemical reagent to neutralize the unused amine or amine functional groups by forming a substituted urea. The surface then may be rinsed with acetone and then with alcohol. The non-solvent may be an alcohol. The neutralizing chemical reagent is a mono-isocyanate or a mono-isothiocyanate. Preferred is an aromatic mono-isocyanate such as phenyl isocyanate, nitrophenyl isocyanate and naplthyl isocyanate.

  1. 二硝酰胺铵与异氰酸酯化合物的红外光谱研究%The Study on FTIR Spectra of Ammonium Dinitramide with Compounds of Isocyanate

    Institute of Scientific and Technical Information of China (English)

    翟进贤; 杨荣杰; 李建民

    2006-01-01

    通过将ADN、ADN/N-100、ADN/TDI、ADN/IPDI分别在室温和45 ℃下处理后进行FTIR谱图分析,研究了二硝酰胺铵(ADN)与三种异氰酸酯化合物(TDI、N-100、IPDI)的相容性.研究表明,在室温和45 ℃下,ADN与N-100、TDI不相容而与IPDI相容.

  2. 78 FR 66107 - National Emissions Standards for Hazardous Air Pollutants Residual Risk and Technology Review for...

    Science.gov (United States)

    2013-11-04

    ... desired shape and size. Molded foam is typically used in automotive seats, packaging and a range of... isocyanate and water. The polyol is either a polyether or polyester polymer with hydroxyl end groups. Other... foam where the gases produced by the isocyanate-water reaction are insufficient to achieve the...

  3. 77 FR 5091 - Certain New Chemicals; Receipt and Status Information

    Science.gov (United States)

    2012-02-01

    ...) Waterproofing inorganic (G) Silane quats. substrates. trade name zycosil; asphalt binder modifier. Trade name...) 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....

  4. Flexible fire retardant polyisocyanate modified neoprene foam. [for thermal protective devices

    Science.gov (United States)

    Parker, J. A.; Riccitiello, S. R. (Inventor)

    1973-01-01

    Lightweight, fire resistant foams have been developed through the modification of conventional neoprene-isocyanate foams by the addition of an alkyl halide polymer. Extensive tests have shown that the modified/neoprene-isocyanate foams are much superior in heat protection properties than the foams heretofore employed both for ballistic and ablative purposes.

  5. 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...

  6. New cation-exchange membranes for hyperfiltration processes

    NARCIS (Netherlands)

    Velden, van der P.M.; Smolders, C.A.

    1977-01-01

    A new route for the preparation of cation exchange membranes from polystyrene-polyisoprene-polystyrene (SIS) block copolymers has been studied, using N-chlorosulfonyl isocyanate. At temperatures of 0° to 20°C, N-chlorosulfonyl isocyanate reacts readily with the olefin group in polyisoprenes, resulti

  7. Polymer Claw: Instant Underwater Adhesive

    Science.gov (United States)

    2012-10-23

    surface. The amine reacts with the sticky, isocyanate putty to form a tough polyurea. The catalyzed isocyanates likewise bond with alcohols, amines, acids...the metal bristles and displaces the gel to make way for the adhesive. The entire system will be sealed in disposable packaging for safe storage and

  8. Dendrimer-like assemblies based on organoclays as multi-host system for sustained drug delivery.

    Science.gov (United States)

    Li, Wei; Sun, Lili; Pan, Lijun; Lan, Zuopin; Jiang, Tao; Yang, Xiaolan; Luo, Jianchun; Li, Ronghua; Tan, Liqing; Zhang, Shurong; Yu, Mingan

    2014-11-01

    Chemical modification of nanoclay will ensure further progress on these materials. In this work, we show that montmorillonite (MTM) nanosheets can be modified with β-cyclodextrin (CD) via a nucleophilic substitution reaction between mono-6-(p-toluenesulfonyl)-6-deoxy-β-CD and an amino group of 3-aminopropyltriethoxysilane (APTES)-functionalized MTM. The resulting MTM-APTES-CD can be further self-assembled into dendrimer-like assemblies, exhibit a well-dispersed property even in Dulbecco's phosphate-buffered saline and do not aggregate for a period of at least 20days. The structure, morphology and assembly mechanism are systematically studied by (29)Si MAS NMR, FT-IR, (1)H NMR, SEM, FE-TEM, DLS and AFM, and the change in assemblies during the drug release is monitored using FE-TEM images. MTT assays indicate that the assemblies only have low cytotoxicity, while CLSM and TEM observations reveal that the assemblies can easily penetrate cultured human endothelial cells. When clopidogrel is used as a guest molecule, the assemblies show not only much higher loading capacities compared to MTM and other containing β-CD assemblies or nanoparticles, but also a sustained release of clopidogrel up to 30days. This is attributed to the fact that the guest molecule is both supramolecularly complexed within the dendritic scaffold and intercalated into CD and MTM hosts. Host-guest systems between assemblies and various guests hold promising applications in drug delivery system and in the biomedical fields.

  9. Dispersive Surface Energy and Acid-Base Parameters of Tosylate Functionalized Poly(ethylene glycol via Inverse Gas Chromatography

    Directory of Open Access Journals (Sweden)

    Feyza Sesigur

    2014-01-01

    Full Text Available An inverse gas chromatographic (IGC study of the sorption properties of poly(ethylene glycol modified with tosylate (PEG-TOS was presented. PEG-TOS was synthesized via the tosylation of the corresponding poly(ethylene glycol (PEG with p-toluenesulfonyl chloride in the basic medium. The synthesized PEG-Tos was characterized by FTIR-ATR and 1HNMR techniques. The retention diagrams of n-hexane, n-heptane, n-octane, n-nonane, n-decane, dichloromethane, chloroform, acetone, tetrahydrofuran, ethyl acetate, and ethanol on the PEG and PEG-Tos were plotted at temperatures in K between 303 and 373 by inverse gas chromatography technique. The dispersive component of the surface-free energy, γSD, of studied adsorbent surface was estimated using retention times of different nonpolar organics in the infinite dilution region. Thermodynamic parameters of adsorption (free energy, ΔGAS, enthalpy, ΔHAS, and entropy, ΔSAS, dispersive components of the surface energies, γSD, and the acid, KA, and base, KD, constants for the PEG and PEG-Tos were calculated and the results were discussed.

  10. Regulated-stereoselective construction of thirteen stereogenic centers necessary for the frame of (+)-discodermolide, based on iterative Lewis acid-promoted aldol reactions.

    Science.gov (United States)

    Kiyooka, Syun-ichi; Shahid, Kazi Abdus; Goto, Fumitaka; Okazaki, Momotoshi; Shuto, Yoshihiro

    2003-10-17

    The segments C(1)-C(13) and C(15)-C(21) containing the 13 stereogenic centers required for the frame of (+)-discodermolide were synthesized in good to excellent enantio- and diastereoselectivities from a common racemic aldehyde, derived from 2-methyl-1,3-propanediol. The enantioselective aldol reactions of the racemic aldehyde with a silylketene acetal, derived from ethyl 2-bromopropionate, in the presence of chiral oxazaborolidinones, prepared in situ with N-p-toluenesulfonyl-(R)- and -(S)-valine and BH(3).THF, proceeded under kinetic control to give the stereotriads with a high degree of enantioselectivity. Enantioselective (chiral borane) and diastereoselective (BF(3).OEt(2) and TiCl(4)) aldol reactions with the silylketene acetal, coupled with diastereoselective radical debrominations (Bu(3)SnH, Et(3)B, with or without MgBr(2)), were used iteratively. This aldol reaction strategy for the construction of the polypropionate frame dramatically shortened the steps needed for the construction of the final segments.

  11. Activation of Microcrystalline Cellulose by Two-step Method and Its Use in Immobilization of Papain%两步法活化微晶纤维素及在固定木瓜蛋白酶中的应用

    Institute of Scientific and Technical Information of China (English)

    郭刚军; 马林; 谢文林; 陈国雄; 古练权

    2001-01-01

    Immobilized papain was prepared using microcrystalline cellulos as support which was activated by two-step method.The microcrystalline cellulose was first activated with p-toluenesulfonyl chloride, followed by coupling with ethyl diamine.After treated with glutaraldehyde, papain was immobilized to the support.Immobilized papain was obtained with activity 103 U/g support and high stability.%微晶纤维素经过两步活化,可在温和条件下实现木瓜蛋白酶固定化.用对甲基苯磺酰氯活化微晶纤维素后,与乙二胺反应向载体引入有机胺基团,再用戊二醒处理所得的二次活化载体可在温和条件固定木瓜蛋白酶.所得固定化酶活力为103 U/g载体,与溶液酶比较,热稳定性有明显提高.

  12. Design, synthesis and antibacterial activity of new phthalazinedione derivatives

    Directory of Open Access Journals (Sweden)

    ABD EL-GALIL M. KHALIL

    2011-03-01

    Full Text Available Dibenzobarallene (1 was utilized as the key intermediate for the synthesis of some new 2-substituted 1,4-dioxo-3,4,4a,5,10,10a-hexahydro-1H-5,10-[1’,2’]-benzenobenzo[g]phthalazine: 2, 5a–d, 8a–c and 10. Condensation of 2 with benzaldehyde or anisaldehyde gave the corresponding acrylonitrile derivatives 3a and b, respectively. Thiophene derivatives 4a and b were obtained via the Gewald reaction of 2 with cyclohexanone or cyclopentanone, respectively. Treatment of 5d with acetyl chloride or p-toluenesulfonyl chloride afforded the corresponding esters 6 and 7, respectively. Cyclization of 8a–c with formalin afforded the corresponding triazine derivatives 9a–c. Ring opening of 10 with sodium hydroxide gave the corresponding triazole derivative 11, which when alkylated with pentyl bromide afforded the pentylthio derivative 12. Representative compounds of the synthesized products were established and evaluated as antibacterial agents.

  13. Automated radiosynthesis of [{sup 18}F]PBR111 and [{sup 18}F]PBR102 using the Tracerlab FX{sub FN} and Tracerlab MX{sub FDG} module for imaging the peripheral benzodiazepine receptor with PET

    Energy Technology Data Exchange (ETDEWEB)

    Bourdier, Thomas, E-mail: thomas@nucmed.rpa.cs.nsw.gov.au [PET and Nuclear Medicine Department, Royal Prince Alfred Hospital, Missenden road, Camperdown NSW 2050, Sydney (Australia); Pham, Tien Q. [LifeSciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC NSW 2232, Sydney (Australia); Henderson, David [PET and Nuclear Medicine Department, Royal Prince Alfred Hospital, Missenden road, Camperdown NSW 2050, Sydney (Australia); Jackson, Timothy [LifeSciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC NSW 2232, Sydney (Australia); Lam, Peter [PET and Nuclear Medicine Department, Royal Prince Alfred Hospital, Missenden road, Camperdown NSW 2050, Sydney (Australia); Izard, Michael; Katsifis, Andrew [LifeSciences, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC NSW 2232, Sydney (Australia)

    2012-01-15

    [{sup 18}F]PBR111 and [{sup 18}F]PBR102 are selective radioligands for imaging of the Peripheral Benzodiazepine Receptor (PBR). We have developed a fully automated method for the radiosynthesis of [{sup 18}F]PBR111 and [{sup 18}F]PBR102 in the Tracerlab FX{sub FN} (30{+-}2% radiochemical yield non-decay-corrected for both tracers) and Tracerlab MX{sub FDG} (25{+-}2% radiochemical yield non-decay-corrected for both tracers) from the corresponding p-toluenesulfonyl precursors. For all tracers, radiochemical purity was >99% and specific activity was >150 GBq/{mu}mol after less than 60 min of preparation time. - Highlights: Black-Right-Pointing-Pointer Radiosynthesis of novel ligands PBR111 and PBR102 with fluorine-18. Black-Right-Pointing-Pointer Fully automated synthesis undertaken using the GE Tracerlab FX{sub FN} and MX{sub FDG} modules. Black-Right-Pointing-Pointer Reproducible high yields suitable for clinical applications. Black-Right-Pointing-Pointer Radiosynthesis and formulation achieved in less than 60 mins. Black-Right-Pointing-Pointer PBR111 and PBR102 prepared in high radiochemical yield and specific activity.

  14. Preparation of amino-terminated poly(ethylene glycol)by periodate oxidation%高碘酸氧化法制备端氨基聚乙二醇的研究

    Institute of Scientific and Technical Information of China (English)

    陈阳建; 许丽丽; 张新波; 彭富君; 宋潇达

    2015-01-01

    Monomethoxy poly( ethylene glycol)tosylate( mPEG5000-OTs)was synthesized by sulfonic esterification from monomethoxy poly(ethylene glycol)5000(mPEG5000)and p-toluenesulfonyl chloride (p-TsCl),and then reacted with ethanolamine as nucleophile to produce a new poly(ethylene glycol)in-termediate with the β-amino alcohol structure at the end. Amino-terminated poly( ethylene glycol ) (mPEG5000-NH2 )with the relative molecular mass of 5 000 was 75. 1% . The structures of products were characterized and identified by IR and 1 H NMR.%单甲氧基聚乙二醇5000(mPEG5000)和对甲苯磺酰氯(p-TsCl)磺酸酯化,得到单甲氧基聚乙二醇对甲苯磺酸酯(mPEG5000-OTs),与乙醇胺亲核取代反应,获得末端具有β-氨基醇结构的聚乙二醇中间体,用高碘酸盐氧化,得相对分子质量5000的端氨基聚乙二醇(mPEG5000-NH2),总收率75.1%,产物结构通过 IR 和1 H NMR 进行表征。

  15. Preparation of 18F-labeled peptides using the copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition.

    Science.gov (United States)

    Gill, Herman S; Marik, Jan

    2011-10-13

    An optimized procedure for preparing fluorine-18 ((18)F)-labeled peptides by the copper-catalyzed azide-alkyne 1,3-dipolar cyloaddition (CuAAC) is presented here. The two-step radiosynthesis begins with the microwave-assisted nucleophilic (18)F-fluorination of a precursor containing a terminal p-toluenesulfonyl, terminal azide and polyethylene glycol backbone. The resulting (18)F-fluorinated azide-containing building block is coupled to an alkyne-decorated peptide by the CuAAC. The reaction is accelerated by the copper(I)-stabilizing ligand bathophenanthroline disulfonate and can be performed in either reducing or nonreducing conditions (e.g., to preserve disulfide bonds). After an HPLC purification, (18)F-labeled peptide can be obtained with a 31 ± 6% radiochemical yield (n = 4, decay-corrected from (18)F-fluoride elution) and a specific activity of 39.0 ± 12.4 Ci μmol(-1) within 77 ± 4 min.

  16. 聚乙烯醇-g-异氰酸酯-脂肪醇梳状接枝共聚物的合成、结构及热性能%Synthesis, Structure and Thermal Properties of Poly ( vinyl alcohol)-g-isocyanate-fatty Alcohol Comb Copolymers

    Institute of Scientific and Technical Information of China (English)

    石海峰; 李剑华; 尹亿平; 张兴祥; 王笃金

    2012-01-01

    通过甲苯-2,4-二异氰酸酯(TDI)的连接作用,利用接枝共聚法将具有储热功能的长链脂肪醇[如十八醇(C18OH)、十六醇(C16OH)和十四醇(C14OH)]接枝到聚乙烯醇(PVA)主链上,制备出储热能力不同的聚乙烯醇-g-TDI -脂肪醇[PVA-g-TDI-C (n)]梳状接枝共聚物.通过傅里叶变换红外光谱(FTIR)、差示扫描量热分析(DSC)、热重分析(TGA)和X射线衍射(XRD)等方法研究了PVA-g-TDI-C (n)共聚物的热行为和结晶结构.结果表明,PVA-g-TDI-C(n)共聚物具有良好的储热能力,储热能力随侧链碳原子数目和侧链接枝度的增加而增大,但明显低于长链脂肪醇的储热能力.PVA-g-TDI-C(n)共聚物具有良好的热稳定性,失重温度在324~330℃之间.从侧链受限运动角度探讨了影响PVA-g-TDI-C(n)共聚物热性能和有序堆砌结构的原因.%Using the bridging role of tolylene diisocyanate ( TDI) , poly ( vinyl alcohol) -g-tolylene diisocya-nate-fatty alcohol[ PVA-g-TDI-C( n) , re = 14,16,18] copolymers were synthesized with the fatty alcohols as the thermal storage units along the PVA backbone via the "grafting to" method. The thermal storage behavior, thermal stability and crystalline structure of PVA-g-TDI-C(n) copolymers were detailed investigated by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry ( DSC ) , thermogravimetric analysis (TGA) , X-ray diffraction(XRD). The results show that PVA-g-TDI-C(re) eopolymers exhibit the better thermal storage ability, and the value of enthalpy increases with the side-chain length and the grafting ratio. Compared with the pure fatty alcohols, the grafted ones show the decreased thermal storage efficiency due to the confined mobility of longer methylene groups. Besides the confined mobility of methylene groups, the effect of PVA backbones and the bridging units of TDI also contribute to the decrement of thermal storage ability of PVA-g-TDI-C(re) copolymers. Additionally, PVA-g-TDI-C(n) copolymers exhibit the higher thermal stability than that of pure re-fatty alcohol, and the thermal degradation temperature is located at 324 330 ℃ , proving that it can be used as the solid-solid phase change materials in the aspects of buildings, fiber and textiles, thermal fluids, etc. So, the packing manner and thermal behavior of PVA-g-TDI-C (re) copolymers were further discussed and analyzed from the viewpoints of microstructural mobility.

  17. Protease activity in gut of Daphnia magna: evidence for trypsin and chymotrypsin enzymes.

    Science.gov (United States)

    von Elert, Eric; Agrawal, Manish Kumar; Gebauer, Christine; Jaensch, Heike; Bauer, Ulrike; Zitt, Anja

    2004-03-01

    Two major protease activities were present in gut homogenates of the cladoceran crustacean Daphnia magna: (i) a trypsin activity that hydrolysed the synthetic substrate N-benzoyl-dl-arginine p-nitroanilide and was strongly inhibited by N-p-tosyl-lysine chloroketone (TLCK) and 4-(amidinophenyl)methanesulfonyl fluoride (APMSF) and not inhibited by chymostatin; and (ii) a chymotrypsin activity that hydrolysed synthetic chymotrypsin substrates containing more than one amino acid, did not hydrolyse N-benzoyl-l-tyrosine p-nitroanilide, and was strongly inhibited by chymostatin and not by TLCK and APMSF. Both activities had alkaline pH optima (pH 7-10), but were shown to be due to distinct types of proteases. These two enzyme activities accounted for 75-83% of the proteolytic activity of gut contents. Substrate SDS-polyacrylamide gel electrophoresis revealed nine different proteases ranging from 15 to 73 kDa.

  18. Development of the 2007 Chemical Decontaminant Source Document

    Science.gov (United States)

    2009-03-01

    steels (vehicle, munitions substrate surface). (k) Brass/ bronze /copper and nickel alloys (munitions substrate surface). (I) Composite and laminate...Ethyleneimine Tungsten hexafluoride Methyl hydrazine Hexachlorocyclopentadiene Methyl isocyanate Hydrogen iodide Methyl mercaptan Iron pentacarbonyl

  19. T3P as an efficient cyclodehydration reagent for the one-pot synthesis of 2-amino-1,3,4-oxadiazoles

    Indian Academy of Sciences (India)

    Andivelu Ilangovan; Shanmugasundar Saravanakumar; Siddappa Umesh

    2015-05-01

    A scalable and environmentally friendly one-pot method for the synthesis of 2-amino-1,3,4-oxadiazoles from acylhydrazides and isocyanates has been achieved with propane phosponic anhydride (T3P) acting as cyclodehydrating reagent.

  20. Solid-state Synthesis of 1-Ethoxycarbonyl-4-substituted-semicarbazides

    Directory of Open Access Journals (Sweden)

    Hedayat A. Taghizadeh

    2003-04-01

    Full Text Available A rapid and simple method for the preparation of 1-ethoxycarbonyl-4-substituted-semicarbazides has been developed. As examples the reaction of six different isocyanates with ethyl carbazate under solvent-free conditions are reported.

  1. Yantai Wanhua Targets for Polyurethane Leader

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Yantai Wanhua Polyurethane Co., Ltd. (Yantai Wanhua, SZ: 000309) is mainly engaged in the research, development, production and sales of isocyanate series products (mainly diphenylmethane diisocyanate), aromatic polyamide series products and thermoplastic polyurethane elastomer series products.

  2. Efficient Regioselective Synthesis of 3-1odoindole N-Carboximidamides and N-Carboximidoates by a Sequential Aza-Wittig/Iodine Induced Cyclization

    Institute of Scientific and Technical Information of China (English)

    聂熠博; 段专; 丁明武

    2012-01-01

    3-Iodoindole N-carboximidamides and N-carboximidoates 4 were prepared regioselectively via a sequential aza-Wittig/iodine induced cyclization, starting from easily accessible 2-alkynylphenyl iminophosphorane, isocyanates, various nucleophiles and iodine.

  3. 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.

  4. 29 CFR 1910.1450 - Occupational exposure to hazardous chemicals in laboratories.

    Science.gov (United States)

    2010-07-01

    .... Examples of such conditions might include: (A) Procedures using chemically-impregnated test media such as... which affect the reproductive capabilities including chromosomal damage (mutations) and effects on... and Embryotoxins (a) Allergens (examples: diazomethane, isocyanates, bichromates): Wear...

  5. 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.

  6. Design of Active Composites

    Science.gov (United States)

    2009-03-30

    long chain diol (either a polyether or polyester) with excess isocyanate to form a prepolymer , followed by the addition of a short chain diol that...acts as a chain extender to link the prepolymers together. Due to the thermodynamic imicisibility of segments of PU, phase separation into a flexible...during the initial prepolymer reactions the NCO:OH ratio is always greater than 2 due to use of excess isocyanate to used to cap the ends of the

  7. Spark Plasma Sintering for Nanostructured Smart Materials

    Science.gov (United States)

    2009-03-02

    polyester) with excess isocyanate to form a prepolymer , followed by the addition of a short chain diol that acts as a chain extender to link the... prepolymers together. Due to the thermodynamic imicisibility of segments of PU, phase separation into a flexible soft segment (long chain diol) and a...other reactions of the isocyanate groups with the other functional groups in the chain. [Hepburn, 1992] However, during the initial prepolymer

  8. Chemically modified bitumens with enhanced rheology and adhesion properties to siliceous aggregates

    OpenAIRE

    Cuadri Vega, Antonio Abad; Partal López, Pedro; Ahmad, Naveed; Grenfell, James; Airey, Gordon

    2015-01-01

    Moisture damage is one of the major premature failures that worsens the performance and shortens service life of pavements. This research assesses the effect that two chemical modifiers (thiourea and an isocyanate-functionalized castor oil prepolymer) exerts on the bitumen rheology and on the resistance to potential moisture damage of asphalt mixtures based on siliceous aggregates. Both thiourea and the isocyanate-based prepolymer improve the viscous and viscoelastic behaviours of bitumen at ...

  9. Investigations of Novel Energetic Materials to Stabilize Rocket Motors

    Science.gov (United States)

    2002-04-30

    and various additives were developed in the second half of the 20th Century. The earliest such propellants were asphalt -based developed at GALCIT with...Decomposition of Energetic Materials 74. Volatile Metal Isocyanates from Flash Pyrolysis of Metal-NTO and Metal-Picrate Salts and an Application Hypothesis...B. Brill, T. L. Zhang and B. C. Tappan, Thermal Decomposition of Energetic Materials 74. Volatile Metal Isocyanates from Flash Pyrolysis of Metal-NTO

  10. Development of a Lightweight, High Strength, Collapsible Hose

    Science.gov (United States)

    1989-02-01

    to protect them somewhat during the weaving process. Two coatings, an isocyanate nnd a polyure- thane, were evaluated. The polyurethane was selected...40, 55D) Cyclohexane A ASTM Reference Fuel C (70C) [158°F] A (63, 72D) Dibutyl Phthatate A Asphalt T Diethyl Sebacate A Barium Hydroxide Solutions T...absorption characteristics of polyester and nylon yarns. The first coating reviewed was Esterweld ( Isocyanate ) on the yarn from Bibb Corporation. The second

  11. Paint Removal from Composites and Protective Coating Development

    Science.gov (United States)

    1991-01-01

    very effective in removing many types of surface contaminants including: grease, tars, dirt, asphalts , and various chemical residue. In this approach...above location. PRECAUTIONS: This material contains high vapor pressure, low flash point organic solvents and adducts cf isocyanates . It is flammable and...should be kept away from heat, sparks and open flames. Inhalation of isocyanates can cause allergic sensitization. Skin sensiti- zation is also

  12. Laboratory and Field Investigations of Small Crater Repair Technologies

    Science.gov (United States)

    2007-09-01

    Sustainment repairs currently employed include stone and grout, concrete cap, rapid set cementitious cap, AM2 mat, and asphalt repair methods. Lessons...upon the chemical reaction of component A (polymeric isocyanate ) with component B (a polyol blend containing certain additives). Each component is...polymeric isocyanate ) with component B (a polyol blend containing certain additives). Products selected include FOAM-iT! in 5, 10 and 15 lb/ft3

  13. Implementation of Plastic Media Blasting (PMB) at US Army Depots

    Science.gov (United States)

    1988-01-01

    Chemical Conversion Materials for Coating Aluminum and Aluminum Alloys MIL-C-83286 Coating, Urethane, Aliphatic Isocyanate . For Aerospace Application...Aluminum and Aluminum Alloys MIL-C-83286 - Coating, Urethane, Aliphatic Isocyanate , For Aerospace Application STANDARDS MILITARY MIL-STD-104 Limit For...For nasuring &V filmn thicktness of any non. ie interiel on a ferrou bees. including Peint. electoplating, porcelain enamel. rmer, plastic. aSphalt

  14. Dendritic polyurea polymers.

    Science.gov (United States)

    Tuerp, David; Bruchmann, Bernd

    2015-01-01

    Dendritic polymers, subsuming dendrimers as well as hyperbranched or highly branched polymers are well established in the field of polymer chemistry. This review article focuses on urea based dendritic polymers and summarizes their synthetic routes through both isocyanate and isocyanate-free processes. Furthermore, this article highlights applications where dendritic polyureas show their specific chemical and physical potential. For these purposes scientific publications as well as patent literature are investigated to generate a comprehensive overview on this topic.

  15. Chemically modified bitumens with enhanced rheology and adhesion properties to siliceous aggregates

    OpenAIRE

    Cuadri Vega, Antonio Abad; Partal López, Pedro; Ahmad, Naveed; Grenfell, James; Airey, Gordon

    2015-01-01

    Moisture damage is one of the major premature failures that worsens the performance and shortens service life of pavements. This research assesses the effect that two chemical modifiers (thiourea and an isocyanate-functionalized castor oil prepolymer) exerts on the bitumen rheology and on the resistance to potential moisture damage of asphalt mixtures based on siliceous aggregates. Both thiourea and the isocyanate-based prepolymer improve the viscous and viscoelastic behaviours of bitumen at ...

  16. 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

    2015-10-13

    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.

  17. 柱前衍生-反相高效液相色谱测定牛磺罗定及固体制剂含量%Determination of Taurolidine by Pre-column Derivatization and Reversed-Phase High Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    陈曦; 雷勇; 张宁; 王业秋; 逢居龙

    2011-01-01

    本文建立了对甲苯磺酰氯柱前衍生-反相高效液相色谱紫外检测法测定牛磺罗定及其固体制剂含量的方法.利用牛磺罗定中含有仲胺基的特点,以对甲基苯磺酰氯柱前衍生牛磺罗定,Venusil XBP C18色谱柱分离,在240 nm波长检测,线性范围为0.016~0.160 g·L-1(r=0.9995),衍生化产物在24 h内稳定,相对标准偏差(RSD)为3.8%,回收率为98.5%~101.2%.本方法简便、灵敏度高,且对检测设备要求低,适用于工业生产中大批量牛磺罗定原料药及其固体制剂的含量测定.%A method using pre-column derivatization and reserved-phase high performance liquid chromatography (RP-HPLC) UV detection was developed to determine taurolidine. Taurolidine was derivated with p-toluenesulfonyl chloride and then separated by Hypersil ODS C18 column, and detected under the 240 nm wavelength. The linear range of taurolidine was from 0. 016 to 0. 160 g/L with the recoveries from 98. 5% to 101. 2%. Derivative products were relatively stable during 24 h (RSD= 3.8%). The method was simple, convenient, sensitive and required low-cost detection device, which is possibly more suitable for the determination of industrial production of taurolidine and in its solid dosage forms.

  18. Homologs of 1,2,5-hexahydro-3-one-1H-1,4-diazepine (DAP) as novel dipeptidomimetics and molecular scaffolds: efficient preparation of synthons.

    Science.gov (United States)

    Han, Yinglin; Mierke, Dale F; Chorev, Michael

    2002-06-01

    Structurally constraint dipeptidomimetics represent an important class of conformationally rigid dipeptide surrogates and molecular scaffolds, which are frequently employed in peptide-based structure-activity relationships (SAR) and construction of combinatorial libraries. We report on the design of an improved and general synthetic procedure to prepare synthons related to the trisubstituted 1,2,5-hexahydro-3-one-1H-1,4-diazepines [DAP(Xxx)(alpha7)] (DAP: 1,2,5-hexahydro-3-one-1H-1,4-diazepine; DAP(Xxx)(alpha7): the homologous series of DAP in which alpha refers to the location of the chiral carbon in the i(th) amino acid, Xxx represents the three letter notation for the i-1 amino acids, and 7 denotes the number of atoms in the ring) and their higher homologs [DAP(Xxx)(alphaN)] [Xxx = Phe, Asp(beta-OcHex) (cHex: cyclohexyl), and Arg(N(G)-Tos] (Tos: p-toluenesulfonyl); N = 8-10]. These dipetidomimetic structures are generated by reductive alkylation-mediated Calpha(i)-to-N(i-1) bridging between a Calpha (i)-(CH(2))(i-1)(n)-COSEt (n = 1-4) and H(2)N-C(i-1)HR-CO(2)Fm (Fm: 9-fluorenylmethyl) followed by H(2)N(i)-to-C(i-1)-CO(2)H lactam formation. We also describe the preparation of blocked N-Ac-[DAP(Phe)(alphaN)]-CONMe(2) (N = 8-10), which serve as model systems for detailed conformational analysis reported in the accompanying article.

  19. Ring expansion reactions of pentaphenylborole with dipolar molecules as a route to seven-membered boron heterocycles.

    Science.gov (United States)

    Huang, Kexuan; Martin, Caleb D

    2015-02-16

    Reactions of pentaphenylborole with isocyanates, benzophenone, and benzaldehyde produced new seven-membered heterocycles in high yields. For 1-adamantyl isocyanate, a BNC5 heterocycle was obtained from the insertion of the C-N moiety into the five-membered borole, whereas for 4-methoxyphenyl isocyanate, a BOC5 heterocycle was generated from the insertion of the C-O unit. These reactions are believed to occur via a mechanism wherein coordination of the nucleophile to the borole (1-adamantyl, N-coordination or O-coordination for 4-methoxyphenyl) is followed by ring expansion to afford the observed seven-membered heterocycles. The selectivity to form B-O- or B-N-containing heterocycles is based on the polarization of the isocyanate implying tunable reactivity for the system. Having observed that isocyanates react as 1,2-dipoles with pentaphenylborole, we examined benzophenone and benzaldehyde, which both reacted to insert C-O units into the ring. This represents a new efficient method for preparing rare seven-membered boracycles.

  20. A composition for insulation operations

    Energy Technology Data Exchange (ETDEWEB)

    Dymant, A.N.; Oborin, Iu.A.

    1979-11-15

    A thermohydroinsulation composition is being patented, and it includes bitumen, an emulsifier, and water, into which, for the purpose of decreasing hydroscopicity and increasing thermotechnical properties and strength, an organic isocyanate, caoutchouc, and an organic solvent are added. The composition has the following properites, in %: bitumen, 21 to 31.8; an emulsifier, 15.8 to 23.8; water, 15.8 to 23.8; organic isocyanate, 9.7 to 18.9; caoutchouc, 6.9 to 13.5; organic solvent, 4 to 15. In order to produce the composition, the organic isocyanate and the caoutchouc are diluted in the organic solvent, and with mixing, it is added into the asphalt mastic (bitumen + emulsifier + water).

