Synthesis, Structure and Mechanical and Thermal Properties of Copolymers of L-Lactide and δ-Valerolactone

초록

Biodegradable copolymers consist of the lactide (LA) and δ-valerolactone (VL) in a variety of compositions (30, 40, 50, 60, and 70 mole ratios). The biodegradable copolymers were synthesized through bulk ring-expansion polymerization using tin(II) 2-ethylhexanoate as a catalyst and salicylic acid as an initiator to improve the toughness of the PLA. The influence of monomer compositions in the crystallite size and lamellar structure of poly(LA-co-VL)s were investigated by SAXS and WAXD, respectively. It was found that increasing VL composition of poly(LA-co-VL)s led to higher elongation at break and thermal stability of the biodegradable copolymers. In addition, Gel permeation chromatography (GPC) and 1H-NMR measurements were performed to determine the molecular weight, composition and chain microstructure of these copolymers. From the results based on SAXS and WAXD demonstrated that the amorphous and crystalline orientation of poly(LA-co-VL)s was varied relating to the monomer composition.