Preparation of Chain-Extended Poly(hexamethylene carbonate)s and their Block Copolymerization with Poly-L-lactide to Synthesize Partly Biobased Thermoplastic Elastomers

摘要

An oligomer of poly(hexamethylene carbonate) (PHMC) that is synthesized by ester-exchanging polycondensation of ethylene carbonate and 1,6-hexanediol is chain-extended by using diphenyl carbonate as chain extender. The resultant PHMC, dihydroxyl-terminated, is then subjected to tin-catalyzed ring-opening polymerization of L-lactide to prepare ABA tri-block copolymers consisting of poly-L-lactide (PLLA: A) and PHMC (B), which retain significantly high molecular weights even at increased contents of PHMC. Polymer films of these block copolymers exhibit high elongation, reaching 700% at a high PHMC content. It is therefore suggested that the present block copolymer system can be a novel thermoplastic elastomer, which is partly bio-based.