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Sample records for acid anhydride cured

  1. Thermal Study of Anhydrides Cured Tetrafunctional Cardo Epoxy Resin

    Jignesh P. Patel

    2013-01-01

    Full Text Available Tetrafunctional cardo epoxy resin (EBCF was cured by using 10 wt% maleic anhydride (MA, pyromellitic dianhydride (PMDA, phthalic anhydride (PA, tetrahydrophthalic anhydride (THPA, tetrabromophthalic anhydride (TBPA, and tetrachlorophthalic anhydride (TCPA as hardeners at 120°C for 40–105 min (gel time and then postcured 1 h at 130°C. Gel time is found to depend on the structure of the anhydrides used. Cured samples were found insoluble in common solvents. Cured and uncured EBCF were characterized by FTIR, DSC, and TGA techniques. Cured and uncured resins followed multistep degradation reactions. Kinetic parameters, namely, order of degradation, energy of activation, frequency factor, and entropy change, were determined according to the Anderson-Freeman method and interpreted in light of the nature of hardeners used for curing purpose. The resins followed integral or fractional order degradation kinetics. Complex degradation reactions are due to different types of linkages in cured resins. Both nature and structure of resin and hardeners affected the curing behavior and the resultant thermal properties of the cured resins.

  2. Properties of modified anhydride hardener and its cured resin

    Qiang, Chen; Bingjun, Gao; Jinglin, Chen; Tongzhao, Xu

    2000-01-01

    Methyl-nadic-tetrahydric-methylanhydride (MNA), nadic-tetrahydric-methylanhydride (NA), anhydride hardener was modified by solid diol molecule to improve the impregnation resin fracture toughness in cryogenic temperature. The lap-shear strength, transverse tension as well as the thermal shock test showed that the resin cured by the modified anhydride hardener had higher bond strength and more toughness at 77 K. After the experiment of vacuum pressure impregnation (VPI) processing, it was found that this resin had a longer usable life, better impregnating properties, but higher initial viscosity than the resin hybrid HY925 as hardener.

  3. Cure reaction and phase behavior of liquid crystalline epoxides-anhydride systems

    Li Yan Liang; Shao Ping Ren; Yi Quan Zheng; Man Geng Lu

    2007-01-01

    A series of novel liquid crystalline epoxides with lateral substituents were cured with anhydrides and the cure kinetics was investigated by non-isothermal DSC technique. The results showed that the lengths of lateral substituents have great effect on the value of Ea. The curing reaction became less active, when the liquid crystalline epoxides have long lateral substituents and were controlled by diffusion at the late stage of cure. A nematic structure was observed by POM and XRD.

  4. Curing behaviors and properties of an extrinsic toughened epoxy/anhydride system and an intrinsic toughened epoxy/anhydride system

    Highlights: ► Two curing systems (ETRS and ITRS) with similar chemical composite were prepared. ► The curing kinetics of the ETRS and the novel ITRS were comparatively studied. ► Crosslinking density can affect the kinetic schemes of the two curing systems. ► Their mechanical properties and thermal stabilities were also comparatively studied. ► Crosslinking density may play an influential role in mechanical properties. - Abstract: The curing kinetics of an extrinsic toughened epoxy (mixture of diglycidyl ether of bisphenol-A and 1,4-butanediol epoxy resin, DGEBA/DGEBD) and an intrinsic toughened epoxy (ethoxylated bisphenol-A epoxy resin with two oxyethylene units, DGEBAEO-2) using hexahydrophthalic anhydride (HHPA) as curing agent and tris-(dimethylaminomethyl) phenol (DMP-30) as accelerator were comparatively studied by non-isothermal DSC with a model-fitting Málek approach and a model-free advanced isoconversional method of Vyazovkin. The dynamic mechanical properties and thermal stabilities of the cured materials were investigated by DMTA and TGA, respectively. The results showed that Šesták–Berggren model can generally simulate well the reaction rates of these two systems. The activation energy of DGEBA/DGEBD/HHPA/DMP-30 at high fractional conversion changed much higher than that of DGEBAEO-2/HHPA/DMP-30, indicating the increased steric hindrance mainly affected the reaction kinetic scheme of DGEBA/DGEBD/HHPA/DMP-30. The Tg and storage moduli of cured DGEBAEO-2/HHPA/DMP-30 were lower than those of cured DGEBA/DGEBD/HHPA/DMP-30 according to DMTA while TGA showed that the thermal stabilities of these two cured systems were similar

  5. Curing behaviors and properties of an extrinsic toughened epoxy/anhydride system and an intrinsic toughened epoxy/anhydride system

    Fan, Mengjin; Liu, Jialin; Li, Xiangyuan [Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Cheng, Jue, E-mail: chengjue@mail.buct.edu.cn [Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China); Zhang, Junying, E-mail: zjybuct@gmail.com [Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029 (China)

    2013-02-20

    Highlights: ► Two curing systems (ETRS and ITRS) with similar chemical composite were prepared. ► The curing kinetics of the ETRS and the novel ITRS were comparatively studied. ► Crosslinking density can affect the kinetic schemes of the two curing systems. ► Their mechanical properties and thermal stabilities were also comparatively studied. ► Crosslinking density may play an influential role in mechanical properties. - Abstract: The curing kinetics of an extrinsic toughened epoxy (mixture of diglycidyl ether of bisphenol-A and 1,4-butanediol epoxy resin, DGEBA/DGEBD) and an intrinsic toughened epoxy (ethoxylated bisphenol-A epoxy resin with two oxyethylene units, DGEBAEO-2) using hexahydrophthalic anhydride (HHPA) as curing agent and tris-(dimethylaminomethyl) phenol (DMP-30) as accelerator were comparatively studied by non-isothermal DSC with a model-fitting Málek approach and a model-free advanced isoconversional method of Vyazovkin. The dynamic mechanical properties and thermal stabilities of the cured materials were investigated by DMTA and TGA, respectively. The results showed that Šesták–Berggren model can generally simulate well the reaction rates of these two systems. The activation energy of DGEBA/DGEBD/HHPA/DMP-30 at high fractional conversion changed much higher than that of DGEBAEO-2/HHPA/DMP-30, indicating the increased steric hindrance mainly affected the reaction kinetic scheme of DGEBA/DGEBD/HHPA/DMP-30. The T{sub g} and storage moduli of cured DGEBAEO-2/HHPA/DMP-30 were lower than those of cured DGEBA/DGEBD/HHPA/DMP-30 according to DMTA while TGA showed that the thermal stabilities of these two cured systems were similar.

  6. Compatibility of anhydride cured epoxies with hexanitroazobenzene (HNAB) and hexanitrostilbene (HNS)

    Massis, T.M.; Wischmann, K.B.

    1985-01-01

    The explosives HNAB (hexanitroazobenzene) and HNS (hexanitrostilbene) have compatibility problems with amine-cured epoxy systems. A program was instituted to find compatible polymeric substitutes for use with these explosives. These polymeric materials must have rigid structures after curing for both adhesive and encapsulant applications. A promising class of epoxy materials using anhydride curing agents with various catalysts to trigger the cure reaction were developed. These polymeric systems have very good compatibility with HNS. Of those tested with HNAB, the anhydride epoxy system that used uranyl nitrate as the catalyst was found to be marginally compatible while the others were incompatible. These results indicated further studies are needed. The CRT (chemical reactivity test) was used to evaluate the compatibility of these materials. 6 references, 2 figures, 5 tables.

  7. Compatibility of anhydride cured epoxies with hexanitroazobenzene (HNAB) and hexanitrostilbene (HNS)

    The explosives HNAB (hexanitroazobenzene) and HNS (hexanitrostilbene) have compatibility problems with amine-cured epoxy systems. A program was instituted to find compatible polymeric substitutes for use with these explosives. These polymeric materials must have rigid structures after curing for both adhesive and encapsulant applications. A promising class of epoxy materials using anhydride curing agents with various catalysts to trigger the cure reaction were developed. These polymeric systems have very good compatibility with HNS. Of those tested with HNAB, the anhydride epoxy system that used uranyl nitrate as the catalyst was found to be marginally compatible while the others were incompatible. These results indicated further studies are needed. The CRT (chemical reactivity test) was used to evaluate the compatibility of these materials. 6 references, 2 figures, 5 tables

  8. Effect of Hyperbranched Polyester on Modification of Epoxy Resins Cured with Anhydride

    Xiu Xia WANG; Zhi Gang JIANG; Yi Feng ZHANG

    2006-01-01

    The synthesis and characterization of hyperbranched polyester (HBP) with different molecular weight are studied. The effect of HBP on the modification of epoxy resins cured with anhydride is mainly discussed. The characteristics of HBP and the morphologies of cured system are determined by nuclear magnetic resonance spectroscopy (NMR), gel permeation chromatography (GPC) and scanning electron microscope (SEM). The impact strength of cured system is detected and Fourier transform infrared (FTIR) measurements were used to pursue the curing process. The investigation shows that HBP can improve the toughness by forming copolymer networks between epoxy resins, HBP and anhydride. Moreover, when the molecular weight of HBP is 1342g/mol the toughening effect is the best, and the changes of toughness are small with the increase of molecular weight of HBP to 3500 g/mol.

  9. Cure monitoring of an epoxy-anhydride system by means of fluorescence spectroscopy

    Cho, D.H.; Kim, D.S.; Lee, J.K. [Kumoh National Univeristy of Technology, Kumi (Korea)

    2001-03-01

    In the present study the cure behavior of diglycidyl ether of bisphenol-A (DGEBA) using an anhydride-based hardener in the presence of N,N-dimethyl benzyl amine (BDMA) or 1-cyanoethyl-2-ethyl-4-methyl imidazole (2E4MZ-CN) as an accelerator has been monitored and interpreted from the viewpoint of photophysical properties by means of fluorescence spectroscopy. To do this, 1,3-bis-(1-pyrene)propane (BPP) was well incorporated in the epoxy resin system by mechanical blending. The BPP probe, which is very sensitive to conformational change of the molecule influenced by the surrounding medium, successfully formed intramolecular excimer fluorescence. It is susceptible to the micro-viscosity or local viscosity and molecular mobility according to the epoxy cure. The cure behavior was explained with monomer fluorescence intensity (I{sub M}), excimer fluorescence intensity (I{sub E}) and I{sub M}/I{sub E} ratio as a function of cure time, cure temperature and accelerator. The present work agreed with the previous report on the cure behavior of an epoxy-anhydride system studied using DSc or torsion pendulum method. This study also suggests that the use of fluorescence technique may provide information on cure behavior of a thermosetting resin in a low temperature region, which has not been well interpreted by other analytical methods. (author). 31 refs., 8 figs.

  10. Preparation of poly(glycidylmethacrylate-divinylbenzene) weak acid cation exchange stationary phases with succinic anhydride, phthalic anhydride, and maleic anhydride for ion chromatography.

    Liu, Junwei; Wang, Yong; Wu, Shuchao; Zhang, Peimin; Zhu, Yan

    2016-08-01

    In this work, poly(glycidylmethacrylate-divinylbenzene) microspheres were prepared and applied for the preparation of weak acid cation exchange stationary phases. Succinic anhydride, phthalic anhydride, and maleic anhydride were selected as carboxylation reagents to prepare three weak acid cation exchangers by direct chemical derivatization reaction without solvent or catalyst. The diameters and dispersity of the microspheres were characterized by scanning electron microscopy; the amount of accessible epoxy groups and mechanical stability were also measured. The weak acid cation exchangers were characterized by Fourier transform infrared spectroscopy; the content of carboxyl groups was measured by traditional acid base titration method. The chromatographic properties were characterized and compared by separating alkali, alkaline earth metal ions and ammonium and polar amines. The separation properties enhanced in the order of succinic anhydride, phthalic anhydride, and maleic anhydride modified poly(glycidylmethacrylate-divinylbenzene) cation exchangers. PMID:27288092

  11. The influence of tertiary amine accelerators on the curing behaviors of epoxy/anhydride systems

    Yang, Tao; Zhang, Chongfeng; Zhang, Junying, E-mail: zjybuct@gmail.com; Cheng, Jue

    2014-02-10

    Highlights: • The influences of two types of accelerators (BDMA and DMP-30) on curing reaction of DGEBF/MeHHPA systems were studied comparatively. • The activation energy and kinetic parameters of DGEBF/MeHHPA systems with accelerator content of 0.2 phr and 0.5 phr were calculated, respectively. • The dependence of autocatalytic and non-autocatalytic curing reaction on the loading of accelerators was discussed. • The non-catalytic curing reaction dominated absolutely in the curing process of DGEBF/MeHHPA systems when the accelerator contents were 0.2 phr. - Abstract: Accelerators have significant effects on the curing behaviors of epoxy/anhydride (diglycidyl ether of bisphenol-F/methylhexahydrophthalic anhydride, DGEBF/MeHHPA) systems. Non-isothermal DSC was used to investigate the influence of dimethyl benzylamine (BDMA, 0.2 phr/0.5 phr) and Tris-(dimethyl aminomethyl) phenol (DMP-30, 0.2 phr/0.5 phr) on the curing behaviors of DGEBF/MeHHPA systems, respectively. When the amount of accelerators was kept constant, the activation energy calculated by Kissinger method changed slightly in the presence of either BDMA or DMP-30. And, with increasing the accelerator content from 0.2 phr to 0.5 phr, the value of activation energy decreased from 115 kJ/mol to 85 kJ/mol. Furthermore, the calculation results of Málek method identified that all systems in this study fitted Sesták–Berggren (SB) model and the corresponding model parameters, m and n, were obtained. It was found that the contribution of autocatalytic reaction with low accelerator content (0.2 phr) was far less than that with high accelerator content (0.5 phr)

  12. Electrolytic Synthesis of Benzoic Anhydride from Benzoic Acid

    TAKAHASHI, Takeshige; KAMADA, Mitsushi; タカハシ, タケシゲ; カマダ, ミツシ; 高橋, 武重; 鎌田, 三司

    1982-01-01

    Electrolysis of benzoic acid was investigated by means of controlled current operation in acetonitrile with platinum disk electrodes. Benzoic anhydride was obtained from an anolyte at 20-30% of current efficiency as one electron reaction. At the same time, acetamide and hydrogen perchlorate were obtained from the anolyte, and triethylamine was obtained from the catholyte. The yield of acetamide was nearly equal to benzoic anhydride. On the other hand, the yield of triethylamine ap...

  13. Anhydrides-Cured Bimodal Rubber-Like Epoxy Asphalt Composites: From Thermosetting to Quasi-Thermosetting

    Yang Kang

    2016-03-01

    Full Text Available The present engineering practices show the potential that epoxy asphalt composites (EACs would be a better choice to obtain long life for busy roads. To understand the service performance–related thermorheological properties of prepared bimodal anhydrides-cured rubber-like EACs (REACs, a direct tensile tester, dynamic shear rheometer and mathematical model were used. Tensile tests demonstrate that all the REACs reported here are more flexible than previously reported anhydrides-cured REACs at both 20 and 0 °C. The better flexibility is attributed to the change of bimodal networks, in which cross-linked short chains decreased and cross-linked long chains increased, relatively. Strain sweeps show that all the REACs have linear viscoelastic (LVE properties when their strains are smaller than 1.0% from −35 to 120 °C. Temperature sweeps illustrate that the thermorheological properties of REACs evolve from thermosetting to quasi-thermosetting with asphalt content, and all the REACs retain solid state and show elastic properties in the experimental temperature range. A Cole–Cole plot and Black diagram indicate that all the REACs are thermorheologically simple materials, and the master curves were constructed and well-fitted by the Generalized Logistic Sigmoidal models. This research provides a facile approach to tune the thermorheological properties of the REACs, and the cheaper quasi-thermosetting REAC facilitates their advanced applications.

  14. Selective deoxygenation of stearic acid via an anhydride pathway

    Hollak, S.A.W.; Bitter, W.; Haveren, van J.; Es, van D.S.

    2012-01-01

    Stearic anhydride is proposed as reactive intermediate in the hydrogen free decarbonylation and ketonization of stearic acid over Pd/Al2O3 at 523 K. This information is crucial towards developing of a selective low temperature decarbonylation process of fatty acids towards olefins.

  15. Synthesis and curing of alkyd enamels based on ricinoleic acid

    Jovičić Mirjana C.; Radičević Radmila Ž.; Simendić Vesna B.

    2010-01-01

    A combination of an alkyd resin with a melamine-formaldehyde resin gives a cured enamel film with the flexibility of the alkyd constituent and the high chemical resistance and hardness of the melamine resin at the same time. The melamine resin is a minor constituent and plays the role of a crosslinking agent. In this paper, alkyd resins of high hydroxyl numbers based on trimethylolpropane, ricinoleic acid and phthalic anhydride were synthesized. Two alkyds having 30 and 40 wt% of ricino...

  16. 21 CFR 872.3500 - Polyvinylmethylether maleic anhydride (PVM-MA), acid copolymer, and carboxymethylcellulose sodium...

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Polyvinylmethylether maleic anhydride (PVM-MA...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3500 Polyvinylmethylether maleic anhydride (PVM-MA.... Polyvinylmethylether maleic anhydride (PVM-MA), acid copolymer, and carboxymethylcellulose sodium (NACMC)...

  17. High biobased content epoxy-anhydride thermosets from epoxidized sucrose esters of Fatty acids.

    Pan, Xiao; Sengupta, Partha; Webster, Dean C

    2011-06-13

    Novel highly functional biobased epoxy compounds, epoxidized sucrose esters of fatty acids (ESEFAs), were cross-linked with a liquid cycloaliphatic anhydride to prepare polyester thermosets. The degree of cure or conversion was studied using differential scanning calorimetry (DSC), and the sol content of the thermosets was determined using solvent extraction. The mechanical properties were studied using tensile testing to determine Young's modulus, tensile stress, and elongation at break. Dynamic mechanical analysis (DMA) was used to determine glass-transition temperature, storage modulus, and cross-link density. The nanomechanical properties of the surfaces were studied using nanoindentation to determine reduced modulus and indentation hardness. The properties of coatings on steel substrates were studied to determine coating hardness, adhesion, solvent resistance, and mechanical durability. Compared with the control, epoxidized soybean oil, the anhydride-cured ESEFAs have high modulus and are hard and ductile, high-performance thermoset materials while maintaining a high biobased content (71-77% in theory). The exceptional performance of the ESEFAs is attributed to the unique structure of these macromolecules: well-defined compact structures with high epoxide functionality. These biobased thermosets have potential uses in applications such as composites, adhesives, and coatings. PMID:21561167

  18. Increasing the electrical discharge endurance of acid anhydride cured DGEBA epoxy resin by dispersion of nanoparticle silica. High Perform. Polym. 11 (1999) pp 281-296 by IOP Publishing Ltd

    Henk, Peter O; Kortsen, T.W.; Kvarts, T.

    1999-01-01

    A fluid DGEBA/methyl nadicanhydride epoxy system has been filled with inorganic particles, cast as bubble-free plates and cured. The ability of both the pure network polymer and the polymer/particle composites to withstand partial electrical discharges has been investigated. Three types of particle...... electrode arrangement was applied, the test comprising the establishment of partial discharges running perpendicularly onto one face of a plate specimen for a period measured until breakdown.Our results show that the endurance of the pure polymer is low. Increased loading with Aerosil increases the...

  19. Indirect rapid prototyping of antibacterial acid anhydride copolymer microneedles

    Microneedles are needle-like projections with microscale features that may be used for transdermal delivery of a variety of pharmacologic agents, including antibacterial agents. In the study described in this paper, an indirect rapid prototyping approach involving a combination of visible light dynamic mask micro-stereolithography and micromolding was used to prepare microneedle arrays out of a biodegradable acid anhydride copolymer, Gantrez® AN 169 BF. Fourier transform infrared spectroscopy, energy dispersive x-ray spectrometry and nanoindentation studies were performed to evaluate the chemical and mechanical properties of the Gantrez® AN 169 BF material. Agar plating studies were used to evaluate the in vitro antimicrobial performance of these arrays against Bacillus subtilis, Candida albicans, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Large zones of growth inhibition were noted for Escherichia coli, S. aureus, Enterococcus faecalis and B. subtilis. The performance of Gantrez® AN 169 BF against several bacteria suggests that biodegradable acid anhydride copolymer microneedle arrays prepared using visible light dynamic mask micro-stereolithography micromolding may be useful for treating a variety of skin infections. (communication)

  20. Preparation of epoxy/zirconia hybrid materials via in situ polymerization using zirconium alkoxide coordinated with acid anhydride

    Highlights: → Novel epoxy/zirconia hybrid materials were synthesized via in situ polymerization using zirconium alkoxide coordinated with acid anhydride. → The half-ester compound of acid anhydride desorbed from zirconium played as curing agent of epoxy resin. → The zirconia was uniformly dispersed in the epoxy matrix on the nanometer or sub-nanometer scale by synchronizing the epoxy curing and sol-gel reactions. → The refractive indices of the hybrid materials significantly improved with an increase in the zirconia content. - Abstract: Novel epoxy/zirconia hybrid materials were synthesized using a bisphenol A epoxy resin (diglycidyl ether of bisphenol A; DGEBA), zirconium(IV)-n-propoxide (ZTNP), and hexahydrophthalic anhydride (HHPA) via in situ polymerization. HHPA played two roles in this system: it acted as a modifier to control the hydrolysis and condensation reactions of zirconium alkoxide and also as a curing agent - the half-ester compound of HHPA desorbed from zirconium reacted with the epoxy resin to form the epoxy network. As a result, both the sol-gel reaction and epoxy curing occurred simultaneously in a homogeneous solution, and organic-inorganic hybrid materials were readily obtained. Further, the zirconia produced by the in situ polymerization was uniformly dispersed in the epoxy matrix on the nanometer or sub-nanometer scale; thus, hybrid materials that exhibited excellent optical transparency were obtained. Furthermore, the heat resistance of the hybrid materials could be improved by hybridization with zirconia. And, the refractive indices of the hybrid materials significantly improved with an increase in the zirconia content.

  1. Preparation of epoxy/zirconia hybrid materials via in situ polymerization using zirconium alkoxide coordinated with acid anhydride

    Ochi, Mitsukazu, E-mail: mochi@ipcku.kansai-u.ac.jp [Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Suita-shi, Osaka 564-8680 (Japan); Nii, Daisuke; Harada, Miyuki [Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Suita-shi, Osaka 564-8680 (Japan)

    2011-09-15

    Highlights: {yields} Novel epoxy/zirconia hybrid materials were synthesized via in situ polymerization using zirconium alkoxide coordinated with acid anhydride. {yields} The half-ester compound of acid anhydride desorbed from zirconium played as curing agent of epoxy resin. {yields} The zirconia was uniformly dispersed in the epoxy matrix on the nanometer or sub-nanometer scale by synchronizing the epoxy curing and sol-gel reactions. {yields} The refractive indices of the hybrid materials significantly improved with an increase in the zirconia content. - Abstract: Novel epoxy/zirconia hybrid materials were synthesized using a bisphenol A epoxy resin (diglycidyl ether of bisphenol A; DGEBA), zirconium(IV)-n-propoxide (ZTNP), and hexahydrophthalic anhydride (HHPA) via in situ polymerization. HHPA played two roles in this system: it acted as a modifier to control the hydrolysis and condensation reactions of zirconium alkoxide and also as a curing agent - the half-ester compound of HHPA desorbed from zirconium reacted with the epoxy resin to form the epoxy network. As a result, both the sol-gel reaction and epoxy curing occurred simultaneously in a homogeneous solution, and organic-inorganic hybrid materials were readily obtained. Further, the zirconia produced by the in situ polymerization was uniformly dispersed in the epoxy matrix on the nanometer or sub-nanometer scale; thus, hybrid materials that exhibited excellent optical transparency were obtained. Furthermore, the heat resistance of the hybrid materials could be improved by hybridization with zirconia. And, the refractive indices of the hybrid materials significantly improved with an increase in the zirconia content.

  2. Synthesis and curing of alkyd enamels based on ricinoleic acid

    Jovičić Mirjana C.

    2010-01-01

    Full Text Available A combination of an alkyd resin with a melamine-formaldehyde resin gives a cured enamel film with the flexibility of the alkyd constituent and the high chemical resistance and hardness of the melamine resin at the same time. The melamine resin is a minor constituent and plays the role of a crosslinking agent. In this paper, alkyd resins of high hydroxyl numbers based on trimethylolpropane, ricinoleic acid and phthalic anhydride were synthesized. Two alkyds having 30 and 40 wt% of ricinoleic acid were formulated by calculation on alkyd constant. Alkyds were characterized by FTIR and by the determination of acid and hydroxyl numbers. Then synthesized alkyds were made into baking enamels by mixing with melamine-formaldehyde resins (weight ratio of 70:30 based on dried mass. Two types of commercial melamine resins were used: threeisobutoxymethyl melamine-formaldehyde resin (TIMMF and hexamethoxymethyl melamine resin (HMMMF. Prepared alkyd/melamine resin mixtures were cured in a differential scanning calorimeter (DSC under non-isothermal mode. Apparent degree of curing as a function of temperature was calculated from the curing enthalpies. Kinetic parameters of curing were calculated using Freeman-Carroll method. TIMMF resin is more reactive with synthesized alkyds than HMMMF resin what was expected. Alkyd resin with 30 wt% of ricinoleic acid is slightly more reactive than alkyd with 40 wt% of ricinoleic acid, probably because it has the high contents of free hydroxyl and acid groups. The gel content, Tg, thermal stability, hardness, elasticity and impact resistance of coated films cured at 150°C for 60 min were measured. Cured films show good thermal stability since the onset of films thermal degradation determined by thermogravimetric analysis (TGA is observed at the temperatures from 281 to 329°C. Films based on alkyd 30 are more thermal stable than those from alkyd 40, with the same melamine resin. The type of alkyd resin has no significant

  3. Curing behavior and structure of a novel nanocomposite from glycerol diglycidyl ether and 3,3-dimethylglutaric anhydride

    Research highlights: → A nanocomposite based on glycerol diglycidyl ether (GDE) was synthesized and characterized. → Kinetics of the reaction was interpreted by means of the advanced isoconversional method. → XRD and SEM were used to demonstrate homogeneous dispersion of the nanoalumina in GDE matrix. - Abstract: A novel nanocomposite was synthesized by curing of glycerol diglycidyl ether (GDE) and 3,3-dimethylglutaric anhydride (DGA) in the presence of alumina nanoparticles. Kinetics of GDE/DGA/nano-Al2O3 cure was studied by DSC measurements at dynamic and isothermal states. It was shown that the reaction kinetics could be described well by the Horie model. The advanced isoconversional method developed by Vyazovkin is utilized to describe the curing behavior of the nanocomposite. A technique of predicting isothermal cure time from the sole dependence of Ea on α was then considered and compared to the experimental results. The structure of the nanocomposite was characterized by X-ray diffraction analysis and scanning electron microscopy imaging. The SEM images showed that the nanocomposite has the morphology of homogeneous dispersion of alumina nanoparticles. It was shown by TGA measurements that the incorporation of nano-Al2O3 into GDE/DGA matrix results in thermal resistance improvement.

  4. Oligoesters and polyesters produced by the curing of sunflower oil epoxidized biodiesel with cis-cyclohexane dicarboxylic anhydride: Synthesis and characterization

    Oligoesters and polyesters produced from sunflower oil biodiesel were synthesized and characterized. The polymers were obtained through the reaction of fatty acid methyl epoxy esters (EE) with cis-1,2-cyclohexane dicarboxylic anhydride (CH) and triethylamine (TEA) as initiator. Some reactions were conducted by adding small amounts of 1,4-butanediol diglycidyl ether (BDGE). The intermediate products of the synthesis process, including sunflower oil, methyl ester, epoxidised methyl esters, and the oligoesters and polyesters produced, were followed by Fourier Transform Infrared Spectroscopy and 1H and 13C nuclear magnetic resonance. The products obtained from the curing of the epoxidised esters with different compositions present similar chemical structures; however, they still depend on the amount of the epoxy resin BDGE that was added in the polymerization reaction. Thermoplastic materials with molecular weights (MW) starting at 3800 g/mol and reaching very high MWs, resulted in cross linked polymers. The thermal behaviour of the different products was investigated using differential scanning calorimetry and thermogravimetric analyses. The presence of BDGE in the structure of the materials increases the bonding capacity, resulting in higher molecular weight materials, which present good thermal stability.

  5. Synthesis of 2,2'-Dipyrryl Ketones from Pyrrole-2-carboxylic Acids with Trifluoroacetic Anhydride

    Kim, Se Hee; Lim, Jin Woo; Yu, Jin; Kim, Jae Nyoung [Chonnam National Univ., Gwangju (Korea, Republic of)

    2013-09-15

    An efficient synthesis of 2,2'-dipyrryl ketones has been carried out from pyrrole-2-carboxylic acids using trifluoroacetic anhydride (TFAA). Simultaneous generation of both mixed anhydride and 2-unsubstituted pyrrole, via facile decarboxylation with in-situ generated TFA, made their cross reaction (intermolecular Friedel-Crafts acylation) possible and efficient.

  6. Synthesis and Characterization of a Novel Biomaterial:Maleic Anhydride-modified Poly(dl-lactic acid)

    Yan Feng LUO; Yuan Liang WANG; Xu Feng NIU; Jun PAN; Liang Ping SHI

    2004-01-01

    A novel modified poly(dl-lactic acid) (PDLLA) was obtained by covalently grafting of maleic anhydride onto the backbone of PDLLA, attempting to improve PDLLA's hydrophilicity and cell affinity and to provide reactive groups for further chemical modification. FTIR, 13C NMR and DSC were used to characterize the maleic anhydride-modified PDLLA.

  7. Preparation and Physical Properties of Chitosan Benzoic Acid Derivatives Using a Phosphoryl Mixed Anhydride System

    Kyu Yun Chai

    2012-02-01

    Full Text Available Direct benzoylation of the two hydroxyl groups on chitosan was achieved using a phosphoryl mixed anhydride system, derived from trifluoroacetic anhydride (TFAA, benzoic acids (BAs, and phosphoric acid (PA. The reaction is operated as a one pot process under mild conditions that does not require neither an inert atmosphere nor dry solvents. The structures of the synthesized compounds were confirmed by NMR and IR spectroscopy. Solubility tests on the products revealed that they were soluble in organic solvents such as N,N-dimethylformamide (DMF, dimethylsulfoxide (DMSO, and acetone. In the meantime, a morphological study by scanning electron microscopy (SEM evidently indicated that the chitosan benzoates underwent significant structural changes after the benzoylation.

  8. Gas-Phase Structures of Ketene and Acetic Acid from Acetic Anhydride Using Very-High-Temperature Gas Electron Diffraction.

