Synthesis of poly(#epsilon#-carprolactone-b-isobutylene)diblock copolymer and poly(#epsilon#-caprolactone-b-isobutylene-b-#epsilon#-caprolctone)triblock copolymer

摘要

Poly(isobutylene-b-#epsilon#-caprolactone)diblock and poly(#epsilon#-caprolactone-b-isobutylene-b-#epsilon#-caprolctone)triblock copolymers have been prepared and characterized.The synthesis involved the living cationic polymerizationh of IB,followed by capping with 1,1-diphenylethylene or 1,1-p-ditolylethylene and end-quenchign with 1-methoxy-1-trimethylsiloxy-2-methyl-propene to yield methoxycarbonyl functional PIB.Hydroxyl end-functional PIB polymers were quantittively obtained by the subsequent reduction of methoxycarbonyl end-functional PIB with LiAlH_4.The structure of hydroxyl end-functional PIBs was confirmed by ~1H NMR and IR spectroscopy.Poly(#epsilon#-caprolactone-b-isobutylene)diblock copolymers and poly(#epsilon#-caprolactone-b-isobutylene-b-#epsilon#-caprolactone)triblock copolymers were synthesized by the living cationic ring-opening polymerization of #epsilon#-carpolactone with hydroxyl end-fucntional PIB as macroinitiator in the presence of HCl·Et_2O via the "activated monomer mechanism".The block copolymers exhibited close to theoretical M_ns and narrow molecular weight distributions.