Studies on Polymerization Activities by Soluble Catalysts Based on Compounds of Organotransition Metals and Aluminum Alkyls
作者:
Naoyuki Koide,
Kazuyoshi Iimura,
Masatami Takeda,
期刊:
Journal of Macromolecular Science: Part A - Chemistry
(Taylor Available online 1975)
卷期:
Volume 9,
issue 6
页码: 961-982
ISSN:0022-233X
年代: 1975
DOI:10.1080/00222337508081503
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
Polymerization activities of the soluble Ziegler-type of catalyst systems, Ti(OR)4-AlEt3, Ti(NEt2)4-AlMe3, and V(NEt2)4-AlEt3, were investigated. In the catalyst system of Ti(OR)4-AlEt3, formation of two types of Ti(III) compounds, i.e., Ti(OR)2Et and its bridged complex with aluminum alkyl, was confirmed by IR and ESR measurements. With the addition of donor molecule to the system, it was found that the polymer yield decreased remarkably and that the bridged complex dissociated into a single or uncomplex Ti(III) paramagnetic species. It has been concluded that the bridged structure of Ti(III) species was responsible for the polymerization activity of styrene. Two reaction products of Ti(NEt2)3Me and Al(NEt2)Me2were found by NMR spectroscopic observation with the Ti(NEt2)4-AlMe3catalyst system. From the kinetic study of polymerization of styrene, it was found that Ti(NEt2)3Me is an active species. An anionic mechanism was proposed for the styrene polymerization by Ti(NEt2)3Me. In the polymerization of MMA with the V(NEt2)4-AlEt3system, a difference in the tacticity of polymer was found to depend on the polymerization conditions, e.g., AI/V ratio and temperature. From an analysis of the tacticity of the polymer, the presence of two active sites in the propagation process is suggested.
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