Syntheses of diblock copolymers polyolefin-b-poly(ε-caprolactone) and their applications as the polymeric compatilizer

An effective route to synthesize the amphiphilic diblock copolymer containing a poly(ε-caprolactone) block and a polyolefin block, such as polyethylene, syndiotactic polystyrene and isotactic polypropylene is discussed in this article. There are two reaction steps including the preparation of polyolefins by the combination of metallocene/methylaluminoxane as catalyst system and various chain transfer agents as well as the subsequent anionic ring-opening polymerization of ε-caprolactone. The molecular structure in terms of composition, molecular weight, molecular weight distribution of the diblock copolymers prepared is controllable by these well-defined reaction mechanisms. The scanning electron microscope (SEM) results showes that the compatibilities of the polyolefins and polycarbonate blends are improved greatly using these amphiphilic diblock copolymers as the polymeric compatilizers.