Synthesis and properties of poly(L-lactide)-polyether-poly(L-lactide) triblock copolymers

Abstract

The influence of the copolymer composition and soft segment molecular weight on the physical properties of poly(L-lactide)-polyether-poly(L-lactide) triblock copolymer were investigated. The triblock copolymers were synthesized by ring opening polymerization of the L-lactide monomer using polyether as the initiator. A comparison between the M (n) level measured by (1)H NMR and the theoretical M (n) level considering the yield showed good agreement in all samples. The PLLA-polyether-PLLA triblock copolymer was prepared by injection molding. An improvement in tensile strength and elongation at break of the copolymer was observed (30%, 70% increase). The impact strength of the block copolymer was also enhanced, from 1.3 to 2.1 kg cm/cm, compared to neat PLLA.