BIODEGRADABLE POLYMERS .2. HOMOIZATION AND COPOLYMERIZATION OF D,L-DILACTIDE

The ring-opening polymerization of D,L-dilactide and an equimolar dilactide-diglycolide mixture with Sn-II-octoate have been investigated. Conversion and molecular mass of the lactide bulk polymerization are not only determined by the kinetics of the primary ring-opening reaction but also by the intensity and extent of consecutive reactions of reactive groups of the formed polyester. Parallel to the polymer formation by the ring-opening reaction proceed inter- and intramolecular transesterifications of ester groups between chains and with end groups and irreversible thermolysis reactions.