Copolymerisation of 1,9-decadiene and propylene with binary and isolated metallocene systems

Abstract

1,9-Decadiene/propylene copolymers were obtained with isolated metallocenes and with a binary metallocene catalyst system activated by methylaluminoxane. The metallocenes under investigation were syndiospecific diphenylmethyl(cyclopentadienyl)(9-fluorenyl)zirconium dichloride ( 1) and isospecific rac-dimethylsilylbis(4- tert-butyl-2-methyl-cyclopentadienyl)zirconium dichloride ( 2). A copolymer structure, in which 1,9-decadiene linked isotactic and syndiotactic polymer chains, was obtained when copolymerisation was started with catalyst 2 at 80 °C followed by injection of catalyst 1 and instantaneous lowering of polymerisation temperature to 40 °C after 15 min of polymerisation. The copolymer was also shown to work as a compatibiliser in a blend of syndiotactic and isotactic polypropylene. We propose that catalyst 2 incorporates 1,9-decadiene into the isotactic main chain without any significant crosslinking within the first 15 min of polymerisation at 80 °C and the produced isotactic macromonomers are further incorporated at 40 °C into the syndiotactic main chain in polymerisation with catalyst 1.