Synthesis of polyolefins with controlled structure and functionality

Abstract

This thesis deals with synthesis of polyolefins with controlled structure and functionality. Chapter I introduces polyolefins and functional polyolefins with viewpoint of synthesis. In Chapter II, hydroxy terminated polyethylenes were synthesized by polymerizations of ethylene with Cp^*_2ZrCl_2 and MAO followed by oxidative work-up. The hydroxy terminated polyethylene was converted to a polyethylene macroinitiator. PE-b-PMMA was synthesized through ATRP of MMA from the polyethylene macroinitiator. The block copolymer promoted the interfacial adhesion between immiscible PE/PMMA blend. In Chapter III, copolymerizations of propylene and allylbenzene with rac-Et(Ind)_2ZrCl_2 and MAO were investigated. With sufficient amount of TMA and allylbenzene, the chain transfer to aluminium on 1,2-inserted allylbenzene became a predominant chain transfer reaction, which was used for the synthesis of hydroxy terminated copolymer of propylene and allylbenzene through oxidative work-up. In Chapter IV new spiro-type polymer was synthesized by the polymerization of 9,9-diallylfluorene with zirconocenes and MAO. rac-Et(Ind)_2ZrCl_2 afforded poly(9,9-diallylfluorene) with high ratio of cyclized unit. At ambient temperature Cp_2ZrCl_2 afforded poly(9,9-diallylfluorene) with high content of 1,2-inserted unit. At 50 °C, poly(9,9-diallylfluorene) obtained with Cp_2ZrCl_2 contained crosslinked units. In Chapter V and VI new unsymmetrical (α-diimine)nickel(II) catalysts having different pendent groups at the ortho positions on aromatic rings were synthesized and subjected to ethylene and propylene polymerizations with MAO. The ortho substituents on the aromatic rings of (α-diimine)nickel(II) catalyst affected significantly the microstructure of polyethylene and polypropylene. When the catalysts have the same composition of the ortho substituents, the catalyst with C_s symmetry produced polyethylenes with higher branching densities and lower molecular weights than the catalyst with C_2...