Ring-Opening Polymerization of L-lactide with Glycidol as Initiator

Glycidol-poly(lactide) (Gly-PLA) were synthesized via L-lactide ring opening polymerization with glycidol as an initiator and Al(O-i-Pr)(3) catalyst. The structure of Gly-PLA was analyzed and successfully confirmed by H-1 NMR. The OH group of glycidol in Gly-PLA was absent according to the H-1 NMR analysis, indicating that the terminal OH group of glycidol successfully served as an initiator in the L-lactide polymerization. The solution and bulk polymerizations of L-lactide with glycidol were performed to examine the effect of L-lactide/glycidol molar ratio, polymerization temperature and time on the molecular characteristics of Gly-PLA. The conversion and molecular weight increased with an increase in L-lactide/glycidol molar ratio. Gly-PLA showed the bimodal type DSC curve. The low T-m peak of low molecular weight reduced but the high T-m peak of high molecular weight increased as L-lactide/glycidol molar ratio increased.