  1. Insulating Materials Comprising Polysilazane, Methods of Forming Such Insulating Materials, and Precursor Formulations Comprising Polysilazane

    Science.gov (United States)

    Larson, Robert S. (Inventor); Fuller, Michael E. (Inventor)

    2013-01-01

    Methods of forming an insulating material comprising combining a polysilazane, a cross-linking compound, and a gas-generating compound to form a reaction mixture, and curing the reaction mixture to form a modified polysilazane. The gas-generating compound may be water, an alcohol, an amine, or combinations thereof. The cross-linking compound may be an isocyanate, an epoxy resin, or combinations thereof. The insulating material may include a matrix comprising one of a reaction product of a polysilazane and an isocyanate and a reaction product of a polysilazane and an epoxy resin. The matrix also comprises a plurality of interconnected pores produced from one of reaction of the polysilazane and the isocyanate and from reaction of the polysilazane and the epoxy resin. A precursor formulation that comprises a polysilazane, a cross-linking compound, and a gas-generating compound is also disclosed.

  2. Occupational obstructive airway diseases in Germany: Frequency and causes in an international comparison

    Energy Technology Data Exchange (ETDEWEB)

    Latza, U.; Baur, X. [University of Hamburg, Hamburg (Germany)

    2005-08-01

    Occupational inhalative exposures contribute to a significant proportion of obstructive airway diseases (OAD), namely chronic obstructive pulmonary disease (COPD) and asthma. The number of occupational OAD in the German industrial sector for the year 2003 are presented. Other analyses of surveillance data were retrieved from Medline. Most confirmed reports of OAD are cases of sensitizer induced occupational asthma (625 confirmed cases) followed by COPD in coal miners (414 cases), irritant induced occupational asthma (156 cases), and isocyanate asthma (54 cases). Main causes of occupational asthma in Germany comprise flour/flour constituents (35.9%), food/feed dust (9.0%), and isocyanates (6.5%). Flour and grain dust is a frequent cause of occupational asthma in most European countries and South Africa. Isocyanates are still a problem worldwide. Although wide differences in the estimated incidences between countries exist due to deficits in the coverage of occupational OAD, the high numbers necessitate improvement of preventive measures.

  3. Photochemical activation of extremely weak nucleophiles: highly fluorinated urethanes and polyurethanes from polyfluoro alcohols.

    Science.gov (United States)

    Soto, Marc; Sebastián, Rosa María; Marquet, Jordi

    2014-06-06

    An efficient and environmentally friendly photoreaction between phenyl isocyanate or pentafluorophenyl isocyanate and polyfluorinated alcohols and diols is described for the first time. New highly fluorinated urethanes and diurethanes, derived from aromatic isocyanates, are produced in good yields in a photoreaction that is apparently governed by the acidic properties of the polyfluoro alcohols and diols. The wettability properties of the new polyfluorinated diurethanes have been tested, some of them showing significantly high values of hydrophobicity and oleophobicity. This new photoreaction has also been tested in the production of a model polyfluorinated polyurethane, establishing the influence of the irradiation power in the outcome of the process, and directly achieving a molecular weight distribution corresponding to a number-average DP(n) = 12 and a highest DP(n) = 20 after 4 h of irradiation (DP(n): "number-average degree of polymerization").

  4. Casting materials

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Grafted, cross-linked carbon black as a double-layer capacitor electrode material

    Energy Technology Data Exchange (ETDEWEB)

    Richner, R.; Mueller, S.; Wokaun, A.

    2001-03-01

    Isocyanate prepolymers readily react with oxidic functional groups on carbon black. On carbon black grafted with diisocyanates, reactive isocyanate groups are available for cross-linking to a polyurethane system. This cross-linked carbon black was considered as a new active material for electrochemical electrodes. Active material for electric double-layer capacitor electrodes was produced which had values of specific capacitance of up to 200 F/g. Cross-linking efficiencies of up to 58 % of the polymers utilised were achieved. (author)

  6. Engineering Design Handbook. Dielectric Embedding of Electrical or Electronic Components

    Science.gov (United States)

    1979-04-06

    Salient Properties of Polyurethanes 4-1 4-2 Hydroxyl Terminated Polymers 4-3 4-3 Isocyanates Used in Polyurethane Elastomers 4-3 4-4 Chain...Extending Agents 4-4 4-5 Some Trade Names/Suppliers of Polyurethane Embedments (Types 4 and 5) .... 4-6 4-6 Typical Isocyanates Used in...encased in dielectric materials. The earliest substances used for such purpose were materials such as waxes and asphaltic materials. These now may

  7. Toughened carbon fibre fabric-reinforced thermoplastic composites

    OpenAIRE

    Abt, Tobias Martin; Sánchez Soto, Miguel; Maspoch Rulduà, Mª Lluïsa; Velasco Perero, José Ignacio

    2014-01-01

    Toughened carbon fibre fabric-reinforced composites were obtained by compression moulding of powder prepregs, using a modified cyclic butylene terephthalate (pCBT) matrix and a bi-directional [0°/90°] carbon fibre fabric. Modification of the pCBT matrix was done by adding small amounts of epoxy resin or isocyanates, acting as toughening agents. Homogeneous CBT/epoxy and CBT/isocyanate blends were obtained by melt blending in a lab-scale batch mixer by applying low temperatures and short proce...

  8. Environmental Compliance Assessment Protocol-Centers for Disease Control and Prevention (ECAP-CDC)

    Science.gov (United States)

    1993-10-01

    chemicals (29 CFR 1910.1450(b)). o Liquid - any material with a fluidity greater than that of 300 penetration asphalt when tested in accordance with ASTM...Isobutyromnitrile 1000 78-82-0 Isocyanic acid,3,4- 500/10,000 102-36-3 dichlorophenyl ester lsodnn 100/10,000 1 P060 465-73-6 Isophorone 5000 78-59-1 Isophorone...Methacrylic anhydride 500 760-93-0 Methacryloyl chlonde 100 920-46-7 Methacryloyloxyethyl 100 30674-80-7 isocyanate Methacrylonutrle 500 1000 U152 126

  9. Physical chemistry of energetic nitrides. Final report, 1 November 1983-30 April 1987

    Energy Technology Data Exchange (ETDEWEB)

    Coombe, R.D.

    1987-05-28

    This program has addressed a number of aspects of the chemistry of energetic nitrogen-based compounds. Topics investigated include the photochemistry of halogen isocyanates and halogen amines, radiative and collisional relaxation processes in electronically excited halogen nitrenes, mechanisms of collisional decomposition of halogen azides, and production of excited metastable nitrogen molecules (in azide-based reactions) for the collisional excitation of laser-candidate species. The data obtained offer insight into the storage of energy in metastable halogen azides, halogen isocyanates, and halogen amines, and the mechanisms by which this energy is released when these molecules are stimulated by photolysis or undergo chemical reactions.

  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. ESI-MS, DFT, and synthetic studies on the H(2)-mediated coupling of acetylene: insertion of C=X bonds into rhodacyclopentadienes and Brønsted acid cocatalyzed hydrogenolysis of organorhodium intermediates.

    Science.gov (United States)

    Williams, Vanessa M; Kong, Jong Rock; Ko, Byoung Joon; Mantri, Yogita; Brodbelt, Jennifer S; Baik, Mu-Hyun; Krische, Michael J

    2009-11-11

    The catalytic mechanism of the hydrogen-mediated coupling of acetylene to carbonyl compounds and imines has been examined using three techniques: (a) ESI-MS and ESI-CAD-MS analyses, (b) computational modeling, and (c) experiments wherein putative reactive intermediates are diverted to alternate reaction products. ESI-MS analysis of reaction mixtures from the hydrogen-mediated reductive coupling of acetylene to alpha-ketoesters or N-benzenesulfonyl aldimines corroborate a catalytic mechanism involving C horizontal lineX (X = O, NSO(2)Ph) insertion into a cationic rhodacyclopentadiene obtained by way of acetylene oxidative dimerization with subsequent Brønsted acid cocatalyzed hydrogenolysis of the resulting oxa- or azarhodacycloheptadiene. Hydrogenation of 1,6-diynes in the presence of alpha-ketoesters provides analogous coupling products. ESI mass spectrometric analysis again corroborates a catalytic mechanism involving carbonyl insertion into a cationic rhodacyclopentadiene. For all ESI-MS experiments, the structural assignments of ions are supported by multistage collisional activated dissociation (CAD) analyses. Further support for the proposed catalytic mechanism derives from experiments aimed at the interception of putative reactive intermediates and their diversion to alternate reaction products. For example, rhodium-catalyzed coupling of acetylene to an aldehyde in the absence of hydrogen or Brønsted acid cocatalyst provides the corresponding (Z)-butadienyl ketone, which arises from beta-hydride elimination of the proposed oxarhodacycloheptadiene intermediate, as corroborated by isotopic labeling. Additionally, the putative rhodacyclopentadiene intermediate obtained from the oxidative coupling of acetylene is diverted to the product of reductive [2 + 2 + 2] cycloaddition when N-p-toluenesulfonyl-dehydroalanine ethyl ester is used as the coupling partner. The mechanism of this transformation also is corroborated by isotopic labeling. Computer model studies

  12. 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.

  13. Porphyrin analogues as novel antagonists of fibroblast growth factor and vascular endothelial growth factor receptor binding that inhibit endothelial cell proliferation, tumor progression, and metastasis.

    Science.gov (United States)

    Aviezer, D; Cotton, S; David, M; Segev, A; Khaselev, N; Galili, N; Gross, Z; Yayon, A

    2000-06-01

    Fibroblast growth factors (FGFs) and vascular endothelial growth factor (VEGF) play a pivotal role in the multistep pathway of tumor progression, metastasis, and angiogenesis. We have identified a porphyrin analogue, 5,10,15,20-tetrakis(methyl-4-pyridyl)-21H,23H-porphine-tetra -p-tosylate salt (TMPP), as a potent inhibitor of FGF2 and VEGF receptor binding and activation. TMPP demonstrated potent inhibition of binding of soluble FGF receptor 1 (FGFR1) to FGF2 immobilized on heparin at submicromolar concentrations. TMPP inhibits binding of radiolabeled FGF2 to FGFR in a cell-free system as well as to cells genetically engineered to express FGFR1. Furthermore, TMPP also inhibits the binding of VEGF to its tyrosine kinase receptor in a dose-dependent manner. In an in vitro angiogenic assay measuring the extent of endothelial cell growth, tube formation, and sprouting, TMPP dramatically reduced the extent of the FGF2-induced endothelial cell outgrowth and differentiation. In a Lewis lung carcinoma model, mice receiving TMPP showed a marked inhibition of both primary tumor progression and lung metastases development, with nearly total inhibition of the metastatic phenotype upon alternate daily injections of TMPP at 25 microg/g of body mass. Finally, novel meso-pyridylium-substituted, nonsymmetric porphyrins, as well as a novel corrole-based derivative, with >50-fold increase in activity in vitro, had a significantly improved efficacy in blocking tumor progression and metastasis in vivo.

  14. Extracellular serine-proteinases isolated from Streptomyces alboniger: Partial characterization and effect of aprotinin on cellular structure

    Directory of Open Access Journals (Sweden)

    Lopes Andréa

    1999-01-01

    Full Text Available Streptomyces alboniger ATCC 12461 grown in brain heart infusion (BHI medium produced two extracellular serine-proteinases, denoted SP I and SP II, which were purified by ammonium sulfate precipitation and aprotinin-agarose affinity chromatography. SP I was purified 88,9-fold and SP II 66,7- fold, with 33.4% and 10.4% yield, respectively. The optimum pH for the proteinases activity, using a-N-p-tosyl-L-arginine-methyl ester (TAME as substrate, was 9-10 and the optimum temperature was 37ºC. The proteolytic activity of SP I and SP II was inhibited by aprotinin and SP I was partially inhibited by leupeptin, both serine-proteinase inhibitors. S. alboniger growth in BHI-liquid medium decreased when 5 mg/ml, 10 mg/ml of aprotinin was used, being completely inhibited with 20 mg/ml and 40 mg/ml. At the ultrastructural level, aprotinin-treated S. alboniger cells showed swelling of the bacterial body and condensation of the genetic material, probably related to the inhibition of its growth.

  15. Atomic resolution structure of a lysine-specific endoproteinase from Lysobacter enzymogenes suggests a hydroxyl group bound to the oxyanion hole.

    Science.gov (United States)

    Asztalos, Peter; Müller, Astrid; Hölke, Werner; Sobek, Harald; Rudolph, Markus G

    2014-07-01

    Lysobacter enzymogenes lysyl endoproteinase (LysC) is a trypsin-type serine protease with a high pH optimum that hydrolyses all Lys-Xaa peptide bonds. The high specificity of LysC renders it useful for biotechnological purposes. The K30R variant of a related lysyl endoproteinase from Achromobacter lyticus has favourable enzymatic properties that might be transferrable to LysC. To visualize structural differences in the substrate-binding sites, the crystal structures of wild-type and the K30R variant of LysC were determined. The mutation is located at a distance of 12 Å from the catalytic triad and subtly changes the surface properties of the substrate-binding site. The high pH optimum of LysC can be attributed to electrostatic effects of an aromatic Tyr/His stack on the catalytic aspartate and is a general feature of this enzyme subfamily. LysC crystals in complex with the covalent inhibitor N(α)-p-tosyl-lysyl chloromethylketone yielded data to 1.1 and 0.9 Å resolution, resulting in unprecedented precision of the active and substrate-binding sites for this enzyme subfamily. Error estimates on bond lengths and difference electron density indicate that instead of the expected oxyanion a hydroxyl group binds to the partially solvent-exposed oxyanion hole. Protonation of the alkoxide catalytic intermediate might be a recurring feature during serine protease catalysis.

  16. Aptamer-based organic-silica hybrid affinity monolith prepared via "thiol-ene" click reaction for extraction of thrombin.

    Science.gov (United States)

    Wang, Zheng; Zhao, Jin-cheng; Lian, Hong-zhen; Chen, Hong-yuan

    2015-06-01

    A novel strategy for preparing aptamer-based organic-silica hybrid monolithic column was developed via "thiol-ene" click chemistry. Due to the large specific surface area of the hybrid matrix and the simplicity, rapidness and high efficiency of "thiol-ene" click reaction, the average coverage density of aptamer on the organic-silica hybrid monolith reached 420 pmol μL(-1). Human α-thrombin can be captured on the prepared affinity monolithic column with high specificity and eluted by NaClO4 solution. N-p-tosyl-Gly-Pro-Arg p-nitroanilide acetate was used as the sensitive chromogenic substrate of thrombin. The thrombin enriched by this affinity column was detected with a detection of limit of 0.01 μM by spectrophotometry. Furthermore, the extraction recovery of thrombin at 0.15 μM in human serum was 91.8% with a relative standard deviation of 4.0%. These results indicated that "thiol-ene" click chemistry provided a promising technique to immobilize aptamer on organic-inorganic hybrid monolith and the easily-assembled affinity monolithic material could be used to realize highly selective recognition of trace proteins.

  17. 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 b

  18. 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...

  19. 75 FR 71688 - Certain New Chemicals; Receipt and Status Information

    Science.gov (United States)

    2010-11-24

    ... primes and lacquers. aliphatic polyurethane dispersion. P-11-0011 10/05/10 01/02/11 Dic International (G.../21/10 CBI (G) Polyurethane (G) Thermoplastic (open, polyurethane. nondispersive). P-10-0574 09/23/10.../26/10 CBI (G) Moisture curing (G) Isocyanate polyurethane terminated urethane adhesive. The...

  20. Is specific IgE antibody analysis feasible for the diagnosis of methylenediphenyl diisocyanate-induced occupational asthma?

    NARCIS (Netherlands)

    Budnik, Lygia Therese; Preisser, Alexandra M.; Permentier, Hjalmar; Baur, Xaver

    2013-01-01

    Early recognition improves the prognosis of isocyanate asthma. A major unanswered question is whether IgE-dependent mechanisms are of diagnostic value? Our objective was to appraise serological methods using various methylenediphenyl diisocyanate (MDI)-albumin conjugates and weigh up the data versus

  1. 78 FR 11871 - Certain New Chemicals; Receipt and Status Information

    Science.gov (United States)

    2013-02-20

    .... glycol, aliphatic ester, aliphatic acid and aromatic isocyanate P-13-0147 12/5/2012 3/4/2013 Sika...) Fatty acid promoter for use amide in aphalt applications; emulsifier for use in asphalt applications. P... applications; emulsifier for use in asphalt applications. P-13-0182 12/19/2012 3/18/2013 CBI (S) Adhesion...

  2. Synthesis of a base-free hafnium nitride from N2 cleavage: a versatile platform for dinitrogen functionalization.

    Science.gov (United States)

    Semproni, Scott P; Chirik, Paul J

    2013-07-31

    The synthesis and characterization of a metastable, base-free isocyanato dihafnocene μ-nitrido complex from CO-induced dinitrogen cleavage is described. The open coordination site at hafnium suggested the possibility of functionalization of the nitrogen atom by cycloaddition and insertion chemistry. Addition of the strained, activated alkyne, cyclooctyne, resulted in N-C bond formation by cycloaddition. The alkyne product is kinetically unstable engaging the terminal hafnocene isocyanate and promoting deoxygenation and additional N-C bond formation resulting in a substituted cyanamide ligand. Group transfer between hafnium centers was observed upon treatment with Me3SiCl resulting in bridging carbodiimidyl ligands. Amidinato-type ligands, [NC(R)N](3-) were prepared by addition of either cyclohexyl or isobutyronitrile to the base free dihafnocene μ-nitrido complex, which also engages in additional N-C bond formation with the terminal isocyanate to form bridging ureate-type ligands. Heterocummulenes also proved reactive as exposure of the nitride complex to CO2 resulted in deoxygenation and N-C bond formation to form isocyanate ligands. With substituted isocyanates, cycloaddition to the dihafnocene μ-nitrido was observed forming ureate ligands, which upon thermolysis isomerize to bridging carbodiimides. Taken together, these results establish the base free dihafnocene μ-nitrido as a versatile platform to synthesize organic molecules from N2 and carbon monoxide.

  3. Homogeneous and heterogenised masked N-heterocyclic carbenes for bio-based cyclic carbonate synthesis

    NARCIS (Netherlands)

    Stewart, Joseph A.; Drexel, Roland; Arstad, Bjornar; Reubsaet, Erik; Weckhuysen, Bert M.; Bruijnincx, Pieter C. A.

    2016-01-01

    (Multifunctional) cyclic carbonates are generating much interest, with bio-based bis-cyclic compounds attracting attention from the polymer sector as potential renewable monomers for systems such as non-isocyanate polyurethanes. Here, the efficient synthesis of one such substrate, diglycerol dicarbo

  4. Alkane-Based Urethane Potting Compounds

    Science.gov (United States)

    Morris, D. E.

    1986-01-01

    New low viscosity urethanes easily mixed, molded, and outgassed. Alkane-based urethanes resist hydrolysis and oxidation and have excellent dielectric properties. Low-viscosity alkane-based urethane prepolymer prepared by one-step reaction of either isophorone diisocyanate or methyl-bis (4-cyclohexyl isocyanate) with hydrogenated, hydroxy-terminated polybutadiene (HTPBD).

  5. Federal Aviation Administration Small Business Innovation Research 5- Year Project Summaries

    Science.gov (United States)

    1990-02-01

    to avoid diluents, etc., that attack asphalt . One part systems such as amine-blocked, moisture-cure silicones, isocyanates , hot melts, UV cure, and... Asphalt Stripping from Aggregates ..... ............... 53 viii Sinnar Associates Infrared Ice Accretion Measurement System ...... 54 Springborn...Methods to Determine the Degree of Asphalt Stripping from Aggregates ....... ............... 80 x OPHIR Corporation An Ice Accumulation Sensor for

  6. Nerve Agent Sensing Biopolymer Wipe

    Science.gov (United States)

    2003-04-01

    minutes. Polymer synthesis is complete in less than 10 minutes. The CO2 evolved during the reaction of water and isocyanate lifts the foam to a...concrete, stone and asphalt . Excessive dirt or any material that significantly masks clear viewing of the sensor polymer may invalidate sensor

  7. JPRS Report, Soviet Union KOMMUNIST No 8, May 1987.

    Science.gov (United States)

    2007-11-02

    rest rooms, food stands and shower stalls. Asphalted roads lead to the farms and the entire territory within them is also asphalted . A medical...reaction which was accompanied by a fast increase in temperature and pressure in the methyl isocyanate . In Chernobyl it was introducing a positive

  8. RAILCAR4 Toxic Industrial Chemical Source Characterization Program (Software User’s Manual)

    Science.gov (United States)

    2011-08-01

    of the release trench.3 Even the over 2,000 deaths in Bhopal, India that resulted from the December 3, 1984 release of 40 tons of methyl isocyanate ... asphalt or even ballast stone will evaporate before the responders are likely to arrive and don protective gear. The final significant observation was

  9. Design Analysis, Basin F Liquid Waste Disposal Facility, Rocky Mountain Arsenal, Commerce City, Colorado, FY81.

    Science.gov (United States)

    1981-08-01

    proposed will probably destroy or reduce the integrity of the existing asphalt liner. If this integrity needs to be maintained then alternate construction...1robnzee u.4STrchlorophenoxypropionic acid (2.4.-5 lodomethanei Pentachloroethane TPI (Silvex) Isocyanic acid, methyl aster Peafchlortmiftobenzene W=CN) ’T

  10. Surface Protection Study for Navy Projectiles,

    Science.gov (United States)

    1997-01-01

    Cavity Paint ( asphalt ), MIL-C-450, with Comp A-3 explosive filler. Alkyd Primer, TT-P-664, with PBXN-type explosive filler. Zn Phosphate only; MIL-G...reactive materials such as the isocyanates and plasticizers should not enter into unwanted side reactions with an interior coating. After the explosive

  11. Plastic Coatings and Wraps for New Marine Timber Piling

    Science.gov (United States)

    1990-05-01

    all fresh asphalt , resin-base curing compounds, or loose paint. Use compressed air to remove dust and dirt prior to applying the waterproofing...nonyellowing) isocyanate with a polycaprolactone backbone. The system is available in colors which are unaffected by solar radiation. Mechanical

  12. Monomers, polymers and articles containing the same from sugar derived compounds

    Science.gov (United States)

    Gallagher, James; Reineke, Theresa; Hillmyer, Marc A.

    2016-11-29

    Disclosed herein are monomers formed by reacting a sugar derived compound(s) comprising a lactone and two hydroxyls with a compound(s) comprising an isocyanate and an acrylate or methacrylate. Polymers formed from such monomers, and articles formed from the polymers are also disclosed.

  13. Facile Synthesis of Ureas in Ionic Liquid

    Institute of Scientific and Technical Information of China (English)

    Wei Xing QIAN; Feng Yang JU; Yong Min ZHANG; Wei Liang BAO

    2004-01-01

    The reaction of isocyanates with aliphatic and aromatic amines in the 1-n-butyl-3- methylimidazolium tetrafluoroborate (bmimBF4) ionic liquid in good to excellent yields is described. Due to its insolubility, the desired urea solids could be recovered by simple filtration from the ionic liquid after reaction.

  14. Impact of cold temperatures on the shear strength of Norway spruce joints glued with different adhesives

    DEFF Research Database (Denmark)

    Wang, Xiaodong; Hagman, Olle; Sundqvist, Bror

    2015-01-01

    × 20 mm × 10 mm) were bonded with seven commercially available adhesives: polyurethane (PUR), polyvinyl acetate (PVAc), emulsion-polymer-isocyanate (EPI), melamine-formaldehyde (MF), phenol-resorcinol-formaldehyde (PRF), melamine-urea-formaldehyde1 (MUF1), and melamine-urea-formaldehyde2 (MUF2). Each...

  15. Stewart Air National Guard Base, NY, C-5M Painting Refurbishment Assessment

    Science.gov (United States)

    2012-12-06

    isocyanate paints can adequately be mitigated through the continued practice of wearing cotton or Tyvek® coveralls and nitrile or neoprene gloves...cotton or Tyvek® coveralls and nitrile or neoprene gloves. 5 Batten, Timothy W. Base Level

  16. 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...

  17. Potato Sprout Inhibitor chlorpropham

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The title compound chlorpropham (CAS number: 101-21-3, C10H12ClNO2, Mr = 213.66) was prepared by the addition reaction of 3-chlorophenyl isocyanate with isopropanol. Spectral data, IR, NMR and MS, were reported. This paper provides some related information about Regulatory Status, Toxicological Effects, Ecological Effects and Environmental Fate also.

  18. New crosslinking method of polyamide-imide membranes for potential application in harsh polar aprotic solvents

    NARCIS (Netherlands)

    Dutczak, S.M.; Cuperus, F.P.; Cuperus, F.P.; Wessling, Matthias; Stamatialis, Dimitrios

    2013-01-01

    We report for the first time successful crosslinking of polyamide–imide (Torlon®) based membranes using di-isocyanates. The crosslinked membranes are resistant to N-methyl pyrrolidone (which is solvent of the non-crosslinked membranes) and have very good mechanical properties. In contrast to the

  19. Preparation and Post-Functionalization of Hyperbranched Polyurea Coatings

    NARCIS (Netherlands)

    Xiang, Fei; Asri, Lia; Ivashenko, Oleksii; Rudolf, Petra; Loontjens, Ton

    2015-01-01

    Postfunctionalizable hyperbranched polyurea coatings were prepared by the bulk polycondensation of AB(2) monomers on preactivated silicon substrates. As previously shown, AB(2) monomers were prepared, comprising a secondary amino group (A) and two blocked isocyanates (B) connected by hexyl spacers,

  20. [Carbamylation of proteins--mechanism, causes and consequences].

    Science.gov (United States)

    Pieniążek, Anna; Gwoździński, Krzysztof

    2016-05-16

    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 free amino 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 biological activity and may contribute to the deterioration of patients with chronic renal failure.

  1. Ocular irritation from product of pesticide degradation among workers in a seed warehouse.

    Science.gov (United States)

    Matsukawa, Takehisa; Yokoyama, Kazuhito; Itoh, Hiroaki

    2015-01-01

    Four workers at a seed supply warehouse in Chiba Prefecture, Japan, complained of ocular irritation on the job. Pesticide-coated seeds were stored in the warehouse but no significant amount of pesticide was detected in the air inside the warehouse. To identify the cause of the ocular irritation and to determine an appropriate solution to the problem, the authors used thermal desorption gas chromatography-mass spectrometry to analyze the profiles of volatile organic compounds (VOCs) in the air of the two warehouses at the site-warehouse A, where the four workers experienced ocular irritation, and warehouse B, where no workers experienced ocular irritation. Comparing the profiles of VOCs in these warehouses indicated that n-butyl isocyanate, a hydrolyzed product of the fungicide benomyl, was the cause of the workers' ocular irritation. n-Butyl isocyanate is known to be a contact irritant and if the benomyl-coated seeds were not properly dried before storage in the warehouse n-butyl isocyanate would have been produced. The results of the study suggest that more attention should be paid both to the pesticide itself and to the products of pesticide degradation. In this study, n-butyl isocyanate was identified as a product of pesticide degradation and a causative chemical affecting occupational health.

  2. The effect of tissue surface modification with collagenase and addition of TGF-beta 3 on the healing potential of meniscal tears repaired with tissue glues in vitro

    NARCIS (Netherlands)

    Bochynska, Agnieszka Izabela; Hannink, Gerjon; Verhoeven, Renate; Grijpma, Dirk W.; Buma, Pieter

    The aim of the current in vitro study was to investigate if tissue surface modification with collagenase and addition of the TGF-beta 3 can increase the number of cells present in meniscus tears repaired with the use of newly developed tissue adhesives based on isocyanate-terminated block

  3. 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…

  4. Efficient Synthesis of 2-(8-Quinolinoxy)-4H-imidazolin-4-ones

    Institute of Scientific and Technical Information of China (English)

    DING Ming-wu; SHU Ya-li; LIU Zhao-jie

    2003-01-01

    The title compounds 2-(8-quinolinoxy)-4H-imidazolin-4-ones(4) were synthesized by means of base catalytic reactions of 8-hydroxyquinoline with each of carbodiimides 2, which were obtained via aza-Wittig reactions of iminophosphoranes 1 with the corresponding aromatic isocyanates.

  5. Monomers, polymers and articles containing the same from sugar derived compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gallagher, James; Reineke, Theresa; Hillmyer, Marc A.

    2016-11-29

    Disclosed herein are monomers formed by reacting a sugar derived compound(s) comprising a lactone and two hydroxyls with a compound(s) comprising an isocyanate and an acrylate or methacrylate. Polymers formed from such monomers, and articles formed from the polymers are also disclosed.

  6. Polyurethane triblock copolymers with mono-disperse hard segments. Influence of the hard segment length on thermal and thermomechanical properties

    NARCIS (Netherlands)

    Arun, Araichimani; Baack, Kasper K.J.; Gaymans, Reinoud J.

    2008-01-01

    Polyurethane triblock copolymers were synthesized by reacting 4,4-methylenebis(phenyl isocyanate) (MDI)-endcapped poly(tetramethylene oxide) (PTMO) with mono-amine-amide (MMA) units. Four different MMA units were used, i.e. no-amide (6m), mono-amide (6B), di-amide (6T6m) and tri-amide (6T6B), based

  7. 77 FR 5096 - Certain New Chemicals; Receipt and Status Information

    Science.gov (United States)

    2012-02-01

    .... producing packaging films. P-12-0089 12/06/2011 03/04/2012 Brueggemann (G) Zinc is a (S) Process Chemical U...) Isocyanate crosslinker P-11-0591 12/02/2011 11/23/2011 (G) Ipdi modified polyester resin P-11-0622 12/16/2011...

  8. C-14 and C-13 labelling of 4-terbutylanilinochlorethylurea. Marquage par [sup 14]C et [sup 3]C du terbutylanilino-4 chloroethyluree

    Energy Technology Data Exchange (ETDEWEB)

    Azim, M.; Madelmont, J.C.; Cussac, C.; Rapp, M. Maurizis, J.C.; Godeneche, D. (INSERM U 71, 63 - Clermont-Ferrand (France)); Gaudreault, R.G. (Hopital Saint-Francois d' Assise, Quebec (Canada). Centre de Recherche); Veyre, A. (INSERM U 71, 63 -Clermont-Ferrand (France) Clermont-Ferrand Univ., 63 -Clermont-Ferrand (France). Lab. de Biophysique Medicale)

    1993-11-01

    The labelling of 2-chloroethylisocyanate with [sup 14]C and [sup 13]C on the carbonyl group from 3-chloropropionic acid [sup 14]C and [sup 13]C is described. This isocyanate was used to synthesize 4-tert butyl [3-(2-chloro ethyl) ureido] (benzene). (Author).

  9. BETA-GLUCURONYL CARBAMATE BASED PRO-MOIETIES DESIGNED FOR PRODRUGS IN ADEPT

    NARCIS (Netherlands)

    LEENDERS, RGG; GERRITS, KAA; RUIJTENBEEK, R; SCHEEREN, HW; Haisma, Hidde; BOVEN, E

    1995-01-01

    A number of pro-moieties 8a - e designed for prodrug preparation have been synthesized (chart 2). The pro-moieties, containing a glucuronyl carbamate group linked to a spacer possessing a terminal carboxylic acid group, have been synthesized from isocyanates 6 and anomerically unprotected glucuronic

  10. Poly(hydroxy urethane)s based on renewable diglycerol dicarbonate

    NARCIS (Netherlands)

    Velthoven, van Juliën L.J.; Gootjes, Linda; Es, van Daan S.; Noordover, Bart A.J.; Meuldijk, Jan

    2015-01-01

    Abstract In this paper, we present a series of amorphous non-isocyanate poly(hydroxy urethane)s (PHU) synthesized from diglycerol dicarbonate in bulk conditions at mild temperatures, without using a catalyst. Diglycerol dicarbonate has been synthesized from diglycerol and dimethyl carbonate and w

  11. One-Pot Synthesis for Biocompatible Amphiphilic Hyperbranched Polyurea Micelles

    NARCIS (Netherlands)

    Xiang, Fei; Stuart, Marc; Vorenkamp, Joop; Roest, Steven; Timmer-Bosscha, Hetty; Fokkink, Remco; Loontjens, Ton

    2013-01-01

    Here we report, for the first time to our knowledge, a method to synthesize AB(2) monomers, the corresponding hyperbranched and the corresponding amphiphilic hyperbranched polymers in a one-pot procedure, starting from two commercial available compounds. Since the B groups were blocked isocyanates

  12. 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

    2014-01-01

    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 user's difficulty in distinguishing 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.

