High molecular weight vinyl‐type polynorbornene was obtained by polymerization of norbornene initiated by NiBr(NPMe3)]4/B(C6F5)3. Polymerization in the presence of olefins resulted in termination of polynorbornene chains by olefinic moieties. Molecular weights of polynorbornenes terminated by vinylidene compounds are lower than those terminated by vinyl and vinylene compounds. Corresponding polymerizations with polybutadiene and polyisoprene yielded graft copolymers with polynorbornene as grafts without contamination by homopolymerized polynorbornene. Grafting reactions were proved by spectroscopy, GPC, and degradation experiments using OsO4.
GPC traces (refractometer detector) of PN obtained for the polymerizations of 2 in the presence of 4d .
