活性自由基聚合反应合成超支化聚苯乙烯及其性能研究

STUDIES ON THE PREPARATION AND PROPERTIES OF HYPER- BRANCHED POLYSTYRENE FROM LIVING RADICAL POLYMERIZATION

以氯甲基化苯乙烯 (CMS)、苯乙烯、2 ,2′-联吡啶 (Bpy)和 Cu Cl组成过渡金属催化原子转移自由基聚合反应体系 ,通过自缩合乙烯基聚合反应合成了带有端双键的超支化聚苯乙烯 (HBPS)。在此基础上 ,研究了 HBPS的共聚合反应行为。并且考察了少量 HBPS的引入对聚碳酸酯熔体流动性能和其它性能的影响。研究结果表明 ,以 Bpy/Cu Cl作为络合催化剂 ,CMS和苯乙烯可以顺利进行自缩合乙烯基聚合反应合成不同支化程度的 HBPS。由于端双键的存在 ,HBPS可以与苯乙烯进行常规自由基共聚合反应合成分子量更高的支化聚苯乙烯。在聚碳酸酯中混入少量的 HBPS,可以明显降低其熔体粘度、改善加工性能 。

A series of hyperbranched polystyrene containing only one double bond on their focal points have been prepared from chloromethylstyrene and styrene by metal catalyzed living radical polymerization catalyzed by the complex of CuCl/2, 2′ bipyridyl. The copolymerization of HBPS with styrene initiated by BPO was investigated and branched polystyrene was prepared. These polymers were characterized by using 1H NMR, inherent viscosity determination and gel permeation chromatography. It was proved that HBPS can be more easily dissolved in solvent compared with linear polystyrene, the polymer solution also exhibits lower viscosity. As expected branched polystyrene from copolymerization of HBPS and styrene also exhibits improved solubility in solvents. Studies on the blend of polycarbonate and HBPS indicated that HBPS is an effective modification agent of the processibility of polycarbonate. The mechanical and thermal properties of the blend are almost the same as those of polycarbonate, except slight decrease in elongation strength, but the melt index has increased more than 25 percent.