Plastic-Rubber Diblock Copolymer from Copolymerization of Dimethyl-1,3-butadiene and Butadiene by Rare-earth Metal Catalyst

Abstract

Coordination polymerization of 2,3-dimethyl-1,3-butadiene (DMB) has been investigated by using rare-earth metal catalysts. Of which the ligand-free gadolinium dibenzyl chloride precursor exhibits the highest activity and perfect cis-1,4 selectivity for DMB homopolymerization and copolymerization with butadiene (BD) to afford plastic poly(2,3-dimethyl-1,3-butadiene) (PDMB) and plastic-rubber diblock copolymer PDMB-b-PBD, respectively. In solution PDMB-b-PBD self-assembles into “core-shell” morphology with the crystalline cis-1,4 regulated PDMB segment as the core and the amorphous cis-1,4 stereoregular PBD unit as the shell, whilst in melt, PDMB block forms physical cross-linking in PBD rubbery matrix, endowing the material with an unusual high stress accompanied by excellent elongation.