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Comprehensive Investigation of Catalyst Structure and Polymerization Conditions for Chain Branching in Ethylene Polymerization with Phillips‐Type Catalysts
Author(s) -
Tonosaki Kiwamu,
Taniike Toshiaki,
Terano Minoru
Publication year - 2011
Publication title -
macromolecular reaction engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.37
H-Index - 32
eISSN - 1862-8338
pISSN - 1862-832X
DOI - 10.1002/mren.201000053
Subject(s) - polymerization , branching (polymer chemistry) , catalysis , polyethylene , polymer chemistry , coordination polymerization , ethylene , chain transfer , olefin polymerization , chain growth polymerization , materials science , living polymerization , ionic polymerization , chemistry , polymer , chemical engineering , solution polymerization , organic chemistry , radical polymerization , engineering
Control factors of branching in ethylene polymerization on CrO x /SiO 2 catalysts were comprehensively investigated by varying catalyst structure and polymerization conditions. Variation of the polymerization conditions such as polymerization time, catalyst concentration, polymerization temperature, and alkylaluminum concentration indicated that the branch frequencies in produced polyethylene were highly relevant to the polymerization yield, plausibly through concentration of in‐situ‐produced α‐olefins. A method to fairly compare the branching abilities of different catalysts was proposed. The application of the method to model catalysts with controlled chromium nuclearity proved an important role of dinuclear species in methyl branching through olefin metathesis.