Mechanical Performance and Biodegradability of Copolymers of L-Lactide and δ-Valerolactone

초록

A series of novel biodegradable homopolymers and copolymers of L-lactide (LA) were polymerized alcohol via various polymerization methods in the presence of catalysts. One of examples were copolymers of LA with δ-valerolactone (VL). The chain topology of these copolymers was suggested to be either cyclic or linear depending on the initiator used. The feeding molar ratio of LA : VL was changed to investigate the chain microstructure, thermal properties, as well as degradability of copolymers. 1H-NMR revealed that incorporating 30, 50, and 70 mol% VL provided blocky, gradient, and random chain copolymers, respectively. Increasing VL content relative to the LA content decreased the Tg, Tm, and crystallinity of the copolymers. All copolymers displayed higher thermal stability than PLA homopolymers due to the presence of the VL comonomer. The cyclic polymers showed higher Tg, lower Tm, and lower crystallinity than their linear counterparts. Furthermore, it was found that the degradability of the copolymers can be controlled by adjusting the compositions of VL and LA and their chain architecture.