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Deviation from Single‐Site Behavior in Zirconocene/MAO Catalyst Systems, 1. Influence of Monomer, Catalyst, and Cocatalyst Concentration
Author(s) -
Frauenrath Holger,
Keul Helmut,
Höcker Hartwig
Publication year - 2001
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(20011201)202:18<3543::aid-macp3543>3.0.co;2-t
Subject(s) - monomer , catalysis , polymerization , polymer chemistry , chemistry , organic chemistry , polymer
The polymerization of 1‐hexene with the catalyst systems Cp 2 ZrCl 2 /MAO and Me 2 SiInd 2 ZrCl 2 /MAO is investigated in order to elucidate the nature of the active species in zirconocene/MAO catalyzed polymerizations. Varying monomer concentration and monomer conversion does not result in any unexpected behavior. However, changing catalyst and cocatalyst concentration leads to broadened, or even bimodal, molecular weight distributions under certain reaction conditions. These results may be interpreted in terms of a coexistence of two active species with different rates of propagation and of termination.