Synthesis and Characterization of Terpolymers of poly(L-lactide-glycolide-epsilon-caprolactone)

Random terpolymers of poly(L-lactide-glycolide-epsilon-caprolactone) (PLLGC) was prepared by ring-opening polymerization of L-lactide, glycolide and epsilon-caprolactone monomers initiated with stannous octanoate. Fourier transform infrared spectra, nuclear magnetic resonance and gel permeation chromatography were employed to characterize the obtained PLLGC terpolymers. The effects of polymerization temperature, reaction time, the amount of initiator and the polymerization pressure on the weight average molecular mass and polydispersity index of the PLLGC were investigated. In addition, the water contact angle of the PLLGC was also tested. The characterization of chemical structure showed that the PLLGC was successfully synthesized. For instance, a PLLGC terpolymer with a weight average molecular mass of about 12.435x10(4)Da and a polydispersity index of 1.28 was obtained when the polymerization was conducted with a molar ratio of monomer to initiator ([M]/[I]) of 2000, polymerization temperature of 140 degrees C, polymerization pressure of 5.0Pa and reaction time of 24h. The random incorporation of epsilon-CL monomer units decreased the wettability of the PLGA copolymers.