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

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 degrees C for 120 h. The resulting copolymers were characterized by H-1 NMR, C-13 NMR, IR, GPC and DSC methods which confirmed the successful synthesis of block copolymers of L-lactide and epsilon-caprolactone. Mechanical properties showed that the introduction of poly(epsilon-caprolactone) made poly(L-lactide) a tough material. Hydroiytic degradation of the copolymers in a buffer of pH 7.4 at 37.0 degrees 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. (C) 2000 Elsevier Science Ltd. All rights reserved.