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Navzer D. Sachinvala David L. Winsor Roger K. Menescal Iraj Ganjian Walter P. Niemczura Morton H. Litt 《Journal of polymer science. Part A, Polymer chemistry》1998,36(13):2397-2413
Two sets of sucrose-based epoxy monomers, namely, epoxy allyl sucroses (EAS), and epoxy crotyl sucroses (ECS), were prepared by epoxidation of octa-O-allyl and octa-O-crotyl sucroses (OAS and OCS, respectively). Synthetic and structural characterization studies showed that the new epoxy monomers were mixtures of structural isomers and diastereoisomers that contained varying numbers of epoxy groups per sucrose. EAS and ECS can be tailored to contain an average of one to eight epoxy groups per sucrose. Quantitative 13C-NMR spectrometry and titrimetry were used independently to confirm the average number of epoxy groups per sucrose. Sucrose-based epoxy monomers were cured with diethylenetriamine (DETA) in a differential scanning calorimeter (DSC), and their curing characteristics were compared with those of diglycidyl ether of bisphenol A (DGEBA) and diepoxycrotyl ether of bisphenol A (DECEBA). EAS and DGEBA cured at 100 to 125°C and exhibited a heat of cure of about 108.8 kJ per mol epoxy. ECS and DECEBA cured at 150 and 171°C, respectively, and exhibited a heat of cure of about 83.7 kJ per mol epoxy. Depending upon the degree of epoxidation (average number of epoxy groups per sucrose) and the concentration of DETA, glass transition temperatures (Tgs) of cured EAS varied from −17 to 72°C. DETA-cured ECS containing an average of 7.3 epoxy groups per sucrose (ECS-7.3) showed no DSC glass transition between −140 and 220°C when the ratio of amine (NH) to epoxy group was 1:1 and 1.5:1. Maximum Tgs obtained for DETA-cured DGEBA and DECEBA polymers were 134 and 106°C, respectively. DETA-cured bisphenol A-based epoxy polymers degraded at about 340°C, as observed by thermogravimetric analysis (TGA). DETA-cured sucrose-based epoxy polymers degraded at about 320°C. Sucrose-based epoxies cured with DETA were found to bind aluminum, glass, and steel. Comparative lap shear tests (ASTM D1002–94) showed that DETA-cured epoxy allyl sucroses with an average of 3.2 epoxy groups per sucrose (EAS-3.2) generated a flexible adhesive comparable in bond strength to DGEBA. However, DETA-cured ECS-7.3 outperformed the bonding characteristics of both DGEBA and EAS-3.2. All sucrose-based epoxy polymers were crosslinked and insoluble in water, N,N-dimethylformamide, tetrahydrofuran, acetone, and dichloromethane. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. A Polym. Chem. 36: 2397–2413, 1998 相似文献
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Yie-Chan Chiu 《Polymer Degradation and Stability》2008,93(3):668-676
A diglycidylether sulfone monomer (sulfone type epoxy monomer, SEP) was prepared from bis(4-hydroxyphenyl) sulfone (SDOL) and epichlorohydrin without any NaOH or KOH as basic catalyst. FT-IR, 1H NMR, 13C NMR and mass spectroscopic instruments were utilized to determine the structure of the SEP monomer. The cured SEP epoxy material exhibited not only a higher Tg (163.81 °C) but also a higher Tg than pristine DGEBA (from 111.25 °C to 139.17 °C) when the SEP monomer moiety had been introduced into the DGEBA system. The thermal stability of cured epoxy herein was investigated by thermogravimetric analysis (TGA). The results demonstrated that the sulfone group of the cured SEP material decomposed at lower temperatures and formed thermally stable sulfate compounds, improving char yield and enhancing resistance against thermal oxidation. Additionally, the IPDT and char yield of the cured SEP epoxy (IPDT = 1455.75, char yield = 39.67%) exceeded those of conventional DGEBA epoxy (IPDT = 667.27, char yield = 16.25%). 相似文献
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采用端甲氧基聚乙二醇、马来酸酐、E-44环氧树脂合成了反应型环氧树脂乳化剂MeO-PEG-Ma-E-44,以相反转乳化技术制备E-44水性环氧树脂,研究了工艺条件对其性能的影响。结果表明:酯化率达98.5%的MeO-PEG-Ma-E-44,用量为E-44的ω=16.5%-20%得到的水性环氧树脂乳液最稳定。DSC和TG分析结果表明:乳化前后的E-44环氧树脂都能室温条件2h内很好的固化,固化后热性能基本不变,分解温度约在380℃,热失重率89%,其玻璃转变温度有所降低,韧性有所提高,其它性能基本不受影响。 相似文献
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Louis Schutz Forouzan Kazemi Elby Mackenzie Jean-Yves Bergeron Eric Gagnon Jerome P. Claverie 《Journal of polymer science. Part A, Polymer chemistry》2021,59(4):321-328
