Synthesis and biodegradation of poly(L-lactide-co-β-propiolactone)

Abstract

Although the copolymerizations of L-lactide (LA) with seven-or six-membered ring lactones have been extensively studied, the copolymerizations of LA with four-membered ring lactones have scarcely been reported. In this work, we studied the copolymerization of LA with β-propiolactone (PL) and the properties of the obtained copolymers. The copolymerization of LA with PL was carried out using trifluoromethanesulfonic acid as a catalyst and methanol as an initiator to produce poly(LA-co-PL) with Mn of ~50, 000 and PL-content of 6-67 mol %. The Tg values of the copolymers were rapidly lowered with increasing PL-contents. The Tm and ∆Hm of the copolymers gradually decreased with increasing PL-contents, indicating their decreased crystallinity. Biodegradation test of the copolymers in compost demonstrated their improved biodegradability in comparison with the homopolymer of LA.