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开发了一种由顺酐直接加氢高选择性及高转化率制备琥珀酸酐的新方法,研究结果表明:钯三苯基膦催化体系对顺酐加氢具有较高的反应活性.在所考察的反应条件下,此催化剂体系对琥珀酸酐的选择性为100%,无其他副产物生成.并考察了三苯基膦/钯摩尔比,反应温度,氢气压力,催化剂和顺酐浓度对顺酐催化加氢生成琥珀酸酐的影响.在反应条件为PdCl2=125×10-3mol/L,n(顺酐)/n(Pd)≤2000,n(三苯基膦)/n(Pd)=4,T=373~393K,25MPa的氢压下于乙二醇二甲醚溶剂中反应1h以上,可使顺酐的转化率大于90%. 相似文献
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Hyuk-Soo Moon Byung-Kyu Ryoo Jung-Ki Park 《Journal of Polymer Science.Polymer Physics》1994,32(8):1427-1435
This paper describes the nonisothermal crystallization of molten blends of two semicrystalline polymers, polypropylene (PP) and Nylon-6 (N6). A discussion details the effect of the concentration of the compatibilizing agent, maleic anhydride grafted polypropylene (MAH-g-PP), on the crystallization behavior. The crystallization thermograms showed one crystallization peak or two crystallization peaks, which were significantly affected by the presence of MAH-g-PP. The crystallization temperature of N6 levels off down as the concentration of MAH-g-PP increases, whereas that of PP stays at a roughly constant temperature. These blends containing the compatibilizing agent exhibited concurrent crystallization at the crystallization temperature of PP. The crystallization behavior are also studied by optical microscopy under crossed polarizers. © 1994 John Wiley & Sons, Inc. 相似文献
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Reactivity and swelling of nanometer films of alternating maleic anhydride copolymers were investigated in dependence on the kind of comonomer and molar mass of copolymer in aqueous solution at pH 7.4 and pH 3.0 in order to reveal their characteristics under physiological conditions. Fully hydrolyzed (maleic acid) chains of the copolymers with styrene, propene, and ethylene comonomers covalently bound to SiO2 substrates showed a "mushroom" swelling behavior at pH 7.4 with a layer thickness scaling of N3/5. Decreasing the environmental pH was found to induce a comonomer-dependent shrinking or collapse of the immobilized polymers due to the change in ionization. From the swelling kinetics of non-hydrolyzed chains, the time constants and characteristics of swelling and anhydride hydrolysis were determined and found to depend on the type of comonomer. The short- and long-term swelling kinetics [l approximately t and approximately ln(t)1/2] were found to be in agreement with theoretical models of polymer swelling, while at intermediate time scales enhanced swelling was observed due to hydrolysis reaction of maleic anhydride groups. The findings elucidate the variety of properties of maleic anhydride copolymer films under physiological conditions, which can advantageously be applied for biofunctionalization of different templates. 相似文献
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Maleated glycidyl 3‐pentadecenyl phenyl ether with styrene: synthesis and application as compatibilizer in SBR/silica composite 下载免费PDF全文
Maleated glycidyl 3‐pentadecenyl phenyl ether with styrene (MGS) was synthesized from glycidyl 3‐pentadecenyl phenyl ether (GPPE), maleic anhydride (MAH) and styrene (St) in the presence of AIBN initiator at 80°C, and then the resultant MGS was applied as a compatibilizer to prepare SBR/silica composites. Meanwhile, the commercial compatibilizer bis‐(triethoxysilylpropyl) tetrasulfide (named Si69) added into composite was also prepared for comparison purpose. The synthetic MGS structure was characterized by GPC and FTIR, and SBR/silica compounds with different compatibilizer were analyzed using RPA, DMA and so on. The results showed that M?n and M?w of MGS were 19,538 g/mol and 23,790 g/mol, respectively. The curing time of compounds with MGS increased, whereas the maximum and minimum torques decreased. The addition of MGS decreased Payne effect of SBR/silica compounds, which implied an improvement of silica dispersion in the compounds. Bound rubber content of compound with MGS was about 1.7 times higher than the absence and 1.5 times higher than that with Si69. The tensile strength of the composites was improved by increasing compatibilizer loading, and the optimum value was observed at 6 phr of MGS. Meanwhile the use of MGS can improve the anti‐aging property of composite. According to DMA, the tanδ value at 0°C of composite with MGS was higher than composite without compatibilizer suggesting that MGS can improve the wet skid resistance of composite. The SEM analysis revealed that introduction of MGS enhanced the compatibility between SBR and silica. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献