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以氰乙酸乙酯和多聚甲醛为原料合成α-氰基丙烯酸乙酯,无催化合成的最优反应条件是:n(CNCH2COOC2H5):n「(HCHO)n」=1.00:1.05、反应温度82~85℃、溶剂(乙酸乙酯)用量200mL/mol氰乙酸乙酯、反应时间3h,合成收率58.2%(质量分数≥99.0%)。 相似文献
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本文采用低分子量聚醚(Mn=300~500)掺入适量聚醚(Mn=3000),在引发剂作用下接枝丙烯腈、苯乙烯合成低分子聚合物多元醇(POP)。研究了反应温度、反应时间对产物的影响以及合成配比与性能的关系。发现随着低分子量聚醚份量增大,所合成的聚合物多元醇粘度增大,聚醚接枝就更加困难。POP羟值与其平均分子量呈线性关系,平均分子量增加其POP的羟值减小,而粘度则随着羟值的递增而增加。用此低分子量POP合成聚氨酯硬泡,聚醚接枝AN/St或St后比未接枝聚醚生成的硬泡压缩强度分别提高了47.8%和69.7%,全部接枝苯乙烯其硬泡压缩强度更高,是由于苯环刚性基团有利于提高其泡沫的压缩强度 相似文献
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采用水热加工技术研究(Mn,Zn)Fe2O4晶体粉末的合成条件,对水热体系的碱度、温度、时间进行了系统实验.结果表明在pH=7~12.5范围内可有效合成(Mn,Zn)Fe2O4.当温度在190~220℃时,完成合成所需的时间为1~2h,提高碱度有利于合成反应.本文还初步探讨了(Mn,Zn)Fe2O4的合成机理,为扩大实验提供依据. 相似文献
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锡在碱土焦磷酸盐中发光特性的研究 总被引:1,自引:0,他引:1
本文合成了Sr2P2O7∶Sn,(Sr1-xCax)2P2O7∶Sn和(Sr0.9Ca0.1)2P2O7∶Sn三个体系系列样品,研究了它们的发光光谱,详细地讨论了Sn2+含量对Sr2P2O7∶Sn和(Sr0.9Ca0.1)2P2O7∶Sn以及Ca2+含量对(Sr1-xCax)P2O7∶Sn发光特性的影响 相似文献
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合成酯基锡化合物的新方法酯基锡化合物(R'OCOCHRCH)nSnCl4-n(n=1,2。R=H,CH3。R'=烷基)是七十年代后期由英国Hutton小组首先开发出来的一类有机锡化合物[1],以它为中间体与巯基乙酸酯、硬脂酸、月桂酸等反应合成出了一类... 相似文献
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本文用高温固相反庆法合成了(Sr1- x Mx )2P2O7 ∶Sn (3.3×10- 2)和(Sr0.9Mg0.1)2P2O7∶xSn 两个体系系列样品,在紫外线激发下,详细测定了它们的激发和发射光谱,讲座了Mg 含量对(Sr1- xMgx)2P2O7∶Sn 和Sn 含量对(Sr0.9Mg0.1)2P2O7∶xSn 体系发光性能的影响。 相似文献
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Ti(OC4H9)4催化酯交换合成碳酸二苯指的研究 总被引:12,自引:0,他引:12
研究了以Ti(OC4H9)4为催化剂,苯酚与碳酸二甲酯(DMC)经酯交换法合成碳酸二苯酯(DPC)的工艺。在常压下,160~190℃,当n(Ti(OC4H9)4:n(PhOH)=0.012:1,n(PhOH):n(DMC)=4:1,反应时间8h,总转化率为28.3%,DPC的产率为25.3%,碳酸甲苯酯(MPC)的产率为3.0%,产物中无苯甲醚,DPC的选择性为89.4%。 相似文献
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Homogenous waterborne polyurethane/polyacrylate emulsions were synthesized based on the prepared polyurethane and polyacrylate through a facile process. The attention was attracted to the miscibility and performance of waterborne polyurethane and polyacrylate. The structures and properties of waterborne polyurethane and waterborne polyurethane/polyacrylate samples were characterized by using Fourier transform infrared spectroscopy, transmission electron microscope, X-ray photoelectron spectroscopy, X-ray diffractometer, thermogravimetric, and so forth, as well as solid content and tensile testing. The results showed that the micro morphology of waterborne polyurethane/polyacrylate emulsion presented single-phase structure with the stoichiometric polyacrylate content increasing from 33% to 80% to waterborne polyurethane. The waterborne polyurethane/polyacrylate films surface is rich in polyacrylate phase. Meanwhile, waterborne polyurethane/polyacrylate composites showed significant improvement in thermal stability and elongation at break, smaller particle size and narrower particle size distribution comparing with waterborne polyurethane. 相似文献
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The performance of acrylic polyurethane composite coating and aliphatic urethane composite coating in 3.5% NaCl solution under ultra-violet radiation was studied with methods of EIS, SEM and FTIR. For aliphatic polyurethane coating, the coating resistance decreased and the coating capacitance and porosity increased more quickly than acrylic polyurethane coating. The acrylic polyurethane composite coatings showed better performance than aliphatic polyurethane composite coatings. IR spectra showed that under UV irradiation conditions, the failure mechanism of the two polyurethane coatings was the transformation of sec-amide to primary amides. The fractured bonds in acrylic polyurethane were mainly C–O bonds, while in aliphatic polyurethane they were mainly C–N bonds. The lower protection property of aliphatic polyurethane coating may be mainly attributed to the C–N bonds which are more liable to be broken. 相似文献
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刘道春 《化学推进剂与高分子材料》2012,10(5):46-52
根据聚氨酯材料在轮胎产业中的发展现状,论述了聚氨酯轮胎的研制及其应用材料,分析了聚氨酯轮胎的性能优势,展望了聚氨酯轮胎的市场前景,同时指出了聚氨酯轮胎的未来发展趋势。 相似文献
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聚氨酯胶黏剂在汽车上的应用及研究进展 总被引:2,自引:1,他引:2
介绍了几种聚氨酯胶黏剂如单组分湿固化聚氨酯挡风玻璃密封胶、双组分聚氨酯胶黏剂、水性聚氨酯胶黏剂、聚氨酯反应性热熔胶等在汽车制造和修理上的应用现状及研究进展,重点介绍了应用最为广泛的单组分湿固化聚氨酯挡风玻璃密封胶。指出汽车用聚氨酯胶黏剂将向环保和高性能方向发展。 相似文献