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Stopped‐flow polymerizations of ethene and propene in the presence of the catalyst system rac ‐Me 2 Si(2‐methyl‐4‐phenyl‐1‐indenyl) 2 ZrCl 2 /methylaluminoxane
Author(s) -
Busico Vincenzo,
Cipullo Roberta,
Esposito Valentina
Publication year - 1999
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/(sici)1521-3927(19990301)20:3<116::aid-marc116>3.0.co;2-a
Subject(s) - methylaluminoxane , propene , ethylene , polymerization , metallocene , monomer , catalysis , polymer chemistry , chemistry , kinetics , homogeneous , ziegler–natta catalyst , polymer , organic chemistry , thermodynamics , physics , quantum mechanics
The kinetics of ethene and propene polymerization at 20–60°C in the presence of the homogeneous catalyst system rac ‐Me 2 Si(2‐methyl‐4‐phenyl‐1‐indenyl) 2 ZrCl 2 /methylaluminoxane was investigated by means of stopped‐flow techniques. The specific rate of chain propagation, measured at the very short reaction times typical of this method, turned out to be ≈10 2 times higher for ethene than for propene; this suggests that diffusion limitations through the poly(ethylene) precipitating at longer reaction times may be responsible for the fact that the two monomers polymerize instead at comparable rates under “standard” conditions. It was also found that the concentration of active sites is significantly lower than the analytical Zr concentration.