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High temperature polymerization of propylene catalyzed by MgCl 2 ‐supported Ziegler–Natta catalyst with various cocatalysts
Author(s) -
Wang Qi,
Lin Yuanzhi,
Zhang Zhenhua,
Liu Boping,
Terano Minoru
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.21964
Subject(s) - natta , ziegler–natta catalyst , tacticity , polymerization , catalysis , polymer chemistry , polymer , reactivity (psychology) , mass fraction , materials science , chemistry , organic chemistry , medicine , alternative medicine , pathology
Four cocatalysts, referred to as ethylaluminoxanes, were synthesized by the reaction between triethylaluminium (AIEt 3 ) and water under various molar ratios of H 2 O/Al at −78°C. Aluminoxanes were used as cocatalysts for a MgCl 2 ‐supported Ziegler–Natta catalyst for propylene polymerization at temperatures ranging from 70 to 100°C. When the polymerization was activated by AlEt 3 , the activity as well as the molecular weight and isotacticity of the resulting polymer gradually dropped as the temperature varied from 70 to 100°C. When ethylaluminoxane was employed as the cocatalyst, good activity and high molecular weight and isotacticity were obtained at 100°C. Furthermore, when the cocatalyst varied from AlEt 3 to ethylaluminoxane, the atactic fraction and polymer fraction with moderate isotacticity decreased and the high isotactic fraction slightly increased, which indicated that the variation of the cocatalyst significantly affects the isospecificity of active sites. It was suggested that the reactivity of the Al‐Et group and the size of the cocatalyst were correlated to the performance of the Ziegler–Natta catalyst at different temperatures. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1978–1982, 2006