Alternating copolymers with degradability and quantitatively controlled thermosensitivity

Abstract

To combine temperature responsivity and degradability, novel alternating copolymers with polyester backbone and oligo(ethylene glycol) side chain were designed and prepared by alternating ring-opening copolymerization of succinic anhydride (SA) and functional epoxide monomer(s). The epoxide monomer containing one ethylene glycol unit, 2-((2-methoxyethoxy)methyl)oxirane (MEMO), has displayed similar copolymerization activity to that containing two ethylene glycol units, 2-((2-(2-methoxyethoxy)ethoxy)methyl)oxirane (ME2MO), when copolymerized with SA. This feature led to the formation of alternating copolymers with statistical random distribution of MEMO/ME2MO units along the backbone when mixed MEMO/ME2MO comonomers were fed. These polyesters possess degradability and quantitatively controlled lower critical solution temperature (LCST; 18–50 °C) and Tg (−40 to −31 °C) both in linear relations with MEMO/ME2MO feed ratio. Fine control of LCST near body temperature is thus realized for the reported degradable and thermoresponsive polyesters, which have promising applications in biomedical fields. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012