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Polymerization of 1,4‐butadiene over MgCl 2 ‐supported cobalt catalysts combined with trimethylaluminium
Author(s) -
Takeuchi Masaki,
Shiono Takeshi,
Soga Kazuo
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.1996.021970226
Subject(s) - polybutadiene , polymerization , polymer chemistry , molar mass distribution , ethylene , chemistry , cobalt , catalysis , chain transfer , chain propagation , solution polymerization , copolymer , polymer , organic chemistry , radical polymerization
MgCl 2 ‐supported Co catalysts with different loading amounts were prepared from the reaction of CoBr 2 [P(C 6 H 5 ) 3 ] 2 or CoBr 2 (C 5 H 5 N) 2 and MgCl 2 in toluene solution. Polymerization of 1,3‐butadiene was conducted with them using Al(CH 3 ) 3 as cocatalyst, which gave polybutadiene composed of 1,2 and cis‐1,4 units. The content of 1,2 units could easily be regulated from approximately 0% up to 90% by controlling the loading amount of Co as well as by changing the amount of suitable Lewis base added. The sequence distribution of each unit was determined by means of 13 C NMR using hydrogenated polybutadiene. Addition of ethylene to the polymerization system caused a marked decrease in the molecular weight of polybutadiene, but ethylene was incorporated neither in the main chain nor at the chain ends. The chain end analysis of very low‐molecular‐weight polybutadiene by 13 C NMR suggested that 1,2 and 2,1 insertion reactions predominantly proceed at the initiation and propagation steps, respectively.