不同内给电子体催化剂对乙烯和丙烯共聚合的影响

Effect of Ziegler-Natta catalysts with different internal electron donors on copolymerization of propylene and ethylene

研究了MgCl2/TiCl4/邻苯二甲酸二异丁酯和MgCl2/TiCl4/9,9-二甲氧基甲基-芴两种催化剂体系催化乙烯和丙烯共聚合的规律、共聚物的热性能及动态力学性能。两种催化剂在40℃催化乙烯和丙烯共聚合时,催化剂活性随着乙烯含量的增加先增后降。对于含有二酯型内给电子体的催化剂,n(C2H4)为10%时,催化剂活性最大;对于含有二醚型内给电子体的催化剂,n(C2H4)为30%时,催化剂活性最大,且二醚型催化剂的活性高于二酯型催化剂。在乙烯含量较低时,用二酯型催化剂催化合成的共聚物中含有更多的嵌段结构,而二醚型催化剂催化合成的共聚物更趋于无规结构。当反应气中乙烯占多数时,共聚物不再具有长的聚丙烯链段,而出现长的聚乙烯链段。

The authors studied the rules in copolymerization of ethylene and propylene catalyzed by either MgCl2diisohutyl phthalate （DIBP） or MgCl2/TiCl2/9,9-dimethoxymethyl fluorene （BMF） and analyzed the resultant copolymer＇s thermal and dynamic mechanical properties. The catalytic activity increased at first and then decreased as ethylene content rose when catalyzing the reaction at 40℃ with either of catalysts. The catalytic activity reached its maximum value when using the catalyst with DIBP as internal electron donor and setting n（C2H4） at 10% or using the catalyst with BMF and setting n（C2H4） at 30%; the latter catalyst system had higher activity than the former. Under the condition of low ethylene content, more block chain segments occurred in the copolymer prepared by DIBP catalyst and whereas, random chain structure appeared in the copolymer synthesized with BMF catalyst. Once the ethylene accounted for the majority of the feed gas, long chain segments of polyethylene instead of polypropylene, was formed in the copolymer.