Effects of cocatalyst on structure distribution of propylene polymers catalyzed by rac-Me₂Si(Ind)₂ZrCl₂/aluminoxane

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• 作者：Wang ; Wei ; Fan ; Zhiqiang ; Zhu ; Yinbang ; Zhang ; Yonghui ; Feng ; Linxian
• 关键词：Polypropylene ; Ansa-zirconocene ; Cocatalyst effect ; Structure distribution
• 刊名：European Polymer Journal
• 出版年：2002
• 出版时间：August, 2002
• 年：2002
• 卷：38
• 期：8
• 页码：1551-1558
• 全文大小：193 K

文摘

Propylene polymerization and propylene/1-octene copolymerization were studied using rac-Me₂SiInd₂ZrCl₂(1)/MAO or rac-Me₂SiInd₂ZrCl₂/(MAO+TIBA) as catalyst (methyl aluminoxane, MAO; AliBu₃, TIBA). The structure distribution of the polymers was characterized by temperature gradient extraction fractionation or precipitation fractionation, as well as by DSC analysis of the thermal segregated samples. By comparing the structure distribution of polypropylene and propylene-1-octene copolymer synthesized by 1/MAO and 1/(MAO+TIBA), it is found that adding TIBA in the catalyst system increase the blockiness of the polymer chain, especially in the copolymerization system. It is assumed that, when iso-butyl is incorporated in the aluminoxane, ion pair of the active center and the aluminoxane counter ion may exist in different states that show different catalytic behaviors, resulting in the formation of polymers with block structure.