  13. Near-edge X-ray absorption fine structure spectroscopy of MDI and TDI polyurethane polymers

    Energy Technology Data Exchange (ETDEWEB)

    Urquhart, S.G.; Smith, A.P.; Ade, H.W. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Physics; Hitchcock, A.P. [McMaster Univ., Hamilton, Ontario (Canada). Brockhouse Inst. for Materials Research; Rightor, E.G. [Dow Chemical USA, Midland, MI (United States); Lidy, W. [Dow Chemical USA, Freeport, TX (United States)

    1999-06-03

    The sensitivity of near-edge X-ray absorption fine structure (NEXAFS) to differences in key chemical components of polyurethane polymers is presented. Carbon is NEXAFS spectra of polyurethane polymers made from 4,4{prime}-methylene di-p-phenylene isocyanate (MDI) and toluene diisocyanate (TDI) isocyanate monomers illustrate that there is an unambiguous spectroscopic fingerprint for distinguishing between MDI-based and TDI-based polyurethane polymers. NEXAFS spectra of MDI and TDI polyurea and polyurethane models show that the urea and carbamate (urethane) linkages in these polymers can be distinguished. The NEXAFS spectroscopy of the polyether component of these polymers is discussed, and the differences between the spectra of MDI and TDI polyurethanes synthesized with polyether polyols of different molecular composition and different molecular weight are presented. These polymer spectra reported herein provide appropriate model spectra to represent the pure components for quantitative microanalysis.

  14. Influence of prepolymer composition on polyurethane morphology

    Science.gov (United States)

    Krishnamoorthy, Jayaraman; Jeong, Young Gyu; Hashida, Tomoko; Hsu, Shaw Ling

    2004-03-01

    Polyurethane chemistry is one of the most studied subjects. Yet many aspects remain unexplained. Polyurethanes are synthesized by the reaction of diisocyanate with diol in the presence of nucleophilic catalysts. Polyurethane prepolymers are obtained by reacting the polyester diol / polyether diol with diisocyanate, with [NCO] / [OH] > 1, resulting in isocyanate-terminated polyester/polyether mixture. Prepolymers thus synthesized can be cured at a later stage to realize various morphologies and structures. Though the initial composition and the final morphology are known, little is known about the intermediate prepolymer mixture. Due to the different reactivity of primary and secondary hydroxyl groups in the polyester and polyether towards isocyanate, prepolymer has a non-random distribution in terms of composition as blends and copolymers. Our aim is to characterize the prepolymer by different techniques and study how the different prepolymer composition, with varying polyester and polyether ratio, affects the morphology and phase separation kinetics of the final product.

  15. Hydrolyzable polyureas bearing hindered urea bonds.

    Science.gov (United States)

    Ying, Hanze; Cheng, Jianjun

    2014-12-10

    Hydrolyzable polymers are widely used materials that have found numerous applications in biomedical, agricultural, plastic, and packaging industrials. They usually contain ester and other hydrolyzable bonds, such as anhydride, acetal, ketal, or imine, in their backbone structures. Here, we report the first design of hydrolyzable polyureas bearing dynamic hindered urea bonds (HUBs) that can reversibly dissociate to bulky amines and isocyanates, the latter of which can be further hydrolyzed by water, driving the equilibrium to facilitate the degradation of polyureas. Polyureas bearing 1-tert-butyl-1-ethylurea bonds that show high dynamicity (high bond dissociation rate), in the form of either linear polymers or cross-linked gels, can be completely degraded by water under mild conditions. Given the simplicity and low cost for the production of polyureas by simply mixing multifunctional bulky amines and isocyanates, the versatility of the structures, and the tunability of the degradation profiles of HUB-bearing polyureas, these materials are potentially of very broad applications.

  16. Polyurethane synthesis reactions in asphalts

    Energy Technology Data Exchange (ETDEWEB)

    Bukowski, A.; Gretkiewicz, J.

    1982-04-01

    A series of asphalt-polyurethane composites was prepared by means of polyurethane synthesis in asphalt and carried out in melt. The applied materials were asphalts of differentiated group components content, polyester polyols of chain structure from linear to strongly branched, 2,4-tolylene diisocyanate, 4,4-methylenebis(phenyl isocyanate), and tinorganic catalyst. The asphalt components react with isocyanates to a minimal degree. The influence of the applied substrates, temperature, and polyurethane content in the system on the basic kinetic relations characterizing the process is presented. Polyurethane synthesis in asphalts does not differ in a fundamental way from the obtaining of polyurethanes, especially when their content in the composition is significant, 20 wt% and more.

  17. Convenient Synthesis and Antimicrobial Activity of Some Novel Amino Acid Coupled Triazoles

    Directory of Open Access Journals (Sweden)

    S. M. El Rayes

    2010-09-01

    Full Text Available This study describes a promising one-pot synthesis of [2-(5-benzyl-4-phenyl-4H-[1,2,4]triazol-3-thio-acetyl]-amino acid methyl esters 6a-h and dipeptides 10a-e, which were successfully synthesized starting from amino acid esters 5a-h, 9a-e and azides 4, 8a,b, respectively. On the other hand, azide 4 underwent Curtius rearrangement to the corresponding isocyanate, which subsequently reacted with selected aliphatic amine and/or aniline derivatives to give the corresponding urea derivatives 11 and 12a,b. Reactions of the isocyanate with secondary amines gave amide derivatives 13a,b. The structural elucidation of products is reported and some of the products were also screened for their antimicrobial activity.

  18. Synthesis and Performance of Polyurethane Coated Urea as Slow/controlled Release Fertilizer

    Institute of Scientific and Technical Information of China (English)

    LI Qingshan; WU Shu; RU Tiejun; WANG Limin; XING Guangzhong; WANG Jinming

    2012-01-01

    Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules,isocyanate,polyols and paraffin.Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea granules surface.Paraffin serves as a lubricant during syntheses of polyurethane skin layers.The structure and nutrient release characteristics of the polyurethane skin layers were investigated by FTIR,SEM and TG.Urea nitrogen slow-release behavior of the polyurethane coated urea was tested.The experimental results indicated that compact and dense polyurethane skin layers with a thickness of 10-15 μm were formed on urea surface,the urea nitrogen slow-release time can reach 40-50 days.Paraffin proves to play a key role in inhibiting water to penetrate into urea,but excessive addition would decrease the polyurethane crosslinking density.

  19. Physical Properties of Soy-Phosphate Polyol-Based Rigid Polyurethane Foams

    Directory of Open Access Journals (Sweden)

    Hongyu Fan

    2012-01-01

    Full Text Available Water-blown rigid polyurethane (PU foams were made from 0–50% soy-phosphate polyol (SPP and 2–4% water as the blowing agent. The mechanical and thermal properties of these SPP-based PU foams (SPP PU foams were investigated. SPP PU foams with higher water content had greater volume, lower density, and compressive strength. SPP PU foams with 3% water content and 20% SPP had the lowest thermal conductivity. The thermal conductivity of SPP PU foams decreased and then increased with increasing SPP percentage, resulting from the combined effects of thermal properties of the gas and solid polymer phases. Higher isocyanate density led to higher compressive strength. At the same isocyanate index, the compressive strength of some 20% SPP foams was close or similar to the control foams made from VORANOL 490.

  20. Oscillatory thermal instability - the Bhopal disaster and liquid bombs

    CERN Document Server

    Ball, Rowena

    2011-01-01

    Thermal runaway reactions were involved in the Bhopal disaster of 1984, in which methyl isocyanate was vented from a storage tank of the liquid, and occur in liquid peroxide explosions, yet to date there have been few investigations into the mechanism of thermal runaway in such liquid thermoreactive systems. Consequently protocols for storing thermally unstable liquids and deactivating liquid bombs may be suboptimal. In this work the hydrolysis of methyl isocyanate and the thermal decomposition of triacetone triperoxide were simulated using a gradientless, continuous-flow reactor paradigm. This approximation enabled stability analyses on the steady state solutions of the dynamical mass and enthalpy equations. The results indicate that thermal runaway in both systems is due to the onset of a large amplitude, hard thermal oscillation initiated at a subcritical Hopf bifurcation. This type of thermal misbehaviour cannot be predicted using classical ignition theory, and may be typical of liquid thermoreactive syst...

  1. High performance of N-alkoxycarbonyl-imines in triethylborane-mediated tin-free radical addition.

    Science.gov (United States)

    Yamada, Ken-ichi; Konishi, Takehito; Nakano, Mayu; Fujii, Shintaro; Cadou, Romain; Yamamoto, Yasutomo; Tomioka, Kiyoshi

    2012-02-03

    Triethylborane-mediated tin-free radical alkylation of N-alkoxycarbonyl-imines, such as N-Boc-, N-Cbz-, and N-Teoc-imines, proceeded smoothly at a low temperature (-78 to -20 °C) to give the corresponding adducts in high yield. Although the formation of isocyanate was the major unfavorable reaction at room temperature, a one-pot conversion of N-Boc-imine to N-ethoxycarbonyl-adduct was possible through the corresponding isocyanate generated in situ. The higher performance of N-alkoxycarbonyl-imine than those of N-Ts- and N-PMP-imines is rationalized by a moderate electron-withdrawing character of an alkoxycarbonyl group that makes both addition of alkyl radical and trapping of the resulting aminyl radical by triethylborane efficiently fast.

  2. Synthesis and antifungal activities of 3-alkyl substituted thieno[2,3-d]pyrimidinones

    Science.gov (United States)

    Wang, H. M.; Deng, S. H.; Zheng, A. H.; Zhang, Q. Y.; Chen, X. B.; Zeng, X. H.; Hu, Y. G.

    2016-08-01

    The 3-aryl substituted thieno[2,3-d]pyrimidinones 3 by sequential reaction of iminophosphorane 1, aromatic isocyanates and various nucleophiles (HY), found some compounds showed good antitumor and antibacterial activities. Meanwhile, aliphatic isocyanates were applied in the reaction to prepare 3-alkyl substituted thieno[2,3- d]pyrimidinones, but there are no reports of their antifungal activities. As a continuation of our research for new biologically active heterocycles, we herein wish to report a facile synthesis and antifungal activities of 3-alkyl substituted thieno[2,3-d]pyrimidinones 6 via easily accessible iminophosphorane 1. The growth inhibitory effect of one concentration (50mg/L) of compounds 6 against five fungus(Fusarium oxysporium, Rhizoctonia solani, Colletotrichum gossypii, Gibberella zeae and Dothiorella gregaria) in vitro was tested by the method of toxic medium. Compound 6d showed the best inhibition rate against Gibberella zeae with 85.68%.

  3. Development of a Polyuretbane Binder System Giving a 'Knottable' Composite Solid Propellant

    Directory of Open Access Journals (Sweden)

    E. Devadoss

    1985-01-01

    Full Text Available Polyurethane propellants, which constitute one of the 'work-horse' binder systems in modern solid rocketry are easily amenable for tailoring the mechanical properties in terms of variations in the molecular structure of the backbone polyols, the isocyanates and stoichiometry of the reactants. The paper deals with studies in developing an advanced binder system based on poly (oxy propylene glycol and toluene-di-isocyanate, which is capable of accommodating high solids loading and conceding elongatlon at maximum stress, of more than 125 per cent. The gum-stock properties of the binder are related with those of a low molecular weight version and the results are explained based on the network theory of condensation polymers.

  4. [3,3]-sigmatropic rearrangements of fluorinated allyl (Thio)cyanates - a tool for the synthesis of fluorinated (Thio)ureas.

    Science.gov (United States)

    Ramb, Daniel C; Kost, Lisa; Haufe, Günter

    2014-01-01

    The first (thio)cyanate to iso(thio)cyanate rearrangements based on 2-fluoroallylic alcohols are presented. Long-chain 2-fluoroallylic alcohols were converted to corresponding N-unsubstituted carbamates by treatment with trichloroacetyl isocyanate. Dehydration using trifluoroacetic anhydride in the presence of triethylamine formed intermediate allylic cyanates, which immediately underwent sigmatropic rearrangement to fluorinated allyl isocyanates. Without isolation the latter delivered fluorinated ureas by addition of amines. The thiocyanate to isothiocyanate rearrangements started from the same fluorinated allylic alcohols, which were first converted to mesylates. Heating in THF with potassium thiocyanate led to fluorinated allyl isothiocyanates, via [3,3]-sigmatropic rearrangement of intermediate allyl thiocyanates. The formed products were further reacted with amines to fluorinated thioureas.

  5. Preparation of polyamide 6/silica nanocomposites from silica surface initiated ring-opening anionic polymerization

    Directory of Open Access Journals (Sweden)

    2007-07-01

    Full Text Available Polyamide 6/silica nanocomposites were synthesized by in situ ring-opening anionic polymerization of ε-caprolactam in the presence of sodium caprolactamate as a catalyst and caprolactam-functionalized silica as an initiator. The initiator precursor, isocyanate-functionalized silica, was prepared by directly reacting commercial silica with excess toluene 2,4-diisocyanate. This polymerization was found to occur in a highly efficient manner at relatively low reaction temperature (170°C and short reaction times (6 h. FTIR spectroscopy was utilized to follow the introduction and consumption of isocyanate groups on the silica surface. Thermogravimetric analysis indicated that the polyamide 6 was successfully grown from the silica surface. Transmission electron microscopy was utilized to image polymer-functionalized silica, showing fine dispersion of silica particles and their size ranging from 20 to 40 nm.

  6. Evaluating Dimethyldiethoxysilane for use in Polyurethane Crosslinked Silica Aerogels

    Science.gov (United States)

    Randall, Jason P.; Meador, Mary Ann B.; Jana, Sadhan C.

    2008-01-01

    Silica aerogels are highly porous materials which exhibit exceptionally low density and thermal conductivity. Their "pearl necklace" nanostructure, however, is inherently weak; most silica aerogels are brittle and fragile. The strength of aerogels can be improved by employing an additional crosslinking step using isocyanates. In this work, dimethyldiethoxysilane (DMDES) is evaluated for use in the silane backbone of polyurethane crosslinked aerogels. Approximately half of the resulting aerogels exhibited a core/shell morphology of hard crosslinked aerogel surrounding a softer, uncrosslinked center. Solid state NMR and scanning electron microscopy results indicate the DMDES incorporated itself as a conformal coating around the outside of the secondary silica particles, in much the same manner as isocyanate crosslinking. Response surface curves were generated from compression data, indicating levels of reinforcement comparable to that in previous literature, despite the core/shell morphology.

  7. 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.

  8. 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

  9. The mineralocorticoid receptor-p38MAPK-NFκB or ERK-Sp1 signal pathways mediate aldosterone-stimulated inflammatory and profibrotic responses in rat vascular smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    Chuan-jiang ZHU; Qing-qing WANG; Jun-lan ZHOU; Han-zhi LIU; Fang HUA; Hong-zheng YANG; Zhuo-wei HU

    2012-01-01

    Aim:To explore the signalling pathways involved in aldosterone-induced inflammation and fibrosis in rat vascular smooth muscle cells (VSMCs).Methods:Using Western blotting and real-time RT-PCR,we investigated the effects of aldosterone on the expression of cyclooxygenase-2 (Cox-2) and IL-6,two important proinflammatory factors,and TGFβ1,a critical profibrotic factor,in VSMCs.Results:Aldosterone treatment significantly increased the expression of Cox-2 and IL-6 and activation of p38MAPK and NF-κB.The expression of both Cox-2 and IL-6 could be blocked by the mineralocorticoid receptor (MR) antagonist spironolactone and the p38MAPK inhibitor SB203580.Also,the rapid phosphorylation of p38MAPK could be suppressed by SB203580 but not by spironolactone,implicating in nongenomic effects of aldosterone.Similar to SB203580 and spironolactone,the NF-κB inhibitor α-p-tosyl-L-lysine chloromethyl ketone (TLCK) markedly attenuated expression of Cox-2,indicating that MR,p38MAPK and NF-KB are associated with aldosterone-induced inflammatory responses.Furthermore,aldosterone enhanced expression of TGFβ1 in rat VSMCs.This result may be related to activation of the MR/ERK-Sp1 signalling pathway because PD98059,an ERK1/2 inhibitor,significantly blocked the rapid phosphorylation of ERK1/2 and function of Sp1 and led to reduced expression of TGFβ1.Spironolactone was also shown to significantly inhibit TGFβ1 and Sp1 expression but not ERK1/2 phosphorylation.Conclusion:These results suggest that aldosterone-induced inflammatory responses and fibrotic responses may be mediated by the MR/p38MAPK-NF-κB pathways and the MR/ERK-Sp1 pathways in VSMCs,respectively.

  10. Partial purification and characterization of trypsin-like proteinases from insecticide-resistant and -susceptible strains of the maize weevil, Sitophilus zeamais.

    Science.gov (United States)

    Silva, L B; Reis, A P; Pereira, E J G; Oliveira, M G A; Guedes, R N C

    2010-01-01

    Serine proteinases from three strains of Sitophilus zeamais (Coleoptera: Curculionidae), one susceptible and two resistant to insecticides--one exhibiting fitness cost (resistant cost strain) and the other lacking it (resistant no-cost strain), were partially purified using an aprotinin-agarose affinity column providing purification factors ranging from 36.5 to 51.2%, with yields between 10 and 15% and activity between 529 and 875 microM/min/mg protein with the substrate N-alpha-benzoyl-L-Arg-p-nitroanilide (L-BApNA). SDS-PAGE of the purified fraction revealed a 56,000 Da molecular mass band in all strains and a 70,000 Da band more visible in the resistant no-cost strain. The purified proteinases from all strains were inhibited by phenylmethyl sulphonyl fluoride (PMSF), N-alpha-tosyl-L-lysine chloromethyl ketone (TLCK), aprotinin, benzamidine and soybean trypsin inhibitor (SBTI) characterizing them as trypsin-like serine proteinases. Trypsin-like proteinases from the resistant strains exhibited higher affinity for L-BApNA. The resistant no-cost strain exhibited V(max)-values 1.5- and 1.7-fold higher than the susceptible and resistance cost strains, respectively. A similar trend was also observed when using N-alpha-p-tosyl-L-Arg methyl ester (L-TAME) as substrate. These results provide support to the hypothesis that the enhanced serine proteinase activity may be playing a role in mitigating physiological costs associated with the maintenance of insecticide resistance mechanisms in some maize weevil strains.

  11. Hazard Concerns: MIC at Bhopal and Virginia and the Indian Nuclear Liability Act

    OpenAIRE

    2012-01-01

    Oblivious to the anger and outrage expressed throughout the world after the methyl isocyanate leak in December 1984, the continued storage of MIC at the parent West Virginia plant until 2011, despite several accidents, indicates the limited effect of public safety concerns on corporate strategy. As in India, neither the US executive nor the judiciary seemed capable of withstanding pressures exerted by the chemical processing industry. This is an ongoing story of struggle. What gave Bhopal a f...

  12. A new peptide-based urethane polymer: synthesis, biodegradation, and potential to support cell growth in vitro

    OpenAIRE

    Zhang, Jian Ying; Beckman, Eric J.; Piesco, Nicholas P.; Agarwal, Sudha

    2000-01-01

    A novel non-toxic biodegradable lysine-di-isocyanate (LDI)-based urethane polymer was developed for use in tissue engineering applications. This matrix was synthesized with highly purified LDI made from the lysine diethylester. The ethyl ester of LDI was polymerized with glycerol to form a prepolymer. LDI–glycerol prepolymer when reacted with water foamed with the liberation of CO2 to provide a pliable spongy urethane polymer. The LDI–glycerol matrix degraded in aqueous solutions at 100, 37, ...

  13. Facile and efficient synthesis of 5, 7-disubstituted thiazolo [5,4-d] pyrimidine-4, 6 (5H, 7H)-diones

    Institute of Scientific and Technical Information of China (English)

    Liang Chen; Zhan Mei Li; Jie Zhou; Hong Rui Song; Bai Ling Xu

    2012-01-01

    A facile and efficient approach was developed to access 5,7-disubstitued thiazolo[5,4-d]pyrimidine-4,6(5H,7H)-diones through condensation of N-substituted 5-amino-4-carbethoxythiazole with structurally diverse isocyanates in the presence of sodium hydride.The easy availability of substrates and tolerance of structural diversity in this reaction make it attractive to he used for constnuction of libraries in drug discovery process.

  14. 77 FR 13596 - Certain New Chemicals; Receipt and Status Information

    Science.gov (United States)

    2012-03-07

    ... 02/13/2012 05/12/2012 CBI (G) Open, non (G) Polyurethane dispersive use. dispersion. P-12-0180 02/13... isocyanate and polyether glycol. P-12-0174 02/02/2012 05/01/2012 CBI (G) Rubber (G) Polyurethane. adhesive.../03/2012 01/05/2012 (G) Alkyl ethoxylate. P-10-0209 02/02/2012 01/05/2012 (G) Polyurethane resin....

  15. Incorporation of CdS nonoparticles from colloidal solution into optically clear ureasilicate matrix with preservation of quantum size effect

    OpenAIRE

    Boev, Victor I.; Soloviev, A.; Silva, Carlos J. R.; Gomes, M.J.M.

    2006-01-01

    Nanocomposite materials based on an organic-inorganic ureasilicate matrix with embedded CdS nanoparticles were produced and characterized by optical (UV/Vis), FTIR, secondary ion mass spectroscopy, inductively-coupled plasma optical emission and steady-state photoluminescence measurements. The ureasilicate precursor was obtained by the reaction between silicon alkoxyde modified by isocyanate groups and polyethylene glycol oligomers with amine terminal groups. The final nanocomposites were pre...

  16. Production of high molecular weight polylactic acid

    Science.gov (United States)

    Bonsignore, Patrick V.

    1995-01-01

    A degradable high molecular weight poly(lactic acid). A poly(lactic acid) has a terminal end group of one of carboxyl or hydroxyl groups with low molecular weight poly(lactic acid) units coupled with linking agents of di-isocyanates, bis-epoxides, bis-oxazolines and bis-ortho esters. The resulting high molecular weight poly(lactic acid) can be used for applications taking advantage of the improved physical properties.

  17. Reactive formulations for a neutralization of toxic industrial chemicals

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. Structure and Properties of Polyurethanes. Part 1,

    Science.gov (United States)

    1979-03-23

    obtaining at the first stages of the reaction of urethane, uric dnd amido groups with isocyanates, is possible the formation of aiucat l...isocyanourate ring, biuret group (carbonyl). (7). Allophanate group (carbonyl). (d). Uric and amido groups (carbonyl). (9). Uretedione ring (oscillations...removal/taking from the specimen/sample of voltage/ stress . Forms f and 7 are easily formed, when the molecular chains of polyurethane are orientea

  19. Bitumen modifiers for reduced temperature asphalts: a comparative analysis between three polymeric and non-polymeric additives

    OpenAIRE

    Cuadri Vega, Antonio Abad; Carrera Páez, Virginia; Izquierdo Rodríguez, María Angeles; García Morales, Moisés; Navarro Domínguez, Francisco Javier

    2014-01-01

    This study presents three bitumen modifiers which may find successful application in the fabrication of binders for warm mix asphalt in the paving industry. In that sense, two non-polymeric additives, thiourea and thiourea dioxide, along with a reactive isocyanate-terminated prepolymer have been evaluated. Viscous flow and linear viscoelasticity tests, at 60 ºC, reveal bituminous modified binders which evolve towards highly viscous materials when subjected to ambient curing. However, at 135 º...

  20. Real-time monitoring of polyurethane production using near-infrared spectroscopy; Produzione di poliuretano : controllo in tempo reale mediante spettroscopia nel vicino infrarosso

    Energy Technology Data Exchange (ETDEWEB)

    Arenaccio, G.A. [Perstorp Analytical, Morena, Rome (Italy); De Thomas, F. A.; Monfre, S.L. [NIRSystems inc., Silver Spring, MD (United States); Hall, J.W. [NIRSystems inc., Toronto, ON (Canada)

    1996-11-01

    A process near-infrared (NIR) spectrophotometer was interfaced directly to a reactor by using a fiber optic bundle interactive immersion probe. This remote sensor configuration enables the production of polyurethanes to be monitored in real-time. A Beer`s Law model was derived for the quantitative determination of isocyanate in the urethane polymerization reaction. Statistical process control was used to observe trends in the polymerization reaction.

  1. Synthesis and Characterization of Polyurethane-Nanoclay Composites

    OpenAIRE

    Manasa Nayani; Subhashini Gunashekar; Nidal Abu-Zahra

    2013-01-01

    In this study polyurethane (PUR)-nanoclay composites were synthesized using methylene diphenyl diisocyanate, polyol, and hectorite clay. The weight percentage of hectorite clay was varied at three different levels to study its effect on the properties of the thermoplastic polyurethane nanocomposite. The nanocomposite polyurethane foam was synthesized in a 2-step reaction process. The first step involved the addition and dispersion of nanoclay into the isocyanate. The mixture was then mixed wi...

  2. Characterization of Polyurethane Foam Added with Synthesized Acetic and Oleic-modified TiO2Nanocrystals

    OpenAIRE

    Caterina Lorusso; Viviana Vergaro; Annagrazia Monteduro; Antonio Saracino; Giuseppe Ciccarella; Paolo Maria Congedo; Barbara Federica Scremin

    2015-01-01

    In this work, the effects due to the addition of nanoparticles in polyurethane foams on thermo-physical and mechanical properties have been evaluated. Two types of nanoparticles were used, acetic and oleic-modified titania nanocrystals TiO2. The nanoparticles were first dispersed in a polyol component via the use of sonication; then, the doped polyol was mixed with isocyanate. The different characterization techniques describe the state of the dispersion of fillers in foam. The effects of the...

  3. Enhanced Preliminary Assessment. Kapalama Military Reservation Honolulu, Hawaii

    Science.gov (United States)

    1990-02-01

    outside. S~Biing 924, Canvas j epair Area & Packagi’ng Area - water- proofing with polymer-type water repellents; packaging with isocyanate foam; "waste...soil sample collected directly under an area of asphalt paving would be contaminated by semivolatile compounds present in the asphalt . In regard to... asphalt (>99%), except for small grassy areas near the perimeter fence and a small area of ornamental shrubs and trees near the mortuary/chapel (Buildings

  4. Non-Lethal Defense III, Johns Hopkins Applied Physics Laboratory, Laurel, Maryland, February 25 & 26, 1998, Revised Agenda.

    Science.gov (United States)

    1998-02-26

    give up all together, looking elsewhere for easier entrance. The rigid foam process is based on two major chemical components - polyol and isocyanate ...applicable for universal usage. On paved non-porous surfaces, such as asphalt roadways or concrete runways, or on well-compacted soils these...Kevlar, or novel biomimetics of Kevlar based on spider silk. Asphalt is degraded by several strains of bacteria, leading to greatly reduced road surface

  5. Response Manual for Combating Spills of Floating Hazardous CHRIS chemicals

    Science.gov (United States)

    1989-01-01

    DISULFIDE ARD No ARSENIC PENTAOXIDE APO No ARSENIC TRICHLORIDE AST No ARSENIC TRIOXIDE ATO No ARSENIC TRISULFIDE ART No ASPHALT ASP Possibly ASPHALT ...BLENDINGS STOCKS: ROOFERS FLUX ARF No ASPHALT BLENDING STOCKS:STRT.RUN RESIDUE ASR No ATRAZINE ATZ No AZINPHOSMETHYL AZM No BARIUM CARBONATE BRC No BARIUM...POLYETHYLENE POLYAMINES PEB No data POLYMETHYLENE POLYPHENYL ISOCYANATE PPI No POLYPHOSPHORIC ACID PPA No POLYPROPYLENE PLP Yes POLYPROPYLENE GLYCOL PGC

  6. High Voltage Design Guide. Volume IV. Aircraft

    Science.gov (United States)

    1983-01-01

    by the reaction of urea with formaldehyde. An amino resin. Urethane. See Isocyanate Resins. Vinyl Resin. A synthetic resin formed by the polymerization...oxidation reactions are sludge, asphalt , a:ids, organic esters, soaps, and oxides. Oil color, as an index of the degree of refineme.. for unused oils...Materials Alkyd resins Acrylic plastics Cellulose esters Asphalt Cork Chloride flux Epoxy resins Copper (bare) Masonite Fiber board Melamine resins Greases

  7. Enhanced Preliminary Assessment Report: Jefferson Proving Ground Madison, Indiana

    Science.gov (United States)

    1990-03-01

    that I was covered over with asphalt or tar. Red lead is a heavy metal, which may be mobile under certain conditions. Excavation work done in these...020 JPG-020 is an approximately 1/2-acre Macadam ( asphalt ) lined test pond (Figure 9). The pond was drained and no munitions-related materials were...mixtures- 55-gal drums Polyols and polymeric isocyanates 110 gal Barium sulfate 8,600 lbs Petroleum wax I i. I (Bldg 227) W eapons Maintenance

  8. Polyurethane Binder Systems for Polymer Bonded Explosives

    Science.gov (United States)

    2006-12-01

    Weight HDI Hexamethylene diisocyanate HMX Cyclotetramethylene tetranitramine, octogen HPLC High performance liquid chromatography HTCE Hydroxy-terminated...standardised ‘VOLUCON’ potassium hydroxide (N/10) is poured into a 200 mL volumetric flask and topped up with methanol. Shake and leave to stand. 3...Titrate until the first appearance of a stable yellow colour . Titrate a blank (prepared exactly as above without adding the isocyanate

  9. Synthesis and antibacterial activity of novel N-acylsulfonamides

    Directory of Open Access Journals (Sweden)

    Malika Berredjem

    2017-02-01

    Full Text Available A series of novel N-acylsulfonamide derivatives were synthesized and characterized by 1H NMR, 13C NMR and HRMS. The N-acylsulfonamides were prepared in four steps (carbamoylation, sulfamoylation, deprotection and acylation starting from chlorosulfonyl isocyanate. These compounds were evaluated in vitro as antimicrobial agents against representative strains of Gram-positive (Staphylococcus aureus and Gram-negative (Escherichia coli, Acinetobacter, Klebsiella pneumonia and Pseudomonas aeruginosa.

  10. 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.

  11. Polyfibroblast: A Self-Healing and Galvanic Protection Additive

    Science.gov (United States)

    2012-11-26

    raising the isocyanate to amine ratio from 1:0.6 to 1:1 appears to accelerate shell-cure to about 4 days. Increasing heat soak temperature and adding an...amino-ether catalyst further reduced shell-cure to 2 days. Upon visual inspection, microcapsules made in this fashion look as good as, if not better... polyurethane -urea (MCPU). When scratched, the foaming action of a propellant ejects the resin from the broken tubes and completely fills the crack. No

  12. A Facile Synthesis of 2, 7-Diaminothieno[2, 3-d:5,4-d]- dipyrimidine-4, 5(3H, 6H)diones

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    2, 7-Diaminothieno[2, 3-d:5, 4-d]dipyrimidine-4, 5(3H, 6H)diones 4 were synthesized by a facile synthetic method, which includes bis-aza-Wittig reaction of bis-iminophosphorane 1with aromatic isocyanate to give bis-carbodiimide 2 and subsequent reaction of 2 with various dialkylamine in the presence of solid K2CO3 or EtONa.

  13. Efficient synthesis of 4(3H)-quinazolinones using a soluble polymeric support

    Institute of Scientific and Technical Information of China (English)

    Chang Xie; Hong Xia Li; Ming Guo Liu; Ming Wu Ding

    2008-01-01

    4(3H)-Quinazolinones have been synthesized from poly(ethylene glycol) (PEG) supported aza-Wittig reaction. 2-Dialkylamino-4(3H)-quinazolinones 6 were synthesized efficiently by reaction of secondary amine with PEG-supported carbodiimides 4, whichwere obtained from aza-Wittig reaction of PEG-supported iminophosphoranes 3 with isocyanates.?2008 Ming Wu Ding. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  14. The Effect of Carboxymethyl Cellulose Addition on the Properties of Starch-based Wood Adhesive

    OpenAIRE

    Zhibang Qiao; Jiyou Gu; Yingfeng Zuo; Haiyan Tan; Yanhua Zhang

    2014-01-01

    Starch adhesive was prepared utilizing corn starch, polyvinyl alcohol, and borax as raw materials. A certain amount of water-soluble carboxymethyl cellulose (CMC) was added in the preparation process, and a certain percentage of polymethylene polyphenylene isocyanate pre-polymer as cross-linking agent was used to improve its water resistance. To evaluate the water resistance, three-layer plywood was fabricated by hot pressing, and bonding strength was measured using a mechanical testing machi...

