Synthesis, characterization and degradation of ABA block copolymer of l-lactide and ε-caprolactone

Abstract

Degradable ABA block copolymers were synthesized by the bulk copolymerization of PCL pre-polymers and l-lactide with stannous octanoate as the catalyst at 120°C for 120 h. The resulting copolymers were characterized by 1H NMR, 13C NMR, IR, GPC and DSC methods which confirmed the successful synthesis of block copolymers of l-lactide and ε-caprolactone. Mechanical properties showed that the introduction of poly(ε-caprolactone) made poly( l-lactide) a tough material. Hydrolytic degradation of the copolymers in a buffer of pH 7.4 at 37.0°C showed that block copolymers of different compositions degraded at different rates. Block copolymers of different properties could be obtained by adjusting the compositions of the copolymers.