    Atkinson, Sandra J; Noble-Eddy, Robert; Masters, Sarah L

    2016-03-31

    The gas-phase molecular structure of ketene has been determined using samples generated by the pyrolysis of acetic anhydride (giving acetic acid and ketene), using one permutation of the very-high-temperature (VHT) inlet nozzle system designed and constructed for the gas electron diffraction (GED) apparatus based at the University of Canterbury. The gas-phase structures of acetic anhydride, acetic acid, and ketene are presented and compared to previous electron diffraction and microwave spectroscopy data to show improvements in data extraction and manipulation with current methods. Acetic anhydride was modeled with two conformers, rather than a complex dynamic model as in the previous study, to allow for inclusion of multiple pyrolysis products. The redetermined gas-phase structure of acetic anhydride (obtained using the structure analysis restrained by ab initio calculations for electron diffraction method) was compared to that from the original study, providing an improvement on the description of the low vibrational torsions compared to the dynamic model. Parameters for ketene and acetic acid (both generated by the pyrolysis of acetic anhydride) were also refined with higher accuracy than previously reported in GED studies, with structural parameter comparisons being made to prior experimental and theoretical studies. PMID:26916368

  9. Perfluorosulfonic acid membrane catalysts for optical sensing of anhydrides in the gas phase.

    Ayyadurai, Subasri M; Worrall, Adam D; Bernstein, Jonathan A; Angelopoulos, Anastasios P

    2010-07-15

    Continuous, on-site monitoring of personal exposure levels to occupational chemical hazards in ambient air is a long-standing analytical challenge. Such monitoring is required to institute appropriate health measures but is often limited by the time delays associated with batch air sampling and the need for off-site instrumental analyses. In this work, we report on the first attempt to use the catalytic properties of perfluorosulfonic acid (PSA) membranes to obtain a rapid, selective, and highly sensitive optical response to trimellitic anhydride (TMA) in the gas phase for portable sensor device application. TMA is used as starting material for various organic products and is recognized to be an extremely toxic agent by the National Institute for Occupational Safety and Health (NIOSH). Resorcinol dye is shown to become immobilized in PSA membranes and diffusionally constrain an orange brown product that results from acid-catalyzed reaction with more rapidly diffusing TMA molecules. FTIR, UV/vis, reaction selectivity to TMA versus trimellitic acid (TMLA), and homogeneous synthesis are used to infer 5,7- dihydroxyanthraquinone-2-carboxylic acid as the acylation product of the reaction. The color response has a sensitivity to at least 3 parts per billion (ppb) TMA exposure and, in addition to TMLA, excludes maleic anhydride (MA) and phthalic anhydride (PA). Solvent extraction at long times is used to determine that the resorcinol extinction coefficient in 1100 EW PSA membrane has a value of 1210 m(2)/g at 271.01 nm versus a value of 2010 m(2)/g at 275.22 nm in 50 vol% ethanol/water solution. The hypsochromic wavelength shift and reduced extinction coefficient suggest that the polar perfluorosulfonic acid groups in the membrane provide the thermodynamic driving force for diffusion and immobilization. At a resorcinol concentration of 0.376 g/L in the membrane, a partition coefficient of nearly unity is obtained between the membrane and solution concentrations and a

  10. Grafting of poly (lactic acid) with maleic anhydride using supercritical carbon dioxide

    Khankrua, R.; Pivsa-Art, S.; Hiroyuki, H.; Suttiruengwong, S.

    2015-07-01

    The aim of this work was to modify poly lactic acid (PLA) via free radical grafting with maleic anhydride (MA) by using supercritical carbon dioxide (SCCO2). Benzoyl peroxide (BPO) was used as an initiator. The solubility of MA in SCCO2 was first determined to estimate the suitable grafting conditions and equilibrium. From the solubility study of MA in SCCO2, it was found that the solubility of MA in SCCO2 increased with the increasing pressure and dissolution time. PLA films were first prepared by compression molding. The ratio of MA to BPO was 2:1. The reaction temperature and pressure were 70°C and 100 bar respectively. The grafting reaction and the degree of grafting were characterized by nuclear magnetic resonance (NMR) spectroscopy and titration, respectively. Scanning electron microscope (SEM) technique and contact angle were used to confirm the changes in physical properties of PLA film grafted MA. NMR spectrum indicated that the grafting of MA onto PLA was successively achieved. Degree of grafting by using SCCO2 was as high as 0.98%. This provided rather high grafting degree compared with other processes. SEM pictures showed the rough surface structure on modified PLA film. In addition, contact angle results showed an improvement of the hydrophilicity by maleic anhydride grafting onto polymers.

  11. Partial oxidation of D-xylose to maleic anhydride and acrylic acid over vanadyl pyrophosphate

    Xylose is the second most abundant sugar after glucose. Despite its tremendous potential to serve as a renewable feedstock, few commercial processes exploit this resource. Here, we report a new technology in which a two-fluid nozzle atomizes a xylose-water solution into a capillary fluidized bed operating above 300 °C. Xylose-water droplets form at the tip of the injector, vaporize then react with a heterogeneous mixed oxide catalyst. A syringe pump metered the solution to the reactor charged with 1 g of catalyst. Product yield over vanadyl pyrophosphate was higher compared to molybdenum trioxide-cobalt oxide and iron molybdate; it reached 25% for maleic anhydride, 17% for acrylic acid and 11% for acrolein. Gas residence time was 0.2 s. The catalyst was free of coke even after operating for 4 h – based on a thermogravimetric analysis of catalyst withdrawn from the reactor. Below 300 °C, powder agglomerated at the tip of the injector at 300 °C; it also agglomerated with a xylose mass fraction of 7% in water. - Highlights: • D-xylose reacts to form maleic anhydride and acrylic acid above 250 °C. • Vanadyl pyrophosphate is both active and selective for maleic and acrylic acid. • Acid and acrolein yield approaches 50% for a xylose mass fraction of 3% in water. • Catalyst agglomerates at low temperatures and high xylose aqueous mass fraction. • Atomization quality is a determining factor to minimize agglomeration

  12. One-pot odourless synthesis of thioesters via in situ generation of thiobenzoic acids using benzoic anhydrides and thiourea.

    Abbasi, Mohammad; Khalifeh, Reza

    2015-01-01

    An efficient and odourless procedure for a one-pot synthesis of thioesters by the reaction of benzoic anhydrides, thiourea and various organic halides (primary, allylic, and benzylic) or structurally diverse, electron-deficient alkenes (ketones, esters, and nitriles) in the presence of Et3N has been developed. In this method, thiobenzoic acids were in situ generated from the reaction of thiourea with benzoic anhydrides, which were subjected to conjugate addition with electron-deficient alkenes or a nucleophilic displacement reaction with alkyl halides. PMID:26425185

  13. Preparation and structural characterisation of novel and versatile amphiphilic octenyl succinic anhydride-modified hyaluronic acid derivatives

    Eenschooten, Corinne Diane; Guillaumie, Fanny; Kontogeorgis, Georgios;

    2010-01-01

    The purpose of the present study was to prepare amphiphilic hyaluronic acid (HA) derivatives and to study the influence of a selection of reaction parameters on the degree of substitution (DS) of the derivatives. Octenyl succinic anhydride (OSA)–modified HA (OSA–HA) derivatives were prepared and...

  14. A NOVEL COPOLYMER-BOUND CIS- DICARBONYLRHODIUM COMPLEX FOR THE CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE

    YUAN Guoqing; CHEN Yuying; CHEN Rongyao

    1989-01-01

    A series of porous microspheres of linear and ethylene diacrylate (M ') cross-linked copolymers of 2 - vinylpyridine (V) and methyl acrylate (M) reacted with tetracarbonyldichlorodirhodium to form a series of cis-dicarbonylrhodium chelate complex (MVRh and MVM 'Rh). They are thermally stable yet very reactive in the carbonylation of methanol to acetic acid, and of methanol - acetic acid mixture to acetic acid and acetic anhydride with a selectivity of 100% under relatively mild and anhydrous conditions.

  15. Fluorescence and Judd-Ofelt analysis of rare earth complexes with maleic anhydride and acrylic acid

    WEN Shipeng; ZHANG Xiaoping; HU Shui; ZHANG Liqun; LIU Li

    2008-01-01

    Two kinds of Eu-complexes, Eu(TTA)2(Phen)(AA) and Eu(TTA)2(Phen)(MA) (HTFA=2-Thenoyltrifluoroacetone, Phen=1,10-phenanthroline, AA=acrylic acid, MA=Maleic anhydride), which combined the excellent fluorescence properties of Eu(TTA)2(Phen)(H2O) and the reactivity of acrylic acid and maleic anhydride with radicals, were synthesized. The two complexes were characterized by elemental analysis, infrared (IR) spectra, and X-ray photoelectron spectroscopy (XPS). Based on the data shown from the fluorescent spectra of the Eu-MA and Eu-AA complexes, the Ωλ (λ=2 and 4) experimental intensity parameters were calculated. The results demonstrated that the Ω2 intensity parameters for the two complexes were smaller than those for the Eu(TTA)2(Phen)(H2O) complex, indicating that a less symmetri-cal chemical environment existed in the complexes. It implied that the radiative efficiency of the 5D0 of these two complexes could be en-hanced by ligand of MA and AA, respectively. The luminescent lifetime of the Eu-AA (τ=7.26×10-4 s) or Eu-MA complex (τ=-8.12×10-4 s) was higher than that of the Eu(TTA)2(Phen)(H2O) complex, which was attributed to the substitution of the water molecule (H2O) in Eu(TTA)2(Phen)(H2O) by the MA or AA ligand.

  16. MECHANICAL RELAXATION AND INTERMOLECULAR INTERACTION IN EPOXY RESINS/POLY (ETHYLENE OXIDE)BLENDS CURED WITH PHTHALIC ANHYDRIDE

    LUO Xiaolie; ZHENG Sixun; MA Dezhu; HU Keliang

    1995-01-01

    The miscibility of the blend,composed of a bisphenol A epoxy resins (Diglycidyl etherof bisphenol A) (DGEBA) and poly(ethylene oxide) (PEO) and crosslinked by phthalicanhydride (PA) was studied using dynamic mechanical method. Single glass transitiontemperatures intermediate between the two pure components were observed for all blendlevels. The secondary relaxation mechanism should relate to not only diester linkage, butalso hydroxyether structural unit in the system. Fourier transform infrared spectroscopy(FTIR) is applied to study the curing reaction and intermolecular specific interaction of thesystem. The results indicate the PEO participates the crosslinking reaction, accelerates thecuring reaction and make the reaction more perfect. The shifts of the hydroxyl band andcarbonyl band demonstrate the presence of the intermolecular interaction in the curedblend. Moreover, the molecular interaction between the side hydroxyl in the hydroxyetherunits and the ether bond in PEO macromolecules is stronger.

  17. Lipase-Catalyzed Esterification of Betulinic Acid Using Phthalic Anhydride in Organic Solvent Media: Study of Reaction Parameters

    M. Ghaffari Moghaddam

    2010-01-01

    Full Text Available The lipase from Candida antarctica immobilized on an acrylic resin (Novozym 435 was employed for the catalytic reaction of betulinic acid and phthalic anhydride. The influence of different reaction parameters, such as effect of single and mixed solvents, substrate molar ratio, reaction time, temperature, amount of enzyme, effect of inorganic bases and effect of substrate support were investigated and optimized. Optimum conditions to produce 3-O-phthalyl- betulinic acid were observed at reaction time; 24 h, temperature; 55°C, amount of enzyme; 176 mg, substrate molar ratio (betulinic acid: phthalic anhydride, 1:1, inorganic base of K2CO3, amount of celite; 170 mg in 1:1 mixture of chloroform and n-hexane as solvent. At optimum conditions, it gave 61.8% of 3-O-phthalyl- betulinic acid.

  18. Preparations and applications in UV curing coatings of epoxy acrylates containing carboxyl

    This paper introduces preparations of epoxy acrylates containing carboxyl through the reactions of epoxy acrylates with butanedioic anhydride, pentanedioic anhydride, cis-butenedioic anhydride, phthalic anhydride, tetrabromophthalic anhydride and -tetrahydrophthalic anhydride. These epoxy acrylates containing carboxyl have been applied to UV-curing coatings and their effects on properties of UV-curing coatings have been studied

  19. EFFECT OF SUBSTITUTION POSITION OF HYDROXY GROUP AT BENZOIC ACID ON THE LUMINESCENT AND DEGRADATION PROPERTIES OF POLY[DI(CARBOXYPHENYL) SUCCINATE-co-SEBACIC ANHYDRIDE]S

    Jun Fan; Hong-liang Jiang; Kang-jie Zhu

    2007-01-01

    In this work, two new diacids, di(m-carboxyphenyl) succinate (m-dCPS) and di(o-carboxyphenyl) succinate (o-dCPS), were synthesized by reaction of m-, o-hydroxy benzoic acid with succinic chloride, respectively. Their corresponding copolymers with sebacic acid (SA), P(m-dCPS:SA) and P(o-dCPS:SA), were prepared by melt copolycondensation and characterized by NMR, UV and DSC methods. Compared with inherently fluorescent poly[di(p-carboxyphenyl) succinateco-sebacic anhydride] (P(p-dCPS:SA)), P(m-dCPS:SA) and P(o-dCPS:SA) displayed different luminescent properties. P(m-dCPS:SA) could emit fluorescence under the excitation of both visible and UV light, while P(o-dCPS:SA) could only emit fluorescence when excited with UV light. Degradation rate of the two new copolyanhydrides increased with the increase of SA fraction in the copolymers. In addition, P(o-dCPS:SA) degraded more rapidly than P(m-dCPS:SA) with the same composition. Typical surface-degradation characteristics of these copolyanhydrides were observed.

  20. Synthesis of high molecular weight polylactic acid from aqueous lactic acid co-catalyzed by tin(II)chloride dihydrate and succinic anhydride

    LEI Ziqiang; BAI Yanbin; WANG Shoufeng

    2005-01-01

    Polylactic acid was synthesized from commercial available cheap aqueous lactic acid (85%―90% w/w) using succinic anhydride and SnCl2·2H2O as catalyst in the absence of organic solvents. As a result, polylactic acid with a molecular weight of 60000 was prepared in 10 h. The new procedure is much simple, cheap and outstanding in that the start material is aqueous lactic acid; the catalytic system is environmentally benign.

  1. Water-soluble metal working fluids additives derived from the esters of acid anhydrides with higher alcohols for aluminum alloy materials.

    Yamamoto, Syutaro; Tomoda, Hideyuki; Watanabe, Shoji

    2007-01-01

    Water-soluble metal working fluids are used for processing of aluminum alloy materials. This short article describes properties of new additives in water-soluble metal working fluids for aluminum alloy materials. Many half esters or diesters were prepared from the reactions of higher alcohols with acid anhydrides. Interestingly, diesters of PTMG (tetrahydrofuran oligomer, MW = 650 and 1000) and polybutylene oxide (MW = 650) with maleic anhydride and succinic anhydride showed both of an excellent anti-corrosion property for aluminum alloy and a good hard water tolerance. The industrial soluble type processing oils including these additives also showed anti-corrosion property and hard water tolerance. PMID:17898514

  2. 亚临界水介质回收酸酐固化环氧树脂/碳纤维复合材料%Recycling of Carbon Fiber Reinforced Epoxy Resin Cured with Anhydride in Subcritical Water

    王一明; 刘杰; 吴广峰; 唐涛

    2013-01-01

    研究了不同添加剂对碳纤维增强酸酐固化环氧树脂复合材料在亚临界水中降解的影响,通过IR、GC-MS等分析,确定了环氧树脂的分解机理主要为酯键的断裂.结果表明,KOH与苯酚对酸酐固化环氧树脂的分解没有协同效应,碱性物质更有利于酯键的断裂.甲基四氢邻苯二甲酸酐固化的环氧树脂增强碳纤维复合材料在反应温度为250℃、反应时间为60 min、KOH浓度为0.2 mol/L时可完全分解,回收碳纤维的拉伸强度和表面形貌未受影响.%Effect of additives on the decomposition behavior of the carbon fiber reinforced epoxy resin cured with anhydride in subcritical water was investigated.IR and GC-MS results show that the decomposition is ascribed to cleavage of ester bond.KOH and phenol does not exhibit the synergetic effect on the decomposition of anhydride cured epoxy resin.Alkaline conditions are found to be favorable to the cleavage of ester linkages.The carbon fiber reinforced methyl-tetrabydrophalic anhydride (MeTHPA) cured epoxy resin composite was totally decomposed with the addition of 0.2 mol/L KOH at 250 ℃ for 60 min.The tensile strength and morphology of the recycled carbon fibers are not influenced.

  3. Monosaccharide anhydrides, monocarboxylic acids and OC/EC in PM1 aerosols in urban areas in the Czech Republic

    Křůmal, Kamil; Mikuška, Pavel; Večeřa, Zbyněk

    2015-01-01

    Roč. 6, č. 6 (2015), s. 917-927. ISSN 1309-1042 R&D Projects: GA MŽP SP/1A3/148/08; GA ČR(CZ) GBP503/12/G147; GA ČR GA13-01438S; GA ČR(CZ) GA14-25558S Institutional support: RVO:68081715 Keywords : Monosaccharide anhydrides * carboxylic acids * fatty acids * organic carbon * biomass burning Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.371, year: 2014

  4. KINETIC STUDY OF CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE OVER A NOVEL COPOLYMER- BOUND CIS- DICARBONYLRHODIUM COMPLEX

    CHEN Yuying; YUAN Guoqing; CHEN Rongyao

    1989-01-01

    The kinetic study of carbonylation of methanol-acetic acid mixture to acetic acid and acetic anhydride over a cis-dicarbonylrhodium complex (MVM' Rh)coordinated with the ethylene diacrylate (M')crosslinked copolymer of methyl acrylate (M) and 2 - vinylpyridine (V) shows that the rate of reaction is zero order with respect to both reactants methanol and carbon monoxide, but first order in the concentrations of promoter methyl iodide and rhodium in the complex . Polar solvents can accelerate the reaction .Activation parameters were calculated from the experimental results, being comparable to that of the homogeneous system . A mechanism similar to that of soluble rhodium catalyst was proposed .

  5. EFFECT OF ACIDITY ON ACID-SENSITIVE UV CURING SYSTEM

    Qi-dao Chen; Bing Wu; Xiao-yin Hong

    1999-01-01

    By using diphenyliodonium salts with different counterions as photo acid generators (PAGs), the effect of acidity on ring-opening polymerization of epoxy monomers and polycondensation of polyol with hexamethoxymethyl melamine (HMMM) was studied. The result shows that the rate of ring-opening polymerization is evidently dependent on the acidity of the acid and strong photo-generated acid is required.However, there is a leveling effect in the polycondensation system; if the photo-generated acid is stronger than protonated HMMM, the acidity does not obviously affect the polycondensation rate.

  6. New Composition of Maleic-Anhydride-Grafted Poly(Lactic Acid)/Rice Husk with Methylenediphenyl Diisocyanate

    Tsou, Chi-Hui; Hung, Wei-Song; Chin-San WU; Chen, Jui-Chin; Chi-Yuan HUANG; Chiu, Shih-Hsuan; Chih-Yuan TSOU; Yao, Wei-Hua; Shang-Ming LIN; Chih-Kuei CHU; Hu, Chien-Chieh; Kueir-Rarn LEE; Suen, Maw-Cherng

    2014-01-01

    Maleic-anhydride-grafted poly(lactic acid) (PLA-g-MAH) was prepared and blended with rice husk (RH). Methylenediphenyl diisocyanate (MDI) was used as the coupling agent for combining RH with PLA-g-MAH, which improved the poor interfacial adhesion between PLA and RH. Various PLA-g-MAH/RH blends, with and without MDI, were prepared by melt processing using a brabender. The effects that inclusion and distribution of MDI had on the mechanical properties and thermal behaviors of the composites wer...

  7. Investigation of the ageing effects on phenol-urea-formaldehyde binder and alkanol amine-acid anhydride binder coated mineral fibres

    Zafar, Ashar; Schjødt-Thomsen, Jan; Sodhi, R.;

    2013-01-01

    Phenol-Urea-Formaldehyde (PUF) binder coated mineral fibres' mechanical properties have been observed to degrade during ageing at elevated temperatures and humidity, while alkanol amine-acid anhydride binder based mineral fibres exhibited better ageing properties for same duration of ageing. X...

  8. Succinic anhydrides from epoxides

    Coates, Geoffrey W.; Rowley, John M.

    2013-07-09

    Catalysts and methods for the double carbonylation of epoxides are disclosed. Each epoxide molecule reacts with two molecules of carbon monoxide to produce a succinic anhydride. The reaction is facilitated by catalysts combining a Lewis acidic species with a transition metal carbonyl complex. The double carbonylation is achieved in single process by using reaction conditions under which both carbonylation reactions occur without the necessity of isolating or purifying the product of the first carbonylation.

  9. Succinic anhydrides from epoxides

    Coates, Geoffrey W; Rowley, John M

    2014-12-30

    Catalysts and methods for the double carbonylation of epoxides are disclosed. Each epoxide molecule reacts with two molecules of carbon monoxide to produce a succinic anhydride. The reaction is facilitated by catalysts combining a Lewis acidic species with a transition metal carbonyl complex. The double carbonylation is achieved in single process by using reaction conditions under which both carbonylation reactions occur without the necessity of isolating or purifying the product of the first carbonylation.

  10. STUDY OF CARBONYLATION OF METHANOL TO ACETIC ACID AND ACETIC ANHYDRIDE OVER A BIDENTATE POLYMER BOUND CIS-DICARBONYLRHODIUM COMPLEX AS CATALYST

    WANG Xiaojun; LIU Zhongyang; PAN Pinglai; YUAN Guoqing

    1996-01-01

    Copolymer of 2-vinylpyridine and vinylacetate coordinated with dicarbonylrhodium used as a catalyst for carbonylation of methanol to acetic acid and anhydride has been studied. The structural characteristics of the copolymer ligand and complex, and the influences of the reaction conditions on the carbonylation catalyzed by this polymer complex have been investigated. In comparison with small molecule catalyst of Rh complex, the bidentate copolymer coordinated complex has better thermal stability. The reaction mechanism of the carbonylation reaction is also illustrated.

  11. Poly(anhydride-ester) and Poly(N-vinyl-2-pyrrolidone) Blends: Salicylic acid-releasing blends with hydrogel-like properties that reduce inflammation

    Ouimet, Michelle A.; Fogaça, Renata; Snyder, Sabrina S; Sathaye, Sameer; Luiz H. Catalani; Pochan, Darrin J.; Uhrich, Kathryn E.

    2014-01-01

    Polymers such as poly(N-vinyl-2-pyrrolidone) (PVP) have been used to prepare hydrogels for wound dressing applications but are not inherently bioactive. For enhanced healing, the release of physically admixed therapeutics from hydrogels has been evaluated, but with limited control over drug release profiles. To overcome these limitations, PVP was blended with salicylic acid-based poly(anhydride-esters) (SAPAE) and shown to exhibit hydrogel properties upon swelling. In vitro release studies de...

  12. Inhibition of lactate transport in Ehrlich ascites tumor cells and human erythrocytes by a synthetic anhydride of lactic acid.

    Johnson, J H; Belt, J A; Dubinsky, W P; Zimniak, A; Racker, E

    1980-08-01

    The synthesis and some of the physical and biological characteristics of a new inhibitor of lactate transport are described. The inhibitor is isobutylcarbonyl lactayl anhydride (iBCLA). It is formed by the condensation of lactic acid and isobutylchloroformate. It inhibits lactate transport 50% at 0.5 microgram/mg of protein in both Ehrlich ascites tumor cells and human erythrocytes. In contrast, 15 microgram of iBCLA/mg of protein is required for 50% inhibition of phosphate transport in erythrocytes, and phosphate transport in Ehrlich ascites tumor cells is unaffected at levels as high as 50 microgram of iBCLA/mg of protein. A time-dependent and concentration-dependent reversal of lactate transport inhibition took place on exposure of iBCLA-treated Ehrlich ascites cells to hydroxylamine or dithiothreitol. These data, along with the observed sensitivity of the lactate transporter to sulfhydryl reagents [Spencer, T. L., & Lehninger, A. L. (1976) Biochem. J. 154, 405-414], suggest that iBCLA acylates an essential sulfhydryl group on the transporter. When glycolyzing Ehrlich ascites tumor cells were treated with concentrations of iBCLA sufficient for complete inhibition of lactate transport, intracellular lactate levels increased, intracellular pH and extra-cellular lactate levels decreased, and overall lactate production was inhibited. PMID:7407072

  13. Melt Free-Radical Grafting of Maleic Anhydride onto Biodegradable Poly(lactic acid by Using Styrene as A Comonomer

    Piming Ma

    2014-05-01

    Full Text Available Maleic anhydride (MA was grafted onto poly(lactic acid (PLA in the presence of styrene (St by using a free-radical grafting methodology. The grafting degree (Dg of MA was increased from 0.65 wt % to 1.1 wt % with the St/MA ratio up to 2/1, where the grafting efficiency (Eg of MA was 27%. However, both Dg and Eg were decreased with further increasing of the St/MA ratio to 4/1. The Dg of MA increased with MA concentration and showed a maximum at 180 °C in the temperature range of 165 °C–190 °C. The grafting mechanisms of MA in the presence of St are analyzed based on titration, thermogravimetric analysis and infrared results, i.e., MA is grafted onto PLA chains via single monomers and a charge-transfer-complex (CTC at St/MA ratios of ≤ 1/1, while dominantly via St-co-MA oligomers at St/MA ratios of around 2/1. Copolymerization rather than grafting of St and MA occurs at St/MA ratios of around 4/1. The thermal stability of PLA was compromised to a certain extent by the grafting of MA, resulting in reductions in the decomposition temperature (Td-5% and molecular weight of the PLA. In addition, the crystallization and melting temperatures of the PLA were slightly reduced after the grafting.

  14. New Composition of Maleic-Anhydride-Grafted Poly(Lactic Acid/Rice Husk with Methylenediphenyl Diisocyanate

    Chi-Hui TSOU

    2014-12-01

    Full Text Available Maleic-anhydride-grafted poly(lactic acid (PLA-g-MAH was prepared and blended with rice husk (RH. Methylenediphenyl diisocyanate (MDI was used as the coupling agent for combining RH with PLA-g-MAH, which improved the poor interfacial adhesion between PLA and RH. Various PLA-g-MAH/RH blends, with and without MDI, were prepared by melt processing using a brabender. The effects that inclusion and distribution of MDI had on the mechanical properties and thermal behaviors of the composites were examined. The results showed that the PLAXRHYMDI specimens had the optimum tensile properties compared with the PLAXRHY, PLA-g-MAHXRHY, and PLA-g-MAHXRHYMDI specimens. The new method of combining MDI and MAH through grafting was expected to be an excellent strategy for mitigating the low functionality of commercial PLA. Possible reasons accounting for the interesting results on tensile strength and thermal properties of the specimens are proposed. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6034

  15. Synthetic studies of coumarin derivatives from o-hydroxybenzophenones with phenylacetic acid and acetic anhydride

    Kang, Soon Hee; Yang, Sung Yun [Ewha Womans Univ., Seoul (Korea, Republic of)

    1999-02-01

    The 8 coumarin derivatives have been synthesized from 8 starting materials(2-hydroxy-benzophenone, 2,2'-dihydroxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-5-methylbenzophenone, 5-chloro-2-hydroxy-4-methylbenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-4'-dimethoxybenzophenone) with phenylacetic acid and Ac{sub 2}O/TEA in acetone at reflux temperature. The ratio of o-hydroxybenzophenone, phenylacetic acid, Ac{sub 2}O and TEA is 1:1:8:8 in acetone. Our results showed higher products yields of coumarin derivatives than Shama and Ray's method in previous papers. A new intermediate form was proposed to our mechanism of coumarin synthetic method.

  16. Thermally cured coil-coatings utilizing novel resins and fatty acid methyl esters as reactive diluents

    Johansson, Katarina

    2008-01-01

    Solvent-borne thermally cured coil-coating resins contain large amounts of volatile organic solvents in order to obtain suitable flow for film application. This work describes how the expensive and environmental hazardous volatile organic solvent content of a solvent-borne thermally cured polyester/melamine coil-coating system can be reduced by introduction of fatty acid methyl esters (FAMEs) as reactive diluents and modification of the polyester binder resin. The evaluated reactive diluents,...

  17. Fatty acid methyl esters as reactive diluents in solvent-borne thermally cured coil-coatings

    Johansson, Katarina

    2006-01-01

    This work describes how a fatty acid methyl ester (FAME) derived from a vegetable oil can be introduced as reactive diluent in a solvent-borne thermally cured coil-coating system. The evaluated reactive diluent, rape seed methyl ester (RME), has been evaluated both in a fully formulated clear coat system and via model studies. A reactive diluent is a compound that acts as a solvent in the liquid paint, lowering the viscosity, and chemically reacts into the final film during cure. Introduction...

  18. Preparation, characterization and thermal properties of styrene maleic anhydride copolymer (SMA)/fatty acid composites as form stable phase change materials

    Fatty acids such as stearic acid (SA), palmitic acid (PA), myristic acid (MA) and lauric acid (LA) are promising phase change materials (PCMs) for latent heat thermal energy storage (LHTES) applications, but high cost is the major drawback of them, limiting their utility area in thermal energy storage. The use of fatty acids as form stable PCMs will increase their feasibilities in practical applications due to the reduced cost of the LHTES system. In this regard, a series of styrene maleic anhydride copolymer (SMA)/fatty acid composites, SMA/SA, SMA/PA, SMA/MA, and SMA/LA, were prepared as form stable PCMs by encapsulation of fatty acids into the SMA, which acts as a supporting material. The encapsulation ratio of fatty acids was as much as 85 wt.% and no leakage of fatty acid was observed even when the temperature of the form stable PCM was over the melting point of the fatty acid in the composite. The prepared form stable composite PCMs were characterized using optic microscopy (OM), viscosimetry and Fourier transform infrared (FT-IR) spectroscopy methods, and the results showed that the SMA was physically and chemically compatible with the fatty acids. In addition, the thermal characteristics such as melting and freezing temperatures and latent heats of the form stable composite PCMs were measured by using the differential scanning calorimetry (DSC) technique, which indicated they had good thermal properties. On the basis of all the results, it was concluded that form stable SMA/fatty acid composite PCMs had important potential for practical LHTES applications such as under floor space heating of buildings and passive solar space heating of buildings by using wallboard, plasterboard or floors impregnated with a form stable PCM due to their satisfying thermal properties, easy preparation in desired dimensions, direct usability without needing additional encapsulation thereby eliminating the thermal resistance caused by the shell and, thus, reducing the cost of

  19. New anhydride/epoxy thermosets based on diglycidyl ether of bisphenol A and 10-undecenoyl modified poly(ethyleneimine) with improved impact resistance

    Acebo Gorostiza, Cristina; Fernández Francos, Xavier; de la Flor López, Sílvia; Ramis Juan, Xavier; Serra Albet, Àngels

    2015-01-01

    New dendritic modifiers have been synthesized by amidation of hyperbranched poly(ethylenimine)(PEIs) with 10-undecenoic acid to obtain hyperbranched polymers (HBPs) with different degree of modification. These HBPs have been used as toughness modifiers in a proportion of 10 and 20% in reference to the epoxy resin in diglycidyl ether of bisphenol A (DGEBA)/methyltetrahydrophthalic anhydride (MTHPA) formulations. The curing process has been studied by dynamic scanning calorimetry and by rheomet...