  15. Nanofibers for drug delivery – incorporation and release of model molecules, influence of molecular weight and polymer structure

    OpenAIRE

    2015-01-01

    Nanofibers were prepared from polycaprolactone, polylactide and polyvinyl alcohol using NanospiderTM technology. Polyethylene glycols with molecular weights of 2 000, 6 000, 10 000 and 20 000 g/mol, which can be used to moderate the release profile of incorporated pharmacologically active compounds, served as model molecules. They were terminated by aromatic isocyanate and incorporated into the nanofibers. The release of these molecules into an aqueous environment was investigated. The influe...

  16. Cobalt-silica magnetic nanoparticles with functional surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Vadala, Michael L. [Department of Chemistry and the Macromolecules and Interfaces Institute, Virginia Polytechnic Institute and State University, Mail Code 0212, Blacksburg, VA 24061-0344 (United States); Zalich, Michael A. [School of Physics, The University of Western Australia, Crawley, WA 6009 (Australia); Fulks, David B. [Department of Chemistry and the Macromolecules and Interfaces Institute, Virginia Polytechnic Institute and State University, Mail Code 0212, Blacksburg, VA 24061-0344 (United States); St Pierre, Tim G. [School of Physics, The University of Western Australia, Crawley, WA 6009 (Australia); Dailey, James P. [Department of Ophthalmology, Case Western Reserve University, Cleveland, OH (United States); Riffle, Judy S. [Department of Chemistry and the Macromolecules and Interfaces Institute, Virginia Polytechnic Institute and State University, Mail Code 0212, Blacksburg, VA 24061-0344 (United States)]. E-mail: judyriffle@aol.com

    2005-05-15

    Cobalt nanoparticles encased in polysiloxane block copolymers have been heated at 600-700 deg C to form protective shells around the particles, which contain crosslinked Si-O structures, and to anneal the cobalt. Methods to functionalize and modify the surfaces of the pyrolyzed/annealed silica-cobalt complexes with amines, isocyanates, poly(ethylene oxide), poly(L-lactide) and polydimethylsiloxane (PDMS) are presented.

  17. Bitumen modifiers for reduced temperature asphalts: a comparative analysis between three polymeric and non-polymeric additives

    OpenAIRE

    Cuadri Vega, Antonio Abad; Carrera Páez, Virginia; Izquierdo Rodríguez, María Angeles; García Morales, Moisés; Navarro Domínguez, Francisco Javier

    2014-01-01

    This study presents three bitumen modifiers which may find successful application in the fabrication of binders for warm mix asphalt in the paving industry. In that sense, two non-polymeric additives, thiourea and thiourea dioxide, along with a reactive isocyanate-terminated prepolymer have been evaluated. Viscous flow and linear viscoelasticity tests, at 60 ºC, reveal bituminous modified binders which evolve towards highly viscous materials when subjected to ambient curing. However, at 135 º...

  18. Flexible composite film for printed circuit board

    Science.gov (United States)

    Yabe, K.; Asakura, M.; Tanaka, H.; Soda, A.

    1982-01-01

    A flexible printed circuit for a printed circuit board in which layers of reaction product composed of a combination of phenoxy resin - polyisocyanate - brominated epoxy resin, and in which the equivalent ratio of those functional groups is hydroxyl group: isocyanate group: epoxy group - 1 : 0.2 to 2 : 0.5 to 3 are laminated on at least one side of saturated polyester film is discussed.

  19. Design and Synthesis of Novel 5-Sulfoxide-substituted Pyrazolo[5,1-d] [1,2,3,5]tetrazin-4(3H)ones

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A series of novel 5-sulfoxide-substituted pyrazolo[5,1-d][1,2,3,5]tetrazin-4(3H)ones 4a-j were designed and efficiently synthesized via a diazotization of 5-amine-3-methylsulfinyl1H-pyrazole, followed by cycloaddition with aryl isocyanate. A possible reaction mechanism is outlined and discussed. These new compounds exhibit some biological activity as preliminary bioassay indicated. Their structures were confirmed with1 H NMR, IR and elemental analysis.

  20. Palladium-Catalyzed Synthesis of N-Aryl Carbamates

    Science.gov (United States)

    Vinogradova, Ekaterina V.; Park, Nathaniel H.; Fors, Brett P.; Buchwald, Stephen L.

    2013-01-01

    An efficient synthesis of aryl carbamates was achieved by introducing alcohols into the reaction of palladium-catalyzed cross-coupling of ArX (X = Cl, OTf) with sodium cyanate. The use of aryl triflates as electrophilic components in this transformation allowed for an expanded substrate scope for direct synthesis of aryl isocyanates. This methodology provides direct access to major carbamate protecting groups, S-thiocarbamates, and diisocyanate precursors to polyurethane materials. PMID:23441814

  1. Liner Technology Program. Volume 3. Liner Development Methodology Manual

    Science.gov (United States)

    1982-05-01

    alkenylsuccinic acids or anhydrides are available. As branched curing agents, DDI and GTRO are among the candidates. 4.1.3 Oxidatively-Stable System ...polarity polymers are carboxyl- or hydroxyl-terminated hydrocatbon I - systems cured with isocyanates or epoxides. The use of imidc epoxy - cured * ! systems ...ester linkages produced by the epoxy cure are the least subject to hydrolytic attack. " 4.1.7 Branched Chain Systems Polymers containing branched

  2. Thermal curing of an epoxy-anhydride system modified with hyperbranched poly(ethylene imine)s with different terminal groups

    OpenAIRE

    Morancho Llena, José María; Fernández Francos, Xavier; Acebo Gorostiza, Cristina; Ramis Juan, Xavier; Salla Tarragó, José María; Serra Albet, Àngels

    2017-01-01

    New hyperbranched polymers (HBP) have been synthesized by reaction of a poly(ethylene imine) with phenyl and t-butyl isocyanates. These HBPs have been characterized by 1H-NMR (nuclear magnetic resonance of hydrogen) and Fourier transform infrared spectroscopy. Their influence on the curing and properties of epoxy-anhydride thermosets has been studied by different techniques: differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetry (TG). The ...

  3. Catalytic Addition of Simple Alkenes to Carbonyl Compounds Using Group 10 Metals.

    Science.gov (United States)

    Ho, Chun-Yu; Schleicher, Kristin D; Jamison, Timothy F

    2009-10-01

    Recent advances using nickel complexes in the activation of unactivated monosubstituted olefins for catalytic intermolecular carbon-carbon bond-forming reactions with carbonyl compounds, such as simple aldehydes, isocyanates, and conjugated aldehydes and ketones, are discussed. In these reactions, the olefins function as vinyl- and allylmetal equivalents, providing a new strategy for organic synthesis. Current limitations and the outlook for this new strategy are also discussed.

  4. 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.

  5. The tris-urea motif and its incorporation into polydimethylsiloxane-based supramolecular materials presenting self-healing features.

    Science.gov (United States)

    Roy, Nabarun; Buhler, Eric; Lehn, Jean-Marie

    2013-07-01

    Materials of supramolecular nature have attracted much attention owing to their interesting features, such as self-reparability and material robustness, that are imparted by noncovalent interactions to synthetic materials. Among the various structures and synthetic methodologies that may be considered for this purpose, the introduction of extensive arrays of multiple hydrogen bonds allows for the formation of supramolecular materials that may, in principle, present self-healing behavior. Hydrogen bonded networks implement dynamic noncovalent interactions. Suitable selection of structural units gives access to novel dynamic self-repairing materials by incrementing the number of hydrogen-bonding sites present within a molecular framework. Herein, we describe the formation of a tris-urea based motif giving access to six hydrogen-bonding sites, easily accessible through reaction of carbohydrazide with an isocyanate derivative. Extension towards the synthesis of multiply hydrogen-bonded supramolecular materials has been achieved by polycondensation of carbohydrazide with a bis-isocyanate component derived from poly-dimethylsiloxane chains. Such materials underwent self-repair at a mechanically cut surface. This approach gives access to a broad spectrum of materials of varying flexibility by appropriate selection of the bis-isocyanate component that forms the polymer backbone.

  6. 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.

  7. 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%.

  8. 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.

  9. TEPIC -- A new high temperature structural foam

    Energy Technology Data Exchange (ETDEWEB)

    L. L. Whinnery; S. H. Goods; M. L. Tootle; C. L. Neuschwanger

    1998-10-01

    The formulation, processing characteristics, microstructure and mechanical properties of a new structural foam, suitable for use at service temperatures up to 200 C, are reported. In each of these respects, the foam is compared to an existing material, called APO-BMI that is currently in use. When these two foams are directly compared, the new foam, called TEPIC, is found to be superior in its mechanical performance. TEPIC is formulated from a non-carcinogenic isocyanate, a di-functional epoxide, and glass microballoons. The authors' approach was to combine chemistries known to form thermally stable products. The principal polymerization products are an oxizolidinone produced by the reaction of the isocyanate with the epoxide and isocyanurate rings formed by the trimerization of the isocyanate. Processing has been examined and large-scale production is discussed in detail. Compared to APO-BMI processing, TEPIC processing is facile and economical. The structure of the foam resembles a traditional rigid polyurethane foam rather than that of the APO-BMI. That is, the foam is comprised of a continuous resin phase rather than weakly bonded glass microballoons. At a density of 0.42 g/cm{sup 3} or greater, maximum pore size in TEPIC was less than 2 mm, as required for the application.

  10. Development of a permeation panel to test dermal protective clothing against sprayed coatings.

    Science.gov (United States)

    Ceballos, Diana M; Yost, Michael G; Whittaker, Stephen G; Reeb-Whitaker, Carolyn; Camp, Janice; Dills, Russell

    2011-03-01

    Design, construct, and characterize an apparatus to evaluate dermal protective clothing for resistance to polymerizing materials. Specifically, we evaluated the permeation of the most common glove material used in automotive collision repair (0.10-0.13 mm or 4-5 mil latex) with representative isocyanate-containing clear coats. Our ultimate goal is to make informed recommendations on dermal protective materials to prevent isocyanate exposures and reduce the likelihood of occupational illness in automotive collision repair and other industries. A novel permeation panel was developed to assess dermal protective clothing. With this apparatus, up to eight test materials may be evaluated under typical-spray application conditions. Solid collection media comprised of 1-(2-pyridyl)-piperazine (2-PP)-coated fiberglass filters or colorimetric SWYPE™ pads were placed behind test materials to capture permeants. The 2-PP-coated filters were subsequently analyzed using a modified OSHA42/PV2034 method. Color change in the SWYPEs provided an immediate field estimate of breakthrough time. In addition, Teflon filters were mounted proximal to the permeation cells to measure the mass of clear coat applied to the panel and to evaluate loading homogeneity. This study evaluated the permeation of isocyanates through 0.10-0.13 mm latex glove material at a fixed time (30 min post-spraying) and over a time course (6-91 min post-spraying). Monomers 1,6-hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI) permeated through (0.10-0.13 mm) latex glove material under typical glove use conditions (30 min). The latex glove material exhibited immediate breakthrough, with a permeation rate of 2.9 ng min(-1) cm(-2). The oligomeric forms of HDI and IPDI did not permeate the latex glove material. The spray application at 71 ± 5 °F was fairly homogeneous (33.7 ± 8 mg weight of dry clear coat per 5 cm(2)). The permeation panel is a viable method to assess dermal protective clothing

  11. 淀粉基木材胶黏剂的耐水性改性及表征%Water resistance modification and characterization of starch based wood adhesive

    Institute of Scientific and Technical Information of China (English)

    谭海彦; 左迎峰; 张彦华; 翁向丽; 顾继友

    2012-01-01

    本文通过用酒石酸对玉米淀粉进行酯化处理制备酯化淀粉胶黏剂,然后用异氰酸酯对淀粉胶黏剂进行改性.讨论了反应温度和PVA用量对淀粉胶黏剂合成过程的影响,以及固含量和异氰酸酯对淀粉胶黏剂胶接强度和耐水性的影响.结果表明,反应温度为50~55℃,10%的PVA用量为淀粉量的15%时,胶液性能最佳;固含量为50%,加入少量异氰酸酯后,淀粉胶黏剂的胶接强度和耐水性有显著提高,达到杨木GB/T9846-2004Ⅱ类胶合板指标.采用差示扫描量热法(DSC)和热重分析仪(TGA)对异氰酸酯改性淀粉胶黏剂进行了表征,结果表明,异氰酸酯可以加快淀粉胶黏剂的固化速率,提高其热稳定性.%The esterified starch adhesive was prepared treated by esterification processing with tartaric acid on corn starch, and then the isocyanate was used to niodifiy the starch adhesive. The influences of reaction temperature and PVA content on starch adhesive synthesis process were studied, as well as the effects of the solid content and isocyanates on the bonding strength and water resistance of starch adhesive were discussed. The results show that when the reaction temperature 50 ~ 55 'C , PVA (10% ) amount to be 15% , the adhesive properties was the best; the starch adhesive bonding strength and water resistance were improved significantly when the solid content to be 50%, adding a small amount of isocyanate, the treatment increased obviously bonding strength and water resistance, the products could meet the requirement of poplar wood GB/T9846-2004 II plywood. By adopting differential scanning calorimetry ( DSC ) and thermo gravimetric analysis (TGA), the esterified starch adhesive with isocyanate were characterized. The findings show that isocyanates could accelerate the curing rate and improve the thermal stability of starch adhesive.

  12. Synthesis and characterisation of coating polyurethane cationomers containing fluorine built-in hard urethane segments.

    Science.gov (United States)

    Król, Bożena; Król, Piotr; Pikus, Stanisław; Chmielarz, Paweł; Skrzypiec, Krzysztof

    2010-08-01

    Polyurethane cationomers were synthesised in the reaction of 4,4'-methylenebis(phenyl isocyanate) with polyoxyethylene glycol (M = 2,000) or poly(tetrafluoroethyleneoxide-co-difluoromethylene oxide) α,ω-diisocyanate and N-methyl diethanolamine. Amine segments were built-in to the urethane-isocyanate prepolymer in the reaction with 1-bromobutane or formic acid, and then they were converted to alkylammonium cations. The obtained isocyanate prepolymers were then extended in the aqueous medium that yielded stable aqueous dispersions which were applied on the surfaces of test poly(tetrafluoroethylene) plates. After evaporation of water, the dispersions formed thin polymer coatings. (1)H, (13)C NMR and IR spectral methods were employed to confirm chemical structures of synthesised cationomers. Based on (1)H NMR and IR spectra, the factors κ and α were calculated, which represented the polarity level of the obtained cationomers. The DSC, wide angle X-ray scattering and atom force microscopy methods were employed for the microstructural assessment of the obtained materials. Changes were discussed in the surface free energy and its components, as calculated independently according to the method suggested by van Oss-Good, in relation to chemical and physical structures of cationomers as well as morphology of coating surfaces obtained from those cationomers. Fluorine incorporated into cationomers (about 30%) contributed to lower surface free energy values, down to about 15 mJ/m(2). That was caused by gradual weakening of long-range interactions within which the highest share is taken by dispersion interactions.

  13. The Atmospheric Fate of Organic Nitrogen Compounds

    Science.gov (United States)

    Borduas, Nadine

    Organic nitrogen compounds are present in our atmosphere from biogenic and anthropogenic sources and have impacts on air quality and climate. Due to recent advances in instrumentation, these compounds are being detected in the gas and particle phases, raising questions as to their source, processing and sinks in the environment. With their recently identified role as contributors to aerosol formation and growth, their novel large scale use as solvents in carbon capture and storage (CCS) technology and their emissions from cigarette smoke, it is now important to address the gaps in our understanding of the fate of organic nitrogen. Experimentally and theoretically, I studied the chemical atmospheric fate of specific organic nitrogen compounds in the amine, amide and isocyanate families, yielding information that can be used in chemical transport models to assess the fate of this emerging class of atmospheric molecules. I performed kinetic laboratory studies in a smog chamber to measure the room temperature rate coefficient for reaction with the hydroxyl radical of monoethanolamine, nicotine, and five different amides. I employed online-mass spectrometry techniques to quantify the oxidation products. I found that amines react quickly with OH radicals with lifetimes of a few hours under sunlit conditions, producing amides as oxidation products. My studies on amides revealed that they have much longer lifetimes in the atmosphere, ranging from a few hours to a week. Photo-oxidation of amides produces isocyanates and I investigated these mechanisms in detail using ab initio calculations. Furthermore, I experimentally measured isocyanic acid's Henry's Law constant as well as its hydrolysis rate constants to better understand its sinks in the atmosphere. Finally, I re-examined the structure-activity relationship (SAR) of organic nitrogen molecules for improved model parameterizations.

  14. Noncovalent functionalization of single-walled carbon nanotubes by aromatic diisocyanate molecules: A computational study

    Science.gov (United States)

    Goclon, Jakub; Kozlowska, Mariana; Rodziewicz, Pawel

    2014-04-01

    We investigate the noncovalent functionalization of metallic single-walled carbon nanotubes (SWCNT) (6,0) by 4,4‧-methylene diphenyl diisocyanate (MDI) and toluene-2,4-diisocyanate (TDI) molecules using the density functional theory (DFT) method with van der Waals dispersion correction. The obtained local minima show the dependence between the molecular arrangement of the adsorbates on SWCNT surface and their binding energies. We analyze the interplay between the π-π stacking interactions and isocyanate functional groups. For the analysis of the changes in the electronic structure we calculate the density of states (DOS) and charge density plots.

  15. One-pot synthesis of tetracyclic fused imidazo[1,2-a]pyridines via a three-component reaction

    Science.gov (United States)

    Yang, Bo; Tao, Chuanye; Shao, Taofeng

    2016-01-01

    Summary A novel three-component reaction has been developed to assemble biologically and pharmaceutically important tetracyclic fused imidazo[1,2-a]pyridines in a one-pot fashion utilizing readily available 2-aminopyridines, isatins and isocyanides. The three-component coupling proceeds through the Groebke–Blackburn–Bienaymé reaction followed by a retro-aza-ene reaction and subsequent nucleophilic reaction of the in-situ generated imidazo[1,2-a]pyridines bearing an isocyanate functional group. PMID:27559401

  16. Oligomers Solidification Depending on the Nature, Molecular Mass, Type and Reactional Group Containing

    Directory of Open Access Journals (Sweden)

    Vasiliyp. Medvedev

    2017-02-01

    Full Text Available The article is devoted to regularity defining of curing oligomers, and prepolymers with hydroxyl and isocyanate groups and double bonds reactive oligomers.The features of the spatial structure of elasticpolyurethane based oligomers and prepolymers with the definition of the physical and chemical bonds share, as well as the chain interval length between grid points were researched. The possibility of oligodiendiolecuring in the presence of a methacrylate component on the mechanism of radical polymerization was experimentally confirmed.To achieve the objectives rheokinetic method of analysis (rotational viscometer, thermometric and iodometric methods, IR spectroscopy, differential scanning calorimetrywere used.

  17. 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.

  18. Elucidating collision induced dissociation products and reaction mechanisms of protonated uracil by coupling chemical dynamics simulations with tandem mass spectrometry experiments.

    Science.gov (United States)

    Molina, Estefanía Rossich; Ortiz, Daniel; Salpin, Jean-Yves; Spezia, Riccardo

    2015-12-01

    In this study we have coupled mixed quantum-classical (quantum mechanics/molecular mechanics) direct chemical dynamics simulations with electrospray ionization/tandem mass spectrometry experiments in order to achieve a deeper understanding of the fragmentation mechanisms occurring during the collision induced dissociation of gaseous protonated uracil. Using this approach, we were able to successfully characterize the fragmentation pathways corresponding to ammonia loss (m/z 96), water loss (m/z 95) and cyanic or isocyanic acid loss (m/z 70). Furthermore, we also performed experiments with isotopic labeling completing the fragmentation picture. Remarkably, fragmentation mechanisms obtained from chemical dynamics simulations are consistent with those deduced from isotopic labeling.

  19. Hafnium carbamates and ureates: new class of precursors for low-temperature growth of HfO2 thin films.

    Science.gov (United States)

    Pothiraja, Ramasamy; Milanov, Andrian P; Barreca, Davide; Gasparotto, Alberto; Becker, Hans-Werner; Winter, Manuela; Fischer, Roland A; Devi, Anjana

    2009-04-21

    Novel volatile compounds of hafnium, namely tetrakis-N,O-dialkylcarbamato hafnium(iv) [Hf((i)PrNC(O)O(i)Pr)(4)] () and tetrakis-N,N,N'-trialkylureato hafnium(iv) [Hf((i)PrNC(O)N-(Me)Et)(4)] (), have been synthesized through the simple insertion reaction of isopropyl isocyanate into hafnium isopropoxide and hafnium ethylmethylamide, respectively; based on the promising thermal properties, compound has been evaluated as a precursor for metalorganic chemical vapor deposition (MOCVD) of HfO(2) thin films, which resulted in the growth of stoichiometric and crystalline layers with a uniform morphology at temperature as low as 250 degrees C.

  20. New occupational and environmental causes of asthma and extrinsic allergic alveolitis.

    Science.gov (United States)

    Fishwick, David

    2012-12-01

    Asthma and extrinsic allergic alveolitis (EAA) remain prevalent respiratory diseases and the cause of a significant disease burden. This article reviews the recent occupational and environmental causes described for these conditions. Even over the limited time spam addressed by this article, novel agents and new data relating to already suggested causes have been described. Various types of work tasks or exposures are described that appear to cause both asthma and EAA. Isocyanates, the best example of dual potential to cause asthma and EAA are discussed, as is the new understanding of the role metal-working fluids play when causing respiratory diseases. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  1. New polyurethane nanocomposites based on soya oil.

    Science.gov (United States)

    Mohammed, Issam Ahmed; Abd Khadir, Nurul Khizrien; Jaffar Al-Mulla, Emad Abbas

    2014-01-01

    New polyurethane (PU) nanocomposites were prepared from a dispersion of 0 - 5% montmorillonite (MMT) clay with isocyanate and soya oil polyol that was synthesized via transesterification of triglycerides to reduce petroleum dependence. FT-IR spectra indicate the presence of hydrogen bonding between nanoclay and the polymer matrix, whereas the exfoliated structure of clay layers was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Optical microscopy, mechanical and thermal analyses were done to investigate significant improvement of the nanocomposites. The results showed PU-3% nanoclay (NC) showed optimum results in mechanical properties such as tensile and flexural strength but the lowest in impact strength.

  2. Synthesis and antibacterial activity of new chiral -sulfamoyloxazolidin-2-ones

    Indian Academy of Sciences (India)

    Fouzia Bouchareb; Malika Berredjem; Samira Ait Kaki; Amel Bouaricha; Abdeslem Bouzina; Billel Belhani; Nour-Eddine Aouf

    2016-01-01

    A new series of , ′-bis-oxazolidinones-sulfone and 5-chloromethylsulfamoyl-oxazolidin-2-ones have been synthesized in three steps (carbamoylation, sulfamoylation and cyclization) starting from 1,3-dichloroporopan-2-ol, chlorosulfonyl isocyanate and primary or secondary amines. Synthesis has been carried out following simple methodology in excellent isolated yields. The structure and purity of the original compounds were confirmed by IR, NMR, and MS. The compounds were evaluated for their in vitro antibacterial activity against some Gram-positive bacteria; Staphylococcus aureus and Gram-negative bacteria; Escherichia Coli, Klebsiella pneumonieae, Acinetobacter, Pseudomonas aeruginosa, Enterococcus, Salmonella sp. The compounds showed moderate to good antibacterial activity.

  3. Environmental Impact Statement for Proposed Closure of Los Angeles Air Force Base, California and Relocation of Space Systems Division

    Science.gov (United States)

    1990-05-01

    cu ft Acetylene No. 4 6,000 cu ft Anyhydrous Ammonia No. 5 25 gal Ammonium Hydroxide No. 6 100 gal Ethylene Glycol Antifreeze No. 7 200 gal Asphalt ...Adhesive No. 8 300 gal Asphalt Emulsion No. 9 1,000 gal Assorted Paints No. 10 200 cans Spray Paint - 14 oz each No. 11 100 cyls Propane - 14 oz...Compressor Lube Oil No. 16 100 gal ENTEC 327 - (loprophyl, Ethyl Aichols) No. 17 125 gal ENTEC 349 - (Dodecylguanideine HC ! ,lsoOHMethyl (bis) Isocyanate

  4. Surface Treatments to Minimize Concrete Deterioration: Report 1 Survey of Field and Laboratory Application and Available Products

    Science.gov (United States)

    1988-04-01

    siloxane + ethyl acrylate Epoxy (polyamine) Alkyl-alkoxy silane Urethane ( isocyanate polyester) Polyisobutyl methacrylate Epoxy (polyamide...Tremco 150 Tremco Asphalt 41.7 37.8 46.7 * wt. treated specimens 100 f h . . d Th d d · h. b d . x or eac t1me per1o • e ata were presente 1n t 1s manner...before failure. Asphalts There are two types, natural asphalt and oil-refinery products. Usually asphalt sealers are the oil-refinery type. Sometimes

  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. Preparation of Organic-Inorganic Hybrid Materials Based on MCM-41 and Its Applications

    OpenAIRE

    Sana M. Alahmadi; Sharifah Mohamad; Mohd Jamil Maah

    2013-01-01

    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 d...

  7. A New Solution—phase Parallel Synthesis of 2—Alkyamino—3—aryl—5—phenylmethylene—3,5—dihydro—4H—imidazol—4—ones

    Institute of Scientific and Technical Information of China (English)

    DING,Ming-Wu; SUN,Yong; LIU,Xiao-Peng; LIU,Zhao-Jie

    2003-01-01

    Thirteen new 2-alkylaminoimidazolones(4) wre rapidly synthesized by a new solution-phase parallel synthetic method,which includes aza-Wittig reaction of iminophosphorane(1) with aromatic isocyanate to give carbodi-imide(2) and subsequent reaction of 2 with various aliphatic primary amine in a parallel fashion.The products were confirmed by 1H NMR,MS,IR and X-ray crystallographic analysis.The unusual selectivity of the cyclization was probably due to the deometry of the guanidine intermediate.

  8. Synthesis and antimicrobial activities of new oxime carbamates of 3-aryl-2-thioquinazolin-4(3H)-one

    Indian Academy of Sciences (India)

    Suresh S Patil; Swati D Jadhav; M B Deshmukh

    2012-09-01

    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 oxime carbamates 4. The synthesized compounds have been confirmed using IR and 1H NMR, mass spectral data together with elemental analysis. All newly synthesized compounds have been tested for their antibacterial and antifungal activities.

  9. The Effect of Reaction Temperature on Retaining Oxirane Oxygen Contents in the Synthesis of Epoxidized Diethanolamides

    Directory of Open Access Journals (Sweden)

    C. S. Lee

    2009-01-01

    Full Text Available Epoxidized diethanolamides were synthesized by reacting diethanolamine (DEA with mixture of Epoxidized Palm Olein (EPOo ,40% w/w and Refined Bleached Deodorized Palm Kernel Olein (RBDPKOo , 60% w/w at 1:3 molar at 80°C for 5 h and continued at 110°C for another 4 h of reaction time. Synthesized diethanolamides with high content of epoxides were reacted with isocyanate in the presence of AlCl3-THF complex catalyst to produce oxazolidone linkages in polyurethane network. The rigid polyurethane foam produced is of better quality as compared to the commercially available foam.

  10. 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.

  11. Urea- and Thiourea-Catalyzed Aminolysis of Carbonates.

    Science.gov (United States)

    Blain, Marine; Yau, Honman; Jean-Gérard, Ludivine; Auvergne, Rémi; Benazet, Dominique; Schreiner, Peter R; Caillol, Sylvain; Andrioletti, Bruno

    2016-08-23

    The aminolysis of (poly)carbonates by (poly)amines provides access to non-isocyanate polyurethanes (NIPUs) that are toxic-reagent-free analogues of polyurethanes (PUs). Owing to their low reactivity, the ring opening of cyclic carbonates requires the use of a catalyst. Herein, we report that the more available and cheaper ureas could advantageously be used for catalyzing the formation of NIPUs at the expense of the thiourea analogues. In addition, we demonstrate a medium-range pKa of the (thio)urea and an unqeual substitution pattern is critical for controlling the efficiency of the carbonate opening.

  12. 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.

  13. The irradiation of pure CH3OH and 1:1 mixture of NH3:CH3OH ices at 30 K using low energy electrons

    Science.gov (United States)

    Jheeta, Sohan; Domaracka, A.; Ptasinska, S.; Sivaraman, B.; Mason, N. J.

    2013-01-01

    The results of an experimental investigation of 1 keV electron irradiation of ices (deposited at 30 K) of (i) pure methanol and (ii) of a 1:1 mixture of NH3:CH3OH are reported. Molecular products formed within the ice were detected and monitored using FTIR spectroscopy. The products observed were methyl formate (H3COHCO), methane (CH4), hydroxymethyl (CH2OH), formamide (HCONH2), formic acid (HCOOH), formaldehyde (H2CO), formyl radical (HCO), cyanate ion (OCN-), isocyanic acid (HNCO), carbon monoxide (CO) and carbon dioxide (CO2). The consequences of these results for prebiotic chemistry in the interstellar medium and star forming regions are discussed.

  14. A facile synthesis and fungicidal activities of 2-(alkylamino-5,6-dimethylthieno[2,3-d]pyrimidin-4(3H-ones

    Directory of Open Access Journals (Sweden)

    2008-12-01

    Full Text Available The aza-Wittig reactions of iminophosphorane 3 with aromatic isocyanates generated carbodiimides 4, which were reacted with alkylamines under mild conditions to give a series of 2-(alkylamino-5,6-dimethylthieno[2,3-d]pyrimidin-4(3H-ones 6 and 8 in satisfactory yield. Their structures were confirmed by 1H NMR, EI-MS, IR and elementary analysis, and compound 8c was further analyzed by single-crystal X-ray diffraction. The preliminary bioassays indicated that these compounds showed excellent fungicidal activities against six kinds of fungi.

  15. 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.

  16. Composites prepared from the waterborne polyurethane cationomers-modified graphene. Part II. Electrical properties of the polyurethane films

    OpenAIRE

    Król, Piotr; Król, Bożena; Zenker, Marek; Subocz, Jan

    2015-01-01

    The research was planned to test electrical properties of polymer films made from polyurethane cationomers with 0–2 wt.% graphene admixture. The cationomers were synthetized in the reaction of 4,4′-methylenebis(phenyl isocyanate), polycaprolactone diol (M = 2000), N-methyldiethanolamine, and formic acid. It was found that addition of approx. 2 wt.% of graphene causes the loss of volume resistivity by three orders of magnitude and percolation threshold is already set at approx. 1 wt.%. The fre...

  17. The Synergize effect of Chain extender to Phosporic acid catalyst to the ultimate property of Soy-Polyurethane

    Science.gov (United States)

    Elvistia Firdaus, Flora

    2016-04-01

    The polyurethanes (PUs) foam were made from vegetable oil; a soybean based polyol. The foams were categorized into flexible and semi rigid. This research is manufacturally designed polyurethane foams by a process requiring the reaction of mixture of 2, 4- and 2, 6-Toluene di Isocyanate isomers, soy polyol in the presence of other ingredients. The objective of this work was to functionalized soy-polyol using phosporic acid catalyst and chain extender, study their collaborative reaction in producing ultimate property of PU foam. Correlates the foam morphology images in accordance to mechanical properties of foams.

  18. Synthesis of novel aryl(heteroaryl)sulfonyl ureas of possible biological interest.

    Science.gov (United States)

    Saczewski, Franciszek; Kuchnio, Anna; Samsel, Monika; Łobocka, Marta; Kiedrowska, Agnieszka; Lisewska, Karolina; Saczewski, Jarosław; Gdaniec, Maria; Bednarski, Patrick J

    2010-02-26

    The course of reaction of aryl and heteroaryl sulfonamides with diphenylcarbonate (DPC) and 4-dimethylaminopyridine (DMAP) was found to depend on the pKa of the sulfonamide used. Aryl sulfonamides with pKa approximately 10 gave 4-dimethylamino-pyridinium arylsulfonyl-carbamoylides, while the more acidic heteroaryl sulfonamides (pKa approximately 8) furnished 4-dimethylaminopyridinium heteroarylsulfonyl carbamates. Both the carbamoylides and carbamate salts reacted with aliphatic and aromatic amines with the formation of appropriate aryl(heteroaryl)sulfonyl ureas, and therefore, can be regarded as safe and stable substitutes of the hazardous and difficult to handle aryl(heteroaryl)sulfonyl isocyanates.

  19. 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.

  20. A base-mediated self-propagative Lossen rearrangement of hydroxamic acids for the efficient and facile synthesis of aromatic and aliphatic primary amines.

