Synthesis and characterization of biodegradable block copolymers of ?-caprolactone and D,L-lactide initiated by potassium poly(ethylene glycol)ate

Abstract

Poly(D,L-lactide)–poly(ϵ-caprolactone)–poly(ethylene glycol)–poly(ϵ-caprolactone)–poly(D,L-lactide) block copolymer (PLA–PCL–PEG–PCL–PLA) was prepared by copolymerization of ϵ-caprolactone (ϵ-CL) and D,L-lactide (D,L-LA) initiated by potassium poly(ethylene glycol)ate in THF at 25°C. The copolymers with different composition were synthesized by adjusting the mole ratio of reaction mixture. The resulted copolymers were characterized by 1H-NMR, 13C-NMR, IR, DSC, and GPC. Efforts to prepare copolymers with the corresponding structure of PCL–PLA–PEG–PLA–PCL and D,L-lactide/ϵ-caprolactone random copolymers were not successful. © 1997 John Wiley & Sons, Inc.