【作者】 门艳茹；

【导师】 杨贤金；

【作者基本信息】 天津大学 ， 材料学， 2004， 硕士

【摘要】 为了提高纳米TiO2的分散性能和与聚苯乙烯的相容性,本文采用钛酸酯偶联剂LICA38对纳米TiO2表面进行预处理,运用正交试验确定最佳的预处理工艺参数,并采用原位聚合工艺制备掺杂纳米TiO2的聚苯乙烯。采用DCA、XRD、FTIR、TEM、XPS、DSC、EDX、GPC等分析手段,对纳米TiO2预处理效果和掺杂材料的形貌、成分及性能进行分析,同时研究掺杂材料的拉伸性能和热性能。结果表明,预处理后纳米TiO2的动态接触角明显增大,偶联处理后的纳米粒子表面附着有机官能团使其极性减弱与水的润湿性下降,亲油性增强,粒子的分散性提高,表明钛酸酯偶联剂在纳米TiO2的表面发生化学吸附。正交试验结果显示较高的反应温度、较长的反应时间、适当的偶联剂用量有利于得到较好的偶联效果。采用80℃下预聚合6h,160℃后聚合10h, 0.25wt%的引发剂得到的纯PS不仅分子量较高,而且拉伸性能好。经过偶联剂预处理的纳米TiO2在PS基体中可以以纳米尺寸存在,且分散比较均匀,使纳米TiO2掺杂PS的拉伸强度有一定的提高,而且纳米TiO2只有在一定含量下掺杂才有助于提高PS的拉伸性能。热性能分析结果表明PS/ TiO2掺杂材料的热分解温度高于纯PS的热分解温度,并且玻璃化温度也得到提高。纳米TiO2不仅没有阻碍聚合,而且不断增大的PS自由基连接到纳米TiO2表面后反而具有更大的活性,从而聚合物的分子量增高。更多还原

【Abstract】 To enhance the dispersity and the consistency of nano-TiO2, the surface organic modification of nano-TiO2 particles with LICA38 was studied in this paper, a cross-cut test was employed to optimize the process of pretreatment in order to confirm the best craft parameter. And the technology of doping nano-TiO2 in polystyrene with free-radical polymerization was also studied. DCA, XRD, FTIR, TEM, XPS, TG, DSC, EDX and GPC measurements were used to analyze the effect of pretreatment, the surface morphology, elements and performance of the specimen. The tensile tests for the PS doped nano-TiO2 were also discussed. Results showed that the dynamic contact angle of nano-TiO2 treated with LICA38 was bigger than nano-TiO2 untreated, which indicated that chemical adsorption was occurred between LICA38 and the surface of nano-TiO2. The oil-solubility of nano-TiO2 was enhanced and the dispersion of nano-TiO2 was improved. The results of cross-cut test indicated that the higher reaction temperature, the longer reaction time and proper coupling agent consumption were favorable to obtain better coupling effect. The pure PS that polymerized at 80℃ for 6 hours, then polymerized at 160℃ for 10 hours, with 0.25 wt % coupling agent, has not only higher molecular weight but also better tensile performance.Nano-TiO2 treated with LICA38 could exist with the size of nanometer in PS matrix, and the dispersion of nano-TiO2 was homogeneous, which improved the tensile strength of PS doped with nano-TiO2 obviously, and nano-TiO2 could contribute to improve the tensile performance of PS when only a certain content nano-TiO2 was doped in PS. Thermal performance test indicated that the thermal decomposition temperature of PS doped with nano-TiO2 was higher than that of pure PS, and the glass transition temperature of PS doped with nano-TiO2 was improved. Nano-TiO2 did not hindered polymerization, and the increasing free-radicals of PS had greater activation after they adsorbed to nano-TiO2 surface, so the molecular weight of polymer was heightened.更多还原