    Science.gov (United States)

    Ohtsuka, Naoya; Okuno, Moriaki; Hoshino, Yujiro; Honda, Kiyoshi

    2016-10-14

    A variety of aromatic and aliphatic hydroxamic acids were converted to the corresponding primary amines via base-mediated rearrangement. This rearrangement could proceed with less than 1 equiv. of K2CO3 in polar solvents under thermal conditions with no external reagents. This rearrangement has several features including no external activating agents needed for promoting the rearrangement, less than one equivalent of a base is sufficient for the reaction, and a clean reaction in which only carbon dioxide is produced as a by-product. A self-propagating mechanism via an isocyanate intermediate is proposed and elementary reaction steps, namely, chain propagation reactions are supported by experiments.

  1. Surface Coating Studies of Polyurethane Derived from [(Alkyd-(Epoxy Resin Treated Castor Oil] Using Isophorene Diisocynate - II

    Directory of Open Access Journals (Sweden)

    Dinesh. P. Patel

    2012-07-01

    Full Text Available Castor oil (C was reacted with profitable epoxy resin (E (diglycidylether of bisphenol-A, DGEBF at a range of mole ratios. The consequential products (Castor oil- Epoxy resin were nominated as CEs. Isocyanate terminated castor oil Polyurethane (ICOPU was prepared by reaction of castor oil and various proportion of Isophoren diisocyanate. A commercial alkyd resin was blended with various proportions of CEs and ICOPU. A unique solvent system, which shows a one – phase clear solution and a clear coat of binder system, was used. All the blends were applied on mild steel panels and characterized for drying time, adhesion, flexibility, hardness, impact resistance and chemical resistance properties.

  2. PROPERTIES OF POLYURETHANE ELASTOMERS BASED ON POLY (OXYETHYLENE-co-OXYTETRAMETHYLENE) DIOL

    Institute of Scientific and Technical Information of China (English)

    Chen-yu Su; Guang-li Zhang; Hong-zhi Zhang

    2001-01-01

    Polyurethane elastomers derived from 4,4′-methylene bis(phenyl isocyanate), butylene glycol and the low oxyethylene moiety content copolyether of tetrahydrofuran and ethylene oxide, obtained by copolymerization using heteropolyacid-ethylene oxide initiator system, were prepared. The polyurethanes exhibited an increased water absorption and much better low temperature resilience, which remained high even at a temperature of-3℃, while that of polyurethane based upon poly(tetramethylene ether) glycol of the same molecular weight, I.e. Being 2000, and molecular weight distribution, I.e. In the range of 1.4-1.5, starts to decrease dramatically at 5℃.``

  3. Preparation of well-defined polystyrene/silica hybrid nanoparticles by ATRP

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Immobilization of the atom transfer radical polymerization(ATRP)macroinitiators at the silica nanoparticle surfaces was achieved through surface modification with excess toluene-2,4-diisocynate(TDI),after which the residual isocyanate groups were converted into ATRP macroinitiators.Structurally well-defined polystyrene chains were grown from the nanoparticle surfaces to yield individual particles composed of a silica core and a well-defined,densely grafted outer polystyrene by ATRP,which was initiated by the as-synthesized silica-based macroinitiator.FTIR,NMR and gel permeation chromatography(GPC)were used to characterize the polystyrene/silica hybrid particles.

  4. Preparation of well-defined polystyrene/silica hybrid nanoparticles by ATRP

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Immobilization of the atom transfer radical polymerization (ATRP) macroinitiators at the silica nanoparticle surfaces was achieved through surface modification with excess toluene-2,4-diisocynate (TDI), after which the residual isocyanate groups were converted into ATRP macroinitiators. Structurally well-defined polystyrene chains were grown from the nanoparticle surfaces to yield individual particles composed of a silica core and a well-defined, densely grafted outer polystyrene by ATRP, which was initiated by the as-synthesized silica-based macroinitiator. FTIR, NMR and gel permeation chro-matography (GPC) were used to characterize the polystyrene/silica hybrid particles.

  5. NIOSH grants research and demonstration projects. Annual report, Fiscal Year 1990

    Energy Technology Data Exchange (ETDEWEB)

    1991-04-01

    The report is designed to stimulate submission of proposals for research of high quality on significant problems of occupational safety and health. The report contains information on studies currently underway or recently completed in the field. The topics of concern includes occupational lung diseases (epithelial surface proteins, environmental toxicity of isocyanates, chemical poisoning, influence of particles on lung disease); musculoskeletal injuries (model studies, ergonomics, quantitative measures of skeletal movements, biomechanics, carpal tunnel syndrome, vibration effects); occupational cancers; traumatic injuries; cardiovascular diseases; disorders of reproduction; neurotoxic disorders; noise induced hearing loss; dermatologic conditions; psychological disorders; control techniques; respirator research; and other occupational needs.

  6. 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.

  7. Study on Glulam Process

    Institute of Scientific and Technical Information of China (English)

    PENG Limin; WANG Haiqing; HE Weili

    2006-01-01

    This paper selected lumbers of Manchurian ash (Fraxinus rnandshurica), Manchurian walnut (Juglans mandshuricd) and Spruce (Picea jezoensis vai.kornamvii) for manufacturing glulam with water-borne polymeric-isocyanate adhesive to determine process variables. The process variables that include specific pressure, pressing time and adhesive application amount influencing the shear strength of the glulam, were investigated through the orthogonal test. The results indicated that optimum process variables for glulam manufacturing were as follows: Specific pressure of 1.5 MPa for Spruce and 2,0 MPa both for Manchurian ash and Manchurian walnut, pressing time of 60 min and adhesive application amount of 250 g/m2.

  8. Synthesis of Conformationally North-Locked Pyrimidine Nucleosides Built on an Oxabicyclo[3.1.0]hexane Scaffold | Center for Cancer Research

    Science.gov (United States)

    Beginning with a known 3-oxabicyclo[3.1.0]-hexane scaffold, the relocation of the fused cyclopropane ring bond and the shifting of the oxygen atom to an alternative location engendered a new 2-oxabicyclo[3.1.0]hexane template that mimics more closely the tetrahydrofuran ring of conventional nucleosides. The synthesis of this new class of locked nucleosides involved a novel approach that required the isocyanate with a hydroxyl-protected scaffold as a pivotal intermediate that was obtained in 11 steps from a known dihydrofuran precursor.

  9. Synthesis of Novel Quinazoline Derivatives as Antimicrobial Agents

    Institute of Scientific and Technical Information of China (English)

    ALY,A.A

    2003-01-01

    Quinazoline isothiocyanate 1 reacts with various nucleophiles(nitrogen nucleophiles,oxygen nucleophiles and sulphur nucleophiles)to afford heterocyclic systemes 2-13,Also,the [4+2] cycloaddition reaction of 1 with phenyl isocyanate,benzylidene aryl amine and cinnamic acid derivatives gave novel heterocyclic compounds 14-16,Moreover,the reaction of 1 with active methylene compounds under Michael reaction conditions also was investigated to yield 17 and 18 and it was found that all these reactions proceede via isothiocyanate heterocyclization to furnish non-condensed heterocyclic compoundes,Some of the newly synthesized compounds were tested for their antimicrobial activities.

  10. Formation of free radicals during mechanical degradation of elastomers.

    Science.gov (United States)

    Devries, K. L.; Williams, M. L.; Roylance, D. K.

    1971-01-01

    Solithane 113 (an amorphous polyurethane elastomer) was prepared by curing equal proportions of castor oil and trifunctional isocyanate for 6 hr 45 min at 170 F. The sample material was mechanically degraded by grinding below and above its glass transition point at liquid nitrogen and room temperatures. The EPR spectra of ground samples were recorded and the number of free radicals were determined by a computer double-integration of the recorded spectra and by a comparison of the values with those of a standard material. Curves of EPR spectra suggest that different molecular mechanisms may be active in degradation of this material below and above its glass transition temperature.

  11. Synthesis of Novel Aryl(heteroarylsulfonyl Ureas of Possible Biological Interest

    Directory of Open Access Journals (Sweden)

    Maria Gdaniec

    2010-02-01

    Full Text Available The course of reaction of aryl and heteroaryl sulfonamides with diphenylcarbonate (DPC and 4-dimethylaminopyridine (DMAP was found to depend on the pKa of the sulfonamide used. Aryl sulfonamides with pKa ~ 10 gave 4-dimethylamino-pyridinium arylsulfonyl-carbamoylides, while the more acidic heteroaryl sulfonamides (pKa ~ 8 furnished 4-dimethylaminopyridinium heteroarylsulfonyl carbamates. Both the carbamoylides and carbamate salts reacted with aliphatic and aromatic amines with the formation of appropriate aryl(heteroarylsulfonyl ureas, and therefore, can be regarded as safe and stable substitutes of the hazardous and difficult to handle aryl(heteroarylsulfonyl isocyanates.

  12. Efficient and Selective Construction of Pyrrolo[3,2-d]pyrimidine Derivatives

    Energy Technology Data Exchange (ETDEWEB)

    He, Ping; Wu, Jing; Hu, Yanggen; Li, Zaifang; Hou, Qiufei; Wang, Yanling; Zhao, Kun; Zhang, Erli [Hubei Univ. of Arts and Science, Xiangyang (China)

    2014-02-15

    An efficient and selective method for the synthesis of ethyl 2-amino/aryloxy-3-aryl-4-oxo-5-phenyl-4,5-dihydro-3H-pyrrolo[3,2-d] pyrimidine-7-carboxylate derivatives has been developed. The main process involved the reaction of diethyl 1-phenyl-3-((triphenylphosphoranylidene)amino)-1H-pyrrole-2,4-dicarboxylate and aromatic isocyanates, followed by addition of amines/phenols in the presence of catalytic amount of sodium ethoxide or solid potassium carbonate.

  13. Dielectric properties of novel polyurethane/silica nanowire composites.

    Science.gov (United States)

    Kim, Mu-Seong; Sekhar, Praveen K; Bhansali, Shekhar; Harmon, Julie P

    2009-10-01

    An aliphatic isocyanate, polyether, polyol thermoplastic polyurethane, Tecoflex SG-85A, was solution processed with the varying amounts of silica nanowire. The dielectric permittivity (epsilon') and loss factor (epsilon") were measured via Dielectric Analysis (DEA) in the frequency range 1 Hz to 100 kHz and between the temperature -150 to 150 degrees C. The electric modulus formalism was used to reveal alpha, beta and conductivity relaxations. The activation energies for the relaxations are presented. Nanocomposites were also characterized by differential scanning calorimetry (DSC) to determine glass transition temperatures. The onset of decomposition temperature was measured by thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) provided images of the polymer-nanocomposites.

  14. TEPIC - A New High Temperature Structural Foam

    Energy Technology Data Exchange (ETDEWEB)

    Whinner, L L; Goods, S H; Tootle, M L; Neuschwanger, C L

    1998-10-01

    The formulation, processing characteristics, microstructure and mechanical properties of a new structural foam, suitable for use at service temperatures up to 200 degrees C, are reported. In each of the respects, the foam is compared to an existing material, called APO-BMI that is currently in use. When these two foams are directly compared, the new foam, called TEPIC, is found to be superior in its mechanical performance. TEPIC is formulated from a non-carcinogenic isocyanate, a di-functional epoxide, and glass microballoons. Compared to APO-BMI processing, TEPIC processing is facile and economical.

  15. Dual cure photocatalyst systems

    Energy Technology Data Exchange (ETDEWEB)

    DeVoe, R.J.; Brown-Wensley, K.A.; Holmes, G.L.; Mathis, M.D.; McCormick, F.B.; Palazzotto, M.C.; Spurgeon, K.M. (Minnesota Mining and Mfg. Co., St. Paul, MN (USA). Corporate Research Labs.)

    1990-01-01

    A family of dual cure photocatalyst systems is being developed to be used in the solventless processing of organic coatings. The photocatalyst systems consist of organometallic compounds often in combination with other agents. Upon photolysis, the photocatalyst system generates a Lewis acid and a free radical. The Lewis acid can initiate the polymerization of epoxies or the addition of isocyanates and polyols to form polyurethanes while the free radical can initiate the polymerization of acrylates. The performance of the various photocatalyst systems will be compared on the basis of the physical properties of the cured compositions they produce. 17 figs.

  16. Preparation and Properties of Starch-Based Composite Adhesive for Wood Bonding%木材用淀粉基复合胶黏剂的制备与性能

    Institute of Scientific and Technical Information of China (English)

    王必囤; 顾继友; 左迎峰; 张彦华

    2012-01-01

    Starch adhesive was synthesized with com starch oxidized by sodium hypochlorite sodium, and then starch-isocyanate composite adhesive was prepared by blending modification with functional inner-crosslinking agent ( isocyanate). The effects of pH, polyvinyl alcohol (PVA) concentration, PVA dosage, starch content, and mixing ratio of isocyanate on the bonding properties of the starch adhesive were studied under different experimental conditions. The best bonding strength and water resistance were obtained as PVA concentration 10% , ratio of starch to PVA 3:5, ratio of starch to water 3 '· 8, and using oxidized modified starch. XPS analysis shows that chemical bond formation between isocyanate and hydroxyl of starch adhesive and wood is key to improving bonding strength and water resistance. The modified starch adhesive exhibits better adhesive properties, which meet the application requirements for type II plywood.%采用次氯酸钠对玉米淀粉进行氧化制备淀粉胶黏剂,再用功能内交联剂(异氰酸酯)共混改性制备淀粉基复合胶黏剂.考查了复合胶黏剂体系的pH、PVA质量分数与用量、淀粉用量、异氰酸酯加入比例对淀粉基复合胶黏剂胶接性能的影响.胶接实验结果表明:利用变性的氧化淀粉,PVA质量分数为10%,PVA加入比例为3/5,淀粉与水比为3/8时,获得最佳的胶结强度和耐水性能.采用XPS分析胶层化学结构,结果表明:异氰酸酯与淀粉胶黏剂、木材中的羟基反应形成化学键结合是提高胶接强度和耐水性关键所在.所制得的改性淀粉胶黏剂性能更加优异,符合Ⅱ类胶合板的使用要求.

  17. 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)

  18. N-(2-Chloroethylmorpholine-4-carboxamide

    Directory of Open Access Journals (Sweden)

    Oguejiofo T. Ujam

    2014-04-01

    Full Text Available The title compound, C7H13ClN2O2, synthesized by the reaction of 2-chloroethyl isocyanate and morpholine, crystallizes with four molecules in the asymmetric unit, which have similar conformations and comprise two pairs each related by approximate non-crystallographic inversion centres. Two of them have a modest orientational disorder of the 2-chloroethyl fragments [occupancy ratio of 0.778 (4:0.222 (4]. In the crystal, molecules are linked by N—H...O=C hydrogen bonds, forming three crystallographically different kinds of infinite hydrogen-bonded chains extending along [001].

  19. Water-curable and biodegradable prepolymers.

    Science.gov (United States)

    Kobayashi, H; Hyon, S H; Ikada, Y

    1991-12-01

    In an attempt to develop biodegradable polymers which can be shaped in situ and adhere to living tissues, we synthesized esterurethane prepolymers which can be cured upon contact with water in living tissues. First, D,L-lactide polymerization or D,L-lactide-epsilon-caprolactone (50:50) copolymerization was carried out using ethylene glycol or poly(ethylene glycol) as initiator to obtain hydroxyl-terminated biodegradable polyesters. They were then reacted with an excess of diisocyanate such as hexamethylene diisocyanate, toluylene diisocyanate, and diphenylmethane diisocyanate to introduce a reactive isocyanate group to both of the end groups of the polyesters. The isocyanate-terminated prepolymers could be cured in the presence of water and the cured polymers were degraded by hydrolysis both in vitro and in vivo. It was found that the presence of appropriate amounts of hydrophilic units in the main chain was essential for giving a high curing rate and a high degradation rate for the biodegradable urethane prepolymers. The tissue responses to the cured polymers were not severe.

  20. Cutaneous sensitization to some polyisocyanate prepolymers in guinea pigs.

    Science.gov (United States)

    Zissu, D; Binet, S; Limasset, J C

    1998-11-01

    Isocyanates are used extensively in the polyurethane industry. Pulmonary and dermal sensitization resulting from exposure to diisocyanates has frequently been reported, but the potential effects of polyisocyanates on health are less well known. Thus, since 1978, occupational exposure limits have been established for diisocyanates only. Nevertheless, respiratory diseases and dermatitis have been reported in the polyurethane industry after accidental isocyanate contact during spills or splashes. The aim of this experimental work was to assess the dermal hypersensitivity of guinea pigs to some polyisocyanate prepolymers by means of a well-conducted standard predictive Buehler test. Our results showed that dicyclohexylmethane 4,4'-diisocyanate (HMDI), toluylene 2,4-diisocyanate (TDI), TDI adduct triol, TDI isocyanurate, 1,6-hexamethylene diisocyanate (HDI), HDI isocyanurate, HDI biuret and isophorone diisocyanate (IPDI) induced dermal sensitization while IPDI isocyanurate did not. In conclusion, the dermal hypersensitivity of guinea pigs to some polyisocyanates was similar to those of their corresponding monomers except for IPDI isocyanurate, suggesting that the results from diisocyanate monomers could not be a valuable approach for the detection of the sensitization potency of the corresponding prepolymers.

  1. Polyurethanes from the crystalline prepolymers resistant to abrasive wear

    Directory of Open Access Journals (Sweden)

    Domańska Agata

    2014-12-01

    Full Text Available The research aimed at the selection of polyurethanes synthesized from poly(tetramethylene ether glycol (PTMEG, as well as from two different isocyanates 4,4′-methylenebis(cyclohexylisocyanate (HMDI and 4.4′-methylenebis(phenyl isocyanate (MDI in order to obtain polyurethane with increased resistance to abrasive wear and degradation for bio-medical application. Polyurethanes were fabricated from crystalline prepolymers extended by water. The paper presents preliminary results on polyurethane surface wettability, friction coefficient for different couples of the co-working materials such as polyurethane-polyurethane, polyurethane-titanium alloy, polyurethane-alumina, in comparison to commonly used polyethylene-titanium alloy. Shear strength of polyurethane-alumina joint, as well as viscosity of prepolymers were also measured. The values of friction coefficient were compared to literature data on commercially available polyurethane with the trade name Pellethane. Polyurethanes obtained are characterized by low abrasive wear and low friction coefficient in couple with the titanium alloy, what makes them attractive as possible components of ceramic-polymer endoprosthesis joints.

  2. Cellulose based hybrid hydroxylated adducts for polyurethane foams

    Science.gov (United States)

    De Pisapia, Laura; Verdolotti, Letizia; Di Mauro, Eduardo; Di Maio, Ernesto; Lavorgna, Marino; Iannace, Salvatore

    2012-07-01

    Hybrid flexible polyurethane foams (HPU) were synthesized by using a hybrid hydroxilated adduct (HHA) based on renewable resources. In particular the HHA was obtained by dispersing cellulose wastes in colloidal silica at room temperature, pressure and humidity. The colloidal silica was selected for its ability of modifying the cellulose structure, by inducing a certain "destructurization" of the crystalline phase, in order to allow cellulose to react with di-isocyanate for the final synthesis of the polyurethane foam. In fact, cellulose-polysilicate complexes are engaged in the reaction with the isocyanate groups. This study provides evidence of the effects of the colloidal silica on the cellulose structure, namely, a reduction of the microfiber cellulose diameter and the formation of hydrogen bonds between the polysilicate functional groups and the hydroxyl groups of the cellulose, as assessed by IR spectroscopy and solid state NMR. The HHA was added to a conventional polyol in different percentages (between 5 and 20%) to synthesize HPU in presence of catalysts, silicone surfactant and diphenylmethane diisocyanate (MDI). The mixture was expanded in a mold and cured for two hours at room temperature. Thermal analysis, optical microscopy and mechanical tests were performed on the foams. The results highlighted an improvement of thermal stability and a decrease of the cell size with respect neat polyurethane foam. Mechanical tests showed an improvement of the elastic modulus and of the damping properties with increasing HHA amount.

  3. 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.

  4. 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 Christopher [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.

  5. Molecules with a peptide link in protostellar shocks: a comprehensive study of L1157

    CERN Document Server

    Mendoza, E; López-Sepulcre, A; Ceccarelli, C; Codella, C; Boechat-Roberty, H M; Bachiller, R

    2014-01-01

    Interstellar molecules with a peptide link -NH-C(=O)-, like formamide (NH$_2$CHO), acetamide (NH$_2$COCH$_3$) and isocyanic acid (HNCO) are particularly interesting for their potential role in pre-biotic chemistry. We have studied their emission in the protostellar shock regions L1157-B1 and L1157-B2, with the IRAM 30m telescope, as part of the ASAI Large Program. Analysis of the line profiles shows that the emission arises from the outflow cavities associated with B1 and B2. Molecular abundance of $\\approx~(0.4-1.1)\\times 10^{-8}$ and $(3.3-8.8)\\times 10^{-8}$ are derived for formamide and isocyanic acid, respectively, from a simple rotational diagram analysis. Conversely, NH$_2$COCH$_3$ was not detected down to a relative abundance of a few $\\leq 10^{-10}$. B1 and B2 appear to be among the richest Galactic sources of HNCO and NH$_2$CHO molecules. A tight linear correlation between their abundances is observed, suggesting that the two species are chemically related. Comparison with astrochemical models favou...

  6. Novel bio-based epoxy-polyurethane materials from modified vegetable oils – synthesis and characterization

    Directory of Open Access Journals (Sweden)

    A. Sienkiewicz

    2017-04-01

    Full Text Available Presented research shows the results of a study on mechanical properties of materials obtained in the course of innovatory application of epoxidized vegetable oil in the synthesis of new bio-based epoxy resins, crosslinked with curing agents which are not typical for epoxy materials. The product was obtained via modern and pro-ecological modification of a well-known synthesis method of epoxies, namely the epoxy fusion process, then it was crosslinked using polyisocyanates of different structure: toluene-2,4-diisocyanate (TDI, hexamethylene diisocyanate (HDI and 4,4’-methylene diphenyl diisocyanate (MDI. The obtained epoxy-polyurethane materials are characterized by various mechanical properties, which depend on the type of chosen isocyanate. Compositions based on HDI exhibit better mechanical characteristics than elastic polyurethane materials based on hydroxylated soybean oil. Materials cured with aromatic isocyanates MDI and TDI are characterized by higher mechanical resistance comparable with cast polyurethane based on petrochemical resources. Epoxy fusion product cured with toluene-2,4-diisocyanate in a presence of Dabco T9 appears to have the best mechanical properties among all tested compositions.

  7. 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.

  8. 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.

  9. 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.

  10. Photolysis and thermolysis of pyridyl carbonyl azide monolayers on single-crystal platinum.

    Science.gov (United States)

    Adkinson, Dana K; Magri, David C; Pitters, Jason L; Griffiths, Keith; Norton, Peter R; Workentin, Mark S

    2013-01-01

    The photochemical and thermal reactivity of a number of acyl azide-substituted pyridine compounds, namely nicotinyl azide, isonicotinyl azide, picolinyl azide and dinicotinyl azide with investigated as saturated monolayers on a single-crystal Pt(111) surface in an ultrahigh vacuum chamber. Multilayers of the substrates exhibited a maximum rate of desorption at 270 K, above which, stable saturated monolayers formed as characterized by reflection-absorption infrared spectroscopy by observation of C=O and N3 bands at 1700 cm(-1), and 2100 and 1300 cm(-1) respectively. The monolayers were stable up to 400 K. Photolysis of the monolayer (or heating above 400 K) results in the formation of the respective isocyanate intermediate after loss of nitrogen as evidenced by the appearance of a new infrared band at 2260 cm(-1) with concomitant loss of the azide bands. The resulting isocyanate saturated monolayer is stable in absence of nucleophiles, but can be quenched with appropriate nucleophiles. © 2013 The American Society of Photobiology.

  11. Experiments to populate and validate a processing model for polyurethane foam :

    Energy Technology Data Exchange (ETDEWEB)

    Mondy, Lisa Ann; Rao, Rekha Ranjana; Shelden, Bion; Soehnel, Melissa Marie; O' Hern, Timothy J.; Grillet, Anne; Celina, Mathias Christopher; Wyatt, Nicholas B.; Russick, Edward Mark; Bauer, Stephen J.; Hileman, Michael Bryan; Urquhart, Alexander; Thompson, Kyle Richard; Smith, David Michael

    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.

  12. 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.

  13. Study on the Comfortability of MDI-Based Viscoelastic Polyurethane Mattress Foam%MDI基聚氨酯慢回弹床垫泡沫的舒适性研究

    Institute of Scientific and Technical Information of China (English)

    王林瑞; 林芳茜; 李鹏敏; 张谦和; 赵怡; 杜中杰

    2013-01-01

    通过对不同泡沫密度、不同异氰酸酯指数的MDI基聚氨酯慢回弹泡沫进行舒适因子、温度敏感性、透气性、压力分布等测试,研究了MDI基聚氨酯慢回弹床垫泡沫的舒适性.结果表明,增加泡沫密度有利于提高慢回弹泡沫的舒适因子,也有利于减小慢回弹泡沫的温度敏感性;MDI基聚氨酯慢回弹泡沫在较宽的密度及异氰酸酯指数范围内具有良好的透气性,且压力分布均匀,舒适性较高.%The comfortability of MDI-based viscoelastic PU foam by SAG, temperature sensitivity, breathability and pressure distribution measurement in different densities and isocyanate indexes was studied. The result showed that increasing density was conducive to increase the SAG of viscoelastic foam. Increasing density or reducing isocyanate index was conducive to reduce the temperature sensibility of viscoelastic foam. The MDI-based viscoelastic PU foam which had good breathability could be used in wide density and index range. This kind of foam had uniformity pressure distribution and good comfortability.

  14. Assessment of exposure to TDI and MDI during polyurethane foam production in Poland using integrated theoretical and experimental data.

    Science.gov (United States)

    Kupczewska-Dobecka, Małgorzata; Czerczak, Sławomir; Brzeźnicki, Sławomir

    2012-09-01

    The aim of this study was to develop an optimal strategy for the assessment of inhalation exposure to isocyanates such as TDI and MDI in the production of polyurethane foam by integration of theoretical and experimental data. ECETOC TRA and EASE predictive models were used to determine the estimated levels of exposure to isocyanates. The results of our study suggest that both applications EASE and ECETOC TRA can be used as a screening 1st Tier tool in this case study. PROC12 ECETOC TRA category can be linked to exposure on TDI during polyurethane foam manufacturing because it is working properly and exceeds 90th percentile measured concentration with factor 3 and the maximum measured value with factor 1, 5. The value estimated by using category PROC2 is underestimated so this category should not be linked to this scenario. At the same time, the applications of EASE overstate the expected concentrations although the scenario "Use in closed process" seems to underestimate the exposure at the "lower end". For MDI the both models estimate exposure in a conservative manner.

  15. RIM聚氨酯弹性体与玻璃粘接性能的研究%Study on bonding between RIM polyurethane elastomer and glass

    Institute of Scientific and Technical Information of China (English)

    宋聪梅; 陈艳明; 吴卫东; 魏永祥

    2011-01-01

    This experiment is the study of the adhesion between RIM polyurethane elastomer and glass. The effect of polyether molecular weight, chain extender, catalyst and isocyanate on its peel strength was investigated. The results showed that the products which have good adhesion were gained using urethane modified MDI, polyether with a molecular weight of about 6 000, chain extender 1,4BG, delayed amine catalyst and controlling the isocyanate index with 98.%研究了反应注射成型(RIM)聚氨酯弹性体对玻璃的粘接性能,考察了聚醚多元醇相对分子质量、扩链剂、催化剂和异氰酸酯对其粘接性能的影响.结果表明,以氨酯改性二苯基甲烷二异氰酸酯(MDI)做异氰酸酯组分,聚醚多元醇相对分子质量为6 000,1,4-丁二醇做扩链剂,使用自制的延迟胺复合催化剂,异氰酸酯指数为98时弹性体对玻璃具有良好的粘接性能.

  16. Effect of charge density in chain extension reactions involving complexes of 4, 4'-diaminodiphenylmethane and various alkali metal salts

    Science.gov (United States)

    Deshmukh, Subrajeet; Carrasquillo, Katherine; Tsai, Fang Chang; Wu, Lina; Hsu, Shaw Ling; University of Massachusetts Amherst Team

    Controlling the reaction of methylene diphenyl diisocyanate (MDI)-terminated polyester prepolymer and 4, 4'-diaminodiphenylmethane (MDA) is extremely important in many large scale applications. The ion-diamine complex has the advantage of blocking the instantaneous reaction between the diamine and isocyanate from taking place until it is released at elevated temperatures. We synthesized complexes of MDA with various alkali metal salts. These complexes create a barrier between the diamine and isocyanate thus preventing the premature reaction. We compared the complexes in terms of their dissociation and the subsequent curing with the prepolymer. Charge density had a tremendous effect. DSC showed that Na complexes dissociated at a lower temperature and needed less energy to dissociate than the Li complexes. The effect of change in cation on complex dissociation was more pronounced compared to the change in anion. Also, the ionic liquid introduced greatly altered the dissociation behavior. Temperature and time resolved IR spectroscopy was used to monitor the urea and NH band. By DSC and IR, we showed that NaCl complex is best suited for the curing of prepolymer with regards to curing temperature and energy.

  17. Green synthesis of a typical chiral stationary phase of cellulose-tris(3, 5-dimethylphenylcarbamate)

    Science.gov (United States)

    2013-01-01

    Background At present, the study on the homogeneous-phase derivatization of cellulose in ionic liquid is mainly focused on its acetylation. To the best of our knowledge, there has been no such report on the preparation of cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) with ionic liquid 1-allyl-3-methyl-imidazolium chloride (AmimCl) so far. Results With ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as a reaction solvent, cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) was synthesized by the reaction of 3,5-dimethylphenyl isocyanate and soluble microcrystalline cellulose in a homogeneous phase. The synthesized CDMPC was then coated onto the surfaces of aminopropyl silica gel to prepare a chiral stationary phase (CSP). The prepared CSP was successfully used in chiral separation of seven racemic pesticides by high performance liquid chromatography (HPLC). Good chiral separation was obtained using n-hexane and different modifiers as the mobile phases under the optimal percentage and column temperature, with the resolution of metalaxyl, diniconazole, flutriafol, paclobutrazol, hexaconazole, myclobutanil and hexythiazox of 1.73, 1.56, 1.26, 1.00, 1.18, 1.14 and 1.51, respectively. The experimental results suggested it was a good choice using a green solvent of AmimCl for cellulose functionalization. Conclusion CDMPC was successfully synthesized as the chiral selector by reacting 3, 5-dimethylphenyl isocyanate with dissolved microcrystalline cellulose in a green ionic liquid of AmimCl. PMID:23890199

  18. Electron Irradiation of Kuiper Belt Surface Ices: Ternary N2-CH4-CO Mixtures as a Case Study

    Science.gov (United States)

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

    2012-10-01

    The space weathering of icy Kuiper Belt Objects was investigated in this case study by exposing methane (CH4) and carbon monoxide (CO) doped nitrogen (N2) 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 N2-CH4 and CO-CH4 systems: nitrogen-bearing products were found in the form of hydrogen cyanide (HCN), hydrogen isocyanide (HNC), diazomethane (CH2N2), and its radical fragment (HCN2); oxygen-bearing products were of acetaldehyde (CH3CHO), formyl radical (HCO), and formaldehyde (H2CO). As in the pure ices, the methyl radical (CH3) and ethane (C2H6) were also detected, as were carbon dioxide (CO2) and the azide radical (N3). 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.

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

    Science.gov (United States)

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

    2011-10-01

    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 FeCl3 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.

  20. Theory-assisted development of a robust and Z-selective olefin metathesis catalyst.

    Science.gov (United States)

    Occhipinti, Giovanni; Koudriavtsev, Vitali; Törnroos, Karl W; Jensen, Vidar R

    2014-08-01

    DFT calculations have predicted a new, highly Z-selective ruthenium-based olefin metathesis catalyst that is considerably more robust than the recently reported (SIMes)(Cl)(RS)RuCH(o-OiPrC6H4) (3a, SIMes = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene, R = 2,4,6-triphenylbenzene) [J. Am. Chem. Soc., 2013, 135, 3331]. Replacing the chloride of 3a by an isocyanate ligand to give 5a was predicted to increase the stability of the complex considerably, at the same time moderately improving the Z-selectivity. Compound 5a is easily prepared in a two-step synthesis starting from the Hoveyda-Grubbs second-generation catalyst 3. In agreement with the calculations, the isocyanate-substituted 5a appears to be somewhat more Z-selective than the chloride analogue 3a. More importantly, 5a can be used in air, with unpurified and non-degassed substrates and solvents, and in the presence of acids. These are traits that are unprecedented among highly Z-selective olefin metathesis catalysts and also very promising with respect to applications of the new catalyst.

