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Lifetime of growing polymer chain in stopped‐flow propene polymerization using pre‐treated Ziegler catalysts
Author(s) -
Mori Hideharu,
Yamahiro Mikio,
Terano Minoru,
Takahashi Masato,
Matsukawa Tetsuya
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/(sici)1521-3935(20000201)201:3<289::aid-macp289>3.0.co;2-m
Subject(s) - polymerization , catalysis , propene , polymer , polymer chemistry , chemistry , yield (engineering) , molar mass distribution , chain termination , melt flow index , radical polymerization , organic chemistry , materials science , copolymer , composite material
The lifetime of a growing polymer chain of monoester‐type and diester‐type supported catalysts was investigated by the stopped‐flow polymerization technique. A linear correlation of the polymerization time with both the polymer yield and the molecular weight was observed for the monoester‐type supported catalyst until a certain time period (0.2 s), where the growing polymer chain is still active. The activity of the diester‐type supported catalyst was found to increase gradually throughout the polymerization (0–1.2 s). The polymer yield and the molecular weight are proportional to time up to 1.2 s when the pre‐treatment of the diester‐type supported catalyst was conducted with triethylaluminium. The active sites on the pre‐treated catalyst exert a longer lifetime (at least 1.2 s) compared with that on the monoester‐type and diester‐type supported catalysts without pre‐treatment. Kinetic studies indicated that the pre‐treatment influences not only the number of active sites, but also the ratio of isospecific active sites to aspecific ones formed on the supported catalyst.