苯乙烯间规聚合

STYRENE SYNDIOTACTIC POLYMERIZATION

对苯乙烯间规聚合的催化体系，聚合机理和研究现状等方面进行了较全面地综述。合成间规聚苯乙烯的催化体系主要由有机钛化合物与甲基铝氧烷组成，钛的配体对催化活性和产物间规度有很大影响。配位聚合时，苯乙烯分子是按二级插入方式进入分子链的，间规序列的形成是活性链末端苯基与前来配位的苯乙烯苯基相互排斥作用的结果。

Styrene syndiotactic polymerization with η 5 cyclopentadienyltrifurfuroxyl titanium(cat 1)/methylaluminoxane(MAO) and η 5 cyclopentadienyltribenzoxyltitanocene(cat 2)/MAO were researched respectively. The effect of temperature on catalytic efficiency, syndiotactic index and viscosity mean molecule weight, and polymerization kinetics, and Al/Ti molar ratio to polymerization were investigated. It is found that the optimum polymerization temperature for cat 1/MAO and cat 2/MAO are 60 ℃ and 65 ℃ respectively. The optimum Al/Ti molar ratios for cat 1/MAO and cat 2/MAO are 400 and 800 respectively. With the temperature going up from 30 ℃ to 70 ℃, the syndiotactic index of polymer is increase and the molecule weight of sPS is come down.