Vast quantities of the natural terpene (R)-limonene can be collected from food waste. Epoxidation of its two double bonds provides limonene dioxide (LDO), a difunctional epoxy monomer. However, LDO is a mixture of four isomers, two of which (trans-LDO) are actually difunctional while the others (cis-LDO) have one epoxide group which is significantly less reactive, as revealed by Fourier transformed infrared spectroscopic analysis of formulations cross-linked with polyethylene imine. These results are also confirmed when preparing epoxy formulations using respectively cis or trans isomers. From DFT calculations, the reactivity of each epoxide group of LDO has been assessed in model reactions with primary and secondary amines, in the presence of amine or alcohol hydrogen-bond donors. The kinetics of cross-linking has also been probed by differential scanning calorimetry. As measured by dynamic mechanical analysis, the resulting epoxy resins based on trans isomers have a storage modulus of ca 1GPa at room temperature and a glass transition temperature (Tg) of 70°C. These results demonstrate that trans LDO is a promising bio-based epoxy monomer, which could be used as an alternative to petroleum-based epoxy monomers. 相似文献
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Several series of multifunctional silicon-containing epoxide monomers and oligomers have been prepared using rhodium catalyzed hydrosilation reactions. Dialkyl and diarylsilanes can be condensed with vinyl epoxides to give high yields of the desired diepoxides while the hydrosilation of alkyl and aryl silanes yields a mixture of di and tri epoxy substituted products. The condensation of αω,? Si? H difunctional compounds with vinyl epoxides can be carried out regioselectively to give α-hydrogen-ω-epoxy intermediates, which can be further reacted with di and tri olefins bearing terminal double bonds to give a series of well characterized epoxy functional oligomers. An investigation of the photoinitiated cationic polymerization of the monomers and oligomers, which were prepared during the course of these studies, was carried out. © 1994 John Wiley & Sons, Inc. 相似文献
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M. Spontón 《Polymer Degradation and Stability》2009,94(2):145-150
The copolymerisation of benzoxazine of bisphenol A and diglycidyl ether of (2,5-dihydroxyphenyl)diphenyl phosphine oxide or diglycidyloxymethylphenylsilane has been studied. In all samples the molar ratio of the benzoxazine-epoxy system was varied to achieve different phosphorus or silicon contents. Their thermal, dynamic-mechanical and flame retardant properties were evaluated. The high limiting oxygen index values confirmed that the phosphorus-containing benzoxazine-epoxy resins are effective flame retardants, but no efficiency of silicon on flame retardation was observed. 相似文献
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J. V. Crivello Daoshen Bi 《Journal of polymer science. Part A, Polymer chemistry》1993,31(12):3109-3119
Silicon-containing epoxide compounds bearing Si ? H groups can be readily prepared in high yields by the regioselective rhodium-catalyzed monohydrosilation of α,ω-dihydrogen functional siloxanes and silanes with vinyl epoxides. The remaining Si ? H groups in these compounds can be further selectively hydrosilated with unsaturated epoxides to give a series of unique ambifunctional monomers containing two different epoxide groups in the same molecule. The photopolymerization of these monomers has been studied using analytical techniques including real time infrared spectroscopy and differential scanning photocalorimetry. On photopolymerization, the new monomers yield interesting networks. © 1993 John Wiley & Sons, Inc. 相似文献
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Nowadays, most superhydrophobic surfaces will lose their superhydrophobic performance once they encounter oil, and adhesive strength of superhydrophobic coating is low. Therefore, the superhydrophobic coating with good oleophobicity and high adhesive strength is popular with people. A superhydrophobic and oleophobic coating is characteristic of antifouling and self-cleaning, due to the appearance of special structures, such as overhang and re-entrant. In this work, flower-like zinc oxide (ZnO) particles free of fluorine and fluorine-containing epoxy were used to establish the coating with a similar re-entrant structure. Flower-like ZnO particles were prepared by a chemical precipitation method, and the water contact angle of flower-like ZnO is up