SYNTHESIS AND CHARACTERIZATION OF BIODEGRADABLE BLOCK-COPOLYMERS OF EPSILON-CAPROLACTONE AND D,L-LACTIDE INITIATED BY POTASSIUM POLY(ETHYLENE GLYCOL)ATE

-lactide)-poly(epsilon-caprolactone)-poly(ethylene glycol)-poly(epsilo n-caprolactone) -poly (D,L-lactide) block copolymer (PLA-PCL-PEG-PCL-P LA) was prepared by copolymerization of epsilon-caprolactone (epsilon- CL) and D,L-lactide (D,L-LA) initiated by potassium poly(ethylene glyc ol) ate in THF at 25 degrees C. The copolymers with different composit ion were synthesized by adjusting the mole ratio of reaction mixture. The resulted copolymers were characterized by H-1-NMR, C-13-NMR, IR, D SC, and GPC. Efforts to prepare copolymers with the corresponding stru cture of PCL-PLA-PEG-PLA-PCL and D,L-lactide/epsilon-caprolactone rand om copolymers were not successful. (C) 1997 John Wiley & Sons, Inc.