  20. Effect of Solvent and Acid-Base on Palladium(ll)-catalyzed Dicarbonylation of Terminal Acetylenes: a General, Efficient andStereoselective Synthesis of Maleic Diesters and Maleic Anhydrides

    JIANG, Huan-Feng; LI, JiN-Heng; CHEN, Ming-Cai

    2001-01-01

    The productions of maleic diesters and maleic anhydrises depend on the effect of solvint and acid-bade of solvent and acid-base in palladium-catalyzed dicarbonylation of terminal acetylenes. For primaryand secondary alcohol in benzene.only maleic diesters wereobtained stereospecifically from the sicabonylation ofacetylenes in the presence of PdCl2,and NaHCO3.For tERTIARy alcohols,maleic anhydrides were synthesized selectively.

  1. DFT Study of Solvent Effects in Acid-Catalyzed Diels-Alder Cycloadditions of 2,5-Dimethylfuran and Maleic Anhydride.

    Salavati-fard, Taha; Caratzoulas, Stavros; Doren, Douglas J

    2015-09-24

    Density functional theory electronic structure calculations were used to explore the mechanism for the Diels-Alder reaction between 2,5-dimethylfuran and maleic anhydride (MA). Reaction paths are reported for uncatalyzed and Lewis and Brønsted acid-catalyzed reactions in vacuum and in a broad range of solvents. The calculations show that, while the uncatalyzed Diels-Alder reaction is thermally feasible in vacuum, a Lewis acid (modeled as Na(+)) lowers the activation barrier by interacting with the dienophile (MA) and decreasing the HOMO-LUMO gap of the reactants. A Brønsted acid (modeled as a proton) can bind to a carbonyl oxygen in MA, changing the reaction mechanism from concerted to stepwise and eliminating the activation barrier. Solvation effects were studied with the SMD model. Electrostatic effects play the largest role in determining the solvation energy of the transition state, which tracks the net dipole moment at the transition state. For the uncatalyzed reaction, the dipole moment is largely determined by charge transfer between the reactants, but in the reactions with ionic catalysts, there is no simple relationship between solvation of the transition state and charge transfer between the reactants. Nonelectrostatic contributions to solvation of the reactants and transition state also make significant contributions to the activation energy. PMID:26331220

  2. Adenoviral transduction of human acid sphingomyelinase into neo-angiogenic endothelium radiosensitizes tumor cure.

    Branka Stancevic

    Full Text Available These studies define a new mechanism-based approach to radiosensitize tumor cure by single dose radiotherapy (SDRT. Published evidence indicates that SDRT induces acute microvascular endothelial apoptosis initiated via acid sphingomyelinase (ASMase translocation to the external plasma membrane. Ensuing microvascular damage regulates radiation lethality of tumor stem cell clonogens to effect tumor cure. Based on this biology, we engineered an ASMase-producing vector consisting of a modified pre-proendothelin-1 promoter, PPE1(3x, and a hypoxia-inducible dual-binding HIF-2α-Ets-1 enhancer element upstream of the asmase gene, inserted into a replication-deficient adenovirus yielding the vector Ad5H2E-PPE1(3x-ASMase. This vector confers ASMase over-expression in cycling angiogenic endothelium in vitro and within tumors in vivo, with no detectable enhancement in endothelium of normal tissues that exhibit a minute fraction of cycling cells or in non-endothelial tumor or normal tissue cells. Intravenous pretreatment with Ad5H2E-PPE1(3x-ASMase markedly increases SDRT cure of inherently radiosensitive MCA/129 fibrosarcomas, and converts radiation-incurable B16 melanomas into biopsy-proven tumor cures. In contrast, Ad5H2E-PPE1(3x-ASMase treatment did not impact radiation damage to small intestinal crypts as non-dividing small intestinal microvessels did not overexpress ASMase and were not radiosensitized. We posit that combination of genetic up-regulation of tumor microvascular ASMase and SDRT provides therapeutic options for currently radiation-incurable human tumors.

  3. Effect of maleic anhydride-aniline derivative buffer layer on the properties of flexible substrate heterostructures: Indium tin oxide/nucleic acid base/metal

    Stanculescu, A., E-mail: sanca@infim.ro [National Institute of Materials Physics, 105 bis Atomistilor Street, P.O. Box MG-7, 077125, Bucharest-Magurele (Romania); Socol, M. [National Institute of Materials Physics, 105 bis Atomistilor Street, P.O. Box MG-7, 077125, Bucharest-Magurele (Romania); Socol, G.; Mihailescu, I.N. [National Institute for Laser, Plasma and Radiation Physics, P.O. Box MG-36, 077125, Bucharest-Magurele (Romania); Girtan, M. [Laboratoire de Photonique d' Angers, Universite d' Angers, 2, Bd. Lavoisier, 49045, Angers (France); Preda, N. [National Institute of Materials Physics, 105 bis Atomistilor Street, P.O. Box MG-7, 077125, Bucharest-Magurele (Romania); Albu, A.-M. [Department of Polymer Science, University ' Politehnica' of Bucharest, Bucharest (Romania); Stanculescu, F. [University of Bucharest, Faculty of Physics, Str. Atomistilor nr.405, P.O. Box MG-11, Bucharest-Magurele, 077125 (Romania)

    2011-12-01

    This paper presents some investigations on the properties of guanine (G) and cytosine (C) based heterostructures deposited on flexible substrates. The effects of two types of maleic anhydride-aniline derivatives (maleic anhydride-cyano aniline or maleic anhydride-2,4 dinitroaniline) buffer layer, deposited between indium tin oxide and (G) or (C) layer, on the optical and electrical properties of the heterostructures have been identified. The heterostructures containing a film of maleic anhydride-2,4 dinitroaniline have shown a good transparency and low photoluminescence in visible range. This buffer layer has determined an increase in the conductance only in the heterostructures based on (G) and (C) deposited on biaxially-oriented polyethylene terephthalate substrate.

  4. Radiation-induced graft polymerization of maleic acid and maleic anhydride onto ultra-fine powdered styrene-butadiene rubber (UFSBR)

    The functionalization of ultra-fine powdered styrene-butadiene rubber (UFSBR) was carried out using gamma radiation-induced graft polymerization of maleic acid (MA) and maleic anhydride (MAH), respectively. It was found that the graft yield of MA onto UFSBR increased rapidly up to the peak and then decreased with increasing MA content. Moreover, the peak shifted to the direction of lower MA content with increasing absorbed dose. Similarly, there was the peak of graft yield with increasing MAH content for grafting of MAH onto UFSBR, whereas the peak of graft yield was achieved at 10 wt% MAH content at different absorbed doses. On the other hand, increasing absorbed dose and decreasing monomer contents are useful to improve the graft efficiency of MA and MAH. At high dose and low monomer content, the graft yield of MAH onto UFSBR is higher than that of MA. FTIR spectra confirmed that both MA and MAH can be grafted successfully onto the UFSBR under gamma irradiation, respectively. Comparing with maleation of rubber by melt grafting, the graft yield of MAH on UFSBR is higher, which can be attributed to the network structure and nanometer size of UFSBR as well as high energy provided by radiation

  5. Alternating Poly(ester-anhydride) by Insertion Polycondensation.

    Haim-Zada, Moran; Basu, Arijit; Hagigit, Tal; Schlinger, Ron; Grishko, Michael; Kraminsky, Alexander; Hanuka, Ezra; Domb, Abraham J

    2016-06-13

    We report on a synthetic method where polyanhydride is used as starting material and the ester monomers are inserted through complete esterification, leading to an alternating ester-anhydride copolymer. The molar ratio of ricinoleic acid (RA) and sebacic acid (SA) was optimized until polysebacic acid is completely converted to carboxylic acid-terminated RA-SA and RA-SA-RA ester-dicarboxylic acids. These dimers and trimers were activated with acetic anhydride, polymerized under heat and vacuum to yield alternating RA-SA copolymer. The resulting alternating poly(ester-anhydride) have the RA at regular intervals. The regular occurrences of RA side chains prevent anhydride interchange, enhancing hydrolytic stability, which allows storage of the polymer at room temperature. PMID:27198864

  6. Technological and safety properties of lactic acid bacteria isolated from Spanish dry-cured sausages.

    Landeta, G; Curiel, J A; Carrascosa, A V; Muñoz, R; de las Rivas, B

    2013-10-01

    Technological and safety-related properties were analyzed in lactic acid bacteria isolated from Spanish dry-cured sausages in order to select them as starter cultures. In relation to technological properties, all the strains showed significative nitrate reductase activity; Lactobacillus plantarum, Lactobacillus paracasei and 52% of the Enterococcus faecium strains showed lipolytic activity and only Lactobacillus sakei strains (43%) were able to form biofilms. Related to safety aspects, E. faecium strains were the most resistant to antibiotics, whereas, L. sakei strains were the most sensitive. In relation to virulence factors, in the E. faecium strains analyzed, only the presence of efaA gene was detected. The analysis of biogenic amine production showed that most E. faecium strains and L. sakei Al-142 produced tyramine. In conclusion, L. paracasei Al-128 and L. sakei Al-143 strains possess the best properties to be selected as adequate and safe meat starter cultures. PMID:23743032

  7. Simultaneous efficient adsorption of Pb2+ and MnO4- ions by MCM-41 functionalized with amine and nitrilotriacetic acid anhydride

    Chen, Feiyun; Hong, Mingzhu; You, Weijie; Li, Chong; Yu, Yan

    2015-12-01

    A novel adsorbent NH2/MCM-41/NTAA, capable of simultaneous adsorption of cations and anions from aqueous solution, was prepared by immobilization of amine and nitrilotriacetic acid anhydride (NTAA) onto MCM-41. The structures and properties before and after surface modification were systematically investigated through X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM), nitrogen adsorption-desorption, and infrared spectroscopy (FTIR), thermogravimetry (TGA) and X-ray photoelectron spectroscopy (XPS). They together confirm that the amine and NTAA group were chemically bonded to the internal surface of the mesoporous. The NH2/MCM-41/NTAA were used to adsorb Pb2+ and MnO4- in an aqueous solution in a batch system, and the maximum adsorption efficiency was found to occur at pH 5.0 and 3.0, respectively. NH2/MCM-41/NTAA exhibit preferable removal of Pb2+ through electrostatic interactions and chelation, whereas it captures MnO4- by means of electrostatic interactions. The experimental data are fitted the Langmuir isotherm model reasonably well, with the maximum adsorption capacity of 147 mg/g for Pb2+ and of 156 mg/g for MnO4-. The adsorption rates of both Pb2+ and MnO4- are found to follow the pseudo-second order kinetics. Furthermore, the NH2/MCM-41/NTAA adsorbent performs good recyclability and reusability for 5 cycles use. This study indicates a potential applicability of NH2/MCM-41/NTAA as new absorbents for effective simultaneous adsorption of hazardous metal ions and anions from wastewater.

  8. Effect of Linear Chain Carboxylic Acid Anhydrides on Physical and Mechanical Properties of Rubber (Hevea brasiliensis), Acacia, (Acacia spp.), and Oil Palm (Tinnera spp.) Woods

    Mohd Afiq Mohtar; Norul Hisham Hamid; Mohd Hamami Sahri

    2014-01-01

    The physical and mechanical properties of Rubber wood, Acacia wood, and Oil palm wood that reacted with acetic, propionic, and butyric anhydrides using a microwave heating for 4 minutes were investigated. A sample dimension of 300 mm × 100 mm × 25 mm (L×W×T) was used for modification and they were cut into smaller specimens for different testing method. This study found that the density increment and void volume changes were not significantly different from anhydrides. The modification of woo...

  9. A new method for the preparation of I131-labelled p-iodo-benzenesulphonic acid anhydride (pipsan)

    I131-labelled pipsan may be used, together with S35-labelled pipsan, in a double-isotope-derivation technique for the analytical determination of various steroids. The preparation of high-specific-activity I131-pipsan involves serious health hazards due to the γ-radiation of I131, and a shielded cell with remote-handling equipment has to be used. Earlier methods, in which I131 is introduced in diazo-benzenesulphonic acid, involve many steps with purification of the intermediary products and necessitate rather complicated equipment. By the introduction of I131 in diazo-benzene and by sulphonation of the labelled iodobenzene with oleum, labelled pipsan is obtained directly. This method has proved feasible for remote handling in a shielded cell. The procedure is based on recent Russian papers. Chemical aspects of the procedure are briefly discussed. Descriptions are given of some of the equipment used in the remote handling, e.g. : a micro steam-distillation apparatus for the preparation of iodobenzene, and a rotating Perspex pipetting station used for the addition of washing liquids, for air-propagation and for removal of supernatants. (author)

  10. Treatments with acetic acid followed by curing reduce postharvest decay on Citrus fruit.

    Venditti, T; Angiolino, C; Dore, A; Molinu, M G; Petretto, A; D'Hallewin, G

    2009-01-01

    Citrus fruit are susceptible to many postharvest diseases and disorders, but Penicillium digitatum and Penicillium italicum are the most common and serious pathogens during storage and marketing. The continuous employ in packing houses of synthetic fungicides such as imazalil (IMZ) or thiabendazote for the control of these pathogens is promoting the selection of resistant biotypes. These considerations together with an increased attention for human health and the environment have multiplied the studies on new ecological technologies. In recent years researchers studies focused on alternatives to the chemical control of post-harvest decay, such as the utilization of GRAS compounds as well as physical methods. In the present study is reported the sequential use of acetic acid (AAC) followed by curing. The lemon variety "Verna" and the orange variety "Jaffa", naturally inoculated, were treated with vapours of AAC performed at three different concentration (15, 25 and 50 microL/L) for 15 minutes, after an incubation period of 24 hours at 27 degrees C and 90% relative humidity (RH). After treatments fruits were cured at 36 degrees C for 36 hours with 90% RH and subsequently stored at 8 degrees C and 90% of RH for eight weeks. Both citrus varieties were also treated with IMZ at a concentration of 200 mL/HL. At the end of the experiment decay and weight loss were evaluated. After 8 weeks of storage, in the lemon variety, the lowest percentage of infected wounds was 1.5% for both the fruit treated with IMZ or with AAC at 25 microL/L. Fruit treated with 15 mciroL/L or untreated (control) showed similar results with 13.6% and 16.6% of rotted fruit respectively. Different results were obtained with the orange variety, in this case the synthetic fungicide was the most effective at the end of the storage period, with 18.0% of decay. AAC treatments were not a successful as on lemons, the best result was achieved even in this case with AAC performed at 25 pL/L, but with 39.9% of

  11. Diastereoselective synthesis of γ- And δ-lactams from imines and sulfone-substituted anhydrides

    Sorto, NA; Di Maso, MJ; Muñoz, MA; Dougherty, RJ; Fettinger, JC; Shaw, JT

    2014-01-01

    Sulfone-substituted γ- and δ-lactams have been prepared in a single step with high diastereoselectivity. Sulfonylglutaric anhydrides produce intermediates that readily decarboxylate to provide δ-lactams with high diastereoselectivity. Substituents at the 3- or 4-position of the glutaric anhydride induce high levels of stereocontrol. Sulfonylsuccinic anhydrides produce intermediate carboxylic acids that can be trapped as methyl esters or allowed to decarboxylate under mild conditions. This met...

  12. Fatty acid profile, total cholesterol, vitamin content, and TBARS value of turkey breast muscle cured with the addition of lycopene.

    Skiepko, N; Chwastowska-Siwiecka, I; Kondratowicz, J; Mikulski, D

    2016-05-01

    The aim of this study was to determine the effect of lycopene addition for curing turkey meat on the profile of fatty acids, total cholesterol, vitamin content, and the TBARS of the final products. The analyzed material comprised 64 breast muscles, of which 16 (RBM) were immediately transported to a laboratory. Another 16 (UBM) were heat treated in a convection steam oven, and 32 muscles were cured for 3 days in two types of curing mixture: without (CBM) and with (CBM+Lyc) tomato peel extract standardized for 5% lycopene content. After completed curing, samples were steamed and grilled under the same conditions as raw samples. Statistical analysis demonstrated the highest (P≤0.01) mean content of vitamin A (0.07 μg/g) in chilled muscles. The content of vitamin E was lower (P≤0.01) in UBM samples than in CBM+Lyc and RBM. The TBARS value was the lowest (P≤0.01) in RBM muscles (0.35 mg MDA/kg of meat). Although there were no differences between products, but lower TBARS were found in CBM+Lyc samples. The content of cholesterol was higher (P≤0.01) in CBM+Lyc products than in the RBM and UBM. RBM samples contained (P≤0.01) the lowest amount of saturated, monounsaturated, and hypercholesterolemic fatty acids, and the highest of unsaturated, polyunsaturated, and hypocholesterolemic fatty acids. CBM+Lyc samples contained (P≤0.01) less hypercholesterolemic and more hypocholesterolemic fatty acids than CBM group. Higher (P≤0.01) unsaturated/saturated and hypocholesterolemic/hypercholesterolemic fatty acid ratios were also found in CBM+Lyc products. The study demonstrated that the used processing technology caused reduction (P≤0.01) of n-3 and n-6 PUFA content. Findings suggest that the addition of lycopene in the process of meat curing and heat treatment in meat industry do not change the content of vitamins and cholesterol or alter the TBARS value in turkey meat products. Nevertheless, lycopene can be used to increase the content of essential

  13. Physical characteristics of cold cured anthracite/coke breeze briquettes prepared from a coal tar acid resin

    Thoms, L.J.; Snape, C.E.; Taylor, D. [University of Strathclyde, Glasgow (United Kingdom). Dept. of Pure and Applied Chemistry

    1999-11-01

    Phenolic resins were synthesised using the whole coal tar acid fraction of the oil from a low temperature carbonisation process. A series of briquettes were prepared using a number of coal tar acid concentrations, cured at ambient temperature with various concentrations of sulphuric acid and were subjected to a variety of physical tests. Excellent briquettes, in terms of mechanical strength, water-proofing characteristics and thermal degradation, were produced with both nominally 10 and 9% w/w resole solution and acid concentrations down to 1.8 M, corresponding to sulphur addition in the briquettes of ca. 0.2% w/w. Briquettes bound with 8% w/w resole solution, however, required stronger acid concentrations to satisfy the test conditions. When the briquettes were combusted up to 850{degree}C, they retained their core shape after 70% weight loss. 16 refs., 4 figs., 4 tabs.

  14. COMPARISON OF THE E44 EPOXY RESINS IN DIFFERENT CONTENTS OF CURING AGENT BY MICROWAVE AND THERMAL CURING METHODS

    2000-01-01

    This paper discusses the fundamental principle of microwave heating, and based on the advantages of microwave heating, use maleic anhydride as curing agent.The technology of microwave curing E44 epoxy resins is investigated,the mechanical properties of cured epoxy resin samples in different contents of curing agent by microwave and thermal curing methods are measured respectively, and then some experimental results for which are obtained.At last, this paper analyses why microwave curing can improve mechanical property of epoxy resin.

  15. Extraction of uranium from coarse ore and acid-curing and ferric sulphate-trickle leaching process

    On the basis of analysis of the problems in the technology of the traditional uranium hydrometallurgy and the limitations of thin layer leaching process (TLL), a new leaching system-acid-curing and ferric sulphate-trickle leaching (AFL) process (NGJ in Chinese) has developed for extraction of uranium from the coarse ore. The ferric sulphate solution was used for trickling the acid-cured uranium ore and the residual leaching reaction incomplete in TLL process can be improved in this process. And the AFL process has a wide applicability to China's uranium ores, being in competition with the traditional agitation leaching process for treating coarse ores. The uranium ore processing technology based on the AFL process will become one of the new basic technologies of uranium hydrometallurgy. A series of difficulties will be basically overcome associated with fine grinding because of its elimination in the presented process. Moreover, the situation of the present uranium hydrometallurgy can be also changed owing to without technological effluent discharge

  16. Curing of natural rubber and epoxy adhesive

    Low molecular weight epoxy resin based on diglycidyl ether of bisphenol A was synthesized and mixed at constant percentages with natural rubber. The rubber epoxy system was cured with various types of curing agents such as ethylene diamine, maleic anhydride as well as the prepared resole phenol formaldehyde. A study of the photo-induced crosslinking of the prepared elastic adhesives and film samples was carried out by exposure to ultraviolet lamp (300 w) for 2 weeks at 20 deg. C. Samples containing ethylene diamine were cured at 25 + - 1 deg. C. for 24 h while samples containing maleic anhydride or resole phenol formaldehyde resins were thermally cured at 150-170 deg. C. for 10 min. Cured adhesive compositions were tested mechanically and physically and evaluated as wood adhesives. While hardness, chemical resistance as well as heat stability of the prepared cured film sample were investigated. The obtained data indicate that the highest epoxy resin content and the presence of resole phenol formaldehyde resin in composition improve the tensile strength and adhesion properties on wood. While their cured film sample have the best hardness properties, chemical resistance and heat stability. (author)

  17. Effects of 1-propylphosphonic acid cyclic anhydride as an electrolyte additive on the high voltage cycling performance of graphite/LiNi0.5Co0.2Mn0.3O2 battery

    Highlights: • PACA is evaluated as a high voltage electrolyte additive. • Enhanced cycling ability of graphite/LiNi0.5Co0.2Mn0.3O2 cells is achieved. • Interface impedance of cells is reduced by adding PACA into the electrolyte. - Abstract: The cycling performance of graphite/LiNi0.5Co0.2Mn0.3O2 battery in the electrolyte with different content (0, 0.5, 1.0, 2.0 wt.%) 1-propylphosphonic acid cyclic anhydride (PACA) is studied in this work. When 0.5 wt.% PACA additive is incorporated into the blank electrolyte, the capacity retention of graphite/LiNi0.5Co0.2Mn0.3O2 battery at high voltage after 100 cycles is increased from 79.12% to 91.84%. Electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) results reveal the mechanism that the surface film derived from PACA can decrease the surface film impedance of the cell (from 40.63 to 16.57 Ω), stabilize the structure of cathode material. Moreover, the investigation of PACA on the cycling performance of graphite electrode demonstrates that PACA function on LiNi0.5Co0.2Mn0.3O2 instead of graphite

  18. The polymerization products of epoxidized oleic acid and epoxidized methyl oleate with cis-1,2-cyclohexanedicarboxylic anhydride and triethylamine as the initiator: Chemical structures, thermal and electrical properties

    Nicolau, Aline; Martignago Mariath, Rubia [Laboratory of Instrumentation and Molecular Dynamics, Department of Physical Chemistry, Federal University of Rio Grande do Sul, Av. Bento Goncalves 9500, CEP: 91501-970 Porto Alegre (Brazil); Agostini Martini, Emilse [Laboratory of Electrochemistry, University of Rio Grande do Sul, Av. Bento Goncalves 9500, CEP: 91501-970, Porto Alegre (Brazil); Santos Martini, Denise dos [Laboratory of Instrumentation and Molecular Dynamics, Department of Physical Chemistry, Federal University of Rio Grande do Sul, Av. Bento Goncalves 9500, CEP: 91501-970 Porto Alegre (Brazil); Samios, Dimitrios, E-mail: dsamios@iq.ufrgs.br [Laboratory of Instrumentation and Molecular Dynamics, Department of Physical Chemistry, Federal University of Rio Grande do Sul, Av. Bento Goncalves 9500, CEP: 91501-970 Porto Alegre (Brazil)

    2010-08-30

    Oligo and polyesters were prepared from epoxidized oleic acid (EOA) and methyl oleate (EMO) in polymerization reaction with cis-1,2-cyclohexanedicarboxylic anhydride (CH) and triethylamine (TEA) as the initiator at 165 deg. C for 3 h. In order to increase the molecular weight of the products, a small amount of butanodiol diglycidil ether (BDGE) was added. The different steps of the reactions were elucidated by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). These same techniques as well as size exclusion chromatography (SEC), thermogravimetric analysis (TGA) and electric impedance spectroscopy (EIS) were used to characterize the products of the EMO/CH/TEA, EMO/CH/BDGE/TEA, EOA/CH/TEA and EOA/CH/BDGE/TEA reaction systems. The formation of internal ester groups was confirmed by NMR and FTIR. The Mw products are between 2500 g/mol and 85000 g/mol. The {Delta}{Eta} values are 44.6 KJ/ee and 42.7 KJ/ee for the EOA and EMO systems, respectively. The thermal degradations of the products start at temperatures higher than 180 deg. C. All of the products reveal glass transitions between - 57 deg. C and - 14 deg. C, while the EMO ones also present crystallization-like behavior at - 7 deg. C and 3 deg. C. The dielectric properties of the products include very high resistivity and low capacitance.

  19. The polymerization products of epoxidized oleic acid and epoxidized methyl oleate with cis-1,2-cyclohexanedicarboxylic anhydride and triethylamine as the initiator: Chemical structures, thermal and electrical properties

    Oligo and polyesters were prepared from epoxidized oleic acid (EOA) and methyl oleate (EMO) in polymerization reaction with cis-1,2-cyclohexanedicarboxylic anhydride (CH) and triethylamine (TEA) as the initiator at 165 deg. C for 3 h. In order to increase the molecular weight of the products, a small amount of butanodiol diglycidil ether (BDGE) was added. The different steps of the reactions were elucidated by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). These same techniques as well as size exclusion chromatography (SEC), thermogravimetric analysis (TGA) and electric impedance spectroscopy (EIS) were used to characterize the products of the EMO/CH/TEA, EMO/CH/BDGE/TEA, EOA/CH/TEA and EOA/CH/BDGE/TEA reaction systems. The formation of internal ester groups was confirmed by NMR and FTIR. The Mw products are between 2500 g/mol and 85000 g/mol. The ΔΗ values are 44.6 KJ/ee and 42.7 KJ/ee for the EOA and EMO systems, respectively. The thermal degradations of the products start at temperatures higher than 180 deg. C. All of the products reveal glass transitions between - 57 deg. C and - 14 deg. C, while the EMO ones also present crystallization-like behavior at - 7 deg. C and 3 deg. C. The dielectric properties of the products include very high resistivity and low capacitance.

  20. Acceleration of curing period of pastrami manufactured from buffalo meat: II-Fatty acids, amino acids, nutritional value and sensory evaluation

    Ibrahim, Hayam M.A.

    2001-04-01

    Full Text Available Upon accelerating the curing period of pastrami (dry cured meat prepared from buffalo lean round muscles using heat treatment (~71ºC internally, the results indicated that: the peroxide and thiobarbituric acid (TBA values increased with increasing the aging period. Percentage of the released free fatty acids was 1.21 after heat treatment and increased gradually to reach 1.47 after hanging in air at room temperature for drying and complete curing up to 6 days. The major saturated and unsaturated fatty acids in all of the pastrami samples were palmitic (16:0, oleic (18:1 and linoleic (18:2 fatty acids. The main three identified polyunsaturated fatty acids (linoleic, linolenic and arachidonic were of high percentages in the accelerated cured samples than in the control one. The ratio of the unsaturated: saturated fatty acids was similar in either the heat treated (1.28:1 and the control (1.27: 1 pastrami samples. Similar findings were found for the ratio of total essential amino acids (EAAS: total amino acids (AAS. The Essential Amino Acids Index (EAAI that possesses higher percentage for the heat treated sample than that for the control one proved the higher biological acceptance of the heat accelerated cured pastrami sample. The predicted protein efficiency ratio (PER of all the investigated samples reached more than 2.42 of casein. Sensory evaluation of the pastrami sample processed to an internal temperature of ~71ºC proved by the panelists to be of attractive color, more tasty, of good characteristic odor and more tender than the control samples which were prepared and cured for 3 weeks without using heat treatment.En relación a la aceleración del período de cura del pastrami (carne curada en seco preparada a partir de carne magra de búfalo usando un tratamiento térmico (~71ºC internamente, los resultados indicaron que los valores de peróxido y ácido tiobarbitúrico (TBA aumentaron con el envejecimiento. El porcentaje de

  1. Influence of paste composition and curing program used for the production of positive plates with PbSnCa grids on the performance of lead acid batteries

    Pavlov, D.; Dimitrov, M.; Rogachev, T.; Bogdanova, L.

    The cycle life performance of lead acid batteries with PbSnCa grids is strongly affected by the structure and properties of PAM and of the interface PAM/grid. The latter interface is formed during curing and formation of the positive plates. The processes that take place on curing of positive lead acid battery plates produced with Concast or Conroll PbSnCa grids and 3PbOPbSO 4·H 2O (3BS) or 4PbOPbSO 4· xH 2O (4BS) pastes are discussed in this paper. The enhanced processes of Sn and Ca segregation in the alloy of the grids during plate curing lead to the formation of a thin layer of a new phase, composed of the intermetallic compound (Pb 1- xSn x) 3Ca, in the spaces between the metal grains or sub-grains. This layer makes the interface heterogeneous and exerts a detrimental effect on the cycle life of the battery. In order to suppress its effect on battery performance, the thickness of this layer should be reduced by reducing the content of Ca in the grid alloy. During plate curing, the heterogeneous surface of the grid alloy is oxidized under the action of oxygen and H 2O at elevated temperature and the alkaline solution in the paste pores. A corrosion layer is formed comprising a thin sub-layer (CL1) and a thick partially hydrated lead oxide sub-layer (CL2). The 4BS/CL2 contact surface is larger and more stable than that between the 3BS particles and the CL2 layer. Both 3BS and 4BS particles are bonded to the CL2 layer through their hydrated layers. When curing is conducted at temperatures above 80 °C, 3BS particles are converted into 4BS ones which contain water. It has been established that positive plates produced with 4BS plates cured at 50 °C have the longest cycle life and adequate capacity performance, but a bit low power output. Positive plates prepared with 3BS pastes, which are then converted into 4BS ones during plate curing at 90 °C, have high initial capacity and power performance, but shorter cycle life. Batteries with plates produced with 4BS

  2. Processing Pa-Lua Uranium ore by Mixing and Curing with Sulfuric Acid on a Scale of 500 kg/Batch to Recover Yellowcake

    Uranium ore in Pa-Lua area is sandstone with different levels of weathering. This kind of ore contains calcium and clay that may cause clogs during heap leaching. In this study, a technique of mixing and curing with strong acids is used and followed by washing to recover uranium. This study also focuses on study of ore processing issues such as crushing, regenerating particles in fine ores, mixing, curing and washing. The leach solution is treated by ion-exchange and precipitation of products by NH4OH. The experiment results show that regenerating a portion of fine ores, mixing and curing help washing residues in the column more effectively. Flow rate of the input solution can be controllable and stable. Columns do not clog even when washing takes place in the ore column of 5 meters high. Efficiency of uranium recovery can reach to 85-90%. Products of technical uranium are obtained with high quality. (author)

  3. Dual cure photocatalyst systems

    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.

