INITIATION AND PROPAGATION STEPS IN THE EQUIBINARY POLYMERIZATION OF BUTADIENE BY BIS(h3-ALLYLNICKEL TRIFLUOROACETATE).

Polymerization of butadiene by (h**3-allylnickel trifluoroacetate) in benzene and o-dichlorobenzene solvents yields an equibinary 1,4-polybutadiene, containing equal amounts of cis and trans isomers. Initiation proceeds by addition of the allylic moiety of the initiator to a butadiene molecule. The rate of initiation is high enough to ensure complete consumption of the catalyst for a monomer/catalyst molar ratio of about 10 at 5 degree C. The propagation exhibits the characteristics of a ″living″ polymerization: the mol. wt is proportional to the conversion, and at the end of the reaction, the average degree of polymerization is equal to the monomer/catalyst molar ratio. Living polybutadienyl-nickel trifluoroacetate is able to reinitiate not only butadiene polymerization but also allene polymerization.