Synthesis of functional polyolefins via chain-end modification reactions

Abstract

This thesis deals with functional polyolefins consisting of polyolefin chains and other functional groups, which allow unique properties such as compatibility and self-healability. It consists of three chapters, concerning the functionalized polyolefins prepared through a combination of coordination polymerization and controlled living radical polymerization/grafting techniques as well as their unique properties. In chapter 2, end-functionalized poly(ethylene-co-propylene) (PEP) macro RAFT chain transfer agents were prepared by a series of end functionalization of PEP with the vinylidene end group via thiol-ene ‘Click’ reaction and esterification. By using these PEP macro chain transfer agents, the controlled living radical polymerizations of styrene were carried out to give PEP-b-PS block copolymers. SEM observation of PE/PS blends compatibilized with the block copolymer revealed that the size of PS domain dispersed in PEP matrix became finer in the range of 5~10μm. Chapter 3 includes synthesis of photo-responsive block copolymer based on end-functionalized PEP macro chain transfer agent. The end-functionalized PEP copolymer was employed as a macro RAFT chain transfer agent for controlled radical polymerization of 7-ethoxy-4-methyl-coumrinm methacrylate and 2-ethylhexylacrylate. 1H NMR analysis confirmed that the chain extension of end-functionalized PEP copolymer from macro CTA was successful PEP-based block copolymers. The block copolymers showed interesting photo-responsive properties like photo-coupling and photo-dissociation under the condition of UVA and UVC irradia-tion. Furthermore, it was shown that the intentional damage of the polymer film disappeared with the irradiation of UV light. In chapter 4, side-chain functionalized polyolefin was prepared by the synthesis of reactive polyolefin from ethylene and 5-ethylidenenorbornene followed by thiol-ene ‘Click’ reaction with mercaptoproponicacid, and esterification with the reagents which can undergo...