화학공학소재연구정보센터
Journal of Polymer Science Part A: Polymer Chemistry, Vol.40, No.10, 1379-1394, 2002
Synthesis of biodegradable copolymers with low-toxicity zirconium compounds. II. Copolymerization of glycolide with epsilon-caprolactone initiated by zirconium(IV) acetylacetonate and zirconium(IV) chloride
The aim of this article is to show a new method of copolymerizing glycolide and caprolactone with the low-toxicity zirconium(IV) acetylacetonate and zirconium(IV) chloride as initiators. Such initiators enabled us to obtain copolymers with very good efficiency and good mechanical properties. The reactivity of the initiators was defined, and the chain-propagation process was examined. On the basis of an NMR examination and differential scanning calorimetry thermograms, we found that the samples obtained at 100 degreesC with the initiators were characterized by a segmental chain microstructure, which provided good mechanical properties. When the synthesis was carried out at 150 degreesC, a more randomized structure was obtained, which caused crucial changes in the properties of the copolymers and decreases in the mechanical properties. Because of their properties, the obtained copolymers could be successfully applied as degradable surgical implants or drug carriers. The results show that the copolymers obtained with zirconium(IV) acetylacetonate and chloride could successfully replace ones obtained in the presence of tin compounds as far as medical applications are concerned.