支化及超支化聚乙烯

系统综述了近年来制备支化及超支化聚乙烯的研究进展。支化聚乙烯可通过乙烯自由基聚合和过渡金属催化剂催化乙烯聚合与共聚合成。Ziegler-Natta催化剂和茂金属催化剂催化乙烯与α-烯烃共聚得到支化聚乙烯;后过渡金属催化剂催化乙烯聚合,通常得到不同支化程度的聚乙烯;某些α-二亚胺后过渡金属催化剂在不同的乙烯压力和聚合温度下,能得到从线型到超支化,甚至树枝状等一系列不同拓扑结构的聚乙烯。

Branched and Superbranched Polyethylene

Advances on technologies of preparing branched and superbranched polyethylene were reviewed. Branched polyethylene could be synthesized by radical and coordination polymerization. Over Ziegler-Natta catalysts or metallocene catalysts, branched polyethylenes were prepared by copolymerization of ethylene with α-olefin. late-transition metal catalysts were used in ethylene polymerization usually to produce branched polyethylene with different branching degree. By changing ethylene pressure and polymerization temperature,linear, branched,superbranched and even dendritic polyethylenes could be synthesized over some α-diimine late-transition metal catalysts.