聚苯乙烯负载单茂钛/RMgBr催化苯乙烯聚合的研究

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

合成了聚苯乙烯负载的单茂钛催化剂 ,并与格氏试剂 (RMg Br)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 .聚合物的 1 3C- 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

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 13 C 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.