  4. Réaction du polyisobutène chloré sur l'anhydride maléique : mécanisme. Catalyse par l'anhydride dichloromaléique Reaction of Chlorinated Polyisobutene on Maleic Anhydride. Mechanism. Catalysis by Dichloromaleic Anhydride

    Sillion B.

    2006-11-01

    Full Text Available Dans cet article le mécanisme de la réaction de condensation du polyisobutène chloré sur l'anhydride maléique, qui sert dans la synthèse d'additif pour lubrifiant, est étudié par une cinétique globale et par un travail sur composés modèles. Il est montré que, dans cette réaction, l'anhydride maléique joue un double rôle : de catalyseur de déshydrochloration par une réactivité de type acide de Lewis organique, de réactif comme diénophile. Grâce à ces résultats, il est proposé une catalyse par l'anhydride dichloromaléique, qui permet une amélioration sensible du procédé. This article examines the mechanism of the chlorinated-polyisobutene condensation reaction on maleic anhydride. The overall kinetics and model compounds are investigated for this reaction which is used in the synthesis of lubricant additives. Maleic anhydride is shown to play the dual role of a dehydrochlorination catalyst by having a reactivity of the organic Lewis acid type and of a reactant like dienophile. These results are used to propose a catalysis by dichloromaleic anhydride which appreciably improves the process.

  5. Vascular Cures

    ... our CEO Board of Directors Scientific Advisory Board History of Vascular Cures Impact Contact Us Vascular Disease What is Vascular Disease? Education and Awareness Vascular Diseases Abdominal Aortic Aneurysm Aortic ...

  6. Kaolinite Nanocomposite Platelets Synthesized by Intercalation and Imidization of Poly(styrene-co-maleic anhydride

    Pieter Samyn

    2015-07-01

    Full Text Available A synthesis route is presented for the subsequent intercalation, exfoliation and surface modification of kaolinite (Kln by an imidization reaction of high-molecular weight poly(styrene-co-maleic anhydride or SMA in the presence of ammonium hydroxide. In a first step, the intercalation of ammonolyzed SMA by guest displacement of intercalated dimethylsulfoxide has been proven. In a second step, the imidization of ammonolyzed SMA at 160 °C results in exfoliation of the kaolinite layers and deposition of poly(styrene-co-maleimide or SMI nanoparticles onto the kaolinite surfaces. Compared with a physical mixture of Kln/SMI, the chemically reacted Kln/SMI provides more efficient exfoliation and hydrogen bonding between the nanoparticles and the kaolinite. The kaolinite nanocomposite particles are synthesized in aqueous dispersion with solid content of 65 wt %. The intercalation and exfoliation are optimized for a concentration ratio of Kln/SMI = 70:30, resulting in maximum intercalation and interlayer distance in combination with highest imide content. After thermal curing at 135 °C, the imidization proceeds towards a maximum conversion of the intermediate amic acid moieties. The changes in O–H stretching and kaolinite lattice vibrations have been illustrated by infrared and FT-Raman spectroscopy, which allow for a good quantification of concentration and imidization effects.

  7. A new process for the valorisation of a bio-alcohol. The oxidehydration of 1-butanol into maleic anhydride

    Caldarelli, A.; Cavani, F.; Garone, O.; Pavarelli, G. [Bologna Univ. (Italy). Dipt. di Chimica Industriale e dei Materiali; Bologna Univ. (Italy). CIRCC, Research Unit; Dubois, J.L. [ARKEMA, Colombes (France); Mitsova, I.; Simeonova, L. [JSC, Russe (Bulgaria). Orgachim

    2012-07-01

    This paper deals with a study on the gas-phase transformation of 1-butanol into maleic anhydride, using different types of catalysts. Indeed, catalytic acid properties are needed to dehydrate 1-butanol into 1-butene, whereas redox-type properties are required for the oxidation of the olefin into maleic anhydride. The two types of active sites can be combined in bifunctional systems, showing both acid and redox-type properties. We found that vanadyl pyrophosphate catalyzes the one-pot reaction, giving a maximum selectivity to maleic anhydride of 28%. In fact, various side reactions contributed to the formation of by-products, eg, 1-butanol (oxidative) dehydrogenation into butyraldehyde, formation of light carboxylic acids and carbon oxides, and condensation of unsaturated C{sub 4} intermediates (butenes and butadiene) with the formed maleic anhydride to yield heavier compounds. (orig.)

  8. Radiation curing

    In the beginning of the seventies the two types of radiation sources applied in industrial processes, electron radiation and UV, had been given rather optimistic forecasts. While UV could succeed in the field of panel and film coating, electron radiation curing seems to gain success in quite new fields of manufacturing. The listing of the suggested applications of radiation curing and a comparison of both advantages and disadvantages of this technology are followed by a number of case studies emphasizing the features of these processes and giving some examplary calculations. The data used for the calculations should provide an easy calculation of individual manufacturing costs if special production parameters, investment or energy costs are employed. (Author)

  9. Biodegradable polymers derived from renewable resources: Highly branched copolymers of itaconic anhydride

    Wallach, Joshua Andrew

    In an effort to design cyclic anhydride containing polymers that are derived from renewable resources and have biodegradable characteristics, three copolymer systems using itaconic anhydride have been studied. Two of the systems were copolymers with stearate based monomers; vinyl stearate and stearyl methacrylate, while the third was a copolymer with a methacrylate terminated poly (lactic acid) (PLA) macromonomer. For the stearate systems, stearyl methacrylate showed good copolymerization with equal conversions for both monomers. On the other hand vinyl stearate did not show as good results due to its decreased reactivity, which resulted in a copolymer highly enriched in itaconic anhydride with significant amounts of unreacted vinyl stearate under all copolymer compositions. These differing results were confirmed through analysis of reactivity ratios showing a results that are more favorable for copolymerization for the methacrylate system. Copolymers from both systems showed single melting transitions in a precarious range of 45--50°C arising from the stearyl side groups, though after quenching from the melt this shifted to below room temperature. Anhydride retention was confirmed through structural analysis. Similar to the stearyl methacrylate system, methacrylate terminated PLA macromonomers were copolymerized with itaconic anhydride. PLA's acceptance as a biodegradable material derived from renewable resources, make it a viable choice, with which to design anhydride containing copolymers. Good copolymerization was shown for all compositions studied with retention of the anhydride, though at high itaconic anhydride concentrations conversions were reduced significantly. Copolymers showed glass transition temperatures ranging from 32°C for 85 mole % PLA macromonomer to 73°C for 85 mole % itaconic anhydride. An effort to produce PLA macromonomers through a process of chemical recycling commercial PLA was also undertaken. Promising results were obtained showing

  10. POLYMERIZATION OF LACTIC O-CARBOXYLIC ANHYDRIDE USING ORGANOMETALLIC CATALYSTS

    Xiu-li Zhuang; Hai-yang Yu; Zhao-hui Tang; Kenichi Oyaizu; Hiroyuki Nishide; Xue-si Chen

    2011-01-01

    The ring-opening polymerization of 5-methyl-l,3-dioxolane-2,4-dione (lactic O-earboxylic anhydride, LacOCA) using organometallic complexes, including Co(Ⅲ) complexes with Schiff base ligands, Tin(Ⅱ) alphatates and Al(Ⅲ)complexes with Schiff base ligands, was explored. The polymerization was carried out by treatment of the organometallic complexes with LacOCA in toluene under mild conditions. The corresponding poly(lactic acid) was characterized by spectroscopy and thermal analyses, which revealed insight into the structure of the effective catalyst for the polymerizationof LacOCA.

  11. Polyisobutylene interaction kinetics with maleic anhydride in fusion

    Киселёва-Логинова, Екатерина Валерьевна; Попов, Евгений Вадимович; Савяк, Роман Прокопович; Кондратов, Сергей Алексеевич

    2012-01-01

    The kinetics of the interaction of maleic anhydride with polyisobutylene to form polyizobuthylene succine anhydride was investigated. It was shown that the kinetics is described by first-order equation

  12. Hydrolysis and stability of thin pulsed plasma polymerised maleic anhydride coatings

    Drews, Joanna Maria; Launay, Héléne; Hansen, Charles M.;

    2008-01-01

    Abstract The stability of plasma polymerised layers has become important because of their widespread use. This study explored the hydrolysis and degradation stability of coatings of plasma polymerised maleic anhydride. Coatings made with different plasma parameters were exposed to aqueous media of...... different pH as a function of time. ATR-FTIR was used for structure analysis and a toluidine blue staining method allowed quantitative analysis of the hydrolysis of anhydride groups to acid groups. Coatings with constant thickness were obtained at different plasma powers and layers with varying thickness...

  13. Actinic-radiation curable polymers prepared from a reactive polymer, halogenated cyclic anhydride and glycidyl ester

    A novel class of photosensitive polymers are disclosed which are prepared by the reaction, preferably in the presence of a catalyst, of a reactive polymer, a halogenated cyclic anhydride and glycidyl ester of an alpha, beta-unsaturated carboxylic acid. These polymers are capable of undergoing vinyl-type polymerization when exposed to actinic radiation

  14. PHOTOCOPOLYMERIZATION OF MALEIC ANHYDRIDE AND VINYL ACETATE IN TETRAHYDROFURAN

    LI Xiaofang; LI Shanjun; QIN Anwei; YU Tongyin

    1991-01-01

    The copo1ymerization of maleic anhydride and vinyl acetate in tetrahydrofuran was studied.Results show that the maximum copolymerization rate is in 0.6 mole fraction of maleic anhydride,indicating the involvement of maleic anhydride-tetrahydrofuran charge-transfer complex in the chain initiation process. ESR study provides collateral evidence for the formation of maleic anhydride radical and tetrahydrofuran radical.

  15. Effect of sucrose on the generation of free amino acids and biogenic amines in Chinese traditional dry-cured fish during processing and storage

    Zhang, Jinjie; Liu, Zhenfeng; Hu, Yaqin; Fang, Zhongxiang; Chen, Jianchu; Wu, Dan; YE, XINGQIAN

    2010-01-01

    The Chinese traditional dry-cured grass carp fish (Layú) was processed with (A) and without (B) sucrose. Higher levels of free amino acids (FAA) and biogenic amines were detected in the final products when compared to the fresh fish. In the presence of sucrose, Layú A had higher total free amino acids (39.9 g/kg DW) but lower total biogenic amines (112.5 mg/kg DW) than those in Layú B (35.4 g/kg DW and 143.7 mg/kg DW, respectively) after ageing. After 60 days, the products storaged at 4 °C ha...

  16. Protein-Semisynthese mit Hilfe gemischter Anhydride und Enzyme

    Zahn, H.; Naithani, V. K.; Gattner, H.-G.; Büllesbach, E. E.; Thamm, P. M.

    1981-02-01

    Proteins play a prominent role in nature and their biosynthesis occurs via stepwise combination of amino acids. One can imitate this method in laboratory or synthesize the polypeptide chain by combining smaller preformed fragments (fragment condensation). Reversible protection of reactive groups and solubility problems arising are the most important features in this regard. Semisynthesis, i.e., coupling of amino acids or peptides to natural material may help to overcome these difficulties. The preparation of hybrid preproinsulin by mixed anhydride synthesis and the conversion of pork insulin to human insulin by enzyme-catalyzed peptide synthesis are two examples of the semisynthesis of proteins. In both cases optimal reaction conditions are essential for maximal yield of the product desired. In spite of the rapid improvement of gene technology, chemical peptide synthesis will retain its value for the preparation of biologically and pharmacologically interesting substances.

  17. Effect of the amount of chestnuts in the diet of Celta pigs on the fatty acid profile of dry-cured lacon

    de Jesús, M. C.

    2016-03-01

    Full Text Available The effect of including chestnuts in the formulation of the feed (0, 15 and 25% chestnut on the fatty acids of dry-cured lacon from Celta pigs was studied. The inclusion of chestnuts decreases the saturated fatty acid content (SFA and the monounsaturated fatty acid content (MUFA. With regards to the polyunsaturated fatty acids (PUFA, the lacon from animals fed with chestnuts presented higher values of total PUFA, n6 PUFAs and n3 PUFAs. This is related to the fact that chestnut diets had the highest amounts of essential fatty acids (C18:2n6 and C18:3n3, therefore the lacon from chestnut-fed animals also presented higher amounts of these fatty acids. According to nutritional ratios, lacon obtained from chestnut-fed pigs was healthier than the one obtained from pigs fed on commercial feed. The main conclusion is that including chestnuts in the diet allows us to obtain healthier dry-cured meat products.Se estudió el efecto de la inclusión de la castaña en la formulación del pienso (0, 15 y 25% de castaña sobre el perfil de ácidos grasos del lacón curado de cerdo Celta. La inclusión de castañas produjo una disminución del contenido de ácidos grasos saturados (SFA y monoinsaturados (MUFA. Con respecto a los ácidos grasos poliinsaturados (PUFA los lacones de animales alimentados por castaña presentaron valores más altos de PUFA totales, PUFA n6 y PUFA n3. Esto está relacionado con que las castañas tienen una mayor cantidad de ácidos grasos esenciales (C18:2n6 y C18:3n3, por tanto los lacones de cerdos alimentados con castaña también presentan mayores contenidos de estos ácidos grasos. De acuerdo con los índices nutricionales, los lacones obtenidos de cerdos alimentados con mayor proporción de castañas fueron más saludables. La inclusión de castañas en la dieta nos permite obtener productos cárnicos curados más saludables.

  18. Interplay of carbonyl-carbonyl, Csbnd H⋯O and Csbnd H⋯π interactions in hierarchical supramolecular assembly of tartaric anhydrides - Tartaric acid and its O-acyl derivatives: Part 11

    Madura, Izabela D.; Zachara, Janusz; Hajmowicz, Halina; Synoradzki, Ludwik

    2012-06-01

    The detailed analysis of molecular and crystal structure of the O-acyltartaric anhydrides is presented. The role of both intra- and intermolecular weak interactions is discussed. The Hirshfeld surfaces analysis in form of dnorm representation and decomposed finger print plots was used to find out the types of weak but directional carbonyl-carbonyl, Csbnd H⋯O and Csbnd H⋯π interactions. The major interactions at the subsequent levels of the crystal architecture were identified. The interplay between carbonyl-carbonyl interactions and Csbnd H⋯O hydrogen bonds both at the molecular level as well as in basic supramolecular motives was analyzed. In all cases the primary supramolecular motif was found to be the ribbon showing the p21 rod group symmetry. The key role of the ribbon motif is reflected in the hexagonal packing of rods.

  19. Thermal degradation of cold cured anthracite/coke breeze briquettes prepared from a coal tar acid resin

    Thoms, L.J.; Snape, C.E.; Taylor, D.; Mullens, J.; Mullens, S. [University of Strathclyde, Glasgow (United Kingdom). Department of Pure & Applied Chemistry

    1999-07-01

    Phenolic resoles were synthesised using a coal tar acid fraction of the oil from a low temperature carbonisation process. Anthracite/coke breeze briquettes were prepared using the tar acid resoles. Thermogravimetric analysis-mass spectrometry of products and combustion of briquettes are described. 4 refs., 1 tab.

  20. Characterization of the curing agents used in epoxy resins with TG/FT-IR technique

    Benedita M. V. Romão; Milton F. Diniz; Margarete F. P. Azevedo; Vera L. Lourenço; Luiz C. Pardini; Rita de C. L. Dutra; Fabrice Burel

    2006-01-01

    Samples of epoxy resin (EP) based on the diglycidyl ether of bisphenol A (DGEBA), cured with nadic methyl anhydride (NMA) and mercaptan (CAPCURE 3-800), or amine-phenol (CAPCURE EH-30), respectively, SE 4 and SE 5, were prepared in the stoichiometric ratio determined by the supplier. The curing behaviour of the epoxy systems SE 4 and SE 5 was followed by DSC (Differential Scanning Calorimetry). These SE and their ingredients were analyzed using FTIR transmission techniques (KBr pellets, pyrol...

  1. Biodegradable Epoxy Networks Cured with Polypeptides

    Nakamura, Shigeo; Kramer, Edward J.

    2006-03-01

    Epoxy resins are used widely for adhesives as well as coatings. However, once cured they are usually highly cross-linked and are not biodegradable. To obtain potentially biodegradable polypeptides that can cure with epoxy resins and achieve as good properties as the conventional phenol novolac hardeners, poly(succinimide-co-tyrosine) was synthesized by thermal polycondensation of L-aspartic acid and L-tyrosine with phosphoric acid under reduced pressure. The tyrosine/succinimide ratio in the polypeptide was always lower than the tyrosine/(aspartic acid) feed ratio and was influenced by the synthesis conditions. Poly(succinimide-tyrosine- phenylalanine) was also synthesized from L-aspartic acid, L- tyrosine and L-phenylalanine. The thermal and mechanical properties of epoxy resins cured with these polypeptides are comparable to those of similar resins cured with conventional hardeners. In addition, enzymatic degradability tests showed that Chymotrypsin or Subtilisin A could cleave cured films in an alkaline borate buffer.

  2. PHOTOCOPOLYMERIZATION OF MALEIC ANHYDRIDE AND VINYL ACETATE

    LI Xiaofang; LI Shanjun; QIN Anwei; YU Tongyin

    1990-01-01

    The charge-transfer complex of maleic anhydride and vinyl acetate was copolymerized under UV light. The chain composition and structure of the copolymer were analyzed with conductometry and NMR, and the chain sequence was determined as alternating. The copolymerization rates at different feed ratios, temperatures and in different solvents were investigated, giving evidence to the very active involvement of the CT complexes in the copolymerization. Terpolymerization with acrylonitrile also showed that the complex mechanism was a proper one for this system.

  3. Effect of maleic anhydride on the physico-mechanical properties of NR/PE blends

    Blending of two or more polymers is considered as a new technique to produce new materials with new properties at low production cost and investment. Rubber / Rubber blends are well known in tire industry. In the last decade rubber and plastic blending attract the interest of many researchers and technologists. In the present work NR and LLDPE was blended in presence of maleic anhydride (MA) on a Brabender premixed at different conditions and namely temperature and time. The obtained blends were cured with sulphur and peroxide curing systems. Peroxide can crosslink both NR and PE, but the sulphur system crosslinks only the rubber phase in the blend. The data showed also that the addition of MA greatly improved the physico-mechanical properties of NR/PE blends. The surface morphology of the blends under investigation was studied by SEM. The results will be presented and discussed in detail

  4. Curing reactions of palm oil alkyd enamels

    Amino resins are the most popularly used cross-linking agents for thermosetting coatings. The most common amino resins are those derived from melamine, 2,4,6-triamino-1,3,5-triazine and formaldehyde. They are attractive for developing high performance and low cost coatings to improve performances of other film-forming resins with reactive functional groups such as hydroxyl, carboxylic, and amide groups. Alkyds modified with melamine are mainly used in industrial baking enamels for metal surfaces. Short-oil alkyds containing 38-45% phthalic anhydride and a high proportion of hydroxyl values in the alkyd resins render good compatibility with melamine-formaldehyde resins. However, the actual mechanisms and pathways of the curing reactions involved are still not fully understood. This paper describes three palm oil alkyds, synthesized with high hydroxyl values. Clear coating enamels were made by mixing 4 parts; of alkyd resin with 1 part of a methylated melamine resin. The complex curing reactions of the clear enamel can be illustrated qualitatively by using DSC (Differential Scanning Calorimeter). Thermogravimetric analysis (TGA) was used to set suitable curing temperatures without degradation. The dry hard time with various curing temperatures was examined. Fourier transform infrared (FTIR) spectroscopy has been used to follow the changes in functional group concentrations as a function of time and temperature. (author)

  5. Properties of Esterified Wood Prepared with Maleic Anhydride / Tetrabr Omophthalic Anhydride / Glycerol Mixture

    Li Jianzhang; Furuno Takeshi; Zhou Wenrui; Yu Zhiming; Sun Yanling; Zhang Derong

    2003-01-01

    For overcoming disadvantages of wood, an esterification process was employed and tetrabromophthalic anhydride (TBPA) was used as a reactive chemical agent to prepare an esterified wood with the high dimensional stability, flame resistance, and resistance to biodegradation from water-leaching. The experimental results indicated that esterification of wood plus maleic anhydride / tetrabromophthalic anhydride / glycerol could endow wood with dimensional stability, the antiswelling efficiency during water absorption (ASEw), reduction in water absorptivity (RWA), antiswelling efficiency during moisture absorption (ASEm), moisture excluding efficiency (MEE), and oxygen index (OI) of treated wood increased with an increase in the weight percent gain (WPG). And the treated wood showed great decay resistance and resistance to water leaching, too.

  6. Novel 4-Arm Poly(Ethylene Glycol)-Block-Poly(Anhydride-Esters) Amphiphilic Copolymer Micelles Loading Curcumin: Preparation, Characterization, and In Vitro Evaluation

    Li Lv; Yuanyuan Shen; Min Li; Xiaofen Xu; Mingna Li; Shengrong Guo; Shengtang Huang

    2013-01-01

    A novel 4-arm poly(ethylene glycol)-block-poly(anhydride-esters) amphiphilic copolymer (4-arm PEG-b-PAE) was synthesized by esterization of 4-arm poly(ethylene glycol) and poly(anhydride-esters) which was obtained by melt polycondensation of α -, ω -acetic anhydride terminated poly(L-lactic acid). The obtained 4-arm PEG-b-PAE was characterized by 1H-NMR and gel permeation chromatography. The critical micelle concentration of 4-arm PEG-b-PAE was 2.38  μ g/mL. The curcumin-loaded 4-arm PEG-b-PA...

  7. Optimization of the DTPA mixed-anhydride reaction with antibodies at low concentration

    Diethylenetriaminepentaacetic acid (DTPA) was conjugated with antibody to human serum albumin (Ab) at low concentration (300 μg/ml, 2.0 μM/ via the DTPA carboxycarbonyl mixed-anhydride method. To study parameters determining the balance between the degree of conjugation and the antibody-binding activaty of Ab, a known concentration of the anhydride prepared at isobutylchloroformate (IBC)-to-DTPA ratios of 1, 2.1, or 4.2 was reacted with Ab. The percentage yields of the anhydride were determined by spectrophotometric and gravimetric titration. By the former method the percentage yields, based on DTPA concentration, were 18, 24, and 220, respectively, when the IBC-to-DTPA ratios were 1, 2.1, and 4.2. The corresponding percentage yields were 17, 39, and 262 when determined by the latter method. When the anhydride was prepared at an IBC-to-DTPA ratio of 2.1, an optimum conjugation giving three indium atoms per Ab was obtained, wtih 64% retention of antibody-binding activity. For an IBC-to-DTPA ratio of 1, the antibody retained almost 100% binding activity but the number of indium atoms incorporated (0.2) was too small. For an IBC-to-DTPA ratio of 4.2, up to 22 indium atoms were incorporated but antibody-binding activity was completely destroyed

  8. Biodistribution in normal mice of an 111In-labelled prostatic acid phosphatase-specific antibody and its F(ab')2 fragments derivatized site-specifically or via bicyclic diethylenetriaminepentaacetic acid anhydride

    We examined the optimization of derivatization of monoclonal antibodies and their fragments intended for use as radiopharmaceutical in radioimaging and/or radioimmunotherapy of prostatic cancer. Two different principles were used to conjugate (DTPA) to a monoclonal antibody (Mab, subclass IgG1) raised against human prostatic acid phosphatase (PAP). In addition, the F(ab')2 fragments of this Mab were also derivatized. The biodistribution of the 111In-labelled derivatives was investigated in normal mice. All the derivatives of IgG1 demonstrated a slower blood clearance than the corresponding derivatives of the F(ab')2 fragments. This property was particularly pronounced in the site-specifically conjugated derivatives of IgG1. All the derivatives studied accumulated in the liver, kidney, and spleen. The CA-DTPA derivatives of F(ab')2 fragments showed the highest kidney-to-blood ratios of radioactivity. The derivatives of IgG1 showed a higher percentage of the injected dose in liver and spleen tissues than the derivatives of the F(ab')2 fragments. The F(ab')2 fragments studied also gave rise to site-specific derivatives, which demonstrated that carbohydrates were also present in this part of the molecule. They behaved similarly to the CA-DTPA F(ab')2 derivative in other respects, but the kidney accumulation was lower at 72 and 120 h. The F(ab')2 fragments studied would be better suited for radioimaging than the derivatives of the IgG1 studied. In contrast, the derivatives of IgG1, especially the p-NH2-Bz-DTPA conjugate, might be more suitable candidates for the development of therapeutic agents. (orig.)

  9. The XPS peak structure of condensed aromatic anhydrides and imides

    Jung, M; Baston, U.; Porwol, T.; Freund, H.-J.; Umbach, E.

    2004-01-01

    Photoelectron spectra of aromatic anhydrides and imides like PTCDA (perylene-tetracarboxylic dianhydride), PTCDI (perylene-tetracarboxylic diimide), and NDCA (naphthalene-dicarboxylic anhydride) on smooth single crystal surfaces show complex double peak structures in both the O1s and the anhydride C1s range. The peak intensity ratios cannot be simply explained by different chemical states of the atoms but are strongly influenced by intense shake-up satellites. Semiempirical SDCI calculations ...

  10. Maleic anhydride grafting on EPDM rubber in the melt

    Oostenbrink, A.J.; Gaymans, R.J.

    1992-01-01

    The grafting of maleic anhydride on a EPDM rubber was studied with a twin screw extruder. The effect of barrel temperatures, throughput, maleic anhydride concentration and peroxide concentration [bis(t-butyl peroxy isopropyl)benzene] on the degree of grafting and melt viscosity was studied. The maleic anhydride concentration was determined by potentiometric titration and a correlation was made with quantitative i.r. analysis.

  11. Diglycerol-based polyesters: melt polymerization with hydrophobic anhydrides.

    Dakshinamoorthy, Deivasagayam; Weinstock, Allison K; Damodaran, Krishnan; Iwig, David F; Mathers, Robert T

    2014-10-01

    The melt polymerization of diglycerol with bicyclic anhydride monomers derived from a naturally occurring monoterpene provides an avenue for polyesters with a high degree of sustainability. The hydrophobic anhydrides are synthesized at ambient temperature via a solvent-free Diels-Alder reaction of α-phellandrene with maleic anhydride. Subsequent melt polymerizations with tetra-functional diglycerol are effective under a range of [diglycerol]/[anhydride] ratios. The hydrophobicity of α-phellandrene directly impacts the swelling behavior of the resulting polyesters. The low E factors (75%), ambient temperature monomer synthesis, and polymer degradability represent key factors in the design of these sustainable polyesters. PMID:25138308

  12. Graft Copolymers of Maleic Anhydride and Its Isostructural Analogues: High Performance Engineering Materials

    Rzayev, Zakir M O

    2011-01-01

    This review summarizes the main advances published over the last 15 years outlining the different methods of grafting, including reactive extruder systems, surface modification, grafting and graft copolymerization of synthetic and natural polymers with maleic anhydride and its isostructural analogues such as maleimides and maleates, and anhydrides, esters and imides of citraconic and itaconic acids, derivatives of fumaric acid, etc. Special attention is spared to the grafting of conventional and non-conventional synthetic and natural polymers, including biodegradable polymers, mechanism of grafting and graft copolymerization, in situ grafting reactions in melt by reactive extrusion systems, in solutions and solid state (photo- and plasma-induced graftings), and H-bonding effect in the reactive blend processing. The structural phenomena, unique properties and application areas of these copolymers and their various modifications and composites as high performance engineering materials have been also described.

  13. Modification of Poly(maleic anhydride-co-styrene) with Hydroxyl Containing Compounds

    ATICI, Oya GALİOĞLU; RAHIMIAN, Ahmet AKAR and Roshan

    2001-01-01

    Soluble and cross-linked poly(maleic anhydride-co-styrene) copolymers were reacted with hydroxyl containing compounds such as salicylic acid, 2-phenyl ethanol, eugenol and paracetamole in acetone or dioxane solution at 50-80°C. The hydrolytic and controlled release behavior of the copolymers containing these compounds in water was studied. The extent of hydrolysis was found to be affected by the type of polymer support as well as time, temperature and the type of supported compound.

  14. Synthesis and physicochemical characterization of chemically modified chitosan by succinic anhydride

    Karine Gargioni Pereira Correa de Mello; Leandra de Cássia Bernusso; Ronaldo Nogueira de Moraes Pitombo; Bronislaw Polakiewicz

    2006-01-01

    The N-succinil-chitosan is a chemically modified derivative of the biopolymer chitosan. The succinic anhydride attached to the free amino groups presented along the chitosan's polymer chain imparts to the molecule different physicochemical properties not exhibited before the modification. These chemical modifications enhance chitosan's solubility in slightly acid, neutral and alkaline media. These properties are related to the long alkyl chains attached to hydrophilic parts. In this case the ...

  15. Immune-spaying as an alternative to surgical spaying in Iberian×Duroc females: effect on quality characteristics and fatty acid profile in dry-cured shoulders and loins.

    Gamero-Negrón, Rafael; Sánchez Del Pulgar, José; García, Carmen

    2015-06-01

    The aim of this study was to assess the effect of immune-spaying on meat quality characteristics and fatty acid profile of dry-cured shoulders and loins by comparing Iberian×Duroc surgically spayed females, immune-spayed females and entire females. There were no significant differences on the physicochemical composition of dry-cured shoulders; however the intramuscular fat content of dry-cured loins was higher in immune-spayed females than entire ones, but not significantly different from spayed females. Immune-spayed females showed the highest values, which could improve the sensory quality of Iberian dry-cured loins, since it is considered an index of high quality. On the other hand, the PUFA content of both dry-cured shoulders and loins proved to be lower in immune-spayed than spayed females, which could prevent excessive fat oxidation responsible for rancidity. Therefore, immune-spaying could be a viable alternative to surgical spaying from the meat quality point of view. PMID:25697853

  16. Maleic anhydride grafting on EPDM rubber in the melt

    Oostenbrink, A.J.; Gaymans, R.J.

