Custom-made polar monomers utilized in nickel and palladium promoted olefin copolymerization
The functionalization of polyolefins through the copolymerization of olefins and polar monomers catalyzed by late transition metals such as nickel and palladium is of academic and industrial significance. In recent years, a variety of versatile catalysts used in these copolymerization reactions have been summarized in many key reviews; however, the indispensable role of polar monomers in these copolymerizations has not been given due attention. In this review, the functions of custom-made polar monomers in these reactions including regulating polymerization via new mechanisms, generating novel polymer architectures, benefiting polymer post-modification, endowing polyolefins with specific properties, and introducing bifunctional groups into polyolefins are comprehensively discussed. The aim is to provide fresh viewpoints from the perspective of polar monomers rather than catalysts as usual.