SYNTHESIS AND CHARACTERIZATION OF BLOCK COPOLYMERS FROM D,L-LACTIDE AND POLY(ETHYLENE GLYCOL) WITH STANNOUS CHLORIDE

Lactic acid is a naturally occurring product of glycolysis. The polylactide (PLA) obtained by means of polymerization of D,L-lactide possess a very low toxicity. It is useful to be the materials for various pharmaceutical and medical applications just taking the advantages of nontoxicity, biocompatibility, and biodegradable property. In order to adapt the good properties of PLA, many efforts have been made to improve this family of the polymer. Frequently the method of copolymerization with other proper monomers has been utilized. The purpose of this article is to investigate the copolymerization of D,L-lactide with poly(ethylene-glycol)s in the presence of some ring-opening catalysts, and to characterize the block copolymers by GPC.DSC.IR. and 1H-NMR analyses.