聚苯乙烯负载单茂然／RMgBr催化苯乙烯聚合的研究

合成了聚苯乙希负载的单茂钛催化剂，并与格氏试剂（RMgBr）组成催化体系。考察了聚合温度、催化体系的组成、单体浓度、 Mg/Ti摩尔比、聚合时间等条件对苯乙烯聚合的影响。结果表明，采用负载单茂钛催化剂与助催化剂格氏试剂反应，可以制备出具有较高催化活性的催化剂。DSC表明，不溶于沸丁酮的聚苯乙烯具有一定的定向性。聚合物^13G-NMR测试表明，该催化体系的聚合机理可能是：苯乙烯插入M－C键，以一级插入反应进行链增长，最后以β－H及β－苯基消除反应致链终止。

Study on the Polymerization of Styrene with Polymer-Supported Metallocene/Grignard Reagent (RMgBr) Catalytic System

The polymer-supported metallocene/Grignard reagent catalyst for polymerization of styrene was prepared. Polymerization of styrene by supported CpTi(OBu)3/RMgBr catalytic system was investigated under different polymerization temperatures、 different Grignard reagents, different monomer concentrations, Mg/Ti molar ratios and polymerization time. The structure of the polymers insoluble in 2-butanone was characterized by 13C-NMR. The results indicated that the catalytic system has rather good catalytic activity. The results of DSC demonstrated that these polymers had a certain degree of stereospecificity. We supposed that they were syndiotactic-rich polystyrene and the possible polymerization mechanism is as follows: the monomer coordinated with the active center inserts in the metal-C bond in the primary fashion and the propagation of polymer chains terminates by the elimination of β-H or β-Ph to form a molecule with an unsaturated end group.