SYNTHESIS AND CHARACTERIZATION OF BLOCK-COPOLYMERS FROM D,L-LACTIDE AND POLY(TETRAMETHYLENE ETHER GLYCOL)

The copolymer from D,L-lactide and poly(tetramethyene ether glycol) (P TMG) was prepared in bulk with an isotributyl aluminum-water-phosphori c acid complex catalyst as the initiator and characterized by H-NMR, G PC, and DSC. The effects of the temperature and the amount of PTMG on the polymerization rate and the molecular weight of copolymers were st udied. The behavior of the degradation and delivery rate of Levonorges trel microspheres in, vitro was observed. The results show that the de gradation and the delivery rate can be controlled by adjusting the mol ar rate of hydrophilic and hydrophobic segments of the copolymer (C) 1 995 John Wiley and Sons, Inc.