RING-OPENING COPOLYMERIZATION OF TRIMETHYLENE CARBONATE AND D,L-LACTIDE BY RARE-EARTH CHLORIDE

Bulk copolymerization of trimethylene carbonate (TMC) and D,L-lactide (D,L-LA) was conducted at 80 degrees C using rare earth chloride as ca talyst. The copolymerization reaction showed an induction period. The effects of reaction time and temperature were examined. The polymeriza tion activity of various rare earth chlorides was in the order: LaCl3> YCl3, PrCl3>NdCl3 much greater than DyCl3. The copolymer was character ized by H-1 NMR. The reactivity ratios of TMC and D,L-LA were determin ed by the Fineman-Ross and Kelen-Tudos methods.