文献类型：期刊文献

英文题名：Effect of Alkyl Aluminums on Ethylene Polymerization Reactions with a Cr-V Bimetallic Catalyst

作者：Liu, Bao[1];Tian, Zhou[2];Jin, Yulong[1];Zhao, Ning[1];Liu, Boping[1]

机构：[1]East China Univ Sci & Technol, State Key Lab Chem Engn, Meilong Rd 130, Shanghai 200237, Peoples R China;[2]East China Univ Sci & Technol, Key Lab Adv Control & Optimizat Chem Proc, Minist Educ, Meilong Rd 130, Shanghai 200237, Peoples R China

年份：2018

卷号：12

期号：2

外文期刊名：MACROMOLECULAR REACTION ENGINEERING

收录：;EI(收录号：20180504689155);WOS:【SCI-EXPANDED(收录号:WOS:000430181800003)】；

基金：This work was financially supported by the National Natural Science Foundation of China (21406061, 21674036) and the Shanghai Municipal Natural Science Foundation (14ZR1410600).

语种：英文

外文关键词：alkyl aluminum; bimetallic catalyst; cocatalyst; ethylene polymerization; pre-reduction

摘要：The effect of introducing various types of alkyl aluminums directly into the catalyst and/or in the polymerization process as cocatalyst on the efficiency of a Cr-V bimetallic catalyst for ethylene polymerization is systematically investigated. Results indicate that polymerization activity, kinetic behavior, and polymer properties of the Cr-V catalyst are strongly affected by using alkyl aluminums in different stages of polymerization, due to the different responses and sensitivities of the two metal centers to alkyl aluminum. When employed as cocatalyst, triisobutyl aluminum gives high activity and polyethylene with relatively low molecular weight, while diethylaluminum chloride cocatalyzes the production of ultra-high molecular weight polyethylene but with very low activity. On the other hand, the pre-reduction of the bimetallic catalyst by alkyl aluminums has a marked promotion effect on catalyst efficiency. It is suggested that the addition of alkyl aluminum to the catalyst and to the reactor as cocatalyst are more or less equivalent in their effects on the improvement of polymerization activity, but they behave in different ways to affect polymer properties.