  1. 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.

  2. Fabrication of Polyimide Membrane Incorporated with Functional Graphene Oxide for CO2 Separation: The Effects of GO Surface Modification on Membrane Performance.

    Science.gov (United States)

    Wang, Ting; Cheng, Cheng; Wu, Li-Guang; Shen, Jiang-Nan; Van der Bruggen, Bart; Chen, Qian; Chen, Di; Dong, Chun-Ying

    2017-06-06

    Two kinds of isocyanate were used to modify graphene oxide (GO) samples. Then, polyimide (PI) hybrid membranes containing GO and modified GO were prepared by in situ polymerization. The permeation of CO2 and N2 was studied using these novel membranes. The morphology experiments showed that the isocyanate groups were successfully grafted on the surface of GO by replacement of the oxygen-containing functional groups. After modification, the surface polarity of the GO increased, and more defect structures were introduced into the GO surface. This resulted in a good distribution of more modified GO samples in the PI polymer matrix. Thus, the PI hybrid membranes incorporated by modified GO samples showed a high gas permeability and ideal selectivity of membranes. In addition, enhancement of the selectivity due to the solubility of CO2 played a major role in the increase in the separation performance of the hybrid membranes for CO2, although the diffusion coefficients for CO2 also increased. Both the higher condensability and the strong affinity between CO2 molecules and GO in the polymer matrix caused an enhancement of the solubility selectivity higher than the diffusion selectivity after GO surface modification.

  3. Study on the Anticorrosion Coating Used in the Middle of the Ship Construction Process%船舶中间施工过程用防腐涂料的研制

    Institute of Scientific and Technical Information of China (English)

    高原; 方斌; 刘华荣; 海洁; 张能; 袁阳; 陈淼

    2011-01-01

    实验以3-氨丙基甲基二乙氧基硅烷、苯甲酰氯与三甲基氯硅烷为原料制备了异氰酸烷基硅烷,并将其与液体有机硅橡胶共混后,制备了船舶中间施工过程用防腐涂料.该涂料固化后,涂层具有良好的柔韧性、耐水性、耐盐雾性、电绝缘性和耐高低温性,且防腐、防尘.%The alkyl-silane isocyanate was prepared with using 3-aminopropyl methyldiethoxy silane, benzoyl chloride and trimethylchlorosilane as raw materials. Then the anticorrosion coating used in the middle of the ship construction process was synthesized by mixing the alkylsilane isocyanate and liquid organic silicon rubber. The coating had better flexibility, water resistant, salt fog resistant, anticorrosion, electric insulation and high-low temperatures resistance and it was dustprcof.

  4. Production, characterization and utility of a panel of monoclonal antibodies for the detection of toluene diisocyanate haptenated proteins.

    Science.gov (United States)

    Ruwona, Tinashe B; Johnson, Victor J; Hettick, Justin M; Schmechel, Detlef; Beezhold, Donald; Wang, Wei; Simoyi, Reuben H; Siegel, Paul D

    2011-10-28

    Diisocyanates (dNCOs) are highly reactive low molecular weight chemicals used in the manufacture of polyurethane products and are the most commonly reported cause of occupational asthma. Mechanistic disease studies and development of biomonitoring and research tools, such as monoclonal antibodies (mAbs) have been hampered by dNCOs' ability to self-polymerize and to cross-link biomolecules. Toluene diisocyanate (TDI)-specific monoclonal antibodies (mAbs), with potential use in immunoassays for exposure and biomarker assessments, were produced and reactivities characterized against mono- and diisocyanate and dithioisocyanate protein conjugates. In general, TDI reactive mAbs displayed stronger recognition of isocyanate haptenated proteins when the NCO was in the ortho position relative to the tolyl group, and were capable of discriminating between isocyanate and isothiocyanate conjugates and between aromatic and aliphatic dNCOs. Preliminary studies using TDI vapor exposed cells suggest potential utility of these mAbs for both research and biomonitoring. Published by Elsevier B.V.

  5. Analytical approaches to identify potential migrants in polyester-polyurethane can coatings.

    Science.gov (United States)

    Louise Bradley, Emma; Driffield, Malcolm; Guthrie, James; Harmer, Nick; Thomas Oldring, Peter Kenneth; Castle, Laurence

    2009-12-01

    The safety of a polyester-polyurethane can coating has been assessed using a suite of complementary analytical methods to identify and estimate the concentrations of potential chemical migrants. The polyester was based on phthalic acids and aliphatic diols. The polyisocyanate cross-linking agent was 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl cyclohexane homopolymer (IPDI) blocked with methylethylketone oxime (MEKO) to make a one-part formulation. The overall migrate, obtained using solvent extraction of cured films, comprised almost completely of 12 cyclic and one linear polyester oligomer up to molecular weight 800 and containing up to six monomer units. These 13 oligomers covered a total of 28 isomeric forms. Other minor components detected were plasticisers and surfactants as well as impurities present in the starting materials. There was no detectable residue of either the blocked isocyanate (<0.01 microg/dm(2)) used as the starting substance or the unblocked isocyanate (<0.02 microg/dm(2)). The level of extractable IPDI was used as an indicator of the completeness of cure in experimental coatings. These studies revealed that there was an influence of time, temperature and catalyst content. Polymerisation was also influenced by the additives used and by the ageing of the wet coating formulation over several months. These studies allow parameters to be specified to ensure that commercial production coatings receive a full cure giving low migration characteristics.

  6. Photoactive binary and ternary lanthanide (Eu3+, Tb3+, Nd3+) hybrids with p-tert-butylcalix[4]arene derived Si-O linkages and polymers.

    Science.gov (United States)

    Qiao, Xiao-Fei; Zhang, Hai-Yan; Yan, Bing

    2010-10-14

    Through the reaction between the hydroxyl groups of p-tert-butylcalix[4]arene derivatives (Calix-Br, Calix-AC) and the isocyanate group of 3-(triethoxysilyl)-propyl isocyanate (TEPIC), two novel kinds of functional polysilsesquioxanes linkage precursors Calix-Br-Si and Calix-AC-Si have been synthesized. Then the binary and ternary hybrid materials are assembled with chemical bonds, which are composed of lanthanide ion centres (Eu(3+), Tb(3+), Nd(3+)), precursors Calix-Br-Si or Calix-AC-Si and the organic polymers [poly(4-vinylpyridine) (PVPD) or poly(methyl methacrylate) (PMMA)]. The composition and physical properties of these hybrids are characterized, especially comparing the photoluminescent characters. It is found that the hybrids with modified p-tert-butylcalix[4]arene derivative units show better photoluminescent properties than pure original p-tert-butylcalix[4]arene units or lanthanide complexes. Besides, introduction of polymer chain is favorable for the thermal stability, regular microstructure and luminescence of hybrid systems. Among the europium hybrids, the hybrids containing the polymer PMMA possesses the longest lifetime and highest quantum efficiency.

  7. 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.

  8. Chemical Kinetics of the TPS and Base Bleeding During Flight Test

    Science.gov (United States)

    Osipov, Viatcheslav; Ponizhovskaya, Ekaterina; Hafiychuck, Halyna; Luchinsky, Dmitry; Smelyanskiy, Vadim; Dagostino, Mark; Canabal, Francisco; Mobley, Brandon L.

    2012-01-01

    The present research deals with thermal degradation of polyurethane foam (PUF) during flight test. Model of thermal decomposition was developed that accounts for polyurethane kinetics parameters extracted from thermogravimetric analyses and radial heat losses to the surrounding environment. The model predicts mass loss of foam, the temperature and kinetic of release of the exhaust gases and char as function of heat and radiation loads. When PUF is heated, urethane bond break into polyol and isocyanate. In the first stage, isocyanate pyrolyses and oxidizes. As a result, the thermo-char and oil droplets (yellow smoke) are released. In the second decomposition stage, pyrolysis and oxidization of liquid polyol occur. Next, the kinetics of chemical compound release and the information about the reactions occurring in the base area are coupled to the CFD simulations of the base flow in a single first stage motor vertically stacked vehicle configuration. The CFD simulations are performed to estimate the contribution of the hot out-gassing, chemical reactions, and char oxidation to the temperature rise of the base flow. The results of simulations are compared with the flight test data.

  9. Postsynthetic Metal and Ligand Exchange in MFU-4l: A Screening Approach toward Functional Metal-Organic Frameworks Comprising Single-Site Active Centers.

    Science.gov (United States)

    Denysenko, Dmytro; Jelic, Jelena; Reuter, Karsten; Volkmer, Dirk

    2015-05-26

    The isomorphous partial substitution of Zn(2+) ions in the secondary building unit (SBU) of MFU-4l leads to frameworks with the general formula [M(x)Zn(5-x)Cl4(BTDD)3], in which x≈2, M = Mn(II), Fe(II), Co(II), Ni(II), or Cu(II), and BTDD = bis(1,2,3-triazolato-[4,5-b],[4',5'-i])dibenzo-[1,4]-dioxin. Subsequent exchange of chloride ligands by nitrite, nitrate, triflate, azide, isocyanate, formate, acetate, or fluoride leads to a variety of MFU-4l derivatives, which have been characterized by using XRPD, EDX, IR, UV/Vis-NIR, TGA, and gas sorption measurements. Several MFU-4l derivatives show high catalytic activity in a liquid-phase oxidation of ethylbenzene to acetophenone with air under mild conditions, among which Co- and Cu derivatives with chloride side-ligands are the most active catalysts. Upon thermal treatment, several side-ligands can be transformed selectively into reactive intermediates without destroying the framework. Thus, at 300 °C, Co(II)-azide units in the SBU of Co-MFU-4l are converted into Co(II)-isocyanate under continuous CO gas flow, involving the formation of a nitrene intermediate. The reaction of Cu(II)-fluoride units with H2 at 240 °C leads to Cu(I) and proceeds through the heterolytic cleavage of the H2 molecule.

  10. Polyester based hybrid organic coatings

    Science.gov (United States)

    Wang, Xiaojiang

    Polyesters are a class of polymers widely used in organic coatings applications. In this work, four types of organic coatings based on polyester polyols were prepared: UV-curable polyester/poly(meth)acrylate coatings, thermal curable polyester polyurethane-urea coatings, thermal curable non-isocyanate polyurethane coatings, and UV-curable non-isocyanate polyurethane coatings. Polyester/poly(meth)acrylate block copolymers are synthesized using a combination of polycondensation and Atom-Transfer Radical Polymerization (ATRP). All block copolymers are characterized by means of Nuclear Magnetic Resonance (NMR) and Gel Permeation Chromatography (GPC). In the case of unsaturated-polyester-based block copolymers the main chain double bond in the polyester backbone remains almost unaffected during ATRP. The unsaturated block copolymers are crosslinkable and can form networks upon photo-irradiation in the presence of a suitable photoinitiator. These copolymers might be interesting candidates for coatings with better overall properties than those based on neat polyesters. Thermal curable polyester polyol based Polyurethane-Urea (PUU) coatings were formulated using Partially Blocked HDI isocyanurate (PBH), Isophorone Diamine (IPDA), and polyester polyol. As a comparison, the polyurethane coatings (PU) without adding IPDA were also prepared. The mechanical and viscoelastic properties of the PUU and PU coating were investigated by using tensile test and Dynamic Mechanical Thermal Analyzer (DMTA). It was found that PUU coating exhibited higher crosslink density, Tg, tensile modulus and strength than the corresponding PU coating. Thermal curable non-isocyanate polyurethane coatings were prepared by using polyamine and cyclic carbonate terminated polyester. Cyclic carbonate terminated polyester was synthesized from the reaction of the carbon dioxide and epoxidized polyester which was prepared from the polyester polyol. The properties of the epoxidized and cyclic carbonate

  11. X-Aerogels for Structural Components and High Temperature Applications

    Science.gov (United States)

    2005-01-01

    Future NASA missions and space explorations rely on the use of materials that are strong ultra lightweight and able to withstand extreme temperatures. Aerogels are low density (0.01-0.5 g/cu cm) high porosity materials that contain a glass like structure formed through standard sol-gel chemistry. As a result of these structural properties, aerogels are excellent thermal insulators and are able to withstand temperatures in excess of l,000 C. The open structure of aerogels, however, renders these materials extremely fragile (fracturing at stress forces less than 0.5 N/sq cm). The goal of NASA Glenn Research Center is to increase the strength of these materials by templating polymers and metals onto the surface of an aerogel network facilitating the use of this material for practical applications such as structural components of space vehicles used in exploration. The work this past year focused on two areas; (1) the research and development of new templated aerogels materials and (2) process development for future manufacturing of structural components. Research and development occurred on the production and characterization of new templating materials onto the standard silica aerogel. Materials examined included polymers such as polyimides, fluorinated isocyanates and epoxies, and, metals such as silver, gold and platinum. The final properties indicated that the density of the material formed using an isocyanate is around 0.50 g/cc with a strength greater than that of steel and has low thermal conductivity. The process used to construct these materials is extremely time consuming and labor intensive. One aspect of the project involved investigating the feasibility of shortening the process time by preparing the aerogels in the templating solvent. Traditionally the polymerization used THF as the solvent and after several washes to remove any residual monomers and water, the solvent around the aerogels was changed to acetonitrile for the templating step. This process

  12. 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

  13. 脂多糖对B类Ⅰ型清道夫受体表达的调节%Lipopolysaccharide Down-regulates SR-BI Expression in a Nucleus Factor-κB Pathway-dependent Manner

    Institute of Scientific and Technical Information of China (English)

    曹冬黎; 王立金; 金韬; 陈慧

    2011-01-01

    目的 观察脂多糖(LPS)对THP-1巨噬细胞源性泡沫细胞B类Ⅰ型清道夫受体(SR-BI)表达和胆固醇流出的影响,并探讨核因子-κB(NF-κB)信号途径在此过程中的作用.方法 THP-1巨噬细胞源性泡沫细胞以LPS单独或NF-κB抑制剂对甲苯磺酰-L-苯丙氨酸氯甲基甲酮(TPCK)预处理后再加入LPS处理.Western blot检测SR-BI及核内NF-κB p65蛋白质的表达,液体闪烁计数器检测细胞内胆固醇流出,高效液相色谱分析细胞内总胆固醇、游离胆固醇和胆固醇酯含量.结果 LPS抑制SR-BI蛋白质的表达,而增加核内NF-κBp65蛋白质的表达,LPS使泡沫细胞细胞内胆固醇流出减少,细胞总胆固醇、游离胆固醇与胆固醇酯增加.TPCK预处理后,LPS的这种作用被部分抑制.结论 NF-κB信号途径介导LPS对SR-BI表达及细胞内胆固醇流出的抑制作用.%Objective To investigate the changes of cholesterol efflux,the scavenger receptor class B type Ⅰ(SR-BI) protein expression in THP-1 maerophage derived foam cells treated with Lippolysaecharide (LPS), and to discover the role of NF-κB pathway in this process.Methods The foam cells were treated with LPS along or treated with N-p-Tosyl-L-phenylalanine chloromethyl ketone(TPCK) for 24 h.The protein levels of SR-BI and intranuclear NF-κB p65 were measured by Western blotting.Cellular lipid accumulation was determined by high performance liquid ehromatograpby analysis.Cholesterol efflux was determined by FJ-2107P type liquid scintillator.Results The expression of SR-BI was decreased after treated with LPS,while the intranuclear NF-κB p65 protein level was increased by LPS.The results also showed that cellular lipid accumulation was increased ,while the cellular cholesterol efflux was decreased in THP-1 maerophage derived foam cells after exposed to LPS for 24 h and these changes can be reversed partly by pretreatment with TPCK.Conclusion LPS could down-regulate the expression of SR-BI, promote the

  14. Kinetic Modelling of Macroscopic Properties Changes during Crosslinked Polybutadiene Oxidation

    Science.gov (United States)

    Audouin, Ludmila; Coquillat, Marie; Colin, Xavier; Verdu, Jacques; Nevière, Robert

    2008-08-01

    The thermal oxidation of additive free hydroxyl-terminated polybutadiene (HTPB) isocyanate crosslinked rubber bulk samples has been studied at 80, 100 and 120 °C in air. The oxidation kinetics has been monitored by gravimetry and thickness distribution of oxidation products was determined by FTIR mapping. Changes of elastic shear modulus G' during oxidation were followed during oxidation at the same temperatures. The kinetic model established previously for HTPB has been adapted for bulk sample oxidation using previously determined set of kinetic parameters. Oxygen diffusion control of oxidation has been introduced into the model. The mass changes kinetic curves and oxidation products profiles were simulated and adequate fit was obtained. Using the rubber elasticity theory the elastic modulus changes were simulated taking into account the elastically active chains concentration changes due to chain scission and crosslinking reactions. The reasonable fit of G' as a function of oxidation time experimental curves was obtained.

  15. Synthesis of Novel 1-(4-Substituted pyridine-3-sulfonyl-3-phenylureas with Potential Anticancer Activity

    Directory of Open Access Journals (Sweden)

    Krzysztof Szafrański

    2015-07-01

    Full Text Available A series of novel 4-substituted-N-(phenylcarbamoyl-3-pyridinesulfonamides 11–27 have been synthesized by the reaction of 4-substituted pyridine-3-sulfonamides 2–10 with the appropriate aryl isocyanates in presence of potassium carbonate. The in vitro anticancer activity of compounds 11, 12, 14–21 and 24–26 was evaluated at the U.S. National Cancer Institute and in light of the results, some structure-activity relationships were discussed. The most prominent compound, N-[(4-chlorophenylcarbamoyl]-4-[4-(3,4-dichlorophenylpiperazin-1-yl]pyridine-3-sulfonamide (21 has exhibited a good activity profile and selectivity toward the subpanels of leukemia, colon cancer and melanoma, with average GI50 values ranging from 13.6 to 14.9 µM.

  16. STUDY ON CASTOR OIL POLYURETHANE/POLY (METHYL METHACRYLATE) AB CROSSLINKED POLYMERS

    Institute of Scientific and Technical Information of China (English)

    DU Ying; HAN Xiaozu; LIU Wenzhong

    1991-01-01

    Castor oil polyurethane/poly(methyl methacrylate) AB crosslinked polymers (ABCP) were synthesized by free radical copolymerization of MMA and vinyl-terminated castor oil polyurethane which was obtained from isocyanate-terminated castor oil polyurethane and hydroxyethyl methacrylate.The mechanical properties, transition and relaxation, as well as compatibility and morphology of the ABCP were investigated by changing the component. The results show that the ABCP is a semicompatible system and the compatibility of the two components decreases with increasing content of the hard segment. The mechanical and damping properties of the ABCP are obviously superior to that of their homopolymers. The damping value is mainly controlled by crosslink density of the ABCP but the Tg value by component.

  17. 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.

  18. Physical properties and flame-retardant effects of polyurethane coatings containing pyrophosphoric lactone modified polyesters

    Energy Technology Data Exchange (ETDEWEB)

    Chung, D.J.; Kim, S.R.; Park, H.J.; Park, H.S. [Myongji University, Yongin (Korea); Kim, S.J. [Korea Institute of Construction Materials, Seoul (Korea)

    2002-05-01

    Pyrophosphoric lactone modified polyester(PATT) containing two phosphorous functional groups in one unit structure was synthesized to prepare a non-toxic reactive flame-retardant coatings. Then the PATT was cured at room temperature with isocyanate, toluene diisocyanate-isocyanurate, to get a two-component polyurethane flame-retardant coatings (PIPUC). Comparing physical properties of the films of PIPUC with those of film of non-flame-retardant coating, there was no deterioration observed in physical properties by the introduction of a flame-retarding component into the resin. We found that the char lengths measured by 45 deg. Meckel burner method were 3.1{approx}4.4 cm and LOI values recorded 27{approx}30%. These results indicate that the coating prepared in this study is a good flame-retardant. The surface structure of coatings investigated with SEM does not show any defects and phase separation. (author). 23 refs., 8 tabs., 3 figs.

  19. Immobilization of nitrifying bacteria in porous pellets of urethane gel for removal of ammonium nitrogen from waste-water

    Energy Technology Data Exchange (ETDEWEB)

    Sumino, T.; Nakamura, H.; Mori, N. (Hitachi Plant Engineering and Construction Corp., Matsudo, Chiba (Japan). Research Div.); Kawaguchi, Y.; Tada, M. (Japan Sewage Works Agency, Toda, Saitama (Japan))

    1992-01-01

    The effects of immobilizing materials on the activity of nitrifying bacteria and removal of ammonium nitrogen (NH{sub 4}-N) from waste-water by immobilized nitrifying bacteria were investigated using six urethane prepolymers. With a urethane prepolymer containing 2.27% free isocyanate, a high activity yield of nitrifying bacteria was obtained. There was a drastic improvement over the conventional method of immobilization by acrylamide in the activity yield. Inorganic synthetic waste-water was treated at a high loading rate of 0.24 kg Nxm{sup -3}xday{sup -1}. The NH{sub 4}-N concentration of the effluent could be reduced to 2 mgxl{sup -1} or less and the removal was 90%. The life of the pellets in terms of activity was at least 120 days. (orig.).

  20. Chitosan-graft poly(p-dioxanone) copolymers: preparation, characterization, and properties.

    Science.gov (United States)

    Wang, Xiu-Li; Huang, Yan; Zhu, Jiang; Pan, Yan-Bo; He, Rui; Wang, Yu-Zhong

    2009-04-21

    A new biodegradable copolymer of chitosan and poly(p-dioxanone) (PPDO) was prepared through a protection-graft-deprotection procedure using N-phthaloyl-chitosan as an intermediate. PPDO terminated with the isocyanate group was allowed to react with hydroxyl groups of the N-phthaloyl-protected chitosan, and then the phthaloyl group was cleaved to give the free amino groups. The length of PPDO graft chains can be controlled easily by using the prepolymers of PPDO with different molecular weights. The resulting products were thoroughly characterized with FT-IR, (1)H NMR, TG, DSC, SEM, and WAXD. The copolymers were used as drug carriers for sinomenine (7,8-didehydro-4-hydroxy-3,7-dimethoxy-17-methyl-9alpha,13alpha,14alpha-morphinan-6-one) and these exhibited a significant controlled drug-releasing behavior whether in artificial gastric juice or in neutral phosphate buffer solution.

  1. 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

  2. Determination of Crosslinking and Grafting in Polyurethane-acrylic Hybrid Material and Their Theoretical Calculations

    Institute of Scientific and Technical Information of China (English)

    JIANG Xu-bao; ZHU Xiao-li; ZHANG Zhi-guo; KONG Xiang-zheng; TAN Ye-bang

    2011-01-01

    A theoretical method to calculate the mode of polyurethane(PU) prepolymers grafted to polyacrylic(PAC) was presented. Using hydroxyethyl acrylate(HEA) as coupling agent, polyurethane-acrylics(PU-AC) hybrid latexes were prepared with varying HEA level and the reaction of HEA with PU prepolymers at different temperatures, and PU grafted to PAC was experimentally determined. The results show that PU grafted to PAC regularly increased, and the non-grafted and linear free PU regularly decreased with increase in HEA/NCO(isocyanate group). The grafted PU on PAC was not proportional to HEA. More than half of linear PU prepolymers were grafted to PAC when HEA was at a low level with HEA/NCO at 0.33. While grafted PU increased to 84.80% (mass fraction), when HEA/NCO increased to 1.0. The results were interpreted based on the theoretical calculation of PU grafted to PAC by the present method.

  3. 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 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.

  4. 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.

  5. The Preparation of Waterborne Two Components Polyurethane Coatings for the Silicon Polyurethane Plastic Floor%用于硅PU塑胶地坪的水性双组分聚氨酯涂料的研制

    Institute of Scientific and Technical Information of China (English)

    史立平; 孔志元; 何庆迪; 蔡青青

    2015-01-01

    The second component of waterborne two components polyurethane coatings was prepared by hydroxyl acrylic emulsion and high efficient additives. And the water dispersible isocyanate was as the first component. The prepared coatings had excellent adhesion,chemical resistance and weather resistance when it was painted on the silicon polyurethane plastic substrate,which greatly improved the durability of silicon polyurethane plastic floor.%采用羟基丙烯酸乳液及高效助剂制得水性双组分聚氨酯涂料的乙组分,以水可分散型异氰酸酯为甲组分,制得的双组分涂料在硅PU塑胶基材上具有极佳的附着力、耐化学介质性及耐候性,大大提高了硅PU塑胶地坪的耐久性.

  6. Incorporation of CdS nanoparticles from colloidal solution into optically clear ureasilicate matrix with preservation of quantum size effect

    Science.gov (United States)

    Boev, Victor I.; Soloviev, Alexei; Silva, Carlos J. R.; Gomes, Maria J. M.

    2006-01-01

    Nanocomposite materials based on an organic-inorganic ureasilicate matrix with embedded CdS nanoparticles were produced and characterized by optical (UV/Vis), FTIR, secondary ion mass spectroscopy, inductively-coupled plasma optical emission and steady-state photoluminescence measurements. The ureasilicate precursor was obtained by the reaction between silicon alkoxyde modified by isocyanate groups and polyethylene glycol oligomers with amine terminal groups. The final nanocomposites were prepared by introducing a colloidal solution of CdS nanoparticles with various sizes into the ureasilicate precursor followed by gelation of the mixture in the presence of ammonia/water vapours. The reliable preservation of the quantum-size effect of nanoparticles after their incorporation into the ureasilicate matrix was observed in all samples. The obtained materials were optically transparent at visible range, exhibiting high flexibility and long-term stability.

  7. Synthesis of Energetic Nitrocarbamates from Polynitro Alcohols and Their Potential as High Energetic Oxidizers.

    Science.gov (United States)

    Axthammer, Quirin J; Krumm, Burkhard; Klapötke, Thomas M

    2015-06-19

    A new synthesis strategy for the preparation of energetic carbamates and nitrocarbamates starting from readily available polynitro alcohols is introduced. The efficient synthesis of mainly new carbamates was performed with the reactive chlorosulfonyl isocyanate (CSI) reagent. The carbamates were nitrated using mixed acid to form the corresponding primary nitrocarbamates. The thermal stability of all synthesized compounds was studied using differential scanning calorimetry, and the energies of formation were calculated on the CBS-4 M level of theory. Detonation parameters and propulsion properties were determined with the software package EXPLO5 V6.02. Furthermore, for all new substances single-crystal X-ray diffraction studies were performed and are presented and discussed as Supporting Information.

  8. 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)

  9. Pulmonary alterations associated with inhalation of occupational and environmental irritants.

    Science.gov (United States)

    Castranova, V; Frazer, D G; Manley, L K; Dey, R D

    2002-02-01

    Many gases, vapors, or particles found in occupational and/or environmental settings can act as irritants. In the present study, sensory irritants are characterized by the stimulation of neuropeptide release from sensory nerves in the nasal mucosa, while pulmonary irritants are characterized by recruitment of PMN into bronchoalveolar airspaces, elevation of breathing frequency, and neuropeptide release from sensory fibers innervating the epithelium of the conducting airways. A review of data from our laboratory as well as results from others indicate that asphalt fume is a sensory irritant; toluene diisocyanate (TDI), methyl isocyanate, and machining fluid act as both sensory and pulmonary irritants; while cotton dust, agricultural dusts, microbial products, leather conditioner, and ozone exhibit responses characteristic of pulmonary irritants.

  10. Impact of coupling agent on properties of wood-plastic composite

    Institute of Scientific and Technical Information of China (English)

    XU Min; LI Shuai

    2007-01-01

    The impact ortwo couphng agents,maleic anhydride (coupling agent 1) and isocyanate (coupling agent 2) on the properties of wood-plastic composites (WPC) was studied.Wood-plastic composites were made with coupling agents 1 and 2 and properties were tested under the condition that the ratio of wood fiber to thermoplastic polymer was 7:3,target density was 0.7 g/cm3,press temperature was 175℃,press time was 8 min,and adding amount of coupling agent 2%.Results show that coupling agent 2 was superior to coupling agent 1 and had great effect on the physical and mechanical properties of WPC.When using the same coupling agent,the impact on their properties varied with different thermoplastic polymers.

  11. Palladium-catalyzed formation of oxazolidinones from biscarbamates: a mechanistic study

    Directory of Open Access Journals (Sweden)

    Metin Balci

    2011-02-01

    Full Text Available Oxazolidinones can be synthesized starting from cyclic biscarbamates via a palladium-catalyzed reaction. To test the proposed mechanism of this reaction, first, bicyclonorcarene endoperoxides derived from cyano and carbomethoxy cycloheptatrienes were synthesized and converted into the corresponding diols. The reaction of diols with toluenesulfonyl isocyanate followed by a palladium catalyzed reaction furnished oxazolidinone derivatives in similar yields. It was shown that, if one face of the double bond is blocked by substituents such as H or CN, the reaction also takes place. On the basis of these results, it was assumed that an antiperiplanar orientation of the metal and nucleophile is not necessary to form oxazolidinones. The metal is probably bonded to the allylic system from the same face as the nucleophile.

  12. On the acid-base properties of microwave irradiated hydrotalcite-like compounds containing Zn2+ and Mn2+.

    Science.gov (United States)

    Sampieri, Alvaro; Lima, Enrique

    2009-04-09

    Microwave irradiated lamellar double hydroxides containing different divalent metals (Mn2+, Zn2+, or Mg2+) were prepared with Al3+ as the trivalent metal. Samples containing Mn2+ and Zn2+ were unstable at 400 degrees C, leading to formation of mixed oxides and spinel phases. Acid-base properties of the samples were characterized by nitromethane and CO2 adsorption followed by FTIR spectroscopy. Decomposition of adsorbed nitromethane leads to isocyanate species that acts as probe molecules of acid-base sites at the surface. These properties determine the ability of materials to retain CO2. Indeed, whereas Mn-O sites are able to interact directly with CO2 molecules, Mg-O and Zn-O are able to form carbonate species as a result of the CO2 sorption.

  13. Novel sulfonyl(thio)urea derivatives act efficiently both as insulin secretagogues and as insulinomimetic compounds.

    Science.gov (United States)

    Mascarello, Alessandra; Frederico, Marisa Jádna Silva; Castro, Alisson Jhonathan Gomes; Mendes, Camila P; Dutra, Márcio Ferreira; Woehl, Viviane Mara; Yunes, Rosendo Augusto; Mena Barreto Silva, Fátima Regina; Nunes, Ricardo José

    2014-10-30

    Glibenclamide is widely used in the management of non-insulin dependent diabetes mellitus, but numerous risks limit its use in therapy. In the search for novel structures that are safer and more efficient than glibenclamide, we obtained new chemical analogs based on bioisosterism, through the treatment of benzenesulfonamide derivatives with isothiocyanates and isocyanates, affording (thio)ureas with good yield. We also verified the hypoglycemic activity, through an in vivo approach. Most of these synthesized compounds improved glucose tolerance, and the mechanism of action of the best compound (7) suggests that its effect is mediated by insulin secretion, while its hypoglycemic action is triggered by glucose uptake involving GLUT4 expression and translocation through PI-3K and PKA activity and active de novo protein synthesis in skeletal muscle. Taking all these factors together, sulfonylthiourea 7 acts as an insulin secretagogue and insulinomimetic agent on glucose homeostasis, and does not exhibit toxicity in acute treatment.

  14. Dielectric Constant and Loss Data, Part 3

    Science.gov (United States)

    1977-05-01

    170.9 10 - 1.86E-7 Isocyanate , SF-52, liquid MIT, Mech. Eng. Dept. TF K’ 83.7 14.7 2.49E-9 96 - 6.28F.-9 105 - 81SOE-9 109 - 9.60E~-9 122 - 1.25E-8 126...72 V-8.9,64,85096,97 Bell LOGs. F-66, IV-3,83; V2-56,57; Asphalt pavement end asphalts , .- 7 P.R.-156 Renotoite, P.R.-l27 Aenhaltri and esmen’. IV...see i~agneiiium meta- Cements &aid asphalt %, :V-56 silicate Cements, alwnina, 8-3 Coal, powdered, P.lR.-191single lump, P.R.-192 Cencoral oti, V5

  15. 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.