    1992-01-01

    The grafting of maleic anhydride on a EPDM rubber was studied with a twin screw extruder. The effect of barrel temperatures, throughput, maleic anhydride concentration and peroxide concentration [bis(t-butyl peroxy isopropyl)benzene] on the degree of grafting and melt viscosity was studied. The male

  17. Controlled Release of Damascone from Poly(styrene-co-maleic anhydride)-based Bioconjugates in Functional Perfumery

    Andreas Herrmann; Wolfgang Fieber; Damien L. Berthier; Alain Trachsel; Nicolas Paret

    2013-01-01

    Poly(styrene-co-maleic anhydride)s were modified with poly(propylene oxide (PO)-co-ethylene oxide (EO)) side chains (Jeffamine®) with different EO/PO molar ratios, varying between 0.11 and 3.60. These copolymers were then further functionalized with a β-mercapto ketone of δ-damascone. The obtained poly(maleic acid monoamide)-based β-mercapto ketones were then studied as delivery systems for the controlled release of δ-damascone by retro 1,4-addition. The release of δ-damascone, a volatile, bi...

  18. Urea- Hydrogen Peroxide (UHP Oxidation of Thiols to the Corresponding Disulfides Promoted by Maleic Anhydride as Mediator

    M. H. Habibi

    2005-10-01

    Full Text Available Urea-hydrogen peroxide (UHP was used in the presence of maleic anhydride as mediator in a simple and convenient method for the oxidation in high yield of some thiols to the corresponding disulfides. Peroxymaleic acid formed in situ from the reaction of UHP with maleic anhydride has a key role in this oxidation. Performance of the reaction in various solvents showed that methanol was the solvent of choice at 0 oC. The products were isolated by simple filtration on silica gel.

  19. Urea- Hydrogen Peroxide (UHP) Oxidation of Thiols to the Corresponding Disulfides Promoted by Maleic Anhydride as Mediator

    M. H. Habibi; M. Montazerozohori; Bahador Karami

    2005-01-01

    Urea-hydrogen peroxide (UHP) was used in the presence of maleic anhydride as mediator in a simple and convenient method for the oxidation in high yield of some thiols to the corresponding disulfides. Peroxymaleic acid formed in situ from the reaction of UHP with maleic anhydride has a key role in this oxidation. Performance of the reaction in various solvents showed that methanol was the solvent of choice at 0 oC. The products were isolated by simple filtration on silica gel.

  20. Co-administration of glycyrrhizic acid with the antileishmanial drug sodium antimony gluconate (SAG) cures SAG-resistant visceral leishmaniasis.

    Bhattacharjee, Amrita; Majumder, Saikat; Majumdar, Suchandra Bhattacharyya; Choudhuri, Soumitra Kumar; Roy, Syamal; Majumdar, Subrata

    2015-03-01

    Since there are very few affordable antileishmanial drugs available, antimonial resistance has crippled antileishmanial therapy, thereby emphasising the need for development of novel therapeutic strategies. This study aimed to evaluate the antileishmanial role of combined therapy with sodium antimony gluconate (SAG) and the triterpenoid glycyrrhizic acid (GA) against infection with SAG-resistant Leishmania (GE1F8R). Combination therapy with GA and SAG successfully limited infection with SAG-resistant Leishmania in a synergistic manner (fractional inhibitory concentration index resistant Leishmania and co-treated with GA and SAG exhibited a significant reduction in hepatic and splenic parasite burden. In probing the mechanism, it was observed that GA treatment suppressed the expression and efflux activity of P-glycoprotein (P-gp) and multidrug resistance-associated protein 1 (MRP1), two host ABC transporters responsible for antimony efflux from host cells infected with SAG-resistant parasites. This suppression correlated with greater intracellular antimony retention during SAG therapy both in vitro and in vivo, which was reflected in the reduced parasite load. Furthermore, co-administration of GA and SAG induced a shift in the cytokine balance towards a Th1 phenotype by augmenting pro-inflammatory cytokines (such as IL-12, IFNγ and TNFα) and inducing nitric oxide generation in GE1F8R-infected macrophages as well as GE1F8R-infected mice. This study aims to provide an affordable leishmanicidal alternative to expensive antileishmanial drugs such as miltefosine and amphotericin B. Furthermore, this report explores the role of GA as a resistance modulator in MRP1- and P-gp-overexpressing conditions. PMID:25600891

  1. Réaction du polyisobutène chloré sur l'anhydride maléique : mécanisme. Catalyse par l'anhydride dichloromaléique Reaction of Chlorinated Polyisobutene on Maleic Anhydride. Mechanism. Catalysis by Dichloromaleic Anhydride

    Sillion B.; Weill J.

    2006-01-01

    Dans cet article le mécanisme de la réaction de condensation du polyisobutène chloré sur l'anhydride maléique, qui sert dans la synthèse d'additif pour lubrifiant, est étudié par une cinétique globale et par un travail sur composés modèles. Il est montré que, dans cette réaction, l'anhydride maléique joue un double rôle : de catalyseur de déshydrochloration par une réactivité de type acide de Lewis organique, de réactif comme diénophile. Grâce à ces résultats, il est proposé une catalyse par ...

  2. Synthesis and Characterization of Poly(maleic Anhydride)s Cross-linked Polyimide Aerogels

    Guo, Haiquan; Meador, Mary Ann B.

    2015-01-01

    With the development of technology for aerospace applications, new thermal insulation materials are required to be flexible and capable of surviving high heat flux. For instance, flexible insulation is needed for inflatable aerodynamic decelerators which are used to slow spacecraft for entry, descent and landing (EDL) operations. Polyimide aerogels have low density, high porosity, high surface area, and better mechanical properties than silica aerogels and can be made into flexible thin films, thus they are potential candidates for aerospace needs. The previously reported cross-linkers such as octa(aminophenyl)silsesquioxane (OAPS) and 1,3,5-triaminophenoxybenzene (TAB) are either expensive or not commercially available. Here, we report the synthesis of a series of polyimide aerogels cross-linked using various commercially available poly(maleic anhydride)s, as seen in Figure 1. The amine end capped polyimide oligomers were made with 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA) and diamine combinations of dimethylbenzidine (DMBZ) and 4, 4-oxydianiline (ODA). The resulting aerogels have low density (0.12 gcm3 to 0.16 gcm3), high porosity (90) and high surface area (380-554 m2g). The effect of the different poly(maleic anhydride) cross-linkers and polyimide backbone structures on density, shrinkage, porosity, surface area, mechanical properties, moisture resistance and thermal properties will be discussed.

  3. Adsorption of maleic anhydride on Pt(111)

    Sinha, Godhuli; Heikkinen, Olli; Vestberg, Matias; Mether, Lotta; Nordlund, Kai; Lahtinen, Jouko

    2014-02-01

    The surface chemistry of maleic anhydride (MA) has been studied on Pt(111) with temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations. Adsorption of MA takes place at 170 K forming multilayers. We have studied the behavior of distinct carbon and oxygen species of MA depending on the surface temperature. MA-TPD indicates three main desorption temperatures; at 240 K, approximately 60% of total MA on the surface shows molecular desorption. At high temperatures (360 and 550 K) MA shows dissociative decomposition with production of C2H2, CO and CO2 fragments. A plausible decomposition pathway of MA on the Pt(111) surface is discussed. DFT calculations provide details of the adsorption geometry.

  4. PRELIMINARY STUDY OF EXTRACTABLE PROTEIN BINDING USING MALEIC ANHYDRIDE COPOLYMER

    Thirawan Nipithakul; Ladawan Watthanachote; Nanticha Kalapat

    2012-01-01

    A preliminary study of using maleic anhydride copolymer for protein binding has been carried out.The polymeric films were prepared by compression of the purified resin and annealing the film to induce efficient back formation of the anhydride groups.The properties of the film surface were analyzed by attenuated total reflection Fourier transforms infrared spectroscopy and water contact angle measurements.The protein content was determined by Bradford assay.To obtain optimum conditions,immersion time for protein binding was examined.Results revealed that proteins can be successfully immobilized onto the film surface via covalent linkage.The efficiency of the covalent binding of the extractable protein to maleic anhydride-polyethylene film was estimated at 69.87 μtg/cm2,although the film had low anhydride content (3%) on the surface.

  5. Effect of Hops Beta Acids on the Survival of Unstressed- or Acid-Stress-Adapted-Listeria Monocytogenes and on the Quality and Sensory Attributes of Commercially Cured Ham Slices.

    Wang, Li; McKeith, Amanda Gipe; Shen, Cangliang; Carter, Kelsey; Huff, Alyssa; McKeith, Russell; Zhang, Xinxia; Chen, Zhengxing

    2016-02-01

    This study evaluated the antilisterial activity of hops beta acids (HBA) and their impact on the quality and sensory attributes of ham. Commercially cured ham slices were inoculated with unstressed- and acid-stress-adapted (ASA)-L. monocytogenes (2.2 to 2.5 log CFU/cm(2) ), followed by no dipping (control), dipping in deionized (DI) water, or dipping in a 0.11% HBA solution. This was followed by vacuum or aerobic packaging and storage (7.2 °C, 35 or 20 d). Samples were taken periodically during storage to check for pH changes and analyze the microbial populations. Color measurements were obtained by dipping noninoculated ham slices in a 0.11% HBA solution, followed by vacuum packaging and storage (4.0 °C, 42 d). Sensory evaluations were performed on ham slices treated with 0.05% to 0.23% HBA solutions, followed by vacuum packaging and storage (4.0 °C, 30 d). HBA caused immediate reductions of 1.2 to 1.5 log CFU/cm(2) (P color or sensory attributes of the ham slices stored in vacuum packages. These results are useful for helping ready-to-eat meat processors develop operational procedures for applying HBA on ham slices. PMID:26748557

  6. Sensitivity of Neurospora crassa to a Marine-Derived Aspergillus tubingensis Anhydride Exhibiting Antifungal Activity That Is Mediated by the MAS1 Protein

    Liat Koch

    2014-09-01

    Full Text Available The fungus Aspergillus tubingensis (strain OY907 was isolated from the Mediterranean marine sponge Ircinia variabilis. Extracellular extracts produced by this strain were found to inhibit the growth of several fungi. Among the secreted extract components, a novel anhydride metabolite, tubingenoic anhydride A (1 as well as the known 2-carboxymethyl-3-hexylmaleic acid anhydride, asperic acid, and campyrone A and C were purified and their structure elucidated. Compound 1 and 2-carboxymethyl-3-hexylmaleic acid anhydride inhibited Neurospora crassa growth (MIC = 330 and 207 μM, respectively and affected hyphal morphology. We produced a N. crassa mutant exhibiting tolerance to 1 and found that a yet-uncharacterized gene, designated mas-1, whose product is a cytosolic protein, confers sensitivity to this compound. The ∆mas-1 strain showed increased tolerance to sublethal concentrations of the chitin synthase inhibitor polyoxin D, when compared to the wild type. In addition, the expression of chitin synthase genes was highly elevated in the ∆mas-1 strain, suggesting the gene product is involved in cell wall biosynthesis and the novel anhydride interferes with its function.

  7. Study of the structure and the mechanical properties of dynamically cured PP/MAH-g-SEBS/epoxy blends

    Xue Liang Jiang; Yin Xi Zhang

    2009-01-01

    A new method concerning with the simultaneous reinforcing and toughening of polypropylene (PP) was reported. Dynamical cure of the epoxy resin was successfully applied in the PP/maleic anhydride-grafted styrene--ethylene-butylene-styrene (SEBS) triblock copolymer, and the obtained blends named as dynamically cured PP/MAH-g-SEBS/epoxy blends. The stiffness and toughness of the blends are in a good balance, and MAH-g-SEBS was acted as not only an impact modifier but also a compatibilizer. The structure of the dynamically cured PP/MAH-g-SEBS/epoxy blends is the embedding of the epoxy particles by the MAH-gSEBS.

  8. Grafting and curing

    Progress in radiation grafting and curing is briefly reviewed. The two processes are shown to be mechanistically related. The parameters influencing yields are examined particularly for grafting. For ionising radiation grafting systems (EB and gamma ray) these include solvents, substrate and monomer structure, dose and dose-rate, temperature and more recently role of additives. In addition, for UV grafting, the significance of photoinitiators is discussed. Current applications of radiation grafting and curing are outlined. The recent development of photoinitiator free grafting and curing is examined as well as the potential for the new excimer laser sources. The future application of both grafting and curing is considered, especially the significance of the occurrence of concurrent grafting during cure and its relevance in environmental considerations

  9. Synthesizing Process and Application of Methyl Nadic Anhydride%甲基纳迪克酸酐合成工艺及应用概述

    陈洪军; 周飞; 黄勇

    2012-01-01

    Methyl Nadic Anhydride is an important downstream product of methyl cyclopentadiene, which is a high performance liquid anhydride epoxy resin curing agent, and is widely used as electrical insulating material. The synthesizing process and application research of methyl nadie anhydride were introduced, and the market was prospected to provide reference for development of methyl nadie anhydride industry.%甲基纳迪克酸酐是甲基环戊二烯下游重要产品,是一种性能优良的液态酸酐类环氧树脂固化剂,广泛应用于电器绝缘材料。文章对甲基纳迪克酸酐的合成工艺及应用研究进行了介绍,对市场前景进行了展望,以期为甲基纳迪克酸酐产业的发展提供参考。

  10. Synthesis and cure behaviors of diglycidylether of bisphenol-S epoxy resins

    Park, S.J.; Jin, F.L.; Lee, J.R. [Korea Research Institute of Chemical Technology, Taejon (Korea); Shin, J.S. [Chungbuk National University, Chongju (Korea)

    2002-07-01

    In this work, diglycidylether of bisphenol-S (DGEBS) epoxy resin was prepared by alkaline condensation of bisphenol-S (BPS) with epichlorohydrin (ECH) in the presence of NaOH catalyst. The structure of the synthesized DGEBS epoxy resin was confirmed by IR, NMR spectra, and elemental analysis. The curing reaction and glass transition temperature (T{sub g}) of DGEBS epoxy resin cured with phthalic anhydride (PA) and tetrahydrophthalic anhydride (THPA) as curing agents were studied by dynamic differential scanning calorimetry (DSC). The thermal stability of the cured specimen was investigated by thermogravimetric analysis (TGA), As a result, the activation energy (E{sub a}) of DGEBS/PA system was higher than that of DGEBS/THPA system, whereas T{sub g}, initial decomposed temperature (IDT), and decomposition activation energy (E{sub t}) of DGEBS/PA were lower than those of DGEBS/THPA. This was probably due to the fact that the crosslinking density of DGEBS/THPA was increased by ring strain of curing agent. (author). 22 refs., 4 tabs., 8 figs.

  11. Preparation and Crystallization of Carbon Nanotube/maleic Anhydride-grafted Polypropylene Composites

    Xiaohua CHEN; Jing HU; Lingping ZHOU; Wenhua LI; Zi YANG; Yanguo WANG

    2008-01-01

    Carbon nanotube (CNT)/maleic acid anhydride (MAH)-grafted polypropylene (PP) composites were prepared by in situ grafting method. Infrared spectroscopy showed that the CNTs were linked to PP by MAH grafting. The microstructures and calorimetry analysis indicated that the crystallization behaviors of the filled and unfilled PP were quite different. The addition of CNTs dramatically reduced the spherulite size, increased crystallization rate and improved the thermal stability of PP. These results confirmed the expected nucleant effect of CNT on the crystallization of PP. Scanning and transmission electron microscopy showed that the CNTs were dispersed homogeneously, indicating that the original CNT bundles were separated into individual tubes by the grafting.

  12. High Flow Addition Curing Polyimides

    Chuang, Kathy C.; Vannucci, Raymond D.; Ansari, Irfan; Cerny, Lawrence L.; Scheiman, Daniel A.

    1994-01-01

    A new series of high flow PMR-type addition curing polyimides was developed, which employed the substitution of 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (BTDB) for p-phenylenediamine (p -PDA) in a PMR-IL formulation. These thermoset polyimides, designated as 12F resins, were prepared from BTDB and the dimethyl ester of 4,4'- (hexafluo- roisopropylidene) -diphthalic acid (HFDE) with either nadic ester (NE) or p-aminostyrene (PAS) as the endcaps for addition curing. The 12F prepolymers displayed lower melting temperatures in DSC analysis, and higher melt flow in rheological studies than the cor- responding PMR-11 polyimides. Long-term isothermal aging studies showed that BTDB- based 12F resins exhibited comparable thermo-oxidative stability to P-PDA based PMR-11 polyimides. The noncoplanar 2- and 2'-disubstituted biphenyldiamine (BTDB) not only lowered the melt viscosities of 12F prepolymers, but also retained reasonable thermal sta- bility of the cured resins. The 12F polyimide resin with p-aminostyrene endcaps showed the best promise for long-term, high-temperature application at 343 C (650 F).

  13. One-pot synthesis of thermoplastic mixed paramylon esters using trifluoroacetic anhydride.

    Shibakami, Motonari; Tsubouchi, Gen; Sohma, Mitsugu; Hayashi, Masahiro

    2015-03-30

    Mixed paramylon esters prepared from paramylon (a storage polysaccharide of Euglena), acetic acid, and a long-chain fatty acid by one-pot synthesis using trifluoroacetic anhydride as a promoter and solvent were shown to have thermoplasticity. Size exclusion chromatography indicated that the mixed paramylon esters had a weight average molecular weight of approximately 4.9-6.7×10(5). Thermal analysis showed that these esters were stable in terms of the glass transition temperature (>90°C) and 5% weight loss temperature (>320°C). The degree of substitution of the long alkyl chain group, a dominant factor determining thermoplasticity, was controlled by tuning the feed molar ratio of acetic acid and long-chain fatty acid to paramylon. These results implied that the one-pot synthesis is useful for preparing structurally-well defined thermoplastic mixed paramylon esters with high molecular weight. PMID:25563938

  14. Rubber curing chemistry governing the orientation of layered silicate

    2007-11-01

    Full Text Available The effect of curing systems on the orientation and the dispersion of the layered silicates in acrylonitrile butadiene rubber nanocomposite is reported. Significant differences in X-ray diffraction pattern between peroxide curing and sulfur curing was observed. Intense X-ray scattering values in the XRD experiments from peroxide cured vulcanizates indicate an orientation of the layers in a preferred direction as evinced by transmission electron micrographs. However, sulfur cured vulcanizates show no preferential orientation of the silicate particles. Nevertheless, a closer inspection of transmission electron microscopy (TEM images of peroxide and sulfur cured samples shows exfoliated silicate layers in the acrylonitrile butadiene rubber (NBR matrix. It was revealed in the prevailing study that the use of an excess amount of stearic acid in the formulation of the sulfur curing package leads to almost exfoliated type X-ray scattering pattern.

  15. Synthesis and uranyl ion adsorption study of cross-linked allyl propionate-maleic anhydride-styrene terpolymer

    AKPEROV, Elchin; MAHARRAMOV, Abel; AKPEROV, Oktay

    2010-01-01

    Allyl propionate-maleic anhydride-styren terpolymer has been modified with glycerin in order to prepare a new cross-linked functional polymer sorbent. The synthesized cross-linked polymer sorbent has a network structure and contains carboxylic acid, carbonyl, hydroxy, and ester groups, all of which are capable ofinteracting with metal ions. The sorption behavior of UO22+ ions under optimum sorption conditions was determined. The sorption properties of the sorbent were determined unde...

  16. Curing metastatic testicular cancer

    Einhorn, Lawrence H.

    2002-01-01

    Our initial studies with cisplatin + vinblastine + bleomycin began 27 years ago in 1974, changing the cure rate for disseminated disease from 5 to 60%. Subsequently, through random prospective clinical trials, we have modified the treatment regimen to reduce both the duration and dosages of the chemotherapy drugs. Cisplatin + etoposide was first used at Indiana University as salvage chemotherapy in 1978, representing the first time that a solid tumor had been cured with second-line chemothera...

  17. Cationic concentration effects on electron beam cured of carbon-epoxy composites

    Electron beam (e-beam) curing is a technology that offers advantages over the thermal curing process, that usually requires high temperature and are time-consuming. E-beam curing is faster and occurs at low temperatures that help reduce residual mechanical stresses in a thermoset composite. The aim of the present study is to analyze the effects of cationic initiator (diaryliodonium hexafluoroantimonate) ranged from 1 to 3 wt% in DGEBA (diglycidyl ether of bisphenol A) epoxy resin when cured by a 1.5 MeV electron beam. The specimens were cured to a total dose of 200.4 kGy for 40 min. Analyses by dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC) show that the e-beam irradiated samples with 2 wt% cationic initiator were 96% cured obtained a glass transition temperature (tan δ) of 167 deg. C. The same epoxy resin, thermally cured for 16 h with an anhydride hardener, reached a Tg (tan δ) of 136 deg. C. So, the irradiated sample had its Tg increased approximately 20% and the curing process was much less time consuming.

  18. Cationic concentration effects on electron beam cured of carbon-epoxy composites

    Nishitsuji, D.A., E-mail: delmo_amari@yahoo.com.b [Brazilian Navy Technological Center, Sao Paulo (Brazil); Marinucci, G. [Brazilian Navy Technological Center, Sao Paulo (Brazil); Energetic and Nuclear Research Institute-IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242-Cidade Universitaria, 05508-000 Sao Paulo/SP (Brazil); Evora, M.C. [Institute of Advanced Studies/CTA, Sao Jose dos Campos/SP (Brazil); Silva, L.G.A. [Energetic and Nuclear Research Institute-IPEN-CNEN/SP, Av. Prof. Lineu Prestes, 2242-Cidade Universitaria, 05508-000 Sao Paulo/SP (Brazil)

    2010-03-15

    Electron beam (e-beam) curing is a technology that offers advantages over the thermal curing process, that usually requires high temperature and are time-consuming. E-beam curing is faster and occurs at low temperatures that help reduce residual mechanical stresses in a thermoset composite. The aim of the present study is to analyze the effects of cationic initiator (diaryliodonium hexafluoroantimonate) ranged from 1 to 3 wt% in DGEBA (diglycidyl ether of bisphenol A) epoxy resin when cured by a 1.5 MeV electron beam. The specimens were cured to a total dose of 200.4 kGy for 40 min. Analyses by dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC) show that the e-beam irradiated samples with 2 wt% cationic initiator were 96% cured obtained a glass transition temperature (tan delta) of 167 deg. C. The same epoxy resin, thermally cured for 16 h with an anhydride hardener, reached a T{sub g} (tan delta) of 136 deg. C. So, the irradiated sample had its T{sub g} increased approximately 20% and the curing process was much less time consuming.

  19. Crystallo-chemistry of boric anhydride and of anhydrous borates

    After an overview of various aspects related to the atomic structure of boron and of its three-bind and four-bind compounds, this report briefly presents the different forms of boric anhydride (in solid, liquid, glassy and gaseous state), presents and comments the structure of these different forms, and addresses the molten boric anhydride which is used as oxide solvent. The next part addresses the structure of anhydrous borates. It presents some generalities on their structure, and describes examples of known structures: dimers, trimers, polymers with a degree higher than three like calcium metaborate, caesium tri-borate, lithium tetraborate, or potassium pentaborate

  20. Completion Of Technology And Equipment For Recovery Of Yellowcake From Pa-lua Sandstone Ores By Mixing And Curing With Strong Acid And Ion Exchange

    Based on data obtained from previous techno-scientific researches in the ITRRE, and experiences learnt from other countries, a project entitled Completion of technology and equipment for recovery of yellowcake from Pa Lua sandstone ores by mixing and curing and ion exchange was conducted and completed. In this project, a technological process was introduced for processing sandstone ores in Pa Lua area on a relatively synchronized equipment system from ore preparation, leaching, ion exchange and precipitation. According to this process, efficiency of uranium recovery is around 76% and quality of yellowcake can be up to 80% U3O8. Operational procedures in each section of the process are simple and easily carried out. In comparison to the previous researches, the major improvements of this process are in the two main sections that are mixing and curing and ion exchange. In the section of mixing and curing, moisture content of the ore during mixing is reduced to 6.6% to ensure an adequate porosity to move it directly to the heap. Replacing the oxidizing agent KClO3 by MnO2 powder helps to prevent generation of chlorine gas which causes direct impacts to workers' health and the environment. It is the first time that the option of spraying water on the ore surface has been used to ensure the even distribution of solution. To treat leached solution, a continuous ion exchange system with a capacity of 20 l/hr was successfully designed, produced and effectively tried. Technological parameters in the sections of adsorption and elution were calculated. Operational procedure for ensuring high rate of uranium recovery and levels of enrichment and purification of the solution was developed. A synchronized equipment system with a relatively reasonable scope and capacity was set up. Yield of the whole process depends on the yield of leaching section. (author)

  1. Cepljenje malein anhidrida na polipropilen: Grafting of maleic anhydride onto polypropylene:

    Dimitrievski, Ilija; Malavašič, Tatjana; Šebenik, Anton; Trček, Urška

    1995-01-01

    The reaction of grafting of maleic anhydride onto polypropylene has been investigated in a Brabender Plasticorder. The effect of temperature, concentration of added maleic anhydride and concentration of added initiator on torque and on the concentration of bound maleic anhydride were studied. The products were analysed by FT-IR and NMR spectroscopy and the content of the bound maleic anhydride was determined by titration. Reakcijo ceplenja malein anhidrida (MAH) na polipropilen (PP) smo pr...

  2. Dissolution of paracetamol crystallized in the presence of poly(vinyl acetate-co-maleic anhydride)

    Raval D; Parikh D; Patel V

    2006-01-01

    Copolymer of vinyl acetate and maleic anhydride, poly (vinyl acetate-co-maleic anhydride) was prepared by precipitation polymerization and characterized. Paracetamol was crystallized in presence of different concentrations of poly (vinyl acetate-co-maleic anhydride). Crystals were characterized by sieve analysis, solubility and dissolution study. Crystallization of paracetamol in presence of poly (vinyl acetate-co-maleic anhydride) caused a marked enhancement in its dissolution rate with incr...

  3. Radiation curing in the eighties

    The subject is discussed under the headings: introduction; what is radiation curing; history; radiation curable resins (with properties of products); ultraviolet and electron beam curing; photoinitiation and the ultraviolet light curing process; electron beam curing (initiation; electron beam accelerators); end uses (graphic arts; wood finishing; paper upgrading; adhesives; metal finishing; electronic chemical; floor coatings). (U.K.)

  4. 21 CFR 177.1820 - Styrene-maleic anhydride copolymers.

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Styrene-maleic anhydride copolymers. 177.1820 Section 177.1820 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and Repeated...

  5. Properties Study of Epoxy/Anhydride Impregnating Resin with Low Viscosity%低粘度环氧/酸酐浸渍树脂性能研究

    曾亮; 黄友根; 朱伟; 高敬民; 姜其斌; 李鸿岩; 李强军

    2014-01-01

    采用不同牌号及纯度的双酚F和双酚A环氧树脂与甲基六氢苯酐制备成环氧/酸酐浸渍树脂,对比研究了不同环氧树脂对环氧/酸酐浸渍体系的粘度、贮存稳定性、固化物力学性能及电性能的影响。结果表明:在无稀释剂条件下,由双酚F配制的浸渍树脂起始粘度低于双酚A环氧配制的浸渍树脂,且环氧树脂纯度越高、有机氯离子含量越少,对浸渍树脂贮存稳定性和固化反应的影响越小,得到的固化物电性能越好。%An epoxy/anhydride impregnating resin was prepared using different types and purity of bisphe-nol F and bisphenol A epoxy resin and methyl hexahydrophthalic anhydride, and the effects of different epoxy on the viscosity and storage stability of the epoxy/anhydride impregnating resin, mechanical proper-ties and dielectric properties of the cured resin were studied. The results show that the viscosity of the impregnating resin prepared by bisphenol F epoxy resin is lower than that of the impregnating resin pre-pared by bisphenol A epoxy resin without diluent. The more the purity of epoxy resin and the less the content of organic chlorine, the less the influence on the storage stability and curing reaction of the im-pregnating resin, and the better the electrical properties of the cured resin is.

  6. Let's Cure Cancer!

    Morrison, Wallace; Schneider, Jessica; Amass, Sandra F

    2012-01-01

    From ancient Egypt to modern times, scientists have been learning new ways to prevent, diagnose, and treat cancer. In this book, you’ll learn about cancer and how veterinarians, veterinary technicians, physicians, and other scientists are working together to find a cure for cancer in people and their pets.

  7. Radiation curing of polymers

    Papers are presented on the surface coating applications, techniques and chemistry of radiation curing of polymers using ultraviolet, electron beam and laser radiation sources. Areas covered include printing, lacquers, wood finishes, adhesives and plastics. New work on photoinitiators is reported. (U.K.)

  8. Characterization of the curing agents used in epoxy resins with TG/FT-IR technique

    Benedita M. V. Romão

    2006-06-01

    Full Text Available Samples of epoxy resin (EP based on the diglycidyl ether of bisphenol A (DGEBA, cured with nadic methyl anhydride (NMA and mercaptan (CAPCURE 3-800, or amine-phenol (CAPCURE EH-30, respectively, SE 4 and SE 5, were prepared in the stoichiometric ratio determined by the supplier. The curing behaviour of the epoxy systems SE 4 and SE 5 was followed by DSC (Differential Scanning Calorimetry. These SE and their ingredients were analyzed using FTIR transmission techniques (KBr pellets, pyrolysis without control and controlled pyrolysis-FT-IR, the CONTROLPIR/FT-IR for characterizing the curing agents (CA. The temperature range used for samples pyrolysis was found from TG (thermogravimetry. Thus, the FT-IR bands of liquid pyrolysate obtained by CONTROLPIR/FT-IR were evaluated, in comparison to the reference spectrum of CA. The characterization of CA was also possible, by the analysis of such SE with the TG/FT-IR technique.

  9. Curing Efficacy of Light Emitting Diodes of Dental Curing Units

    2009-01-01

    Background and aims The aim of the present study was to compare the efficacy of quartz tungsten halogen (QTH) and light emitting diode (LED) curing lights on polymerization of resin composite. Materials and methods A hybrid resin composite was used to prepare samples which were cured using two QTH and ten LED light curing sources. Twelve groups, each containing ten samples, were prepared using each light source. The cured depth of the resin was determined using ISO 4049 method and Vickers har...

