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化工学报  2015 

稀土催化苯乙烯配位聚合制备富含间规聚苯乙烯

DOI: 10.11949/j.issn.0438-1157.20150665, PP. 3084-3090

Keywords: 催化剂,聚苯乙烯,聚合,间规度,动力学

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Abstract:

由稀土羧酸盐(RE)、烷基铝(AL)与含氯活化剂(CL)组成的催化体系用于苯乙烯(St)定向聚合,研究了催化剂配比及反应条件对苯乙烯聚合反应动力学和产物结构的影响,采用凝胶渗透色谱仪(GPC)、核磁共振波谱仪(13CNMR)、偏光显微镜(POM)及差示扫描量热仪(DSC)等分析测试手段表征聚苯乙烯(PS)的分子量及其分布、立构规整度、结晶性及热性能。实验结果表明:含氯活化剂为氯代羧酸酯(CE)时,聚合速率对单体浓度均呈现一级动力学关系,表观增长活化能为34.4kJ·mol-1,可得到数均分子量(Mn)为2.8×105~6.8×105g·mol-1、熔点为160~260℃的可结晶聚苯乙烯。对于CE与卤代烃(RX)复合的催化体系,可明显提高催化活性,当聚合温度为50、60、70℃时,表观增长速率常数可分别提高3.9倍、5.6倍及9.2倍,分子量降低(Mn为0.5×104~5.0×105g·mol-1),并可得到间规度[rrrr]约为60%的可结晶聚苯乙烯,熔点为170~240℃。

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