  16. Synthesis and Characterization of Polyurethane-Nanoclay Composites

    Directory of Open Access Journals (Sweden)

    Manasa Nayani

    2013-01-01

    Full Text Available In this study polyurethane (PUR-nanoclay composites were synthesized using methylene diphenyl diisocyanate, polyol, and hectorite clay. The weight percentage of hectorite clay was varied at three different levels to study its effect on the properties of the thermoplastic polyurethane nanocomposite. The nanocomposite polyurethane foam was synthesized in a 2-step reaction process. The first step involved the addition and dispersion of nanoclay into the isocyanate. The mixture was then mixed with the polyol, and the foam was cast in a preheated closed mold. The PUR-nanocomposite foams were analyzed for cell structure, physical, mechanical, and thermal properties. The composite foam showed significant increase in tensile and flexural strengths, abrasion resistance, and thermal properties.

  17. Applying Raman spectroscopy to the assessment of the biodegradation of industrial polyurethanes wastes.

    Science.gov (United States)

    Cregut, Mickael; Bedas, Marion; Assaf, Ali; Durand-Thouand, Marie-José; Thouand, Gérald

    2014-01-01

    Polyether-based polyurethanes (PBP) are extremely problematic polymers due to their long persistence in the environment. Moreover, the assessment of PBP biodegradation remains biased due to the inability of conventional methods to determine how their diverse subunits are degraded. To improve our knowledge of PBP biodegradation, we used Raman spectroscopy to identify patterns of PBP biodegradation. Specifically, PBP biodegradation was assessed using a microbial inoculum isolated from an industrial soil in which polyurethanes have been buried for 40 years. During a 28-day biodegradation assay, the PBP biodegradation level reached 27.5% (w/w), in addition to undergoing profound alteration of the PBP composition as identified by chemical analyses. After microbial degradation, Raman analyses revealed the disappearance of the polymer's amorphous region, which contains a high polyol content, whereas the isocyanate-rich crystalline regions were preserved. The use of Raman spectroscopy appears to be a particularly useful tool to enhance our assessment of polymer biodegradation.

  18. Improved adhesion performances of aramid fibers with vinyl epoxy via supercritical carbon dioxide modification

    Science.gov (United States)

    Qin, M. L.; Kong, H. J.; Yu, M. H.; Teng, C. Q.

    2017-06-01

    In this paper, aramid fibers were treated under supercritical carbon dioxide (SCCO2) with isocyanate terminated liquid nitrile rubber to improve the adhesion performances of vinyl epoxy composites. The interfacial shear strength (IFSS) of vinyl epoxy composites was investigated by micro-bond test. The results indicate that the surface modification of aramid fibers in SCCO2 was an efficient method to increase the adhesion performances between fibers and vinyl epoxy. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were adopted to investigate the surface structure and composition of aramid fibers. The flexural strength and interlaminar shear strength (ILSS) of treated aramid fibers/vinyl epoxy composites was improved by 18.1% and 28.9% compared with untreated aramid fibers, respectively. Furthermore, the fractured surfaces of the composites were observed by SEM, which showed that the interfacial adhesion of composites has been remarkably changed.

  19. Synthesis of /sup 14/C-propoxur (o-isopropoxyphenyl N-methylcarbamate-/sup 14/C) insecticide

    Energy Technology Data Exchange (ETDEWEB)

    Hossaini, M.A.; Zareh, Z. (Atomic Energy Organization of Iran, Teheran. Nuclear Research Centre)

    1984-08-01

    /sup 14/C-propoxur (Baygonsub(circled R)) is an insecticide with a broad spectrum of activity and a very low order of mammalian toxicity. Radiosynthesis of propoxur was performed by the reaction of acetyl-1-/sup 14/C chloride and sodium azide to produce methyl isocyanate which then reacted with o-isopropoxyphenol at 100 degC. A two-compartment reaction tube with a break seal was utilized. Chromatograhic procedures for isolating the N-methylcarbamates from their reaction mixtures are reported. Acetyl-1-/sup 14/C chloride was prepared from thionyl chloride and sodium acetate-1-/sup 14/C. Grignard reaction between methyl iodide and carbon-14 dioxide yielded acetic acid-/sup 14/C which was neutralized by sodium hydroxide solution to give sodium acetate-1-/sup 14/C. 9 refs.

  20. 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 (SiO2 NPs) were first prepared as core component, through the efficient reaction between amino group containing SiO2 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 SiO2 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.

  1. IR study on hydrogen bonding in epoxy resin-silica nanocomposites

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Abbas A. Dehghani-Sanij; Richard S. Blackburn

    2008-01-01

    The chemical and physical interactions between ingredients in composites play an important role in the improvement of service prop-sity loss of isocyanate absorption band in conjunction with the intensity growth of carboxyl absorption band indicates the progress of reaction. FT-IR spectroscopy was also adopted to examine the intermolecular hydrogen bonding of epoxy resin with silica as well as intramolecular one within polymer matrix. The vibration frequency of carboxyl group (-C=O) and hydroxyl group (-OH) shifts from 1736 to 1728 cm-1and 3420 to 3414 cm-1, respectively, indicating the occurrence of hydrogen bonding between -C=O and -OH. The vibration frequency of Si-OH moves from 3435 to 3414 cm -1, suggesting the involvement of silica. Whereas the vibration frequency of pending -OH in polymer chain moves from 3435 to 3420 cm-1 or 3414 cm-1, proposing that this kind of interaction can also happen within polymer matrix.

  2. Synthesis of tritium labelled (R) and (S)-3-aminoquinuclidine: a ubiquitous component of serotonin receptor ligands. Pt. 2

    Energy Technology Data Exchange (ETDEWEB)

    Masjedizadeh, M.R.; Parnes, Howard [Syntex Discovery Research, Palo Alto, CA (United States). Chemical Research and Development

    1996-01-01

    (S)-3-Aminoquinuclidine-{sup 3}H 10c-S having a specific activity of 66 Ci/mmol was prepared in eight steps from isonicotinic acid (2). Reduction of 2 with carrier free tritium gas over PtO{sub 2} in DMF gave isonipecotic acid-{sup 3}H 3c. Conversion to {alpha}-bromo ketone 5c followed by cyclization afforded 3-quinuclidone-{sup 3}H 6c. Racemic 3-amino-quinuclidine-{sup 3}H 8c was prepared by conversion of 6c to oxime 7c followed by reduction with NaBH{sub 4}/NiCl{sub 2}.6H{sub {sub 2}}O. Racemic 8c was resolved with (R)-methylbenzyl isocyanate. Hydrolysis of 9c-S.R afforded (S)-3-aminoquinuclidine-{sup 3}H 10c-S. The enantiopurity was >99.5% (S). (author).

  3. 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.

  4. Toxicology evaluation and hazard review for non-CFC containing rigid foams BKC 44317 and last-a-foam MSL-02A

    Energy Technology Data Exchange (ETDEWEB)

    Greulich, K.A.; Archuleta, M.M.

    1996-06-01

    New pour-in-place, low density, rigid polyurethane foam kits have been developed to mechanically stabilize damaged explosive ordnance. Although earlier foam systems used chlorofluorocarbons as blowing agents, the current versions rely on carbon dioxide generated by the reaction of isocynates with water. In addition, these kits were developed to manually generate small quantifies of rigid foam in the field with minimal or no protective equipment. The purpose of this study was to evaluate and summarize available hazard information for the components of these rigid foam kits and to provide recommendations for personal protective equipment to be used while performing the manual combination of the components. As with most rigid foam systems, these kits consist of two parts, one a mixture of isocyanates; the other, a combination of polyols, surfactants, and amine catalysts. Once completely deployed, the rigid foam is non-toxic. The components, however, have some important health effects which must be considered when establishing handling procedures.

  5. 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.

  6. Synthesis of Cellulose-2,3-bis(3,5-dimethylphenylcarbamate) in an Ionic Liquid and Its Chiral Separation Efficiency as Stationary Phase

    Science.gov (United States)

    Liu, Runqiang; Zhang, Yijun; Bai, Lianyang; Huang, Mingxian; Chen, Jun; Zhang, Yuping

    2014-01-01

    A chiral selector of cellulose-2,3-bis(3,5-dimethylphenylcarbamate) (CBDMPC) was synthesized by reacting 3,5-dimethylphenyl isocyanate with microcrystalline cellulose dissolved in an ionic liquid of 1-allyl-3-methyl-imidazolium chloride (AMIMCl). The obtained chiral selector was effectively characterized by infrared spectroscopy, elemental analysis and 1H NMR. The selector was reacted with 3-aminopropylsilanized silica gel and the CBDMPC bonded chiral stationary phase (CSP) was obtained. Chromatographic evaluation of the prepared CSPs was conducted by high performance liquid chromatographic (HPLC) and baseline separation of three typical fungicides including hexaconazole, metalaxyl and myclobutanil was achieved using n-hexane/isopropanol as the mobile phase with a flow rate 1.0 mL/min. Experimental results also showed that AMIMCl could be recycled easily and reused in the preparation of CSPs as an effective reaction media. PMID:24733066

  7. Synthesis of Cellulose-2,3-bis(3,5-dimethylphenylcarbamate in an Ionic Liquid and Its Chiral Separation Efficiency as Stationary Phase

    Directory of Open Access Journals (Sweden)

    Runqiang Liu

    2014-04-01

    Full Text Available A chiral selector of cellulose-2,3-bis(3,5-dimethylphenylcarbamate (CBDMPC was synthesized by reacting 3,5-dimethylphenyl isocyanate with microcrystalline cellulose dissolved in an ionic liquid of 1-allyl-3-methyl-imidazolium chloride (AMIMCl. The obtained chiral selector was effectively characterized by infrared spectroscopy, elemental analysis and 1H NMR. The selector was reacted with 3-aminopropylsilanized silica gel and the CBDMPC bonded chiral stationary phase (CSP was obtained. Chromatographic evaluation of the prepared CSPs was conducted by high performance liquid chromatographic (HPLC and baseline separation of three typical fungicides including hexaconazole, metalaxyl and myclobutanil was achieved using n-hexane/isopropanol as the mobile phase with a flow rate 1.0 mL/min. Experimental results also showed that AMIMCl could be recycled easily and reused in the preparation of CSPs as an effective reaction media.

  8. Efficient Synthesis of Primary Nitrocarbamates of Sugar Alcohols: From Food to Energetic Materials.

    Science.gov (United States)

    Axthammer, Quirin J; Klapötke, Thomas M; Krumm, Burkhard

    2016-02-18

    The synthesis of various new polyvalent nitrocarbamates derived from sugar alcohols was accomplished by an economically benign two-step synthesis. The precursor carbamates were synthesized with the reagent chlorosulfonyl isocyanate (CSI) and further nitrated using mixed acid. The starting materials, sugar alcohols, are renewable biomass, mainly used in food and cosmetic industry. The structures of one carbamate and one nitrocarbamate were exemplary described by single-crystal X-ray-analysis. The heat of formation is calculated by the use of isodesmic reactions and the energetic performance data were estimated. All compounds were fully characterized by elemental analysis, vibrational spectroscopy, (1)H, (13)C, and (14/15)N NMR spectroscopy and thermal analysis (DSC). The nitrocarbamates exhibit good detonation performance and have significantly lower sensitivities compared to the commonly used nitrate ester explosive PETN.

  9. 聚氨酯弹性体的紫外线稳定性%Polyurethane elastomer ultraviolet stabilization

    Institute of Scientific and Technical Information of China (English)

    刘凉冰

    2001-01-01

    A review is cited with 15 references.Effects of soft segment(polyester and polyether),di-isocyanate,chain extenders,concentration of hard segment,exposure time on ultraviolet stabilization of polyurethane elastomer were discussed.%指出影响聚氨酯(PU)弹性体紫外线稳定性的主要因素有软段(聚酯、聚醚)、二异氰酸酯、硬段质量分数及照射时间、样品厚度,同时讨论了这些因素对紫外线照射后的PU弹性体某些力学性能的影响,添加紫外线吸收剂和炭黑可改善PU弹性体紫外线稳定性。

  10. Infrared light actuated shape memory effects in crystalline polyurethane/graphene chemical hybrids

    Science.gov (United States)

    Park, J. H.; Kim, B. K.

    2014-02-01

    A series of crystalline shape memory polyurethanes (SMPUs) were synthesized from polycaprolactone diols and 4,4‧-methylenedicyclohexyl diisocyanate (H12MDI) with chemical incorporation of allyl isocyanate modified graphene oxide (iGO) into the PU. Actuation of hybrid SMPUs by infrared (IR) absorption of iGO as well as the direct heat actuated SMPUs has been studied in terms of the isothermal crystallization rate, near-IR absorption, and thermal, mechanical, and shape memory properties. It was found that iGO functions as a multifunctional cross-linker at low contents and a nucleating agent at high contents, and as a reinforcing filler, while light absorption by the iGO induced melting of the PU soft segment, giving rise to a shape recovery of over 90% at 1% iGO (G10).

  11. Composites prepared from the waterborne polyurethane cationomers-modified graphene. Part II. Electrical properties of the polyurethane films.

    Science.gov (United States)

    Król, Piotr; Król, Bożena; Zenker, Marek; Subocz, Jan

    The research was planned to test electrical properties of polymer films made from polyurethane cationomers with 0-2 wt.% graphene admixture. The cationomers were synthetized in the reaction of 4,4'-methylenebis(phenyl isocyanate), polycaprolactone diol (M = 2000), N-methyldiethanolamine, and formic acid. It was found that addition of approx. 2 wt.% of graphene causes the loss of volume resistivity by three orders of magnitude and percolation threshold is already set at approx. 1 wt.%. The frequency characteristic of a real part of permittivity ε' and imaginary part of permittivity ε″ were measured for the tested films. On the base of Havriliak-Negami equation, parameters of relaxation functions in frequency domain were estimated for samples containing various contents of graphene. The influence of the cationomer phase structure on observed changes of dielectric losses coefficient tgδ in the full-measuring frequency spectrum was discussed.

  12. Hydrogenation at low temperatures does not always lead to saturation: the case of HNCO

    CERN Document Server

    Noble, J A; Congiu, E; Dulieu, F; Bonnin, M; Bassas, A; Duvernay, F; Danger, G; Chiavassa, T

    2015-01-01

    Context. It is generally agreed that hydrogenation reactions dominate chemistry on grain surfaces in cold, dense molecular cores, saturating the molecules present in ice mantles. Aims. We present a study of the low temperature reactivity of solid phase isocyanic acid (HNCO) with hydrogen atoms, with the aim of elucidating its reaction network. Methods. Fourier transform infrared spectroscopy and mass spectrometry were employed to follow the evolution of pure HNCO ice during bombardment with H atoms. Both multilayer and monolayer regimes were investigated. Results. The hydrogenation of HNCO does not produce detectable amounts of formamide (NH2CHO) as the major product. Experiments using deuterium reveal that deuteration of solid HNCO occurs rapidly, probably via cyclic reaction paths regenerating HNCO. Chemical desorption during these reaction cycles leads to loss of HNCO from the surface. Conclusions. It is unlikely that significant quantities of NH2CHO form from HNCO. In dense regions, however, deuteration o...

  13. Nanofibers for drug delivery - incorporation and release of model molecules, influence of molecular weight and polymer structure.

    Science.gov (United States)

    Hrib, Jakub; Sirc, Jakub; Hobzova, Radka; Hampejsova, Zuzana; Bosakova, Zuzana; Munzarova, Marcela; Michalek, Jiri

    2015-01-01

    Nanofibers were prepared from polycaprolactone, polylactide and polyvinyl alcohol using Nanospider(TM) technology. Polyethylene glycols with molecular weights of 2 000, 6 000, 10 000 and 20 000 g/mol, which can be used to moderate the release profile of incorporated pharmacologically active compounds, served as model molecules. They were terminated by aromatic isocyanate and incorporated into the nanofibers. The release of these molecules into an aqueous environment was investigated. The influences of the molecular length and chemical composition of the nanofibers on the release rate and the amount of released polyethylene glycols were evaluated. Longer molecules released faster, as evidenced by a significantly higher amount of released molecules after 72 hours. However, the influence of the chemical composition of nanofibers was even more distinct - the highest amount of polyethylene glycol molecules released from polyvinyl alcohol nanofibers, the lowest amount from polylactide nanofibers.

  14. Epoxy Resin and Polyurethane Compositions from Glycolized Poly (ethylene terephthalate Wastes

    Directory of Open Access Journals (Sweden)

    Gintaras MACIJAUSKAS

    2013-09-01

    Full Text Available The possibility to use poly(ethylene terephthalate (PET bottles production waste as raw material for compositions with high adhesion ability has been investigated. PET waste was glycolyzed with polypropylene glycol and three kinds of oligoesters were formed after depolymerization reaction. The polydispersity of product formed was 1.05. The possibilities to use PET glycolysis products – oligoesters for epoxy resin and polyurethanes were studied. Two-step reaction of oligoesters with epichlorohydrin was chosen for epoxy resin synthesis, while glycolyzed PET reaction with aliphatic isocyanate was used for polyurethane synthesis. The structure and properties of the obtained polymers were investigated. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.5237

  15. Palm kernel oil-based polyurethane film: Biocompatibility and antibacterial activity studies

    Science.gov (United States)

    Zulkifli, Nurul Nabilah bt; Badri, Khairiah bt Hj; Nor, Mohd Al Amin Muhamad; Amin, Khairul Anuar Mat

    2017-02-01

    In this study, polyurethane (PU) film was prepared from palm kernel oil-based polyester (PKO-p) via pre-polymerization with isocyanate/polyol group ([NCO/OH]). PU films were physically characterized to investigate the mechanical properties, thermal behavior, water uptake, water vapor transmission rates as well as biocompatibility and antibacterial activities against Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). Results showed that PU 2 film exhibited optimum mechanical performance and thermal properties with the water vapor transmission rates at 267 ± 17 g m-2 d-1, comparable to commercial dressing. Biocompatibility studies revealed that PU films were non-cytotoxic to the human skin fibroblast cells (CRL2522) and exhibited bactericidal effect against both bacteria.

  16. Catalytic properties of maltogenic α-amylase from Bacillus stearothermophilus immobilized onto poly(urethane urea) microparticles.

    Science.gov (United States)

    Straksys, Antanas; Kochane, Tatjana; Budriene, Saulute

    2016-11-15

    The immobilization of maltogenic α-amylase from Bacillus stearothermophilus (BsMa) onto novel porous poly(urethane urea) (PUU) microparticles synthesized from poly(vinyl alcohol) and isophorone diisocyanate was performed by covalent attachment to free isocyanate groups from PUU microparticles, or by physical adsorption of enzyme onto the surface of the carrier. The influence of structure, surface area and porosity of microparticles on the catalytic properties of immobilized BsMa was evaluated. The highest efficiency of immobilization of BsMa was found to be 72%. Optimal activity of immobilized BsMa was found to have increased by 10°C compared with the native enzyme. Influence of concentration of sodium chloride on activity of immobilized BsMa was evaluated. High storage and thermal stability and reusability for starch hydrolysis of immobilized enzyme were obtained. Immobilized BsMa has a great potential for biotechnology.

  17. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU; TaJung

    2001-01-01

    The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.  ……

  18. ANALISIS KERAGAAN PANEL SANDWICH UNTUK RUMAH PRA-PABRIKASI

    Directory of Open Access Journals (Sweden)

    Naresworo Nugroho

    2010-12-01

    Full Text Available In the last five years, several earthquakes struck several places in Indonesia and thousands of people died caused of their masonry house. Therefore, the idea of bamboo utilization in the form of structural sandwich panel components for anti-seismic pre-fabrication house is one of appropriate way out. This research describes the performance and behavior of engineered structure wooden-bamboo sandwich panel in full sized test. The wall frame being use were meranti wood, this frame attached by plywood as face and back, then 5 cm bamboo cutting as core; the fastener used in this study were isocyanate resin and nails. This study carried out by experimental data of full scale structural tests on shear wall (ISO 22452. These result showed that the seismic reliability of the wall frame system made of bamboo sandwich panel was appropriate and will be useful for pre-fabrication houses as anti-seismic and environment friendly residential building

  19. Novel Composite Materials for Chiral Separation from Cellulose and Barium Sulfate

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2013-01-01

    Full Text Available Cellulose was dissolved in an aqueous solution of sodium hydroxide (NaOH and urea followed by the addition of barium sulfate (BaSO4 to yield the BaSO4/cellulose composite particles. The morphology, particle size, and BaSO4 content of the composite particles were adjusted by controlling the feed ratio of cellulose and BaSO4. The cellulose within the composite particles then reacted with 3,5-dimethylphenyl isocyanate. The resulting materials were utilized as the chiral stationary phases (CSPs whose enantioseparation capabilities were evaluated by various chiral analytes. Due to the mechanical enhancement effect of BaSO4, the composite particles could be applied to the chromatographic packing materials.

  20. 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

  1. 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}.

  2. Novel urea and thiourea derivatives of thiazole-glutamic acid conjugate as potential inhibitors of microbes and fungi.

    Science.gov (United States)

    Sharma, A; Suhas, R; Chandan, S; Gowda, D C

    2013-01-01

    Since discovery and development of effective as well as safe drugs has brought a progressive era in human healthcare that is accompanied by the appearance of drug resistant bacterial strains, there is constant need of new antibacterial agent having novel mechanisms of action to act against the harmful pathogens. In the present study, several N-terminal substituted urea/thiourea derivatives were synthesized by the reaction of glutamic acid and 3-(1-piperazinyl)-1,2-benzisothiazole with various substituted phenyl isocyanates/isothiocyanates. Elemental analysis, IR, 1H NMR, 13C NMR and mass spectral data confirmed the structure of the newly synthesized compounds. The derivatives were investigated for their antibacterial and antifungal activities against various pathogens of human origin by agar well diffusion method and microdilution method. The preliminary antimicrobial bioassay reveals that the compounds containing fluoro and bromo as substituents showed promising antimicrobial activity.

  3. Heat sterilizable solid-propellant development

    Science.gov (United States)

    Kalfayan, S. H.

    1981-01-01

    The binders tested were polyurethanes made from two hydroxy-terminated polybutadienes, R-45 and Butarez HT, one hydroxy-terminated butadiene-acrylonitrile copolymer, Hycar 1300X 17, and a hydroxy-terminated prepolymer, Esterdiol 560, made from the dimerized fatty acid Empol 1010. The isocyanates used most extensively were isophorone diisocyanate (IPDI) and a polymeric diisocyanate, DDI. Stress relaxation was used to examine the chemical changes that took place in the binder when subjected to the sterilization temperatures. The thermal stability of the oxidizer, ammonium perchlorate (AP), was tested by thermogravimetry in the isothermal and nonisothermal modes. The effect of particle size, recrystallization, moisture content, and doping on the heat stability of AP could be evaluated by this method. The volatile degradation products, obtained when AP samples were aged at 135 C for prolonged periods, were analyzed by mass spectroscopy.

  4. Liner material and manufacturing process for the Ariane 5 solid propellant boosters

    Science.gov (United States)

    Lecoustre, M.; Maucourt, J.

    1992-07-01

    The specifications and installation procedure for the liners of Ariane 5 boosters are set forth with attention given to functional and manufacturing requirements. The liner is made up of reinforcing fillers, a bond promoter, and a binder developed with the polymer HTPB, aliphatic isocyanate as a curing agent, and polymerization catalysts. The industrial manufacturing sequence is outlined discussing the preheating and chemical activation of the thermal insulation before the spraying process begins. Spraying tests are conducted of the substance to measure the liner thickness and secant modulus. The average measured thickness is found to be about 1 mm, and the secant modulus does not vary significantly. The liner formula is shown to be suitable for spraying and to meet such functional specifications as strain and peel capabilities.

  5. Application of microgels as polymer supports for organic synthesis: preparation of a small phthalide library, a scavenger, and a borohydride reagent.

    Science.gov (United States)

    Shimomura, Osamu; Clapham, Bruce; Spanka, Carsten; Mahajan, Suresh; Janda, Kim D

    2002-01-01

    Microgel polymers containing a series of functional groups have been prepared. These microgels were composed of cross-linked poly(styrene) and were prepared by radical polymerization in solution. The microgel polymers exhibit good solubility in an array of different organic solvents, and in addition, they can be efficiently precipitated by the addition of methanol and isolated by filtration. A nine-member phthalide library was synthesized using an aminomethyl-functionalized microgel 5. To further demonstrate the versatility of these microgel polymers, tris(2-aminoethyl)amino microgel 11 was examined as a scavenger reagent to remove unreacted isocyanate after a urea synthesis. Finally, a microgel-supported ammonium borohydride reagent 14 was successfully prepared and used as a reducing agent. Notable features of these microgels are that in all applications the progress of the reaction could be monitored by standard NMR techniques and their preparation is performed using common glassware and techniques found in all organic laboratories.

  6. Surface modification with both phosphorylcholine and stearyl groups to adjust hydrophilicity and hydrophobicity

    Energy Technology Data Exchange (ETDEWEB)

    Lv Jiuan; Ma Jiani; Huangfu Pengbo; Yang Shan [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Department of Chemistry, Northwest University, Xi' an 710069 (China); Gong Yongkuan [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Department of Chemistry, Northwest University, Xi' an 710069 (China)], E-mail: gongyk@nwu.edu.cn

    2008-11-15

    A new monolayer film with tunable hydrophilicity and hydrophobicity was constructed on glass coverslips by stepwise grafting with both phosphorylcholine (PC) and stearyl groups. The glass coverslips were firstly hydroxylized to provide reactive sites on the surfaces. Subsequently, chlorodimethyl-n-octadecylsilane was chemically adsorbed onto the surface to impart the required hydrophobicity. The remaining hydroxyl groups were grafted with 1,6-diisocyanatohexane. Finally, 2-hydroxy-2-ethylphosphorylcholine was grafted onto the attached isocyanate groups. Dynamic contact angle (DCA) measurement and X-ray photoelectron spectroscopy (XPS) analysis confirmed that the step-by-step modification process was successful. The adsorption of bovine serum albumin and bovine plasma fibrinogen, as well as the adhesion and aggregation of platelets were suppressed with the introduction of phospholipid moieties on the surfaces. This tunable surface may have potential applications in the fields of separation science, tissue engineering, cytobiology, drug delivery and gene therapy.

  7. Epoxy Resin and Polyurethane Compositions from Glycolized Poly (ethylene terephthalate Wastes

    Directory of Open Access Journals (Sweden)

    Gintaras MACIJAUSKAS

    2013-09-01

    Full Text Available The possibility to use poly(ethylene terephthalate (PET bottles production waste as raw material for compositions with high adhesion ability has been investigated. PET waste was glycolyzed with polypropylene glycol and three kinds of oligoesters were formed after depolymerization reaction. The polydispersity of product formed was 1.05. The possibilities to use PET glycolysis products – oligoesters for epoxy resin and polyurethanes were studied. Two-step reaction of oligoesters with epichlorohydrin was chosen for epoxy resin synthesis, while glycolyzed PET reaction with aliphatic isocyanate was used for polyurethane synthesis. The structure and properties of the obtained polymers were investigated. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.5237

  8. Preparation of polystyrene/silica nanocomposites by radical copolymerization of styrene with silica macromonomer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A two-stage process has been developed to generate the silica-based macromonomer through surface-modification of silica with polymerizable vinyl groups. The silica surfaces were treated with excess 2,4-toluene diisocynate (TDI), after which the residual isocyanate groups were converted into polymerizable vinyl groups by reaction with hydroxypropylacrylate (HPA). Thus, polystyrene/silica nanocomposites were prepared by conventional radical copolymerization of styrene with silica macromonomer. The main effecting factors, such as ratios of styrene to the macromonomer, together with polymerization time on the copolymerization were studied in detail. FTIR, DSC and TGA were utilized to characterize the nanocomposites. Experimental results revealed that the silica nanoparticles act as cross-linking points in the polystytene/silica nanocomposites, and the glass transition temperatures of the nanocomposites are higher than that of the corresponding pure polystyrene. The glass transition temperatures of nanocomposites increased with the increasing of silica contents, which were further ascertained by DSC.

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

    Directory of Open Access Journals (Sweden)

    José Humberto Santos Almeida Júnior

    2013-01-01

    Full Text Available 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 (≈ 220 °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.

  10. Excitation, abundance, and distribution of HNCO in Sagittarius B2

    Energy Technology Data Exchange (ETDEWEB)

    Churchwell, E.; Wood, D.; Myers, P.C.; Myers, R.V.

    1986-06-01

    Snyder and Buhl (1972) have discovered isocyanic acid (HNCO) in Sgr B2. It is pointed out that HNCO is a particularly interesting interstellar molecule because under certain conditions it can be employed in a study of the far-infrared radiation field of the cloud in which it resides. The present study was mainly conducted with the aim to establish empirically the extent to which HNCO is populated by radiative processes in a source with a measured far-infrared radiation field. It is attempted to deduce the radiation field from the HNCO excitation conditions. Attention is given to an energy-level diagram of HNCO in the ground electronic and vibrational states, the antenna and receiver properties, a table with the observed parameters toward Sagittarius B2, the velocity structure, the HNCO intensity distribution, a summary of the Sgr B2 properties, the population distribution and column density, and the excitation of HNCO. 27 references.

  11. 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.

  12. Microwave-Accelerated Organic Reactions

    Institute of Scientific and Technical Information of China (English)

    LU TaJung

    2001-01-01

    @@ The use of microwave technology in accelerating organic reactions has received intense attention leading to immense growth recently. Accordingly, we have been interested in improving the efficacy of organic processes by microwave irradiation. Here we report our results on the microwave assisted 1,3-dipolar cycloaddition reaction of nitrile oxides with allylic alcohols, the cleavage reaction of 1,3-diketones under alkaline conditions, and the formation of carbamates from isocyanates with alcohols. The reactions carried out under microwave irradiation, in general, required considerably less reaction time and afforded the desired products in higher yields than those under classical conditions. In all the cases we have studied, the procedures are simplified, the purity of the products are higher, and the cost of reaction is greatly reduced employing microwave.

  13. Tetramethyl-1-silacycloprop-2-ene: its characterization and reactions

    Energy Technology Data Exchange (ETDEWEB)

    Cornett, B.J.

    1980-05-01

    The object of this research is to fully characterize and study some of the reactions of tetramethyl-1-silacycloprop-2-ene. The final characterization of this compound was accomplished by obtaining both Si29 and 13C nuclear magnetic resonance spectra. The reactions studied included those with fluorenone, acetone, styrene, phenylacetylene, acetonitrile, t-butylcyanide, methyl isocyanate, phenyl azide, and azobenzene. Product analyses suggest that aside from addition reactions tetramethylsilacyclopropene can react either via a radical chain polymerization or an anionic chain polymerization mechanism with the latter being the more prevalent. Other reactions studied included the photolysis of tetramethylsilacyclopropene and its reactions in the presence of Pd(PPh/sub 3/)/sub 2/Cl/sub 2/. An appendix includes a study of trimethylsilyl radical disproportionation in the liquid phase to a sila olefin. Trimethylsilyl radicals in solution undergo disproportionation as well as recombination in a 1:5 ratio. The sila olefin formed by disproportionation was trapped by alcohols.

  14. 聚醚多元醇合成封端型水性聚氨酯乳液%Synthesis of waterborne blocked polyurethane emulsion based on polyether polyols

    Institute of Scientific and Technical Information of China (English)

    陡媛; 赵振河; 刘晶

    2015-01-01

    Using polyether triol and toluene diisocyanate as the basic raw materials, isopropanol as the diluent and sodium bisulfite as the blocking agent, the waterborne blocked polyurethane emulsion was synthesized. And the effects of isocyanate index (R value), temperature and time of prepolymerization, blocking agent amount and temperature and time of blocking on the properties of blocked waterborne polyurethane emulsion were analyzed and discussed.%以聚醚三元醇和甲苯二异氰酸酯(TDI)为基本原料,异丙醇为稀释剂,亚硫酸氢钠为封端剂制得水性聚氨酯。分析并讨论预聚温度和时间、R值、封端剂用量、封端温度及时间等因素对水性聚氨酯性能的影响。

  15. Response of flakeboard properties to changes in steam-injection-pressing environments. Forest Service research paper

    Energy Technology Data Exchange (ETDEWEB)

    Geimer, R.L.; Johnson, S.E.; Kamke, F.A.

