SYNTHESIS OF NEW BIODEGRADABLE CROSS-LINKED POLYESTERS FOR BIOMEDICALAPPLICATIONS AND THEIR IN-VITRO DEGRADATION

Two kinds of new aliphatic diols were synthesized by the ring-opening reaction of lactide and glycolide with 1, 4-butanediol, a difunctional initiator, in the presence of stannous octoate. The resulting aliphat ic diols were melt-polymerized with D-tartaric acid at 150 degrees C t o produce new crosslinkable polyesters. They were reacted with hexamet hylene diisocyanate in THF at 65 degrees C in a tenon mold for 24 h to prepare sequentially ordered crosslinked polyesters (BD/LT/GL/D-tarta rate). Degradation of the prepared yellow crosslinked films was carrie d out in a buffer solution in order to examine the effect of time, pH, temperature and crosslinking degree on their degradation rate and mec hanism. The rate of degradation increased with an increase in pH and t emperature, but it decreased with increasing degree of crosslinkage in corporated into the crosslinked polyesters. We also found that the cro sslinked polymers were converted into the acidic compounds such as lac tic, glycolic, and D-tartaric acids during the degradation.