Journal of the Brazilian Chemical Society | |
Styrene polymerization by nickel and titanium catalysts based on tris(pyrazolyl)borate ligands | |
Maria C. A. Kuhn1  Jaqueline L. Da Silva1  Adriana C. A. Casagrande1  Osvaldo L. Casagrande Jr.1  | |
[1] ,Universidade Federal do Rio Grande do Sul Instituto de Química Porto Alegre RS ,Brazil | |
关键词: nickel; titanium; tris(pyrazolyl)borate ligand; polystyrene; | |
DOI : 10.1590/S0103-50532008000800016 | |
来源: SciELO | |
【 摘 要 】
Styrene polymerization with a series of nickel and titanium complexes based on sterically hindered tris(pyrazolyl)borate ligands, TpMs = HB(3-mesityl-pyrazolyl)3 and TpMs* = HB(3-mesityl-pyrazolyl)2(5-mesityl-pyrazolyl) have been studied in the presence of MAO cocatalyst under various polymerization conditions. All complexes showed to be active for styrene polymerization producing almost exclusively atactic polystyrene. The catalytic activities as well as the styrene conversions with nickel complexes were higher than those with the titanium analogues. Higher activities were found at 80 ºC. Polystyrene properties are substantially affected by the reaction conditions such as temperature of polymerization, time, and [Al]/[M] molar ratio. The GPC results showed that the molecular weight (Mw) of the polystyrene is sensitive to the temperature of polymerization varying from 16,300 to 138,300 g mol-1.
【 授权许可】
CC BY
All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License
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