Nickel catalysts for the addition polymerization of norbornene and its derivatives and for their copolymerization with ethylene

Abstract

The addition polymerization of norbornene and its derivatives has been carried out in the presence of a nickel complex or carboxylate and an electron acceptor to obtain amorphous polymers with bicyclic units. Norbornene copolymers with conjugated dienes or ethylene cannot be obtained with these catalysts because of rapid chain transfer reactions. Norbornene can be copolymerized with ethylene under mild conditions in the presence of nickel phosphorylide chelates without using any cocatalyst. In most cases, the backbone of the resulting copolymer consists of alternating comonomer units. The new catalysts allow ethylene to be copolymerized with norbornene derivatives containing ester substituents.