亚环烷基桥联茂金属催化乙烯与α-烯烃共聚合的研究

COPOLYMERIZATION OF ETHYLENE AND α-OLEFINS WITH CYCLOALKYLIDENE-BRIDGED METALLOCENE/MAO

采用两种亚环己基桥连的茂金属催化剂[(CH_2)_5C](t-BuCp)_2ZrCl_2(Ⅰ)、[(CH_2)_5C](t-BuCp)_2TiCl_2(Ⅱ),在助催化剂甲基铝氧烷的活化下,研究了乙烯与α-烯烃共聚合反应,考察了催化剂的结构对产物性能的影响。相同条件下,催化剂Ⅰ的共聚活性略高于催化剂Ⅱ。随着共聚单体浓度的增加,乙烯与1-己烯、1-辛烯共聚均可产生共单体效应,共聚物的熔点和结晶度均随共聚单体浓度的增加而降低。

Copolymerization of ethylene and a-olefins via novel cyclohexylidene-bridged metallocenes [- （CH2） 5 C] （t-BuCp） 2 ZrC12 （ Ⅰ ） or [ （CH2） 5C-] （t-BuCp） 2 TIC12 （ Ⅱ ） activated with MAO was studied. The effects of catalyst structure on the catalytic properties were investigated. In copolymerization, the activity of metallocene Ⅱ is lower than that of catalyst I. Both catalyst l and Ⅱ present a comonomer effect in copolymerization activity by increasing the initial concentration of a-olefin （1-hexene, 1-octene）. The melting points of the copolymers decrease with increasing comonomer. The enthalpies of fusion decrease greatly due to the lower crystallinity.