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Ethylene and propylene polymerizations with the MgCl 2 ‐supported tris(acetylacetonato)chromium‐diethylaluminium chloride catalyst system
Author(s) -
Takawaki Kouichi,
Uozumi Toshiya,
Ahn CheolHee,
Tian Gonglu,
Sano Tsuneji,
Soga Kazuo
Publication year - 2000
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/1521-3935(20000901)201:14<1605::aid-macp1605>3.0.co;2-d
Subject(s) - polymer chemistry , catalysis , tacticity , polyethylene , monomer , polymerization , ethylene , molar mass distribution , polymer , chemistry , organic chemistry
Highly isotactic poly(propylene) with T m = 169.5°C and [mmmm] > 99% in high selectivity (I.I. > 99.9%) was prepared with the catalyst system Cr(acac) 3 /MgCl 2 ‐DEAC. 13 C NMR analysis of low molecular weight isotactic polypropylene indicates that the propylene monomer was inserted in the polymer‐metal bond via 1,2‐addition selectively. Polymerization activities and isospecificity of the catalyst markedly increase with decreasing Cr content in the catalyst. In ethylene homopolymerization, the Cr(acac) 3 /MgCl 2 catalyst showed almost constant activity for 3 h and produced high molecular weight polyethylene with narrow molar mass distribution.