    1992-01-01

    Mechanical strength properties and dimensional stability of composite wood products are determined to some extent by the environment within the mat during pressing. The objectives of the study were to define time-related temperature and vapor-pressure parameters occurring in a mat during different steam injection pressing (SIP) schedules and to relate these conditions to board properties. Acceptable boards, as measured by internal bond strength, were produced with the isocyanate resin at all steaming schedules. Press times could often be reduced to less than half of that needed to bond boards made with phenolic resins. Shear and thickness swelling properties followed the same trends measured for internal bond strength. However, bending properties of SIP boards were influenced by the reduced density gradient of the boards and were below the bending properties of boards pressed in a conventional manner.

  16. Isocyanide based [4+1] cycloaddition reactions: an indispensable tool in multi-component reactions (MCRs).

    Science.gov (United States)

    Kaur, Tanpreet; Wadhwa, Preeti; Bagchi, Sourav; Sharma, Anuj

    2016-05-19

    The advent of cycloaddition reactions in the synthesis of heterocycles and their ever burgeoning applications in the fields of material chemistry, catalysis and drugs have been a profound scientific development. In particular, isocyanide based cycloaddition reactions have been harbingers of an exciting new chapter in the realms of organic synthesis. The emergence of numerous synthetic protocols utilizing formal cycloaddition of isocyanides with conjugated heterodienes has unleashed countless opportunities to design and synthesize diverse heterocyclic scaffolds. To date, there has not been any exclusive review on a formal [4+1] cycloaddition involving isocyanides. The present review highlights the journey of formal [4+1] cycloaddition reactions of isocyanides with diverse electrophilic substrates viz. oxadienes, azadienes, thioacyl imines, alkylidene amides, alkylidene hydrazines, α,β-unsaturated nitro compounds, α-thioxothioamides, nitroso alkenes, acyl imines, vinyl ketenes, vinyl isocyanates, etc. to afford functionalized pyrroles, imidazoles, furans, oxazoles, pyrazoles, etc.

  17. Selective modification of polylactide by introducing acrylate groups: IR spectroscopy, gel permeation chromatography, and differential thermal analysis

    Science.gov (United States)

    Shashkova, V. T.; Matveeva, I. A.; Glagolev, N. N.; Zarkhina, T. S.; Timashev, P. S.; Bagratashvili, V. N.; Solov'eva, A. B.

    2016-10-01

    One-stage modification of polylactide has been performed to obtain the acrylate derivatives of the polymer capable of further polymerization and preparation of cross-linked polymer materials suitable for creating implants. The reaction mechanism was determined by IR spectroscopy, gel permeation chromatography, and differential thermal analysis. It was shown for the first time that the reaction path changes depending on the ratio of components so that the desired product polylactide acrylate forms with a ~90% yield only in the presence of large (approximately tenfold) excesses of the isocyanate and acrylate components; at the equimolar ratio of components generally used in urethane formation, a mixture of the desired product (~30%), oligourethane diacrylates, and unchanged polylactide forms.

  18. Nanofibers for drug delivery – incorporation and release of model molecules, influence of molecular weight and polymer structure

    Directory of Open Access Journals (Sweden)

    Jakub Hrib

    2015-09-01

    Full Text Available Nanofibers were prepared from polycaprolactone, polylactide and polyvinyl alcohol using NanospiderTM technology. Polyethylene glycols with molecular weights of 2 000, 6 000, 10 000 and 20 000 g/mol, which can be used to moderate the release profile of incorporated pharmacologically active compounds, served as model molecules. They were terminated by aromatic isocyanate and incorporated into the nanofibers. The release of these molecules into an aqueous environment was investigated. The influences of the molecular length and chemical composition of the nanofibers on the release rate and the amount of released polyethylene glycols were evaluated. Longer molecules released faster, as evidenced by a significantly higher amount of released molecules after 72 hours. However, the influence of the chemical composition of nanofibers was even more distinct – the highest amount of polyethylene glycol molecules released from polyvinyl alcohol nanofibers, the lowest amount from polylactide nanofibers.

  19. Preparation and Properties of Tung Oil-Based Polyurethane

    Institute of Scientific and Technical Information of China (English)

    袁才登; 赵晓明; 邵丽英; 唐克华

    2014-01-01

    Tung oil-based polyols were synthesized by the esterification and transesterification between Tung oil-based anhydride and butanediol. The hydroxyl values of the polyols prepared were tested and discussed. Polyurethane was prepared by using Tung oil-based polyols and/or poly(propylene glycol) as polyols and by using isophorone diisocyanate as isocyanate. The effect of the ratio of Tung oil-based polyols to poly(propylene glycol) on the proper-ties of polyurethane prepared was investigated by the water resistance, alcohol resistance and hardness tests. The re-sults show that Tung oil-based polyols are effective to improve the hardness, water resistance and alcohol resistance of polyurethane.

  20. Self-Repair of Polymer Films Through Monomer Filled Ni-Zn Microcapsules

    Science.gov (United States)

    Patchan, Marcia; Baird, Lance; Rhim, Yo-Rhin; Labarre, Erin; Maisano, Adam; Deacon, Ryan; Benkoski, Jason

    2011-03-01

    A novel polymer additive composed of isocyanate resin-filled metal microcapsules has been successfully synthesized through a combination of emulsification, interfacial polymerization, and electroless Ni-Zn deposition. The resulting metallic microcapsules impart self-healing and galvanic protection capabilities to off-the-shelf primers. Once scratched, the microcapsules release their contents into the scratch, where they harden and restore the moisture barrier. If healing is incomplete, the Ni-Zn shell acts as a sacrificial anode to galvanically protect the underlying steel. ASTM adhesion, wear resistance, and moisture resistance tests evaluated the ability of microcapsule-filled primers to heal scratches, provide galvanic protection, and prevent corrosion. We found that self- healing was most effective for broad, shallow scratches (3 mm) and narrow scratches (75 μ m).

  1. Characterization of polyurethane based on polyol synthesized from glycerol and hexamethylene diisocyanate;Caracterizacao de poliuretano baseado em poliol sintetizado a partir de glicerol e hexametileno diisocianato

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Sabrina M.; Weber, Vanessa; Silva, Tailu N.; Barreto, Pedro L.M., E-mail: barreto@cca.ufsc.b [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC(Brazil). Dept. de Ciencia e Tecnologia de Alimentos. Lab. de Reologia e Polimeros Naturais

    2009-07-01

    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)

  2. 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.

  3. 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

  4. Rheology and microstructure of MDI PEG reactive prepolymer-modified bitumen

    Science.gov (United States)

    Navarro, F. J.; Partal, P.; Martínez-Boza, F.; Gallegos, C.; Bordado, J. C. M.; Diogo, A. C.

    2006-12-01

    This paper deals with the use of a new bitumen modifier, a reactive prepolymer, based on the reaction of 4,4‧-diphenylmethane diisocyanate (MDI) and a low molecular weight polyethylene glycol (PEG). The rheological and thermal behaviours of modified bitumen containing a low MDI PEG concentration, as well as its morphology, have been studied. A relatively low amount of MDI PEG (0.5 to 1.5% wt.) yields a significant improvement in the modified bitumen rheological properties, mainly in the high in-service temperature region. In this range of temperature, the rheological properties are clearly affected by curing time at room temperature. These results indicate that chemical changes, due to the reaction of MDI isocyanate groups with the most polar groups ( OH; NH) of asphaltenes and resins, are produced. Thus, new chemical structures, non-visible by optical microscopy, slowly develop in MDI PEG modified bitumen when samples are cured at room temperature.

  5. 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.

  6. Bio-based polyurethane foams from renewable resources

    Science.gov (United States)

    Stanzione, M.; Russo, V.; Sorrentino, A.; Tesser, R.; Lavorgna, M.; Oliviero, M.; Di Serio, M.; Iannace, S.; Verdolotti, L.

    2016-05-01

    In the last decades, bio-derived natural materials, such as vegetable oils, polysaccharides and biomass represent a rich source of hydroxyl precursors for the synthesis of polyols which can be potentially used to synthesize "greener" polyurethane foams. Herein a bio-based precursor (obtained from succinic acid) was used as a partial replacement of conventional polyol to synthesize PU foams. A mixture of conventional and bio-based polyol in presence of catalysts, silicone surfactant and diphenylmethane di-isocyanate (MDI) was expanded in a mold and cured for two hours at room temperature. Experimental results highlighted the suitability of this bio-precursor to be used in the production of flexible PU foams. Furthermore the chemo-physical characterization of the resulting foams show an interesting improvement in thermal stability and elastic modulus with respect to the PU foams produced with conventional polyol.

  7. Preparation and Structure Characterization of Polyester-polyurethane Dispersion%聚酯-聚氨酯分散体的制备与结构表征

    Institute of Scientific and Technical Information of China (English)

    周铭; 侯翠红; 蒋登高

    2003-01-01

      Polyester-polyurethane dispersion was prepared with the raw material of elastic hexaester synthesized by the reaction of adipic acid and glycol .The film pattern and structure were studied by FT-IR and SEM, the experimental results indicated that film pattern of the dispersion varied with the index of isocyanate. With the increment of index of isocyanate, the film surface was becoming fish-scale like gradually. Thermo-stability of the dispersion was also studied, its DSC, TG/DTG curves proved that the film decomposition temperature was higher than that of conventional solvent-based polyurethane owing to the chain extension of the participation of H2O.%  采用由己二酸与乙二醇合成的弹性己酯为原料制备了聚酯-聚氨酯分散体,并用傅立叶红外光谱、扫描电镜对成膜物的表面形态和结构进行研究,发现分散体的成膜物形态随聚合物异氰酸酯指数的变化而变化。随异氰酸酯指数增大,成膜物表面逐渐呈现鱼鳞斑状。并研究了聚酯聚氨酯聚合物的热稳定性,其DSC、TG/DTG分析表明由于H2O参与,扩链聚合物的起始分解温度远高于传统的溶剂型聚氨酯材料。

  8. Computational tools for mechanistic discrimination in the reductive and metathesis coupling reactions mediated by titanium(IV) isopropoxide

    Indian Academy of Sciences (India)

    Akshai Kumar; Ashoka G Samuelson

    2012-11-01

    A theoretical study has been carried out at the B3LYP/LANL2DZ level to compare the reactivity of phenyl isocyanate and phenyl isothiocyanate towards titanium(IV) alkoxides. Isocyanates are shown to favour both mono insertion and double insertion reactions. Double insertion in a head-to-tail fashion is shown to be more exothermic than double insertion in a head-to-head fashion. The head-to-head double insertion leads to the metathesis product, a carbodiimide, after the extrusion of carbon dioxide. In the case of phenyl isothiocyanate, calculations favour the formation of only mono insertion products. Formation of a double insertion product is highly unfavourable. Further, these studies indicate that the reverse reaction involving the metathesis of N,N'-diphenyl carbodiimide with carbon dioxide is likely to proceed more efficiently than the metathesis reaction with carbon disulphide. This is in excellent agreement with experimental results as metathesis with carbon disulphide fails to occur. In a second study, multilayer MM/QM calculations are carried out on intermediates generated from reduction of titanium(IV) alkoxides to investigate the effect of alkoxy bridging on the reactivity of multinuclear Ti species. Bimolecular coupling of imines initiated by Ti(III) species leads to a mixture of diastereomers and not diastereoselective coupling of the imine. However if the reaction is carried out by a trimeric biradical species, diastereoselective coupling of the imine is predicted. The presence of alkoxy bridges greatly favours the formation of the d,l (±) isomer, whereas the intermediate without alkoxy bridges favours the more stable meso isomer. As a bridged trimeric species, stabilized by bridging alkoxy groups, correctly explains the diastereoselective reaction, it is the most likely intermediate in the reaction.

  9. Fabrication and Properties of 3D Graphene Oxide Nanoribbons-carbon Nanotubes/TPU Composite Films

    Directory of Open Access Journals (Sweden)

    ZHENG Hui-dong

    2016-06-01

    Full Text Available A solution method for modifying thermoplastic polyurethane (TPU by the introduction of 3D functionalized nanohybrids composed of two-dimensional GONRs and one-dimensional CNTs was applied. FTIR, XRD, XPS and TEM were employed to characterize the structure and properties of GONRs-CNTs hybrids before and after modification. The functionalized GONRs-CNTs (pGONRs-CNTs/TPU composite films were subsequently prepared by solution coating method on a coating machine. Furthermore, by means of oxygen transmission rate test, tensile test and the observation of surface morphology, the synergetic effect between GONRs and CNTs and the effect of different pGONRs-CNTs content on the barrier and tensile properties of TPU composite films were also studied. The results show that a unique three-dimensional (3D crosslinked nanostructure is successfully obtained, in which GONRs are bridged by CNTs. We also find that the as-prepared pGONRs-CNTs with neat shape and low defect are evenly dispersed in TPU matrix and form strong interfacial adhesion with the matrix, while the existing of CNTs play the role of supporting frame to prevent GONRs from sliding and aggregation; modified by phenyl isocyanate, the lipophilicity of pGONRs-CNTs composite is obviously improved, while, by the introduction of huge isocyanate, the interlayer spacing is further improved, which is good for uniform dispersion in the polymer matrix. As a result, when the mass fraction of pGONRs-CNTs is 0.5%, the barrier and tensile properties of pGONRs-CNTs/TPU composite films reach to the optimal values:the oxygen transmission rate decreases by 63.08% and the tensile strength increases by 46.55%, compared with those of the neat TPU, which will lead to great benefit for the barrier and mechanical properties of TPU films.

  10. Preparation of Controlled-Release Polyurethane Coated Urea%聚氨酯包膜尿素的制备

    Institute of Scientific and Technical Information of China (English)

    周桂南

    2011-01-01

    Isocyanate and polyethylene oxide propylene glycol (PPG) were used to synthesize polyurethane coating material and polyurethane coated urea was obtained. The controlled-release curves of polyurethane coated urea was obtained by the colorimetry, and the influences of molar ratio of NCO/OH, coating rate, reaction mode, isocyanate and PPG molecular weight on the controlled-release performance of polyurethane coated urea were discussed. It was proved that 5 % polyurethane coated urea met the requirement for controlled-release fertilizer according to Europe Standard, which was prepared by PPG-3000 reacting with MDI for 1 h first and then reacting with urea for 2 h in acetone at 50~60℃ with NCO/OH of 1.1.%用异氰酸酯与聚氧化丙烯二醇(PPG)合成聚氨酯,再以其包裹尿素制成聚氨酯包膜尿素.采用比色法绘制聚氨酯包膜尿素的缓释曲线,讨论了异氰酸酯与羟基摩尔比(NCO/OH)、包膜率、反应方式、异氰酸酯、PPG分子量对包膜尿素缓释性能的影响.结果发现,以丙酮为溶剂,NCO/OH为1.1,在50~60℃的水浴温度下,PPG-3000先与MDI反应1 h、再与尿素反应2 h,得到的包膜率为5%的聚氨酯包膜尿素满足欧洲标准委员会的缓释肥料标准.

  11. ELECTRON IRRADIATION OF KUIPER BELT SURFACE ICES: TERNARY N{sub 2}-CH{sub 4}-CO MIXTURES AS A CASE STUDY

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y. S.; Kaiser, R. I., E-mail: ralfk@hawaii.edu [Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

    2012-10-10

    The space weathering of icy Kuiper Belt Objects was investigated in this case study by exposing methane (CH{sub 4}) and carbon monoxide (CO) doped nitrogen (N{sub 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{sub 2}-CH{sub 4} and CO-CH{sub 4} systems: nitrogen-bearing products were found in the form of hydrogen cyanide (HCN), hydrogen isocyanide (HNC), diazomethane (CH{sub 2}N{sub 2}), and its radical fragment (HCN{sub 2}); oxygen-bearing products were of acetaldehyde (CH{sub 3}CHO), formyl radical (HCO), and formaldehyde (H{sub 2}CO). As in the pure ices, the methyl radical (CH{sub 3}) and ethane (C{sub 2}H{sub 6}) were also detected, as were carbon dioxide (CO{sub 2}) and the azide radical (N{sub 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.

  12. Cysteine-functionalized silica-coated magnetite nanoparticles as potential nanoadsorbents

    Science.gov (United States)

    Enache, Daniela F.; Vasile, Eugenia; Simonescu, Claudia M.; Răzvan, Anca; Nicolescu, Alina; Nechifor, Aurelia-Cristina; Oprea, Ovidiu; Pătescu, Rodica-Elena; Onose, Cristian; Dumitru, Florina

    2017-09-01

    Fe3O4, Fe3O4@SiO2, and Fe3O4@SiO2@ICPTES-cysteine MNPs have been prepared by the deposition of silica onto magnetite nanoparticles via controlled hydrolysis of TEOS. The new formed silica surface has been functionalized by grafting 3-(triethoxysilyl) propyl isocyanate (ICPTES) and, subsequently, by condensation of isocyanate moiety with cysteine. The morphology of magnetic silica nanoparticles has been investigated by FTIR, PXRD, TEM-HRTEM/SEM/EDX as well as TG experiments. HRTEM microscopy revealed that the Fe3O4, Fe3O4@SiO2 and Fe3O4@SiO2@ICPTES-cysteine nanoparticles are all of spherical shape with particle of ca. 10-30 nm diameters and the silica-coated magnetites have a core-shell structure. Fe3O4, Fe3O4@SiO2, and Fe3O4@SiO2@ICPTES-cysteine MNPs have been tested for their sorption capacity of Pb(II) from synthetic aqueous solutions and the influence of pH solution, contact time, initial heavy metal ion concentrations, and adsorption isotherms on the sorption behavior were also studied. The kinetic studies revealed that the Pb(II) sorption process is mainly controlled by chemical mechanisms. Fe3O4@SiO2@ICPTES-cysteine, with a sorption capacity of 81.8 mg Pb(II)/g, has the potential to be an efficient Pb(II) adsorbent.

  13. Reducing nitrogen oxides in exhaust gases by means of urea. Final report; Reduzierung von Stickoxiden in Abgasen mittels Harnstoff. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-11-01

    Ammonia has been used for about twenty years as a selective reducing agent for reducing NO{sub x} in lean exhaust gases containing excess oxygen. Although urea has distinct advantages compared with ammonia (solid substance, cheap, practically nontoxic, not explosive) it has hardly been considered for this purpose. In the present work the possibilities of using aqueous urea solutions for the DeNOx processes based on selective catalytic reduction (SCR) and selective non catalytic reduction (SNCR) are explored. SCR: Urea-SCR poses little problems: If the process equipment is properly designed, no appreciable emissions of flue gas components related to urea are found, e.g. isocyanic acid, hydrogen cyanide, nitrous oxide, urea, biuret, cyanuric acid and melamine. On the other hand, like ammonia, use of urea leads to an emission of ammonia which limits the maximum attainable degree of NO{sub x} reduction. With industrial bulk catalysts based on TiO{sub 2}-WO{sub 3}-V{sub 2}O{sub 5} and gas hourly space velocities of 10`000 h{sup -1}, NO{sub x} reductions of over 98% at an ``ammonia slip`` below 10 ppm may be attained. SNCR: The use of urea instead of ammonia shifts the optimum temperature window upwards by about 50 K. Besides an ``ammonia slip``, some isocyanic acid is found, and the emissions of carbon monoxide and nitrous oxide are definitely higher. As nitrous oxide is considered to be a greenhouse gas and a scavenger of stratospheric ozone, the use of urea is no longer recommended in future SNCR installations. If the advantages of storage convenience of urea to be combined optimally with the advantages of ammonia as selective reducing agent, the hydropyrolysis of urea in an external reactor is a possible solution. (author) 38 figs., 5 tabs., 36 refs.

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

    Science.gov (United States)

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

    2017-04-01

    The aim of the present work is to unravel the radiolytic decomposition of adenine (C5H5N5) 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 (CO2), isocyanic acid (HNCO), isocyanate (OCN‑), carbon monoxide (CO), and nitrogen monoxide (NO); an oxidation product containing carbonyl groups (R1R2–C=O) with a constrained five-membered cyclic structure could also be observed. Cyanamide (H2N–C≡N) was detected in both irradiated samples as well.

  15. Development and validation of a method for air-quality and nuisance odors monitoring of volatile organic compounds using multi-sorbent adsorption and gas chromatography/mass spectrometry thermal desorption system.

    Science.gov (United States)

    Ribes, Alejandra; Carrera, Guillem; Gallego, Eva; Roca, Xavier; Berenguer, M A José; Guardino, Xavier

    2007-01-26

    An analytical method based on thermal desorption (TD) coupled to gas chromatography (GC) and mass spectrometry detection (MS) has been developed and validated for the determination of a wide range of odor nuisance and air-quality volatile organic compounds (VOC) in air. New generation isocyanates, isocyanato- and isothiocyanatocyclohexane, have been included for the first time as target compounds due to their high occurrence in air samples. A dynamic air sampling method to trap gas and vapor on multi-sorbent tubes using portable pump equipment has been also developed. Sorbent tubes were filled with Carbotrap (70mg), Carbopack X (100mg) and Carboxen-569 (90mg). Validation of the TD-GC-MS method showed good selectivity, sensibility and precision according to Compendium Method TO-17 (US Environment Protection Agency) criteria. Limits of detection (signal-to-noise=3, ng in tube) ranges were 0.004-0.03ng (alcanes), 0.001-0.1ng (aromatics), 0.03-14ng (aldehydes), 0.003-7ng (alcohols), 0.003-0.04ng (chlorides), 0.02-0.5ng (esters), 0.002-0.1ng (ketones), 0.01-0.53ng (terpenes), 14-97ng (amides), 0.2-10ng (isocyanates) and 0.001ng (carbon disulfide). The linear dynamic range was over 3-5 orders of magnitude, depending of the VOC. TD-GC-MS analysis was reproducible, with relative standard deviation (n=5) within 20%. VOCs breakthrough examination showed no significant losses when about 2000ng standard was prepared. In order to evaluate the performance of the developed method on real samples, several industrial and urban air samples were analysed. VOCs were found to be stable on the sorbent tubes for at least 1 week when stored at 4 degrees C.

  16. Measurement of Gas-phase Acids in Diesel Exhaust

    Science.gov (United States)

    Wentzell, J. J.; Liggio, J.; Li, S.; Vlasenko, A. L.; Staebler, R. M.; Brook, J.; Lu, G.; Poitras, M.; Chan, T.

    2012-12-01

    Gas-phase acids were measured using chemical ionization mass spectrometry (CIMS) as part of the Diesel Engine Emission Research Experiment (DEERE). The CIMS technique, utilizing acetate ion (CH3COO-) as a reagent ion, proved to be a rapid (measurements on the order of seconds) and sensitive (several counts/pptv) method of quantifying the acid emissions. Diluted diesel exhaust measurements were made from a Constant Volume Sampling dilution tunnel using a light duty (1.9L turbocharged Volkswagen Jetta TDI) diesel engine equipped with an OEM diesel oxidation catalyst and exhaust gas recirculation, mounted on an engine dynamometer. Acids measured included isocyanic, nitrous, nitric, propionic and sum of lactic and oxalic, as well as other unidentified compounds. Complimentary measurements of CO, CO2, Total Hydrocarbon (THC), and NOx, were also performed. Several engine modes (different engine rpm and torque outputs) at steady state were examined to determine their effect on acid emissions. Emission rates with respect to NOx and fuel based emission factors were determined. Measurements of HONO fuel emission factors agree well with real-world measurements within a traffic tunnel.1 The first estimate of isocyanic acid emission factors from a diesel engine is reported, and suggests that the emission of this highly toxic compound in diesel exhaust should not be ignored. 1. Kurtenbach, R., Becker, K. H., Gomes, J. A. G., Kleffmann, J.,Lorzer, J. C., Spittler, M., Wiesen, P., Ackermann, R., Geyer, A.,and Platt, U.: Investigations of emissions and heterogeneous formation of HONO in a road traffic tunnel, Atmos. Environ., 35, 3385-3394, doi:10.1016/S1352-2310(01)00138-8, 2001.

  17. Protective coatings for the Ontario Power Generation Inc. dry storage container

    Energy Technology Data Exchange (ETDEWEB)

    Lewak, R. [Kinectrics Inc., Toronto, Ontario (Canada)]. E-mail: richard.lewak@kinectrics.com; Ellsworth, B. [Ontario Power Generation Inc., Tiverton, Ontario (Canada)]. E-mail: brad.ellsworth@opg.com

    2006-07-01

    Ontario Power Generation (OPG), formerly Ontario Hydro, has been storing used CANDU fuel in the irradiated fuel bays (IFBs) at its nuclear generating stations since they began operation. As the IFBs began reaching capacity, the dry storage of previously cooled used fuel became an economically viable alternative to the construction of additional wet fuel bays and the OPG Dry Storage Container (DSC) was developed. The OPG DSC is a free standing reinforced concrete container, with an inner and outer carbon steel shell, for the storage and transportation of used CANDU fuel. The outer steel shell of the DSC is protected by an applied coating system to facilitate decontamination of the outer shell and to provide protective corrosion resistance. In 1990 a study was performed to determine the optimal commercial coating system to be considered as a protective coating on the DSC outer shell. An experimental program was undertaken to identify the optimal commercial coating system, which had the best decontamination characteristics as well as maximum resistance to abrasion, weathering and durability. A total of nine coating systems were selected for study, five epoxy coatings, three epoxy/polyurethane coatings, and one polyurethane coating. Sand blasted carbon steel coupons, similar to the DSC outer shell, were coated by the manufacturers and submitted for testing of the decontamination characteristics such as activity uptake, decontamination of the coating, and the activity 'sweating' phenomenon. Tests identified four commercially available pure epoxy and epoxy/polyurethane protective coating systems as being the most promising for the exterior of the DSC surface. Of these four, the coating system chosen for use on the DSC was an epoxy/polyurethane system. After a decade of use, however, several safety and environmental concerns centering on the isocyanate content present in the polyurethane and the Volatile Organic Component (VOC) content of the coating system have

  18. Imidazol-2-ylidene-N'-phenylureate ligands in alkali and alkaline earth metal coordination spheres--heterocubane core to polymeric structural motif formation.

    Science.gov (United States)

    Naktode, Kishor; Bhattacharjee, Jayeeta; Nayek, Hari Pada; Panda, Tarun K

    2015-04-28

    The synthesis and isolation of two potassium, one lithium and two calcium complexes of imidazol-2-ylidene-N'-phenylureate ligands [Im(R)NCON(H)Ph] [(R = tBu (1a); Mes (1b) and Dipp (1c); Mes = mesityl, Dipp = 2,6-diisopropylphenyl] are described. Potassium complexes, [{κ(2)-(Im(Mes)NCONPh)K}4] (2b) and [{κ(3)-(Im(Dipp)NCONPh)K}2{KN(SiMe3)2}2]n (2c), were prepared in good yields by the reactions of 1b and 1c, respectively, with potassium bis(trimethyl)silyl amide at ambient temperature in toluene. Lithium complex [{(2,6-tBu2-4-Me-C6H2O)Li(Im(tBu)NCON(H)Ph)}2{Im(tBu)NCON(H)Ph}] (3a) was isolated by a one-pot reaction between 1a and LiCH2SiMe3, followed by the addition of 2,6-tBu2-4-Me-C6H2OH in toluene. Calcium complex [{κ(2)-(Im(tBu)NCONPh)Ca{N(SiMe3)2}-{KN(SiMe3)2}]n (4a) was isolated by the one-pot reaction of 1a with [KN(SiMe3)2] and calcium diiodide in THF at ambient temperature. The solid-state structures of ligand 1a and complexes 2b, 2c, 3a and 4a were confirmed by single-crystal X-ray diffraction analysis. It was observed that potassium was coordinated to the oxygen atom of urea group and to the nitrogen atom of the imidazolin-2-imine group, in the solid-state structure of 2b. In complex 4a, the calcium ion was ligated to the monoanionic imidazol-2-ylidene-N'-phenylureate ligand in a bi-dentate (κ(2)) fashion through the oxygen and nitrogen atoms of the isocyanate building block leaving the imidazolin-2-imine fragment uncoordinated. In the solid state of the potassium complex 2c, tri-dentate (κ(3)) coordination from the imidazol-2-ylidene-N'-phenylureate ligand was observed through the oxygen and nitrogen atoms of the isocyanate building block and of the imidazolin-2-imine fragment. In contrast, in the dimeric lithium complex 3a, the neutral imidazol-2-ylidene-N'-phenylureate ligand was bound to the lithium centre in a mono-dentate fashion (κ(1)) through an oxygen atom of the isocyanate moiety. It is to be noted that in each complex thus observed, the

  19. Preparation of Jute Fibers Reinforced Epoxy Resin Composites by VARTM%VARTM 制备麻纤维增强环氧树脂复合材料研究

    Institute of Scientific and Technical Information of China (English)

    李伟; 黄虹云; 吴永庆

    2015-01-01

    通过对黄麻纤维热处理、碱处理、硅烷偶联剂处理和异氰酸酯处理进行表面改性,并对改性黄麻纤维布进行热压工艺处理,最后采用 VARTM 成型工艺制备黄麻纤维增强环氧树脂复合材料,并对其性能进行了系统研究.通过扫描电镜(SEM)分析表明,热处理和碱处理的黄麻纤维增强环氧树脂复合材料的界面粘结未得到明显改善,而通过硅烷偶联剂和异氰酸酯处理的黄麻纤维增强环氧树脂复合材料的界面粘结性能得到了显著的提高.将硅烷偶联剂和异氰酸酯处理的黄麻纤维布通过热压处理不仅可以增加复合材料中黄麻纤维体积含量,而且可以提高复合材料的综合性能,复合材料力学性能研究表明,经硅烷偶联剂处理后的黄麻纤维增强复合材料拉伸强度、模量和弯曲强度分别提高了18.6%,71.4%和50.2%.经异氰酸酯处理的黄麻纤维增强复合材料的拉伸强度、模量和弯曲强度分别提高了16.3%,34.0%和50.3%.%In this research,the jute fibers were first treated with heating,alkali,silane coupling agent and isocyanate respectively,then the jute fibers fabrics were treated with hot pressing process,and finally, the jute fiber reinforced epoxy resin composites were fabricated with VARTM molding process.Scanning Electron Microscopy (SEM)analysis shows that the interface bonding of jute fibers treated with heating and alkali reinforced epoxy resin composites has not been improved,but the interface bonding of compos-ites has been significantly improved with the jute fibers treated with silane coupling agent and isocyanate. The hot-pressing process can not only increase the jute fibers volume content in the composites but also im-prove the performance of composites by the jute fibers treated in advance with silane coupling agent and i-socyanate.The mechanical properties of the composites show that tensile strength

  20. 水稻秸秆液化物制备聚氨酯泡沫的研究%Preparation of Polyurethane Foam from Liquefied Rice Straw

    Institute of Scientific and Technical Information of China (English)

    王万雨; 王敦; 张玉苍

    2015-01-01

    The rice straw was liquefied by using polyethylene glycol 400 and glycerol as mixed liquefier and concentrated sulfuric acid as catalyst. And this liquefied rice straw was employed to prepare the polyurethane ( PU ) foam, and followed by a characterization of its structure and performance. The effects of isocyanate index,water content,the proportion of the catalyst,and the amount of silicone oil on properties of the PU foam were studied. The results showed that the PU foam can be prepared with good properties by using the liquefied rice straw and isocyanate ( PAPI) as raw materials,under the optimum condition,namely, 2% weight content of water against the mass of the liquefied rice straw, triethylenediamine and stannous octoate composite catalysts with the weight ratio of 0. 1:0. 3(g:g),4% silicone oil as foam stabilizer against liquid agent and the isocyanate index of 1. 2. And the properties of these PU foam i. e. the density, the tensile strength and the compressive strength were 35.78 kg/m3,222. 60 kPa,110. 90 kPa,respectively. TGA analysis indicated that rice straw-based PU foam had good heat resistance with the initial decomposition temperature of 241 ℃ and the most rapid decomposing temperature of 420 ℃.%以聚乙二醇400与丙三醇为混合液化剂,浓硫酸为催化剂,对水稻秸秆进行液化,并对水稻秸秆液化产物制备的聚氨酯泡沫进一步分析,讨论了异氰酸根指数、发泡剂水的用量、催化剂比例及硅油用量对聚氨酯泡沫性能的影响. 实验结果表明:以水稻秸秆液化产物10 g和异氰酸酯( PAPI)为原料,水作发泡剂最佳用量为稻杆液化物质量的2%,三乙烯二胺和辛酸亚锡为复合催化剂,最佳用量比为0. 1:0. 3(g:g),水溶性硅油为泡沫稳定剂,最佳用量为液化物质量的4%,异氰酸根指数为1. 2,此条件下制备的聚氨酯( PU)泡沫材料,其性能良好,泡沫的密度为35. 78 kg/m3 ,拉伸强度为222. 60 kPa,压缩强度为110. 90 kPa,TGA分