to 149 ± 1°. For the coating, flower-like ZnO particles were almost covered by fluorine-containing epoxy synthesized through click reaction so that the adhesive strength between the coating and the matrix is high, superior to some coatings in the references. The surfaces made of flower-like ZnO and fluorinated epoxy possess superhydrophobic and oleophobic properties. The contact angle of the coating for water, diiodomethane, glycerol, and glycol is 154 ± 0.7°, 138 ± 0.6°, 156 ± 0.7°, and 150 ± 0.7°, respectively. After withstanding 70 cycles under the pressure of 1 kPa, the coating is still superhydrophobic. Also, the coating possesses a good self-cleaning and anti-icing property. 相似文献
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用双酚A型环氧树脂(E-51)和2-丙烯酰胺基-2-甲基丙磺酸(AMPS)合成了可用于紫外光固化的双酚A型环氧磺酸酯(AMPS-EP).研究了影响反应的多种因素,优化的合成条件为:以N,N-二甲基甲酰胺(DMF)为溶剂,AMPS与E-51的摩尔投料比为1:0.5,对苯二酚为阻聚剂,用量为环氧树脂质量的0.2%,反应时间... 相似文献
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Novel epoxy nanocomposites based on a diglycidyl ether of bisphenol A (DGEBA) epoxy, an epoxy functionalized hyperbranched polymer (HTTE) and nano‐Al2O3 were synthesized with the aim of determining the effect of the nano‐Al2O3 particles and HTTE on the structure and properties of epoxy nanocomposites. The mechanical properties, thermal conductivity, bulk resistivity, and thermal stability of the nano‐Al2O3/HTTE/DGEBA ternary composites were evaluated and compared with the corresponding matrix. The improvement in impact properties of these nanocomposites was explained in terms of fracture surface analysis by SEM. The results indicate that the incorporation of nanoparticles and hyperbranched epoxy effectively improved the toughness of epoxy composites without sacrificing thermal conductivity and bulk resistivity compared to the neat epoxy and Al2O3/DGEBA, obtaining a well dispersion of nanoparticles in epoxy matrix and solving the drawbacks for single fillers filled epoxy nanocomposite. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Lun‐Zhi Dai Dr. Min Shi Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(8):2496-2502
We report here the intramolecular reactions between α,β‐epoxy ketones and alkynes cocatalyzed by gold(I) and Yb(OTf)3. This new catalytic system based on a combination of gold(I) and Yb(OTf)3 allows facile transformation of epoxy alkynes to give novel indene derivatives in moderate to good yields under mild conditions. Moreover, we describe here the first observation of a transfer of a carbonyl group in a five‐membered carbocycle during gold‐catalyzed reactions. This proposed mechanism is corroborated by isotope‐labeling experiments (D and 13C). Furthermore, the probable role of each catalyst in this interesting domino reaction has been examined by 31P NMR experiments. The utilization of gold catalysts combined with rare‐earth metal salts offers a new concept for the design of catalyst combinations for domino or cascade reactions. 相似文献
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本文针对聚二甲基硅氧烷改性环氧树脂相溶性太差,性能不够理想等问题,提出用氰丙基替代部分甲基以减小聚硅氧烷与环氧树脂的溶度参数差,改善两相的相溶性。采用氨丙基封端的聚氰丙基甲基硅氧烷低聚体(表1)单独或与二乙烯三胺(固化剂)一同与双酚A环氧树脂反应,合成了一系列不同聚硅氧烷分子量和重量百分比的样品(表2)。并用示差扫描量热计(DSC)、动态力学谱(DMA)、光电子能谱(XPS)、接触角仪、扫描电子显微镜(SEM)、电子拉力试验机对其进行研究。结果表明在聚硅氧烷软段中引入氰丙基可提高两相的相溶性并使增韧效果明显改善。 相似文献
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Poly(dopamine) assisted epoxy functionalization of hexagonal boron nitride for enhancement of epoxy resin anticorrosion performance 下载免费PDF全文
Hexagonal boron nitride (h‐BN) is modified by a simple and green method based on self‐oxidation of dopamine and epoxy groups functionalized silane (KH560) grafting. The surface modification and microstructure of h‐BN are characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. The poly(dopamine) and epoxy groups not only increase the compatibility of the h‐BN and enhance its interaction with epoxy matrix but also exhibit a remarkable superiority in enhancing the anticorrosion performance of epoxy coatings. In addition, the anticorrosion mechanisms of h‐BN@PDA‐KH560 are tentatively discussed. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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采用二乙烯三胺(DETA)与聚丙二醇二缩水甘油醚(PPGDGE)反应合成出DETA-PPGDGE-DETA型的多元胺加成物,然后再用一定比例环氧树脂E-20封端加成,制备出了水性环氧树脂固化剂。红外光谱(IR)及飞行时间质谱(TOF-MS)验证了该水性环氧固化剂的结构。考察了不同反应条件对固化剂结构与性能的影响,结果表明,二乙烯三胺/聚丙二醇二缩水甘油醚环氧基物质的量比为10∶1,用沸点稍高的二乙二醇丁醚(DGBE)将体系中残留小分子DETA蒸除干净,环氧树脂E-20封端20%伯胺氢时,固化剂与环氧乳液混合后的涂膜性能最佳。 相似文献