Synthesis and thermal behavior of triblock copolymers from L-lactide and ethylene glycol with long center PEG block

Abstract

In this study, poly(L-lactide)-poly (ethylene glycol) (PLLA-PEG) ABA triblock copolymers with the PEG mole fraction ranging from 27 to 57% have been synthesized, and their thermal properties were investigated. Differential scanning calorimetric thermograms of copolymers obtained from specimens dissolved in CH2Cl2 solution and precipitated with hexane exhibit no crystallization exotherms, but those cast from CHCl3 solution show some crystallinity. Water absorption depended on the PEG content of copolymers; thus, with a PEG mole fraction of 57, the water absorption was 82%. © 1998 John Wiley & Sons, Inc.