【作者】 李欢；

【导师】 孙义明；

【作者基本信息】 湖北工业大学 ， 材料学， 2010， 硕士

【摘要】 聚丙烯由于低廉的价格,优良的机械和热性能,是被广泛应用的通用塑料之一。但是其低温脆性大大限制了其推广。本文选用低温性能十分优良的液体硅橡胶对其进行增韧改性。因为聚丙烯和液体硅橡胶,不是热力学相容体系,本文通过熔融接枝的方法制备了PP接枝有机硅相容剂,来改善两相之间的界面作用。选用的接枝物有乙烯基封端的聚二甲基硅氧烷、乙烯基三乙氧基硅烷、γ-巯基丙基三乙氧基硅烷、N-β-胺基乙基-γ-胺基丙基-三甲氧基硅烷。通过流变仪的扭矩和红外测试证明成功制得了接枝物,并具体分析了其接枝机理。选用自制相容剂和硅烷偶联剂作为界面相容剂,通过扫描电镜对其低温冲击断面的观察、力学性能对比、界面张力计算得到结论,其中自制聚丙烯接枝乙烯基三乙氧基硅烷的增容效果最好。共混工艺对多相体系的力学性能也有很大的影响。通过对共混体系力学性能,流变性能、微观结构的对比,认为利用哈克流变仪对其进行共混时,温度用190℃～200℃,密炼8min得到的共混体系的力学性能最佳。对加成型液体硅橡胶和缩合型液体硅橡胶进行对比,发现加成型液体硅橡胶因为硫化无副产物,硫化完全,增韧效果更优,缩合型液体硅橡胶在硫化时析出极性小分子物质对两相界面结合产生不良影响,使得共混体系的力学性能受到影响。研究发现当加成型液体硅橡胶的含量为10份时,其改性效果最好,其在0℃、-24℃和-50℃时冲击强度分别为34.63KJ/m2、24.56 KJ/m2、17.11 KJ/m2,较纯PP分别提高了156.71%、135.25%、84.38%。其低温性能得到大大改善。通过-140℃～120℃的动态力学性能研究发现,加入自制界面相容剂聚丙烯接枝乙烯基三乙氧基硅烷,可以增强聚丙烯和液体硅橡胶的界面结合,改善两相间的力的传递使得橡胶粒子更容易成为应力集中点。当硅橡胶分散相粒径为0.9～1.0μm左右时,使共混体系有足够多的应力集中点,既可以引发因为银纹又可以终止银纹发展成为裂纹,达到最好的增韧改性效果。更多还原

【Abstract】 Polypropylene (PP) is one of main commodity polymer with widespread applications due to its good mechanical and thermal properties, as well as low cost.However,its impact proterties at low temperature is very poor,which limit its generalizing use. Liquid silicone rubbe has excellent low temperature flexibility.In this paper,two types of liquid silicone rubber which are two components additional type and condensation-type,were used to toughen polypropylene.The blends of PP and liquid silicone rubber are thermodynamically immiscible components.In order to improve their compatibilization, compatibilizer was synthesized with melt grafting method.Grafting reactants includes inyl-terminated polydimethylsiloxane,vinyl triethoxysilane, N-0-(Aminoethyl)-y-aminopropyl trimethoxysilane, y-mercaptopropyl triethoxy silame. And the tentative mechanism was discussed.Through the study of SEM, processing and mechanical properties,it showed that the compatibility between PP and liquid silicone rubber were improved most when the compatibilizer is PP-g- vinyl triethoxysilane.The mechanical properties of blends were effect by process conditions. The effects were discussed.Temperature of 190℃～200℃and mixing time of 8min were considered the optimum mixing conditions.The results of SEM, mechanical properties test and MFR indicate that the interfacial interaction between two components additional liquid silicone rubber and PP is stronger. Polarity substances were created when condensation-type vulcanzated.The impact strength of the composites at 0℃,-24℃,-50℃can reach 34.63KJ/m2、24.56 KJ/m2. 17.11 KJ/m2.Compared with pure PP,they are increased by 156.71%.135.25%.84.38%. Its impact proterties at low temperature is improved.The results of DMA tested between-140℃～120℃,the grafting produces are suitable compatibilizer and the interface can be improved by the compatibilizer.And when the particle size is about 0.9～1.0μm,the mechanical properties of blends are the best in the paper.更多还原