  10. Characterization of electron beam cured epoxy acrylate

    Epoxy resin has wide application in various industrial fields because of their good mechanical strength, superiority adhesion and low shrinkage etc. And the typical curing method for epoxy resins is thermal and press compaction. However, a curing method was used electron beam process in this study. Epoxy acrylate was fabricated from mixture of epoxy, acrylic acid, tetraphenylporphyrin (TPP) and hydroquinone monomethyl ether (MEHQ) with mole ratios. Then electron beam irradiation effect on the curing of the epoxy acrylate resin was investigated various absorption dose in nitrogen atmospheres at room temperature. The dynamic mechanical and thermal properties of the irradiated epoxy acrylate resins were characterized using dynamic mechanical analysis (DMA) and thermogravimetric analyzer (TGA). And the tensile and flexural strength were measured by an universal tensile machine (UTM)

  11. Cure of skin cancer. Surgical cure of skin cancer

    In this chapter authors studied the cure of skin cancer in particular the surgical cure of skin cancer. They noted that surgical cure of skin cancer is remain one of the primary and most important methods in treatment of skin cancer

  12. CHARACTERIZATION AND THERMAL STABILITY OF PMR POLYIMIDES USING 7-OXA-BICYCLO[2,2,1]HEPT-5-ENE-2, 3-DICARBOXYLIC ANHYDRIDE AS END CAPS

    Chen-liang Gong; Yan-feng Li; Hai-xia Yang; Xiao-long Wang; Shu-jiang Zhang; Shi-yong Yanga

    2011-01-01

    An anhydride monomer containing ether oxide bridge,7-oxa-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic anhydride (ONA),was successfully synthesized by Diels-Alder reaction of furan and maleic anhydride.The ONA was also studied as an end-cap for the polymerization of monomer reactant (PMR) type polyimides.Three molecular weight levels of the ONA end-capped PMR resins were evaluated.The effects of process conditions of these novel PMR resins on thermal and mechanical properties were investigated.It was demonstrated that the imidized prepolymers using the end-cap have good processability,and the cured polyimide specimens exhibited good thermal stability.The initial decomposition temperature,Td (ca.580℃) and glass transition temperature,Tg (330℃) of the novel resin (PI-20),prepared under optimum process conditions,compare favorably with the Td (ca.620℃) and Tg (ca.348℃) of the state-of-the-art resin (PI'-20),respectively.

  13. Relationship of airborne trimellitic anhydride concentrations to trimellitic anhydride--induced symptoms and immune responses

    Eighteen workers exposed to trimellitic anhydride (TMA) powder were evaluated in 1979. Twelve of these workers were available for longitudinal study until 1982. Annual clinical evaluations and serum radioimmunoassays for total antibody binding and specific IgE binding to 125I-TM-HSA were performed. In 1979, five workers had antibody against TM-HSA. Of these, three workers were diagnosed with the late respiratory systemic syndrome (LRSS) and one worker with TMA-induced allergic rhinitis. The LRSS workers had significantly elevated total antibody binding of 125I-TM-HSA and the worker with rhinitis had significantly elevated specific IgE binding of 125I-TM-HSA per milliliter of serum. Although TMA handling was intermittent throughout the year, average airborne dust concentrations from 1974 to 1978 at job stations of the two heaviest TMA-exposed occupations, operator and assistant operator, were 2.1 and 0.82 mg/m3, respectively. After local exhaust ventilation had been improved, average airborne dust concentrations of TMA at the two latter job stations fell to levels of 0.03 and 0.01 mg/m3, respectively, in 1982. The decrease in TMA exposure coincided with a gradual fall in total antibody binding of 125I-TM-HSA per milliliter in 1982 and symptomatic improvement in the three individuals with the LRSS. The continuous low-level exposure of the worker with TMA rhinitis was sufficient to elicit a rise in specific IgE against TM-HSA from 1.1 ng of 125I-TM-HSA bound per milliliter in 1979 to 2.12 in 1982

  14. Relationships of Non-volatile Organic Acids and Higher Fatty Acids in Flue-cured Tobacco with its Other Chemical Components and Smoking Quality%烤烟非挥发有机酸、高级脂肪酸与其他成分及其感官品质的关系

    杜咏梅; 张怀宝; 付秋娟; 徐光军; 商耀; 林建胜

    2011-01-01

    The relationships of non-volatile organic acids and higher fatty acids with routine chemical components, calcium, neutral aroma components and sensory quality of tobacco were studied with 176 flue-cured tobacco samples. The results showed that; 1) Non-volatile organic acids and higher fatty acids closely related to major chemical indexes and aroma components, particularly malonic acid related to total nitrogen, malic acid to calcium, lactic acid to megastigmatrienone, palmitic acid to nicotine, geranylacetone, damascene and megastigmatrienone, linoleic acid + oleic acid to geranylacetone, with higher correlation coefficients and in scatter diagrams fitted to a straight line, or a quadratic, cubic or power curve. 2) The smoking quality of flue-cured tobacco was mainly influenced by malonic acid, oxalic acid, the ratio of total non-volatile organic acids to nicotine, the ratio of malic acid to citric acid, and calcium to malic acid, particularly, malonic acid and the ratio of total non-volatile organic acids to nicotine. The contents of palmiticacid and linoleic acid + oleic acid affected the flavor style and smoking quality significantly. The contents of palmitic acid and linoleic acid + oleic acid and the ratios of total non-volatile organic acids to nicotine and malic acid to citric acid in tobacco leaves of better quality were relatively higher, however, the contents of malonic acid and oxalic acid and the ratio of calcium to malic acid were relatively lower. The contents of palmitic acid and linoleic acid + oleic acid in thick flavor style tobacco were relatively lower.%研究了176份烤烟样品中的非挥发有机酸、高级脂肪酸含量与其常规化学成分、钙、中性致香成分和吸食品质的关系.结果表明:非挥发有机酸、高级脂肪酸均与烤烟主要化学指标及香气成分相关关系密切,尤其是丙二酸与总氮,苹果酸与钙、乳酸与巨豆三烯酮,棕榈酸与烟碱、香叶基丙酮、二氢大马酮、巨豆

  15. Distance to Cure

    Capachi, Casey

    2013-01-01

    Distance to Cure A three-part television series by Casey Capachi www.distancetocure.com   Abstract   How far would you go for health care? This three-part television series, featuring two introductory segments between each piece, focuses on the physical, cultural, and political obstacles facing rural Native American patients and the potential of health technology to break down those barriers to care.   Part one,Telemedici...

  16. Microwave-assisted addition of azomethines to isatoic anhydride

    E Dominic Jacob; Lopez Mathew; Baby Thomas

    2007-01-01

    Diels-Alder addition of azomethines to isatoic anhydride in a solvent-free and eco-friendly condition is investigated using a microwave oven. The product is exclusively 2,3-diaryl-2,3-dihydroquinazolin-4(1H)-ones 4a-d. HOMO-LUMO energy of the iminoketene and the dienophiles were calculated using semi-empirical AM1 calculations.

  17. Changes in malic acid concentrations of tobacco leaves and the relative enzyme activities during the curing process%烘烤过程中烟叶苹果酸含量及相关代谢酶活性的变化

    宋朝鹏; 全琳; 武圣江; 张勇刚; 宫长荣

    2011-01-01

    【目的】分析烘烤过程中烟叶苹果酸及相关代谢酶活性的变化,为进一步探明烘烤过程中烟叶内在化学成分的变化及调控机制提供理论依据。【方法】以K326、云烟87和豫烟6号为试验材料,研究不同品种烤烟烟叶在烘烤前、烘烤过程中关键温度点(38,42,48,54℃)及烘烤结束后苹果酸、总有机酸含量及苹果酸脱氢酶(MDH)、磷酸烯醇式丙酮酸羧化酶(PEPC)及琥珀酸脱氢酶(SDH)活性的变化,并对总有机酸、苹果酸含量与代谢酶活性的相关性进行分析。【结果】不同品种烤烟的MDH、PEPC和SDH酶活性变化均表现出一定的规律性%【Objective】 The change mechanism of malic acid concentrations and the relative enzyme activities in tobacco leaves during the curing process were analyzed in order to provide a theoretical basis for intensive study of chemical composition change and control mechanism during flue-curd process.【Method】 Research was conducted on the contrast of malic acid and total organic acid content and enzyme activities changes of MDH,PEPC and SDH in different flue-cured tobacco varieties such as K326,Yunyan 87 and Yuyan 6 at different stages(before curing,during curing at 38,42,48,54 ℃ and after curing) and the correlation between enzyme activity and malic acid and total organic acid content was analyzed.【Result】 The MDH,SDH and PEPC enzyme activities of different tobacco varieties showed some regularities.During the flue-cured process,the MDH activity increased first and then decreased and reached its peak at 48 ℃;the PEPC activity first rose and then declined and then rose again,as a whole,the degree of the activity had a ascend trend;the SDH activity steadily declined after 38 ℃ and reached its bottom at 54 ℃.During the curing process,malonic acid content had an up trend and reached its peak at 54℃.Malic acid and total organic acids contents of K326,yunyan 87 and yuyan 6 increased

  18. Accelerated Hazards Mixture Cure Model

    Zhang, Jiajia; Peng, Yingwei

    2009-01-01

    We propose a new cure model for survival data with a surviving or cure fraction. The new model is a mixture cure model where the covariate effects on the proportion of cure and the distribution of the failure time of uncured patients are separately modeled. Unlike the existing mixture cure models, the new model allows covariate effects on the failure time distribution of uncured patients to be negligible at time zero and to increase as time goes by. Such a model is particularly useful in some...

  19. Relaxed Poisson cure rate models.

    Rodrigues, Josemar; Cordeiro, Gauss M; Cancho, Vicente G; Balakrishnan, N

    2016-03-01

    The purpose of this article is to make the standard promotion cure rate model (Yakovlev and Tsodikov, ) more flexible by assuming that the number of lesions or altered cells after a treatment follows a fractional Poisson distribution (Laskin, ). It is proved that the well-known Mittag-Leffler relaxation function (Berberan-Santos, ) is a simple way to obtain a new cure rate model that is a compromise between the promotion and geometric cure rate models allowing for superdispersion. So, the relaxed cure rate model developed here can be considered as a natural and less restrictive extension of the popular Poisson cure rate model at the cost of an additional parameter, but a competitor to negative-binomial cure rate models (Rodrigues et al., ). Some mathematical properties of a proper relaxed Poisson density are explored. A simulation study and an illustration of the proposed cure rate model from the Bayesian point of view are finally presented. PMID:26686485

  20. Novel nonadride, heptadride and maleic acid metabolites from the byssochlamic acid producer Byssochlamys fulva IMI 40021 - an insight into the biosynthesis of maleidrides.

    Szwalbe, Agnieszka J; Williams, Katherine; O'Flynn, Daniel E; Bailey, Andrew M; Mulholland, Nicholas P; Vincent, Jason L; Willis, Christine L; Cox, Russell J; Simpson, Thomas J

    2015-12-14

    The filamentous fungus Byssochlamys fulva strain IMI 40021 produces (+)-byssochlamic acid 1, its novel dihydroanalogue 2 and four related secondary metabolites. Agnestadrides A, 17 and B, 18 constitute a novel class of seven-membered ring, maleic anhydride-containing (hence termed heptadride) natural products. The putative maleic anhydride precursor 5 for both nonadride and heptadride biosynthesis was isolated as a fermentation product for the first time and its structure confirmed by synthesis. Acid 5 undergoes facile decarboxylation to anhydride 6. The generic term maleidrides is proposed to encompass biosynthetically-related compounds containing maleic anhydride moieties fused to an alicyclic ring, varying in size and substituents. PMID:26452099

  1. Designing maleic anhydride-{alpha}-olifin copolymeric combs as wax crystal growth nucleators

    Soni, Hemant P. [Department of Chemistry, Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara-390 002 (India); Kiranbala; Bharambe, D.P. [Department of Applied Chemistry, Faculty of Technology and Engineering, The Maharaja Sayajirao University of Baroda, Vadodara-390 001 (India); Agrawal, K.S. [Department of Petrochemical Technology, Polytechnic, The Maharaja Sayajirao University of Baroda, Vadodara-390 002 (India); Nagar, A. [MH ASSET, ONGC, Mumbai (India)

    2010-09-15

    Modification of the wax crystal habit is of great practical interest during transportation and processing of crude oil at low temperature. Various pour point depressant (PPD) additives can facilitate this modification by different mechanisms. Comb shaped polymer additives are known to depress the pour point of crude oil by providing different nucleation sites for the precipitation of wax. This paper describes performance based design, synthesis, characterization and evaluation of comb shaped polymeric diesters. Copolymers of maleic anhydride with different unsaturated C{sub 22} esters were synthesized and copolymers then reacted with two unsaturated fatty alcohols. All products were characterized by Fourier Transform Infra Red (FTIR) spectroscopy and Gel Permeation Chromatography (GPC). Rheological properties of crude (with and without additive) were studied by Advance Rheometer AR-500. In this study the additive based on oleic acid was evaluated as good PPD and rheology modifier. (author)

  2. 利用顺酐渣合成聚羧酸减水剂的研究%Synthesis of polycarboxylate superplasticizer using maleic anhydride slag

    王景华; 张静; 贾吉堂; 段彬; 张培林; 崔洪友; 王惠忠

    2013-01-01

    顺酐渣是顺酐生产过程产生的副产物,其中主要含有顺酐、顺丁烯二酸和反丁烯二酸等,经研究可用于混凝土外加剂的合成,在烯丙基聚氧乙烯醚(APEG)与顺酐渣(MALS)摩尔比为1.0∶3.0(顺酐渣按有效含量90%、平均相对分子质量110计算)条件下,引发剂过硫酸钾(KPS)的用量为单体总质量的6.0%,链转移剂烯丙基磺酸钠(SAS)的用量为单体总质量的3.5%时,合成的减水剂性能最佳.顺酐渣异构化对合成减水剂的性能基本没有影响,活性炭脱色能在一定程度上提高合成减水剂的性能,但成本较高.顺酐渣合成的减水剂可以1.1倍替代顺酐合成的减水剂,能有效提高合成聚羧酸减水剂的性价比.%Maleic anhydride slag is by-products during maleic anhydride production, which mainly contain maleic anhydride, maleic acid and fumaric acid. Experiments show it can be used in the synthesis of concrete admixtures. The optimal performance of polycarboxylate superplasticizer (PC) was obtained as the molar ratio of monomers n(APEG) :n(MALS) =1.0:3.0 (Effective content of maleic anhydride slag was 90%,and the average molecular weight was calculated by 110). The dosage of sodium methyl allyl sulfonate and potassium persulfate are 3.5% and 6.0% of total monomers by mass. Isomerization of maleic anhydride slag has no influence on PC,Performance of PC can be improved after decolorization but the cost is higher. The PC using maleic anhydride slag can replace that of using maleic anhydride by 1.1 times,which can improve the performance/cost ratio effectively.

  3. 大理烤烟苹果酸含量的空间变异分析%Spatial variability of malic acid content of flue-cured tobacco in Dali

    周喜新; 周冀衡; 武德传; 樊在斗; 李文璧; 杨程

    2011-01-01

    采用GPS定位,在云南大理州主要烟区选取100个采样点,分别于2007、2008年采集C3F烤烟样品各100份.将各取样点2年烤烟样品苹果酸含量的平均值作为原始统计数据,对苹果酸含量的原始数据、对数转化和Box-Cox转换后的数据进行正态分布性检验,采用地统计学进行烤烟苹果酸含量的空间趋势和空间变异分析.结果表明:大理烤烟苹果酸含量经对数转换后服从正态分布,在进行普通Kriging插值时宜选择1阶趋势效应和指数理论模型;大理烤烟苹果酸含量具有中等的空间相关性和线性空间趋势效应;大理烤烟苹果酸含量为41.26~124.45 mg/g,平均含量为81.00 mg/g,背景值为65.01~80.00 mg/g,苹果酸含量最高(100.01~123.45 mg/g)的板块分布在南涧县、巍山县和弥渡县;大理州南部烟区烤烟苹果酸含量自南向北呈梯度状由高到低分布.%Dali flue-cured tobacco plays an important role in formula of several core cigarette brands. Malic acid is one of major nonvolatile organic acids of tobacco leaf, and it is one of common aroma additives for high-grade cigarettes, so researchers highly focus on tobacco malic acid. The objective of the study was to investigate spatial distribution of malic acid content of Dali flue-cured tobacco, and to provide references for layout of tobacco planting and using of tobacco leaf. The main tobacco planting areas in Dali were selected as the experiment sites. 200 flue-cured tobacco samples of C3F grade were collected from 100 sites in 2007 and 2008 via global position system (GPS). Malic acid contents of tobacco samples were determined. The mean value of tobacco malic acid content of samples in each site was regarded as the original data. The original data, data obtained after logarithmic transformation and Box-Cox transformation were tested for normal distribution. Surface trend and spatial distribution of tobacco malic acid content were analyzed by geostatistical

  4. 腐殖酸对重茬烤烟氮积累及产量与质量的影响%Effects of humic acid on nitrogen accumulation,production and quality of continuously cropped and flue-cured tobacco

    张吉立; 孙海人; 孟蕾; 肖瑶; 王鹏

    2015-01-01

    为研究腐殖酸对克服烤烟重茬障碍的效果,试验在田间试验条件下设置对照(B1),当地常规施肥(B2),腐殖酸复混肥(B3)3个处理,研究了烤烟氮积累与烟叶品质变化规律。结果表明:根系氮积累生育期内呈现出增加的趋势,收获期B3处于最高值,与B2相比提高32.62%;茎内氮积累成熟期B3比B2处理提高41.62%,差异显著;下部叶成熟期B3比B2处理提高35.37%;中部叶B3比B2处理提高14.61%,差异显著;上部叶B3比B2处理提高32.64%,差异显著;B3促进氮在茎内的分配,比B1和B2处理分别提高5.27%、1.84%;B3产量与产值分别比B2提高6.94%、7.94%,烟叶质量评分下部叶、中部叶、上部叶分别低于B2处理1.50分、2.00分、2.00分。综合分析认为,腐殖酸对提高烤烟氮积累量和产量效果最佳。%In order to study the effects of humic acid in overcoming cropping obstacles of flue-cured tobacco ,three trials in the field were set including control (B1 ) ,local conventional fertilization (B2 ) ,and humic acid fertilizer (B3 ) , to investigate the changes of nitrogen accumulation and quality in flue-cured tobacco .The results showed that root nitro-gen accumulation tended to be increased during reproduction ,reaching the highest level with B3 treatment ,32 .62%higher than that by B2 during harvest .Stem nitrogen accumulation with B3 treatment was 41 .62% higher than that with B2 ,exhibiting significant differences .Nitrogen accumulation in lower leaves with B3 treatment was 35 .37% higher than that with B2 treatment .Middle leaves with B3 were 14 .61% higher than those with B2 treatment ,displaying significant differences .Upper leaves with B3 were 32 .64% higher than those with B2 treatment ,showing significant differences . B3 treatment promoted distribution of nitrogen into stem ,5 .27% and 1 .84% higher than B1 and B2 treatments ,respec-tively .Yield

  5. Comparative static curing versus dynamic curing on tablet coating structures.

    Gendre, Claire; Genty, Muriel; Fayard, Barbara; Tfayli, Ali; Boiret, Mathieu; Lecoq, Olivier; Baron, Michel; Chaminade, Pierre; Péan, Jean Manuel

    2013-09-10

    Curing is generally required to stabilize film coating from aqueous polymer dispersion. This post-coating drying step is traditionally carried out in static conditions, requiring the transfer of solid dosage forms to an oven. But, curing operation performed directly inside the coating equipment stands for an attractive industrial application. Recently, the use of various advanced physico-chemical characterization techniques i.e., X-ray micro-computed tomography, vibrational spectroscopies (near infrared and Raman) and X-ray microdiffraction, allowed new insights into the film-coating structures of dynamically cured tablets. Dynamic curing end-point was efficiently determined after 4h. The aim of the present work was to elucidate the influence of curing conditions on film-coating structures. Results demonstrated that 24h of static curing and 4h of dynamic curing, both performed at 60°C and ambient relative humidity, led to similar coating layers in terms of drug release properties, porosity, water content, structural rearrangement of polymer chains and crystalline distribution. Furthermore, X-ray microdiffraction measurements pointed out different crystalline coating compositions depending on sample storage time. An aging mechanism might have occur during storage, resulting in the crystallization and the upward migration of cetyl alcohol, coupled to the downward migration of crystalline sodium lauryl sulfate within the coating layer. Interestingly, this new study clearly provided further knowledge into film-coating structures after a curing step and confirmed that curing operation could be performed in dynamic conditions. PMID:23792043

  6. Ab initio study of chemical bond interactions between covalently functionalized carbon nanotubes via amide, ester and anhydride linkages

    Ben Doudou, Bessem; Chen, Jun; Vivet, Alexandre; Poilâne, Christophe

    2016-03-01

    In this paper, we have investigated the chemical bond interactions between covalently functionalized zigzag (5,0) and (8,0) SWCNT-SWCNT via various covalent linkages. Side-to-side junctions connected via amide, ester and anhydride linkages were particularly studied. The geometries and energy of the forming reaction were investigated using first-principles density functional theory. Furthermore, the band structures and the total density of states (DOS) of the junctions have also been analyzed. Our results show that several promising structures could be obtained by using chemical connection strategy and particularly the junctions formed by coupling amino functionalized SWCNT and carboxylic acid functionalized SWCNT was more favorable.

  7. SYNTHESIS AND CHARACTERIZATION OF A NEW COMBLIKE POLYMER BASED ON POLY (VINYL METHYL ETHER-ALT-MALEIC ANHYDRIDE) BACKBONE

    DING Liming; LIN Yunqing; ZHOU Zinan; NI Jianlong; CHEN Donglin

    1995-01-01

    A new comblike polymer host for polymer electrolyte was synthesized by reacting monomethyl ether of poly(ethylene glycol) with poly(vinyl methyl ether-alt-maleic anhydride) and endcapping the residual carboxylic acid with methanol. Butanone was selected as a solvent for the esterification in order to obtain a completely soluble product. The synthesis process was traced through by IR. Compared with the model compounds, the presumed structure of this comblike polymer has been proved to be valid by 13C NMR. The comb polymer is a white rubbery solid. It can be dissolved in butanone and THF, and manifests good film forming ability.

  8. Plasma Polymerized Thin Films of Maleic Anhydride and 1,2-methylenedioxybenzene for Improving Adhesion to Carbon Surfaces

    Drews, Joanna Maria; Goutianos, Stergios; Kingshott, Peter;

    2007-01-01

    different plasma powers and monomer compositions was used. Maleic anhydride (MAR) and 1,2-methylenedioxybenzene (MDOB) were plasma deposited separately and as mixtures to create layers with different surface compositions. In all cases the MAR was hydrolyzed to form carboxylic acid groups. Some carboxylic...... total veflectanc~ Fourier transform infrared spectroscopy. Atomic force microscopy was used to measure the thickness of the plasma films and to monitor the surface roughness for the different polymerization conditions. Finally, preliminary results of fracture energy measurements of the plasma modified...

  9. Modeling HIV Cure

    Perelson, Alan; Conway, Jessica; Cao, Youfang

    A large effort is being made to find a means to cure HIV infection. I will present a dynamical model of post-treatment control (PTC) or ``functional cure'' of HIV-infection. Some patients treated with suppressive antiviral therapy have been taken off of therapy and then spontaneously control HIV infection such that the amount of virus in the circulation is maintained undetectable by clinical assays for years. The model explains PTC occurring in some patients by having a parameter regime in which the model exhibits bistability, with both a low and high steady state viral load being stable. The model makes a number of predictions about how to attain the low PTC steady state. Bistability in this model depends upon the immune response becoming exhausted when over stimulated. I will also present a generalization of the model in which immunotherapy can be used to reverse immune exhaustion and compare model predictions with experiments in SIV infected macaques given immunotherapy and then taken off of antiretroviral therapy. Lastly, if time permits, I will discuss one of the hurdles to true HIV eradication, latently infected cells, and present clinical trial data and a new model addressing pharmacological means of flushing out the latent reservoir. Supported by NIH Grants AI028433 and OD011095.

  10. Cold-Curing Structural Epoxy Resins: Analysis of the Curing Reaction as a Function of Curing Time and Thickness

    Carola Esposito Corcione; Fabrizio Freuli; Mariaenrica Frigione

    2014-01-01

    The curing reaction of a commercial cold-curing structural epoxy resin, specifically formulated for civil engineering applications, was analyzed by thermal analysis as a function of the curing time and the sample thickness. Original and remarkable results regarding the effects of curing time on the glass transition temperature and on the residual heat of reaction of the cold-cured epoxy were obtained. The influence of the sample thickness on the curing reaction of the cold-cured resin was als...

  11. SYNTHESIS OF MESOPOROUS POLY(STYRENE-co-MALEIC ANHYDRIDE)/SILICA HYBRID MATERIALS VIA A NONSURFACTANT-TEMPLATED SOL-GEL PROCESS

    Jie-bin Pang; Kun-yuan Qiu; Yen Wei

    2000-01-01

    Mesoporous poly(styrene-co-maleic anhydride)/silica hybrid materials have been prepared. The synthesis was achieved by the HCl-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) and styrene-maleic anhydride copolymer in the presence of 3-aminopropyl triethoxysilane (APTES) as a coupling agent and citric acid as a nonsurfactant template or pore-forming agent, followed by ethanol extraction. Characterization results from nitrogen sorption isotherms and powder Xray diffraction indicate that polymer-modified mesoporous materials with large specific surface areas (e.g. 900 m2/g) and pore volumes (e.g. 0.6 cm3/g) could be prepared. As the citric acid concentration is increased, the specific surface areas, pore volumes and pore diameters of the hybrid materials increase.

  12. Quality of cured fishery products from Malabar and Kanara coasts

    Joseph, K.G.; Muraleedharan, V.; Unnikrishnan Nair, T.S.

    1983-01-01

    Results of chemical, bacteriological and organoleptic quality studies of cured fishery products of commerce collected from six major fish curing centres on the west coast of India are presented. 77.12% of the samples had moisture above 35%, 97.18% showed salt content below 25% and all samples had acid insoluble ash above 1.5%. 42.32% gave standard plate counts above 10,000 and 45.77% were contaminated with 'Red' halophiles. The major defects in curing were imperfect cleaning, inadequate salti...

  13. Multibunch Instabilities and Cures

    Fox, J

    2003-01-01

    The common approach to achieve the high luminosity needed for high precision measurements adopted by the particle factories now under construction consists in storing high current e sup + e sup - beams distributed in many bunches in separate rings. The beams are brought together to collide at one interaction point. An inconvenience of this strategy is that the performances can be seriously limited by unstable coupled-bunch oscillations excited by transients or noise and sustained by long-lasting parasitic resonating modes (high order modes-HOM) in the vacuum chamber, mainly in the RF cavities. Minimization of the HOM content and broad-band feedback systems together with the reduction of the driving transients are the complementary cures to this kind of disease. This paper introduces the subject with some examples and special emphasis on bunch-by-bunch feedback systems.

  14. Preliminary report of rice to cure acid type soil conditioner%水稻施用治酸型土壤调理剂试验初报

    魏之茂; 陈金洪; 高敏

    2014-01-01

    Unreasonable application of fertilizer, potential negative impacts on the environment and the quality of agro-ecological agricultural soils, water resources and other atmospheric become one source of pollution of rural surface major cause. Through the using of governance in Guangxi Tiandeng acid soil amendment applied comparative tests on rice, the growth and economic conditions of rice have good performance. The effect of increasing production is obvious.%化肥的不合理施用,对土壤、水资源大气等农业生态环境和农产品质造成潜在的负面影响,成为我国农村面源污染的主要诱因之一。通过在广西天等县利用治酸型土壤调理剂对水稻施用的对比试验,水稻的生长发育及经济性状表现良好,增产增收效果明显。

  15. 水稻施用治酸型土壤调理剂试验初报%Preliminary report of rice to cure acid type soil conditioner

    魏之茂; 陈金洪; 高敏

    2014-01-01

    Unreasonable application of fertilizer, potential negative impacts on the environment and the quality of agro-ecological agricultural soils, water resources and other atmospheric become one source of pollution of rural surface major cause. Through the using of governance in Guangxi Tiandeng acid soil amendment applied comparative tests on rice, the growth and economic conditions of rice have good performance. The effect of increasing production is obvious.%化肥的不合理施用,对土壤、水资源大气等农业生态环境和农产品质造成潜在的负面影响,成为我国农村面源污染的主要诱因之一。通过在广西天等县利用治酸型土壤调理剂对水稻施用的对比试验,水稻的生长发育及经济性状表现良好,增产增收效果明显。

  16. TRIMELLITIC ANHYDRIDE-INDUCED EOSINOPHILIA IN A MURINE MODEL OF OCCUPATIONAL ASTHMA

    TRIMELLITIC ANHYDRIDE-INDUCED EOSINOPHILIA IN A MURINE MODEL OF OCCUPATIONAL ASTHMA. J F Regal, ME Mohrman, E Boykin and D Sailstad. Dept. of Pharmacology, University of Minnesota, Duluth, MN, USA and NHEERL, ORD, US EPA, RTP, NC, USA.Trimellitic anhydride (TMA) is a small m...

  17. Initiation precursors and initiators in laser-induced copolymerization of styrene and maleic anhydride in acetone

    Miner, Gilda A.; Meador, Willard E.; Chang, C. Ken

    1990-01-01

    The initiation step of photopolymerized styrene/maleic anhydride copolymer was investigated at 365 nm. UV absorption measurements provide decisive evidence that the styrene/maleic anhydride charge transfer complex is the sole absorbing species; however, key laser experiments suggest intermediate reactions lead to a monoradical initiating species. A mechanism for the photoinitiation step of the copolymer is proposed.

  18. MALEIC ANHYDRIDE HYDROGENATION OF PD/AL2O3 CATALYST UNDER SUPERCRITICAL CO2 MEDIUM

    Hydrogenation of maleic anhydride (MA) to either y-butyrolactone of succinic anhydride over simple Pd/Al2O3 impregnated catalyst in supercritical CO2 medium has been studied at different temperatures and pressures. A comparison of the supercritical CO2 medium reaction with the c...

  19. 40 CFR 721.524 - Alcohols, C6-12, ethoxylated, reaction product with maleic anhydride.

    2010-07-01

    ... product with maleic anhydride. 721.524 Section 721.524 Protection of Environment ENVIRONMENTAL PROTECTION... with maleic anhydride. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alcohols, C6-12, ethoxylated, reaction product with...

  20. Curing mechanism of TDE-85/MeTHPA epoxy resin modified by polyurethane

    LI Zhi-hua; ZHENG Zi-qiao; REN Dong-yan; HUANG Yao-peng

    2007-01-01

    Diglycidyl 4,5-epoxy tetrahydro phthalate/methyl tetrahydrophthalic anhydride (TDE-85/MeTHPA) epoxy resin modified by polyurethane (PU) was prepared with 1,4-butanediol (1,4-BDO), trimethylol propane (TMP) and polyurethane prepolymer synthesized by polypropylene glycol and toluene diisocynate. Chemical reaction and curing mechanism of this system were discussed by incorporating the results of infra spectrum analysis. The results indicate that the epoxy polymeric network Ⅰ is obtained by the curing reaction between TDE-85 and MeTHPA, while the PU polymeric network Ⅱ is obtained by the chain-extended and crosslinking reaction between 1,4-BDO, TMP and polyurethane prepolymer(PUP). The graft chemical bonds are formed between polymer networks Ⅰ and Ⅱ that therefore increase the degree of blend and compatibility between epoxy polymer and PU.

