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Single site polymerization of ethylene and 1‐olefins initiated by rare earth metal complexes
Author(s) -
Ihara Eiji,
Nodono Mitsufumi,
Yasuda Hajime,
Kanehisa Nobuko,
Kai Yasushi
Publication year - 1996
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/macp.1996.021970611
Subject(s) - methylaluminoxane , chemistry , polymerization , ethylene , polyethylene , polymer chemistry , metal , molar mass distribution , hexene , stereospecificity , stereochemistry , medicinal chemistry , metallocene , organic chemistry , catalysis , polymer
Ethylene polymerization was explored by using the racemic SiMe 2 (2‐SiMe 3 ‐4‐tBuC 5 H 2 ) 2 Sm(THF) 2 complex ( 1 ), meso type Me 2 Si(Me 2 SiOSiMe 2 )(3‐tBuC 5 H 2 ) 2 Sm‐(THF) 2 complex ( 2 ), and C 1 ‐symmetric SiMe 2 [2,4‐(SiMe 3 ) 2 C 5 H 2 ][3,4‐(SiMe 3 ) 2 C 5 H 2 ]‐Sm(THF) 2 complex ( 3 ) in the absence of methylaluminoxane. As a result, the meso isomer exhibits highest initiating activity, but the number‐average molecular weight is relatively low ( M n = 50000). In contrast to these complexes, the C 1 ‐symmetric complex provides the highest molecular weight of polyethylene, M n > 1, with relatively narrow molecular weight distribution ( M w / M n = 1.60). Only the racemic complex exhibits good activity for the polymerization of propylene, 1‐pentene and 1‐hexene.