Noncopolymerization Approach to Copolymers via Concurrent Transesterification and Ring-Opening Reactions

Inter- and intrachain transesterification, normally regarded as a detrimental side reaction for the synthesis of polyesters, is utilized herein to formulate a novel strategy for the modification of polyesters. Addition of an organic superbase into the mixture of hydroxyl-terminated poly(ε-caprolactone) and an epoxide, for example, propylene oxide or 1,2-butylene oxide, triggers concurrent nucleophilic ring-opening of the epoxide and transesterification reaction. The synergetic effect enables convenient and efficient transformation of the polyester into poly(ester-ether) random copolymers and thus advances the preparation of functional degradable polymeric materials taking advantage of the variety of commercial and laboratory-made polyesters and epoxides.