  1. Controversies in HIV cure research

    Johnston Rowena

    2012-03-01

    Full Text Available Abstract Background Antiretroviral therapy significantly reduces HIV viral burden and prolongs life, but does not cure HIV infection. The major scientific barrier to a cure is thought to be the persistence of the virus in cellular and/or anatomical reservoirs. Discussion Most efforts to date, including pharmaco, immuno or gene therapy, have failed to cure patients, with the notable exception of a stem cell transplant recipient commonly known as the Berlin patient. This case has revived interest in the potential to cure HIV infection and has highlighted the need to resolve critical questions in the basic, pre-clinical and clinical research spheres as they pertain specifically to efforts to eradicate HIV from the body of an infected person (a sterilizing cure or at least render the need for lifelong antiretroviral therapy obsolete (functional cure. This paper describes ongoing debates in each of these research spheres as they were presented and discussed at a satellite session that took place at the 6th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention in Rome in July 2011. Summary The resolution of these debates may have important implications for the search for a cure, the most efficient ways to identify and test promising interventions, and ultimately the availability of such a cure to diverse groups of HIV patients around the world.

  2. Radiation curing silicone acrylate systems

    Radiation curing silicone systems by either ultra violet light (UV) or electron beam (EB) is introduced. The cure is based on the polymerization of the acrylic C = C double bond via a radical chain reaction. In the EB curing process a sufficient number of radicals for spontaneous polymerization is produced due to the high radiation energy whereas with UV light the energy is not as intensive thus a photo-initiator is required for a UV process. The required high local radical concentration provided by its decay. The radical generation immediate chain-growing leads to rapid and efficient crosslinking even at room temperature. It is for this reason that silicone acrylates cure immediately. All coater capable of handling 100% thermally curing silicones are suitable for the use with Goldschmidt's RC systems

  3. CURING EFFICIENCY OF DUAL-CURE RESIN CEMENT UNDER ZIRCONIA WITH TWO DIFFERENT LIGHT CURING UNITS

    Pınar GÜLTEKİN

    2015-04-01

    Full Text Available Purpose: Adequate polymerization is a crucial factor in obtaining optimal physical properties and a satisfying clinical performance from composite resin materials. The aim of this study was to evaluate the polymerization efficiency of dual-cure resin cement cured with two different light curing units under zirconia structures having differing thicknesses. Materials and Methods: 4 zirconia discs framework in 4 mm diameter and in 0.5 mm, 1 mm and 1.5 mm thickness were prepared using computer-aided design system. One of the 0.5 mm-thick substructures was left as mono-layered whereas others were layered with feldspathic porcelain of same thickness and ceramic samples with 4 different thicknesses (0.5, 1, 1.5 and 2.0 mm were prepared. For each group (n=12 resin cement was light cured in polytetrafluoroethylene molds using Light Emitting Diode (LED or Quartz-Tungsten Halogen (QHT light curing units under each of 4 zirconia based discs (n=96. The values of depth of cure (in mm and the Vickers Hardness Number values (VHN were evaluated for each specimen. Results: The use of LED curing unit produced a greater depth of cure compared to QTH under ceramic discs with 0.5 and 1 mm thickness (p<0.05.At 100μm and 300 μm depth, the LED unit produced significantly greater VHN values compared to the QTH unit (p<0.05. At 500 μm depth, the difference between the VHN values of LED and QTH groups were not statistically significant. Conclusion: Light curing may not result in adequate resin cement polymerization under thick zirconia structures. LED light sources should be preferred over QTH for curing dual-cure resin cements, especially for those under thicker zirconia restorations.

  4. Transparent Films from CO2 -Based Polyunsaturated Poly(ether carbonate)s: A Novel Synthesis Strategy and Fast Curing.

    Subhani, Muhammad Afzal; Köhler, Burkhard; Gürtler, Christoph; Leitner, Walter; Müller, Thomas E

    2016-04-25

    Transparent films were prepared by cross-linking polyunsaturated poly(ether carbonate)s obtained by the multicomponent polymerization of CO2 , propylene oxide, maleic anhydride, and allyl glycidyl ether. Poly(ether carbonate)s with ABXBA multiblock structures were obtained by sequential addition of mixtures of propylene oxide/maleic anhydride and propylene oxide/allyl glycidyl ether during the polymerization. The simultaneous addition of both monomer mixtures provided poly(ether carbonate)s with AXA triblock structures. Both types of polyunsaturated poly(ether carbonate)s are characterized by diverse functional groups, that is, terminal hydroxy groups, maleate moieties along the polymer backbone, and pendant allyl groups that allow for versatile polymer chemistry. The combination of double bonds substituted with electron-acceptor and electron-donor groups enables particularly facile UV- or redox-initiated free-radical curing. The resulting materials are transparent and highly interesting for coating applications. PMID:27028458

  5. Preparation of acid-resistant non-solvent epoxy adhesive with low curing temperature for lead-storage battery%低温固化铅酸蓄电池用防腐耐酸无溶剂环氧胶粘剂的研制

    孟季茹; 梁国正; 赵磊; 秦华宇

    2001-01-01

    选用环氧树脂、T-31固化剂、低分子聚酰胺类固化剂、促进剂、活性稀释剂及各种填料等原料制备了低温固化防腐耐酸无溶剂胶粘剂,测试了胶粘剂的粘接强度及耐酸性能。%The low curing temperature, acid-resistant, and non-solvent adhesive is prepared by using epoxy resin, T-31 and low molecular weight polyamide cure agents, accelerator and various fillers. Some major properties such as adhesion and acid resistance are tested and properly discussed.

  6. The effect of gamma radiation on the ageing of sulfur cured nr/csm and nbr/csm rubber blends reinforced by carbon black

    Gordana Marković

    2009-10-01

    Full Text Available In this work the effect of the γ-radiation dose on ageing of carbon black reinforced elastomeric materials was studied. The compounds based on natural rubber/chlorosulfonated rubber blend (NR/CSM and butadiene acrylonitrile rubber/chlorosulfonated rubber blend (NBR/CSM (50:50, w/w with different loadings (0, 20, 40, 50, 60, 80 and 100 phr of the filler with the average particle size of 40 nm were cured by sulfur. The obtained elastomeric composites were subjected to radiation doses (100, 200, 300 and 400 kGy in the presence of oxygen. The changes of material mechanical properties were estimated after radiation accelerated ageing. By using Fourier transform infrared measurements (ATR-FTIR it was assessed that after exposure to doses of 100 kGy alcohols, ethers, lactones, anhydrides, esters and carboxylic acids are formed in materials. The formation of shorter polyene sequences and aromatic rings in aged samples are assumed on the basis of the obtained spectra.

  7. Excimer UV curing in printing

    It is the aim of this study to investigate the potential of 308 run excimer UV curing in web and sheet fed offset printing and to discuss its present status. Using real-time FTIR-ATR and stationary or pulsed monochromatic (313 nm) irradiation chemical and physical factors affecting the curing speed of printing inks such as nature and concentration of photo-initiators, reactivity of the ink binding system, ink thickness and pigmentation, irradiance in the curing plane, oxygen concentration and nitrogen inerting, multiple pulse exposure, the photochemical dark reaction and temperature dependence were studied. The results were used to select optimum conditions for excimer UV curing in respect to ink reactivity, nitrogen inerting and UV exposure and to build an excimer UV curing unit consisting of two 50 W/cm 308 run excimer lamps, power supply, cooling and inerting unit. The excimer UV curing devices were tested under realistic conditions on a web offset press zirkon supra forte and a sheet fed press Heidelberg GTO 52. Maximum curing speeds of 300 m/min in web offset and 8000 sheets per hour in sheet fed offset were obtained

  8. Electron curing of surface coatings

    The technical development of electron curing of surface coatings has received great impetus since 1970 from dramatic changes in the economics of the conventional thermal process. The most important of these changes are reviewed, including: the Clear Air Act, increasing cost and restrictive allocation of energy, decreased availability and increased costs of solvents, competitive pressure for higher line productivity. The principles of free-radical initiated curing as they pertain to industrial coatings are reviewed. Although such electron initiated processes have been under active development for at least two decades, high volume production applications on an industrial scale have only recently appeared. These installations are surveyed with emphasis on the developments in machinery and coatings which have made this possible. The most significant economic advantages of electron curing are presented. In particular, the ability of electron curing to eliminate substrate damage and to eliminate the curing station (oven) as the pacing element for most industrial surface coating curing applications is discussed. Examples of several new processes of particular interest in the textile industry are reviewed, including the curing of transfer cast urethane films, flock adhesives, and graftable surface finishes

  9. Slide Rule For Calculating Curing Schedules

    Heater, Don

    1995-01-01

    Special-purpose slide rule devised for calculating schedules for storing and curing adhesives, sealants, and other materials characterized by known curing times and shelf lives. Prevents mistakes commonly made in determining storage and curing schedules.

  10. A fully coupled diffusion-reaction scheme for moisture sorption-desorption in an anhydride-cured epoxy resin

    El Yagoubi, Jalal

    2012-11-01

    Thermoset materials frequently display non-classical moisture sorption behaviors. In this paper, we investigated this issue from an experimental point of view as well as in terms of modeling the water transport. We used the gravimetric technique to monitor water uptake by epoxy samples, with several thicknesses exposed to different levels of humidity during absorption and desorption tests. Our results revealed that the polymer displays a two-stage behavior with a residual amount of water that is desorbed progressively. We proposed a phenomenological reaction-diffusion scheme to describe this behavior. The model describes water transport as a competition between diffusion and the reaction, during which the local diffusivity and solubility depend on the local advancement of the reaction. We then implemented our model using COMSOL Multiphysics and identified it using a MATLAB-COMSOL optimization tool and the experimental data. We discussed the relation between the hydrophilicity of the product of the reaction and the diffusion behavior. We examined the reaction-induced modification of the water concentration field. It is worth noting that part of the phenomenology can be explained by the presence of hydrolyzable groups. © 2012 Elsevier Ltd. All rights reserved.

  11. Radiation curing of printing inks

    The use of radiant energy to dry or assist in the drying of printing inks has been in practice since ancient times when oxidizing ink systems were placed in the sun to speed drying. The two radiation curing methods discussed in this chapter are ultraviolet (UV) and electron beam (EB) curing. This chapter introduces the radiation curing rationale, describes different printing processes, discusses UV and EB considerations, assesses UV sources, introduces the chemistry of ink and photoinitiators, discusses the formulation of UV and EB inks, and describes manufacturing and safety considerations. 10 refs., 17 tabs

  12. Perylenetetracarboxylic anhydride as a precursor of fluorescent carbon nanoonion rings

    Baldoví, Herme G.; Herance, José Raul; Manuel Víctor, Víctor; Alvaro, Mercedes; Garcia, Hermenegildo

    2015-07-01

    Thermal annealing at 400 °C of perylenetetracarboxylic anhydride in low molecular mass PEG gives rise to the formation of well defined nanoobjects of 2.5 nm height and size distribution from 10 to 65 nm (average 40 nm) after purification of the raw mixture with silicagel chromatography. TEM reveals that the flat nanoobjects are constituted of concentric graphenic rings (0.34 nm interlayer distance). The morphology of the nanoparticles resembles onion rings of nanometric dimensions (nanoonion rings C-NOR). C-NOR particles have an excitation dependent emission with λem from 430 to 570 nm and a maximum emission quantum yield of 0.49. C-NOR particles can be internalized into Hep3B human hepatoma cells as determined by confocal fluorescence microscopy and are remarkably biocompatible affecting slightly cell viability according to the MTT test.

  13. Low Viscosity Imides Based on Asymmetric Oxydiphthalic Anhydride

    Chuang, Kathy C.; Criss, Jim M., Jr.; Mintz, Eric A.; Scheiman, Daniel A.; Nguyen, Baochau N.; McCorkle, Linda S.

    2008-01-01

    A series of low-melt viscosity imide resins were prepared from asymmetric oxydiphthalic dianhydride (a-ODPA) and 4-phenylethynylphthalic anhydride as the endcap, along with 3,4' - oxydianiline (3,4' -ODA), 3,4' -methylenedianiline (3,4' -MDA), 3,3' -methylenedianiline (3,3' - MDA) and 3,3'-diaminobenzophenone (3,3'-DABP), using a solvent-free melt process. These imide oligomers displays low-melt viscosities (2-15 poise) at 260-280 C, which made them amenable to low-cost resin transfer molding (RTM) process. The a-ODPA based RTM resins exhibits glass transition temperatures (Tg's) in the range of 265-330 C after postcure at 343 C. The mechanical properties of these polyimide/carbon fiber composites fabricated by RTM will be discussed.

  14. Effects of Citric Acid and Malic Acid on Nicotine Content in Flue-cured Tobacco%柠檬酸和苹果酸对烤烟烟碱含量的影响

    张洁; 陆引罡; 余洁

    2012-01-01

    为了解决上部烟叶烟碱含量过高的问题,以云烟87为试材,通过大田和盆栽试验相结合,于烟株打顶后分别用不同浓度柠檬酸、苹果酸浸泡的棉球包扎茎顶端进行抑制烟碱上行积累的研究.结果表明:不同浓度柠檬酸、苹果酸处理均能降低烟叶中的烟碱含量,其中,浓度为2 mmol/L的柠檬酸和浓度为6 mmol/L的苹果酸均能明显降低上部烟叶的烟碱含量,降幅分别为36.9%和40.3%.结论:该方法降低烟叶尤其是上部烟叶烟碱含量的效果较为显著.%In order to reduce the content of nicotine in upper leaves, citric acid and malic acid were used to reduce nicotine of upper leaves through restraining uplink transportation of nicotine. The test material was the Yunyan87, through the field trial and pot experiment. After removing the shoot apex, the stem tops were binded with tampons soaked with citric acid, malic acid in different concentrations. The results showed that different concentrations of citric acid and malic acid treatment could reduce the content of nicotine in tobacco. Compared with blank control, 2 mmol/L and 6 mmol/L of citric acid could significantly reduce the content of upper leaves, with the decreasing range of 36. 9% and 40. 3%, respectively.

  15. Industrial application of radiation curing

    The contents are advantages of radiation processes - a solvent-free system, less energy consumative, higher production rate, processability at ambient temperature; electron beams vs. ultraviolet curing; applications -broad spectrum of markets use radiation curable materials

  16. Radiation curing: coatings and composites

    The initial experiments conducted in the late 1960's at Radiation Dynamics, Inc. (now IBA Industrial, Inc.) showed that by removing the pigment from a radiation curable coating formulation, the same binder system could be used as a matrix system for electron beam (EB) cured fiber reinforced composites. Recently, the binder systems used for EB curable coatings have also been successfully used (without pigments) as the matrices for EB and X-ray cured fiber composites. Insights gained from the development of coatings were translated into desirable properties for matrix materials. For example, understanding the surface wetting characteristics of a coating facilitated the development of a matrix that would wet fibers; the development of coatings that would adhere to rigid substrates as metal while being bent, as for coil coatings, and which would exhibit impact resistance when cured on a metal also imparted impact resistance to cured composite materials. Thermal analyses conducted on the coating binder cured at low energies were consistent with analyses performed on thick cross-sections as used for matrices. The configuration of the final product then dictated the modality of curing, be it low-energy EB for coatings or higher energy EB or X-ray curing for composites. In industrial radiation chemistry, one deals with monomers and oligomers (∼ 102 and ∼ 103 to 104 Daltons molecular weight, respectively). Thus, one can approach the development of coating binders or matrix systems as one would approach the synthesis of organic polymers. The desired final material is a fully cured and cross-linked polymer. In contrast, concepts involved in '' formulating '' are often derived from dealing with high molecular weight polymers (∼ 105 + Daltons) in which intense mechanical mixing is used to bring different ingredients together. When synthesizing a radiation curable coating or matrix system, greater attention is given to microphase compatibility as reflected in the

  17. Strain development in a filled epoxy resin curing under constrained and unconstrained conditions as assessed by Fibre Bragg Grating sensors

    2007-04-01

    Full Text Available The influence of adhesion to the mould wall on the released strain of a highly filled anhydride cured epoxy resin (EP, which was hardened in an aluminium mould under constrained and unconstrained condition, was investigated. The shrinkage-induced strain was measured by fibre optical sensing technique. Fibre Bragg Grating (FBG sensors were embedded into the curing EP placed in a cylindrical mould cavity. The cure-induced strain signals were detected in both, vertical and horizontal directions, during isothermal curing at 75 °C for 1000 minutes. A huge difference in the strain signal of both directions could be detected for the different adhesion conditions. Under non-adhering condition the horizontal and vertical strain-time traces were practically identical resulting in a compressive strain at the end of about 3200 ppm, which is a proof of free or isotropic shrinking. However, under constrained condition the horizontal shrinkage in the EP was prevented due to its adhesion to the mould wall. So, the curing material shrunk preferably in vertical direction. This resulted in much higher released compressive strain signals in vertical (10430 ppm than in horizontal (2230 ppm direction. The constrained cured EP resins are under inner stresses. Qualitative information on the residual stress state in the molding was deduced by exploiting the birefringence of the EP.

  18. Synthesis and reactions of a nucleoside derivative of phosphoric sulfonic anhydride. Studies related to the mechanisms of coupling reactions in the chemical synthesis of oligodeoxyribonucleotides by phosphotriester procedures.

    Dabkowski, W; Skrzypczynski, Z; Michalski, J; Piel, N; McLaughlin, L W; Cramer, F

    1984-01-01

    The synthesis of a model compound, diphenylphosphoric toluene-p-sulfonic anhydride, an arylsubstituted phosphoric sulfonic mixed anhydride, is described. Using the same procedure a thymidyl substituted derivative was prepared. The phosphoric sulfonic anhydride is the presumed intermediate in oligonucleotide coupling reactions involving phosphodiester activation by arenesulfonyl derivatives. This mixed anhydride reacts with a variety of nucleophiles. It can be converted to phophotriester deriv...

  19. Crystal structure of 2,3-dimethylmaleic anhydride: continuous chains of electrostatic attraction

    Wiscons, Ren A.; Matthias Zeller; Rowsell, Jesse L. C.

    2015-01-01

    In the crystal structure of 2,3-dimethylmaleic anhydride, C6H6O3, the closest non-bonding intermolecular distances, between the carbonyl C and O atoms of neighboring molecules, were measured as 2.9054 (11) and 3.0509 (11) Å, which are well below the sum of the van der Waals radii for these atoms. These close contacts, as well as packing motifs similar to that of the title compound, were also found in the crystal structure of maleic anhydride itself and other 2,3-disubstituted maleic anhydride...

  20. Controlled Release of Damascone from Poly(styrene-co-maleic anhydride-based Bioconjugates in Functional Perfumery

    Andreas Herrmann

    2013-02-01

    Full Text Available Poly(styrene-co-maleic anhydrides were modified with poly(propylene oxide (PO-co-ethylene oxide (EO side chains (Jeffamine® with different EO/PO molar ratios, varying between 0.11 and 3.60. These copolymers were then further functionalized with a β-mercapto ketone of δ-damascone. The obtained poly(maleic acid monoamide-based β-mercapto ketones were then studied as delivery systems for the controlled release of δ-damascone by retro 1,4-addition. The release of δ-damascone, a volatile, bioactive molecule of the family of rose ketones, was studied by dynamic headspace analysis above a cotton surface after deposition of a cationic surfactant containing fabric softening formulation, as a function of the ethylene oxide (EO/propylene oxide (PO molar ratio of the grafted copolymer side chains. The polarity of the EO/PO side chain influenced the release efficiency of the damascone in a typical fabric softening application. PO-rich copolymers and the corresponding poly(styrene-co-maleic anhydride without Jeffamine® side chains were found to be less efficient for the desired fragrance release than the corresponding bioconjugate with a EO/PO ratio of 3.60 in the side chain. This copolymer conjugate seemed to represent a suitable balance between hydrophilicity and hydrophobicity to favor the release of the δ-damascone and to improve the deposition of the conjugate from an aqueous environment onto a cotton surface.

  1. Storage Stability of Epoxy/Anhydride VPI Impregnating Resin%环氧酸酐VPI浸渍树脂贮存稳定性的研究

    黄友根; 曾亮; 张浩; 李鸿岩; 赵惠宇

    2011-01-01

    对比测试了不同环氧树脂、液体酸酐、活性稀释剂的基本性能,并对其制备的环氧酸酐浸渍树脂进行了贮存试验.结果表明:环氧树脂的环氧当量和有机氯的含量、液体酸酐的纯度、水分和游离酸含量及活性稀释剂的氯含量是影响环氧酸酐浸渍树脂贮存稳定性的主要因素.%The basic properties of different types of epoxy resin, liquid anhydride and reactive diluent were studied, and the prepared epoxy/anhydride VPI impregnating resin was stored at certain temperature to test the storage stability. The results show that the epoxy equivalent and organic chlorine content of epoxy resin, the purity, water and free acid content of liquid anhydride, the chlorine content of reactive diluent are the main factors affecting the storage stability of the resin.

  2. Investigation of Plasma Polymerized Maleic Anhydride Film in a Middle Frequency Dielectric Barrier Discharge

    TANG Wenjie; CHEN Qiang; ZHANG Yuefei; GE Yuanjing

    2008-01-01

    Plasma polymerized maleic anhydride (MA) was carried out by using maleic anhydride supersaturated ethanol solution as a precursor in a dielectric barrier discharge (DBD). The film properties were characterized by water contact angle (WCA), Fourier transfer infrared (FTIR), X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) analysis, and a thickness profilometer. The influence of the processing parameters on the film properties such as the power frequency, and polymerization zone was investigated. The results show that anhydride group incorporated into the growing films is favorable at the frequency of 80 kHz and working pressure of 50 Pa. The poly (maleic anhydride) film is uniform and compact at an average deposition rate of 8 nm/min.

  3. Studying the effect of high pressure on the cycloaddition reactions of maleic anhydride and substituted anthracenes

    Kiselev, V. D.; Shakirova, I. I.; Kornilov, D. A.; Kashaeva, E. A.; Potapova, L. N.; Konovalov, A. I.

    2013-01-01

    The kinetics (rate, activation, and volume) of the high-pressure (up to 2500 bar) Diels-Alder reactions of maleic anhydride with 9-phenylanthracene and 9,10-dimethylanthracene in toluene is investigated.

  4. Differential labeling of the subunits of respiratory complex III with [3H]succinic anhydride, [14C]succinic anhydride, and p-diazobenzene-[35S]sulfonate

    Exposure of antimycin-treated Complex III (ubiquinol-cytochrome c reductase) purified from bovine heart mitochondria to [3H]succinic anhydride plus [35S]p-diazobenzenesulfonate (DABS) resulted in somewhat uniform relative labeling of the eight measured subunits of the complex by [3H]succinic anhydride. In contrast, relative labeling by [35S]DABS was similar to [3H]succinic anhydride for the subunits of high molecular mass, i.e., core proteins, cytochromes, and the iron-sulfur protein, but greatly reduced for the polypeptides of molecular mass below 15 kDa. With Complex II depleted in the iron-sulfur protein the relative labeling of core protein I by exposure of the complex to [3H]succinic anhydride was significantly enhanced, whereas labeling of the polypeptides represented by SDS-PAGE bands 7 and 8 was significantly inhibited. Dual labeling of the subunits of Complex III by 14C- and 3H-labeled succinic anhydride before and after dissociation of the complex by sodium dodecyl sulfate, respectively, was measured with the complex in its oxidized, reduced, and antimycin-inhibited states. Subunits observed to be most accessible or reactive to succinic anhydride were core protein II, the iron-sulfur protein, and polypeptides of SDS-PAGE bands 7,8, and 9. Two additional polypeptides of molecular masses 23 and 12kDa, not normally resolved by gel-electrophoresis, were detected. Reduction of the complex resulted in a significant change of 14C/3H labeling ratio of core protein only, whereas treatment of the complex with antimycin resulted in decreases in 14C/3H labeling ratios of core proteins I and II, cytochrome c1, and a polypeptide of molecular mass 13kDa identified as an antimycin-binding protein

  5. Mechanistic Studies on a Sulfoxide Transfer Reaction Mediated by Diphenyl Sulfoxide/Triflic Anhydride

    Fascione, Martin A; Adshead, Sophie J; Mandal, Pintu K; Kilner, Colin A; Leach, Andrew G; Turnbull, W Bruce

    2012-01-01

    Sulfoxides are frequently used in organic synthesis as chiral auxiliaries and reagents to mediate a wide variety of chemical transformations. For example, diphenyl sulfoxide and triflic anhydride can be used to activate a wide range of glycosyl donors including hemiacetals, glycals and thioglycosides. In this way, an alcohol, enol or sulfide is converted into a good leaving group for subsequent reaction with an acceptor alcohol. However, reaction of diphenyl sulfoxide and triflic anhydride wi...

  6. Morphologies and Thermal Variability of Patterned Polymer Films with Poly(styrene-co-maleic anhydride)

    Pieter Samyn; Gustaaf Schoukens

    2014-01-01

    Patterned films of poly(styrene-co-maleic anhydride) copolymers were deposited by dip-coating from acetone solutions. A qualitative study of the film morphologies shows the formation of polymer spheres with smaller diameters at higher amounts of maleic anhydride (MA), and long-fibrous features at higher molecular weights. Upon heating, the films progressively re-assemble with short- and long-fibrous structures as a function of heating time and temperature. In parallel, the film morphologies a...

  7. Physicochemical Characterization and the Comparison of Chitin and Chitin Modified with Maleic Anhydride

    İlhan Uzun; Ömer Çelik

    2015-01-01

    Firstly, chitin was modified via ring-opening reaction with maleic anhydride in lithium chloride/N,N-dimethylacetamide. Then, both chitin and chitin modified with maleic anhydride (CMA) were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) method, ultraviolet-visible (UV-Vis) spectroscopy, and scanning electron microscopy (SEM). Thermogravimetric analysis (TGA) was performed to investigate the thermal stability of chitin and CMA. TGA results showed that...

  8. Styrene-maleic anhydride copolymerization in a recycle tubular reactor: reactor stability and product quality

    Belkhiria, Sahbi; Meyer, Thierry; Renken, Albert

    1994-01-01

    A tubular recycle reactor was developed to ensure good homogeneity of concn. and temp. in the copolymn. of styrene and maleic anhydride. The compn. of the copolymer obtained is in good agreements with predicted values and the uniformity of compn. was measured for the entire mol.-wt. distribution. The characterization of the reactor (both hydrodynamic and stability) and the quality of the resulting polymer are presented herein. The limits of use of this reactor for the styrene-maleic anhydride...

  9. Diels-Alder Reactions of Furans with Itaconic Anhydride: Overcoming Unfavorable Thermodynamics.

    Pehere, Ashok D; Xu, Shu; Thompson, Severin K; Hillmyer, Marc A; Hoye, Thomas R

    2016-06-01

    Unfavorable thermodynamics often render furans reluctant to engage in high-yielding Diels-Alder (DA) cycloaddition reactions. Here, we report the highly efficient conversion of the biosourced reactants itaconic anhydride (IA) and furfuryl alcohol (FA) to a single DA adduct. The free energy advantages provided by anhydride ring opening and crystal lattice energy of the product overcome the loss of aromaticity of the furanoid diene. Detailed (1)H NMR studies provided valuable insights about relevant kinetic and thermodynamic features. PMID:27214494

  10. An efficient acetylation of dextran using in situ activated acetic anhydride with iodine

    MUHAMMAD A. HUSSAIN

    2010-02-01

    Full Text Available A facile, efficient, cost-effective and solvent-free acetylation method has been developed for the acetylation of dextran. Dextran acetates were successfully synthesized using different molar ratios of acetic anhydride in the presence of iodine as a catalyst without the use of any solvent. The reactions were realized at 50 °C for 3 h under stirring and nitrogen. This efficient method yielded highly pure and organosoluble dextran esters. The reaction appears highly effective for obtaining higher degrees of substitution (DS with great efficiency. Under solvent-free conditions, dextran triacetates were efficiently synthesized. It was also observed that the molar ratio can easily control the DS of pendant groups onto the polymer backbone. Hence, a range of products with varying DS were successfully designed, purified and characterized. Covalent attachment of the pendant groups onto the polymer backbone was verified by spectroscopic techniques. Thermogravimetric analysis indicated that the obtained dextran esters were thermally as stable as dextran. The DS of the pendant groups onto the polymer backbone was calculated using standard acid base titration after saponification. Furthermore, all products were thoroughly characterized by thermal analysis (TG and DTG, and FTIR and 1H-NMR spectroscopic analysis.

  11. Reactive blending of thermoplastic starch and polyethylene-graft-maleic anhydride with chitosan as compatibilizer.

    Jantanasakulwong, Kittisak; Leksawasdi, Noppol; Seesuriyachan, Phisit; Wongsuriyasak, Somchai; Techapun, Charin; Ougizawa, Toshiaki

    2016-11-20

    Cassava starch was melt-blended with glycerol (70/30wt%/wt%) at 140°C to prepare thermoplastic starch (TPS). Chitosan (CTS) was premixed with starch and glycerol, in acidified water (lactic acid 2wt%), at 1, 5 and 10wt%/wt%. TPS/CTS was then melt-blended (160°C) with polyethylene-graft-maleic anhydride (PE-MAH). Phase determination and scanning electron microscopy indicated TPS/PE-MAH/CTS had a co-continuous morphology and CTS-induced phase inversion to give dispersed PE-MAH particles in a TPS matrix. Tensile strength at break and elongation, melt viscosity, fracture toughness and water contact angle of TPS/PE-MAH were improved by CTS incorporation. TPS/PE-MAH/CTS blends decreased the melting temperature of TPS and PE-MAH compared to the neat polymers. FTIR confirmed a reaction had occurred between amino groups (NH2) of CTS and the MAH groups of PE-MAH. This reaction and the enhanced miscibility between TPS and CTS improved the mechanical properties of the TPS/PE-MAH/CTS blend, particularly at 5wt%/wt% CTS. PMID:27561475

  12. Heteroscedastic transformation cure regression models.

    Chen, Chyong-Mei; Chen, Chen-Hsin

    2016-06-30

    Cure models have been applied to analyze clinical trials with cures and age-at-onset studies with nonsusceptibility. Lu and Ying (On semiparametric transformation cure model. Biometrika 2004; 91:331?-343. DOI: 10.1093/biomet/91.2.331) developed a general class of semiparametric transformation cure models, which assumes that the failure times of uncured subjects, after an unknown monotone transformation, follow a regression model with homoscedastic residuals. However, it cannot deal with frequently encountered heteroscedasticity, which may result from dispersed ranges of failure time span among uncured subjects' strata. To tackle the phenomenon, this article presents semiparametric heteroscedastic transformation cure models. The cure status and the failure time of an uncured subject are fitted by a logistic regression model and a heteroscedastic transformation model, respectively. Unlike the approach of Lu and Ying, we derive score equations from the full likelihood for estimating the regression parameters in the proposed model. The similar martingale difference function to their proposal is used to estimate the infinite-dimensional transformation function. Our proposed estimating approach is intuitively applicable and can be conveniently extended to other complicated models when the maximization of the likelihood may be too tedious to be implemented. We conduct simulation studies to validate large-sample properties of the proposed estimators and to compare with the approach of Lu and Ying via the relative efficiency. The estimating method and the two relevant goodness-of-fit graphical procedures are illustrated by using breast cancer data and melanoma data. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26887342

  13. Challenging Roadblocks to Cancer Cure.

    Loda, Massimo

    2016-09-01

    The Pezcoller Symposium in Trento, Italy, June 2015, focused entirely on the question of why advanced cancer cure is so uncommon despite the extraordinarily rapid growth of invaluable therapeutic information. Participants were asked to define and to critically evaluate real and potential obstacles to permanent disease eradication. High-level concepts on potential road blocks to cures as well as opportunities for intervention in diverse areas of investigation ranging from genomic alterations to metabolism, microenvironment, immunity, and mechanotransduction were discussed. Provocative concepts and novel therapeutic avenues were proposed. What follows is a critical analysis of the highlights of this meeting. Cancer Res; 76(17); 4924-30. ©2016 AACR. PMID:27520451

  14. Selective hydrogenation of maleic anhydride over Pd/Al2O3 catalysts prepared via colloid deposition

    Hongjing Yuan; Chunlei Zhang; Weitao Huo; Chunli Ning; Yong Tang; Yi Zhang; Dequan Cong; Wenxiang Zhang; Jiahuan Luo; Su Li; Zhenlu Wang

    2014-01-01

    Pd/Al2O3 catalysts were prepared via colloid deposition and the performance of the catalysts was examined in the selective hydrogenation of maleic anhydride to succinic anhydride. When the reaction was carried on in a batch system with 1,4-dioxane as the solvent (353K and 1.0MPa), high conversion of maleic anhydride (>98%) and high selectivity (>99%) for succinic anhydride were observed after 5 h. The as-prepared Pd/Al2O3 catalyst also showed excellent performance in solvent-free system and fixed-bed systems. The maleic anhydride (MA) conversion was greater than 98%, and high selectivity (>99%) for succinic anhydride was obtained after 1600 h in a fixed bed reacter. The results showed that the activity of the Pd/Al2O3 catalysts was excellent due to its high active surface area.

  15. Studies of miscibility and specific interactions of antitumor-active anhydride copolymer and poly(ethylene glycol) blends.

    Can, Hatice Kaplan; Parvizikhosroshahi, Shahed; Uluışık, Erdem C

    2016-01-01

    The blending of polymers is of great interest, since the modification gives rise to diverse physical properties with the functionality of a polymer, without synthesis. Water-soluble antitumor-active poly(maleic anhydride-alt-acrylic acid) poly(MA-alt-AA) and poly(ethylene glycol) (PEG) blends were prepared by casting, and compatible properties were investigated by dilute solution viscometry. Viscosity measurements were made on ternary systems of polymer (1)/polymer (2)/solvent (H2O) and p-dioxane, at different concentrations of PEG and poly(MA-alt-AA). The interaction parameters Δβ, μ, Δk, Δb, β and α, which have been proposed, have been obtained using the viscosity data, to probe the miscibility of the polymer blends. The solid blends prepared were characterized with ATR-FTIR, (1)H-NMR, DTA and TGA. PMID:25406735

  16. Comparison of Catalysts Preyssler and Silica-Supported Nano Preyssler in the Synthesis of Acetyl Salicylic Acid

    Nazari, H.; A. Ahmadpour; Bamoharram, F. F.; M. M. Heravi; Eslami, N.

    2012-01-01

    The extensive demand for cleaner environment is forcing chemical industry to use less hazardous materials. In this regard, heteropolyacids attracted considerable amount of interest due to the less toxic behavior in addition of possessing higher acidity. Heteropoly acids have been used as catalysts for the reaction of salicylic acid with acetic anhydride. The performance of different forms of heteropoly acids in the presence of acetic anhydride as acetylating agent for acetylation of salicylic...

  17. Mixture proportioning for internal curing

    Bentz, Dale P.; Pietro, Lura; Roberts, John W.

    2005-01-01

    additional internal water that is not part of the mixing water.” The additional internal water is typically supplied by using relatively small amounts of saturated, lightweight, fine aggregates (LWA) or superabsorbent polymer (SAP) particles in the concrete. Benefits of internal curing include increased...

  18. Advances in spot curing technology

    A brief review of spot curing technology was presented. The process which a spot of energy of a specific wavelength bandwidth and irradiance is used to cause a coating, encapsulant or adhesive to change from a liquid to a solid state

  19. Inverse Secondary Deuterium Kinetic Isotope Effect in Diels-Alder Reaction of Orthonaphtho [3.3] orthoanthracenophane with Maleic Anhydride

    Mataka, Shuntaro; Ma, Jiang; Tsuzuki, Hirohisa; Nishiyama, Kozaburo; Thiemann, Thies; Tashiro, Masashi

    1996-01-01

    The Diels-Alderreactions of rigid [3.3] orthoanthracenophanes 1 and 2 with maleic anhydride and deuterium-labeled maleic anhydride-d_2, were studied. In the reaction of naphtophane 1, a large inverse secondary kinetic isotope effect (SDKIE) (kH_2/kD_2=0.78) was observed, while benzophane 2 shows a SDKIE similar to that of anthracene itself (kH_2/kD_2=0.95 and 0.96).

  20. Radiation cure of detonation transfer explosive

    The radiation cured detonation transfer plastic bonded explosive (PBX) provides the potential for achieving improvements in processability, storability, cure reproducibility, physical strength, and reliability of performance over the Navy's present injectable detonation transfer communications explosive. The composition and properties of the radiation cured system will be presented. Radiation cure of energetic materials is a relatively new process. It combines the advantages of an indefinitely long pot-life and storage life for the material mix with a very rapid cure. Neither of these features is available with conventional catalyzed thermal cure reactions. (Auth.)

  1. Melt Modification of Poly(styrene-co-maleic anhydride) with Alcohols in the Presence of 1,3-Oxazolines

    Bruch, Matthias; Mäder, Dietmar; Bauers, Florian; Loontjens, Ton; Mülhaupt, Rolf

    2000-01-01

    Various copolyesteramides were prepared by melt compounding at 220 °C involving reaction of poly(styrene-co-maleic anhydride), SMA, with 6, 17, and 28 wt % maleic anhydride content, and 1-dodecanol, C12OH, in the presence of 2-undecyl-1,3-oxazoline, C11OXA. Copolymer architectures were examined by means of 1H NMR, FTIR, DSC, and TGA using model compounds prepared via solution reactions. While conversion of anhydride with alcohol was poor due to the thermodynamically favored anhydride ring for...

  2. Transparent Films from CO2‐Based Polyunsaturated Poly(ether carbonate)s: A Novel Synthesis Strategy and Fast Curing

    Subhani, Muhammad Afzal; Köhler, Burkhard; Gürtler, Christoph; Leitner, Walter

    2016-01-01

    Abstract Transparent films were prepared by cross‐linking polyunsaturated poly(ether carbonate)s obtained by the multicomponent polymerization of CO2, propylene oxide, maleic anhydride, and allyl glycidyl ether. Poly(ether carbonate)s with ABXBA multiblock structures were obtained by sequential addition of mixtures of propylene oxide/maleic anhydride and propylene oxide/allyl glycidyl ether during the polymerization. The simultaneous addition of both monomer mixtures provided poly(ether carbonate)s with AXA triblock structures. Both types of polyunsaturated poly(ether carbonate)s are characterized by diverse functional groups, that is, terminal hydroxy groups, maleate moieties along the polymer backbone, and pendant allyl groups that allow for versatile polymer chemistry. The combination of double bonds substituted with electron‐acceptor and electron‐donor groups enables particularly facile UV‐ or redox‐initiated free‐radical curing. The resulting materials are transparent and highly interesting for coating applications. PMID:27028458

  3. Rapid Development of the Radiation Curing Sector

    2007-01-01

    @@ Radiation curing is an advanced material surface treatment technology using ultraviolet (UV) radiation and electronic beams (EB). With the greater attention paid to environ mentel protection in recent years ,radiation curing has developed rapidly.

  4. Accelerated Cure Project for Multiple Sclerosis

    ... main content Accelerating research toward a cure for multiple sclerosis Home Contact Us Search form Search Connect Volunteer ... is to accelerate efforts toward a cure for multiple sclerosis by rapidly advancing research that determines its causes ...

  5. Development situation of radiation curing materials

    Due to fitting the '4E' principle, radiation curing technology, known as green technology, have shown its own superiority in many applications. It has been rapid developed in China and abroad in recent years, especially ultraviolet/electron beam (UV/EB) radiation curing technology. In order to let the researchers have a general understanding on the radiation curing materials and their development, in this paper a briefly introducing on the related radiation sources, chemical systems, curing mechanism, and the application, the common and difference of ultraviolet curing and electron beam curing has been made. A brief account of development of radiation-curable material in China and the outlook of the development of materials can be found in this paper. At last, we have proposed that the development of radiation curing technology will promote the development of the radiation curing material and benefit in the humanity. (authors)

  6. Interplay between viscoelastic and chemical tunings in fatty-acid-based polyester adhesives: engineering biomass toward functionalized step-growth polymers and soft networks.

    Vendamme, Richard; Olaerts, Katrien; Gomes, Monica; Degens, Marc; Shigematsu, Takayuki; Eevers, Walter

    2012-06-11

    This Article describes the synthesis and characterization of renewable self-adhesive coatings with tunable viscoelastic properties and equipped with well-defined amounts of carboxylic acid "sticker" groups with adhesion promoting characteristics. Hydroxyl-ended polyesters with various architectures (linear, branched) were synthesized by melt polycondensation of dimerized fatty acids and fatty diols and then cured with maleic anhydride-modified triglycerides (such as maleinized soybean oil) in the presence of the amidine catalyst 1,8-diazabicyclo[5.4.0]undec-7-ene. The curing reaction of alcoholysis has the dual effect of chain extending/cross-linking the base polymers via creation of polymeric half-esters linkages while introducing carboxylic acid functions within the gel structure. We demonstrated how the adhesion properties can be finely tuned from molecular design and formulation of the network precursors and how the rheology and functionality of the coatings influence the adhesive bond formation and development. These renewable polyester adhesives proved to be suitable materials for pressure-sensitive adhesives applications with respect to adhesion strength, viscoelasticity, and functionality. In addition, the environmental benefits of such materials are briefly discussed. PMID:22612310

  7. 7 CFR 51.1412 - Well cured.

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Well cured. 51.1412 Section 51.1412 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Pecans in the Shell 1 Definitions § 51.1412 Well cured. Well cured means that...

  8. Clinical rabies: is cure possible?

    Mithun C. Mohan; Sudeep K; Nived; Pramod V K; Ajith Kumar; Prasanna KvS; Narayanan P V

    2014-01-01

    Rabies is a fatal disease in humans and till date survivors of the disease after the clinical onset of the illness are rare. The approach to management of rabies is usually palliative. In rare cases of paralytic rabies a trial for cure has been tried. No single therapeutic agent is likely to be effective, but a combination of specific therapies could be considered, including rabies vaccine, rabies immunoglobulin, monoclonal antibodies, ribavirin, interferon alpha, ketamine etc. the only repor...

  9. Cancer: the consequences of cure

    The author considers the consequences of curing children treated for cancer in terms of their relation to society and society's responsibility to them. However serious the interruption of their schooling, these children achieve normal educational standards, and, despite adverse reports on central nervous system function, appear in practice to do as well as their peers. They deserve to be encouraged to succeed at school and later, an attitude not always shown by their teachers. For whatever reason, earlier maturity, earlier close contact with the adult world, these young people achieve well in work and at university. They deserve better of the public services, various professions, and even the armed services, who frequently reject them out of hand. Now that there are large numbers of these youngsters entering adulthood (it has been estimated, e.g., that by 1990 one in every two thousand individuals aged 20 will be a cured childhood cancer patient), it is necessary to see that these young people integrate satisfactorily with society and that cure produces no adverse consequences. (author)

  10. BATAN's experiences on radiation curing

    A pilot plant for the radiation curing of surface coating on wood products was installed in Jakarta at the end of 1984 under UNDP, IAEA-RCA and the government of Indonesia Project. The total budget spent for the plant investment was about one million US dollars. The main objective of this plant was training course, demonstration and the study on both technical and economical aspects of the radiation curing technology for surface coating. In this plant, a low energy (300 keV) electron beam machine of scanning type with variable beam current of 50 mA at maximum was installed, and also a number of wood coating and wood handling equipments are available. Although the size of the plant is commercially usable, technically it was not designed for commercial application. For a typical application, the flowsheet of the processes cannot be followed with the available plant layout. In this case, a batch process should be used. A number of activities were carried out in the last five years, therefore, the experiences are reported. The principle of radiation curing technology for surface coating, the specification of the pilot plant, local and regional activities, the troubles in the operation and so on are described. (K.I.)

  11. Isothermal (vapor + liquid) equilibria of maleic anhydride + di-isobutyl hexahydrophthalate and maleic anhydride + di-n-butyl phthalate systems at T = (413.2, 433.2 and 453.2) K

    Isothermal (vapor + liquid) equilibrium for the two binary systems (maleic anhydride + di-isobutyl hexahydrophthalate and maleic anhydride + di-n-butyl phthalate) at T = (413.2, 433.2, and 453.2) K were determined using the ebulliometric method. The parameters of the NRTL model for the two binary systems were obtained from the correlation of the experimental data

  12. Biophysical properties of phenyl succinic acid derivatised hyaluronic acid

    Neves-Petersen, Maria Teresa; Klitgaard, Søren; Skovsen, Esben;

    2010-01-01

    Modification of hyaluronic acid (HA) with aryl succinic anhydrides results in new biomedical properties of HA as compared to non-modified HA, such as more efficient skin penetration, stronger binding to the skin, and the ability to blend with hydrophobic materials. In the present study, hyaluronic...

  13. Pinosylvin-Based Polymers: Biodegradable Poly(Anhydride-Esters) for Extended Release of Antibacterial Pinosylvin.

    Bien-Aime, Stephan; Yu, Weiling; Uhrich, Kathryn E

    2016-07-01

    Pinosylvin is a natural stilbenoid known to exhibit antibacterial bioactivity against foodborne bacteria. In this work, pinosylvin is chemically incorporated into a poly(anhydride-ester) (PAE) backbone via melt-condensation polymerization, and characterized with respect to its physicochemical and thermal properties. In vitro release studies demonstrate that pinosylvin-based PAEs hydrolytically degrade over 40 d to release pinosylvin. Pseudo-first order kinetic experiments on model compounds, butyric anhydride and 3-butylstilbene ester, indicate that the anhydride linkages hydrolyze first, followed by the ester bonds to ultimately release pinosylvin. An antibacterial assay shows that the released pinosylvin exhibit bioactivity, while in vitro cytocompatibility studies demonstrate that the polymer is noncytotoxic toward fibroblasts. These preliminary findings suggest that the pinosylvin-based PAEs can serve as food preservatives in food packaging materials by safely providing antibacterial bioactivity over extended time periods. PMID:27071713

  14. Crystal structure of 2,3-di-methyl-maleic anhydride: continuous chains of electrostatic attraction.

    Wiscons, Ren A; Zeller, Matthias; Rowsell, Jesse L C

    2015-08-01

    In the crystal structure of 2,3-di-methyl-maleic anhydride, C6H6O3, the closest non-bonding inter-molecular distances, between the carbonyl C and O atoms of neighboring mol-ecules, were measured as 2.9054 (11) and 3.0509 (11) Å, which are well below the sum of the van der Waals radii for these atoms. These close contacts, as well as packing motifs similar to that of the title compound, were also found in the crystal structure of maleic anhydride itself and other 2,3-disubstituted maleic anhydrides. Computational modeling suggests that this close contact is caused by strong electrostatic inter-actions between the carbonyl C and O atoms. PMID:26396764

  15. Solid—Liquid Equilibria of Several Binary and Ternary Systems Containing Meleic Anhydride

    MAPeisheng; CHENMingming; 等

    2002-01-01

    Solid-liquid equilibria(SLE) of three binary systems and seven ternary systems containing maleic anhydride(MA) are measured by visual method. The experimental data are compared with the calculated ones with modified universal quasichemical functional group activity coefficient(UNIFAC) method in which the interaction parameters between groups come from two sources,dortmund data bank (DDB), if there′s any,and correlations based on our former presented experimental SLE data of twenty binary systems.New groups of MA,ACCOO group,COO group,>C=O group and cy-CH2 group are defined and the SLE data of maleic anhydride in isopropyl acetate in literature are cited in order to assess the new interaction parameters,correlated with Wilson equation and the λh equation.The modified UNIFAC method with these new regressed interaction parameters is also used to predict other three binary systems containing maleic anhydride.

  16. Crystal structure of 2,3-dimethylmaleic anhydride: continuous chains of electrostatic attraction

    Ren A. Wiscons

    2015-08-01

    Full Text Available In the crystal structure of 2,3-dimethylmaleic anhydride, C6H6O3, the closest non-bonding intermolecular distances, between the carbonyl C and O atoms of neighboring molecules, were measured as 2.9054 (11 and 3.0509 (11 Å, which are well below the sum of the van der Waals radii for these atoms. These close contacts, as well as packing motifs similar to that of the title compound, were also found in the crystal structure of maleic anhydride itself and other 2,3-disubstituted maleic anhydrides. Computational modeling suggests that this close contact is caused by strong electrostatic interactions between the carbonyl C and O atoms.

  17. Synthesis of first row transition metal carboxylate complexes by ring opening reactions of cyclic anhydrides

    Jubaraj Bikash Baruah

    2011-03-01

    Hydrolytic and solvolytic ring opening reactions of phthalic anhydride, pyromellitic dianhydride and 2,3-pyridine dicarboxylic anhydride in the presence of various transition metal salts with or without a ancillary ligands were studied. The reactions were found to be dependent on stoichiometry of ligand and types of anhydride used. In the case of pyromellitic dianhydride selective ring opening reaction by cobalt(II) ions gave 1,3-benzene dicarboxylate derivatives, whereas use of copper(II) ions gave 1,4-benzene dicarboxylate derivatives. Preference for methanolysis was seen in the case of copper (II) promoted reactions of pyromellitic dianhydride in the presence of 1:1 metal to 1,10-phenanthroline ratio.

  18. Surface Characterization of Hematin Anhydride: A Comparison between Two Different Synthesis Methods.

    Guerra, E Danae; Bohle, D Scott; Cerruti, Marta

    2016-05-10

    During the intraerythrocytic stage of malaria, the parasite digests hemoglobin and aggregates the released heme as an insoluble crystalline material called hemozoin. This detoxification step is an excellent drug target for developing new antimalarials, which can bind to hemozoin surface to inhibit further growth. Although the bulk crystalline properties of hemozoin are well-known, the surface properties remain poorly defined. Here, we use a combination of spectroscopic and adsorption techniques to study the surface of synthetic hemozoin, hematin anhydride, produced by two different methods. We show that the two synthetic methods produce crystals with major differences, such as the amount of water adsorbed on the surface and surface carboxylate groups. These results imply that the methodology to produce hematin anhydride affects its surface reactivity; this information needs to be considered whenever hematin anhydride is used as a model to study host immune response or to design new antimalarials. PMID:27089176

  19. Structural properties of pepsin-solubilized collagen acylated by lauroyl chloride along with succinic anhydride

    Li, Conghu [The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065 (China); College of Life Sciences, Anqing Normal University, Anqing 246011 (China); Tian, Zhenhua; Liu, Wentao [The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065 (China); Li, Guoying, E-mail: liguoyings@163.com [The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu 610065 (China)

    2015-10-01

    The structural properties of pepsin-solubilized calf skin collagen acylated by lauroyl chloride along with succinic anhydride were investigated in this paper. Compared with native collagen, acylated collagen retained the unique triple helix conformation, as determined by amino acid analysis, circular dichroism and X-ray diffraction. Meanwhile, the thermostability of acylated collagen using thermogravimetric measurements was enhanced as the residual weight increased by 5%. With the temperature increased from 25 to 115 °C, the secondary structure of native and acylated collagens using Fourier transform infrared spectroscopy measurements was destroyed since the intensity of the major amide bands decreased and the positions of the major amide bands shifted to lower wavenumber, respectively. Meanwhile, two-dimensional correlation spectroscopy revealed that the most sensitive bands for acylated and native collagens were amide I and II bands, respectively. Additionally, the corresponding order of the groups between native and acylated collagens was different and the correlation degree for acylated collagen was weaker than that of native collagen, suggesting that temperature played a small influence on the conformation of acylated collagen, which might be concluded that the hydrophobic interaction improved the thermostability of collagen. - Highlights: • Acylated collagen retained the unique triple helix conformation. • Acylated collagen had stronger thermostability than native collagen. • Amide I was the most sensitive band to the temperature for acylated collagen. • Amide II was the most sensitive band to the temperature for native collagen. • Auto-peak at 1680 cm{sup −1} for acylated collagen disappeared at higher temperature.

  20. 不同种类有机酸及其配施对烤烟生长和叶片非酶促活性氧代谢的影响%Effect of different types of organic acids and their combined application on the growth and leaf non-enzymatic active oxygen metabolism of flue-cured tobacco

    胡皓月; 许自成; 李志刚; 张蕊; 冉法芬; 王满

    2011-01-01

    The effects of different types of organic acids and their combined application on the growth and leaf non-enzymatic active oxygen metabolism of flue-cured tobacco were studied. The results showed that applying organic acids accelerated the plant height, the largest leaf length and width, the dry weight of steam and leaf, the dry weight of root to promote the growth of flue-cured tobacco, single application of oleic acid or malic acid, combined application of malic acid and oleic acid, or combined application of malic acid, oleic acid and humic acid had most obvious influence on it. Moreover, applying organic acids increased the content of ascorbic acid (ASA) and reduced glutathione ( GSH ), decreased the accumulation of superoxide radical ( O2- · ), which were beneficial for the balance of the leaf non-enzymatic active oxygen metabolism of tobacco.The results indicated that humic acid and oleic acid were most effective in single application of organic acids, the production rate of O2- · reduced by 35. 33% and 37. 08% than the control, the content of ASA increased by 28. 64% and 36. 03%,the content of GSH increased by 19. 75% and 15.24%; combined application of malic acid and humic acid , or combined application of malic acid and oleic acid were most effective in combined application of organic acids, the production rate of O2- · reduced by 31.00% and 29. 96% than the control, the content of ASA increased by 28. 31% and 34. 05%, the content of GSH increased by 13.87% and 10. 18%.%研究了不同种类有机酸及其组合对烤烟生长和非酶促活性氧代谢的影响.结果表明,施用有机酸有效提高了烤烟株高、最大叶长、最大叶宽、茎叶干重和根系干重,促进了烤烟的生长,其中以油酸、苹果酸、苹果酸+油酸配施、苹果酸+油酸+腐殖酸配施处理的效果较好.施用有机酸显著提高了抗氧化物质抗坏血酸(ASA)和还原性谷胱甘肽(GSH)的含量,减少了

  1. Melt Modification of Poly(styrene-co-maleic anhydride) with Alcohols in the Presence of 1,3-Oxazolines

    Bruch, Matthias; Mäder, Dietmar; Bauers, Florian; Loontjens, Ton; Mülhaupt, Rolf

    2000-01-01

    Various copolyesteramides were prepared by melt compounding at 220 °C involving reaction of poly(styrene-co-maleic anhydride), SMA, with 6, 17, and 28 wt % maleic anhydride content, and 1-dodecanol, C12OH, in the presence of 2-undecyl-1,3-oxazoline, C11OXA. Copolymer architectures were examined by m

  2. Influence of the degree of hydrolysis of poly(styrene-alt-maleic anhydride) on miscibility with poly(vinyl acetate)

    Bosma, M.; Vorenkamp, E.J.; Brinke, G. ten; Challa, G.

    1988-01-01

    The influence of the hydrolysis of anhydride groups in poly(styrene-alt-maleic anhydride) (PSMA) on its miscibility with poly(vinyl acetate) (PVAc) is investigated. The cloudpoint curves of these blends are determined as a function of the degree of hydrolysis. The miscibility is shown to improve wit

  3. 40 CFR 721.6183 - Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow alkyl amines...

    2010-07-01

    ... - maleic anhydride polymer and hydrogenated tallow alkyl amines, sodium salts, compds. with ethanolamine... Substances § 721.6183 Amides, from ammonium hydroxide - maleic anhydride polymer and hydrogenated tallow... subject to reporting. (1) The chemical substance identified as amides, from ammonium hydroxide -...

  4. CATALYSIS OF POLYSTYRENE N-HYDROXYL SULFONAMIDE FOR ESTERIFICATION OF BUTANOL WITH ACETIC ANHYDRIDE

    LI Shufeng; LI Qian; YANG Xinlin; HUANG Wenqiang

    2004-01-01

    Polystyrene N-hydroxyl sulfonamide resin 1 was prepared and used to catalyze the esterification of n-butanol and acetic anhydride. The mechanism of catalytic esterification proved by IR spectra of the resins was found that O-H and N-H of the N-hydroxyl sulfonamide resin reacted with the acetic anhydride respectively to form the active intermediate polystyrene N,O-diacetyl sulfonamate which was cleaved by n-butanol to produce butyl acetate. The catalytic esterification by resin 1 was in good agreement with the kinetic model of "bi-bi-ping-pong" mechanism.

  5. Blends of Styrene-Butadiene-Styrene Triblock Copolymer with Random Styrene-Maleic Anhydride Copolymers

    Piccini, Maria Teresa; Ruggeri, Giacomo; Passaglia, Elisa; Picchioni, Francesco; Aglietto, Mauro

    2002-01-01

    Blends of styrene-butadiene-styrene triblock copolymer (SBS) with random styrene-maleic anhydride copolymers (PS-co-MA), having different MA content, were prepared in a Brabender Plastigraph mixer. The presence of polystyrene (PS) blocks in the SBS copolymer and the high styrene content (93 and 86 wt.-%, respectively) in the two kinds of used PS-co-MA samples afforded a good compatibility between the PS phases of the two polymers. On the other hand, the presence of polar anhydride groups allo...

  6. Solvent-free esterification of poly(vinyl alcohol) and maleic anhydride through mechanochemical reaction

    2007-01-01

    A solid-state mechanochemical processing, that is, pan-milling, was used to conduct the esterification of poly(vinyl alcohol)(PVA) with maleic anhydride (MA) through stress-induced reaction. FTIR spectrum study indicated the presence of ester linkages and olefinic double bonds in maleic anhydride cross-linked PVA. Thermal properties of the cross-linked product were characterized by DSC. The results showed its glass transition temperature was 20 ℃ higher than the original linear PVA and the thermal stability was also improved.

  7. Enhancement of Adhesion between EPDM and Polyester Fabric by Using Natural Rubber Modified by Maleic Anhydride

    A. A. El-Wakil

    2011-01-01

    Full Text Available This study presents a new method for improving adhesion between ethylene propylene diene monomer (EPDM rubber and polyester fabric. In this work, natural rubber was modified by maleic anhydride in order to improve the adhesion force between ethylene propylene diene monomer rubber and polyester fabric. The effect of thermal aging and ionizing radiation on the stability of the rubber mix as well as on the peel strength of the rubber-coated fabric was investigated. It was observed that the natural rubber modified by maleic anhydride improved the peel strength of the EPDM rubber-coated polyester fabric.

  8. Grafting of maleic anhydride on polypropylene by reactive extrusion: Effect of maleic anhydride and peroxide concentrations on reaction yield and products characteristics

    Berzin, Françoise; Flat, Jean-Jacques; Vergnes, Bruno

    2013-01-01

    International audience A series of polypropylenes (PPs) grafted with maleic anhydride (MA), prepared by reactive extrusion in a twin screw extruder with different contents of peroxide and MA, was characterized. For each sample, the amount of grafted MA, the molecular weight distribution, the viscoelastic properties in small amplitude oscillatory shear and the transition temperatures and enthalpies were measured. The respective influence of initial MA and peroxide concentrations on these pa...

  9. Novel 4-Arm Poly(Ethylene Glycol-Block-Poly(Anhydride-Esters Amphiphilic Copolymer Micelles Loading Curcumin: Preparation, Characterization, and In Vitro Evaluation

    Li Lv

    2013-01-01

    Full Text Available A novel 4-arm poly(ethylene glycol-block-poly(anhydride-esters amphiphilic copolymer (4-arm PEG-b-PAE was synthesized by esterization of 4-arm poly(ethylene glycol and poly(anhydride-esters which was obtained by melt polycondensation of α-, ω-acetic anhydride terminated poly(L-lactic acid. The obtained 4-arm PEG-b-PAE was characterized by 1H-NMR and gel permeation chromatography. The critical micelle concentration of 4-arm PEG-b-PAE was 2.38 μg/mL. The curcumin-loaded 4-arm PEG-b-PAE micelles were prepared by a solid dispersion method and the drug loading content and encapsulation efficiency of the micelles were 7.0% and 85.2%, respectively. The curcumin-loaded micelles were spherical with a hydrodynamic diameter of 151.9 nm. Curcumin was encapsulated within 4-arm PEG-b-PAE micelles amorphously and released from the micelles, faster in pH 5.0 than pH 7.4, presenting one biphasic drug release pattern with rapid release at the initial stage and slow release later. The hemolysis rate of the curcumin-loaded 4-arm PEG-b-PAE micelles was 3.18%, which was below 5%. The IC50 value of the curcumin-loaded micelles against Hela cells was 10.21 μg/mL, lower than the one of free curcumin (25.90 μg/mL. The cellular uptake of the curcumin-loaded micelles in Hela cell increased in a time-dependent manner. The curcumin-loaded micelles could induce G2/M phase cell cycle arrest and apoptosis of Hela cells.

  10. Triflic Anhydride-Mediated Beckmann Rearrangement Reaction of Β-Oximyl Amides: Access to 5-Iminooxazolines

    MANGFEI YU; QIAN ZHANG; JIA WANG; PENG HUANG; PENGFEI YAN; RUI ZHANG; DEWEN DONG

    2016-06-01

    Facile and efficient synthesis of 5-iminooxazolines fromΑ, Α-disubstituted Β-oximyl amidesmediated by triflic anhydride $(Tf_{2}O)$ in the presence of 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) indichloromethane at room temperature is developed, and a mechanism involving tandem Beckmann rearrangementand intramolecular cyclization reaction is proposed.