Hydrolytic degradation of glycolide/L-lactide/-caprolactone terpolymers initiated by zirconium (IV) acetylacetonate
Résumé
A series of terpolymers obtained from glycolide/L-lactide/ε-caprolactone were compression molded and allowed to degrade in a pH 7.4 phosphate buffer at 37oC. Analytical techniques such as 1H NMR, DSC, ESEM and SEC were used to monitor the degradation. Heterogeneous degradation was observed due to internal autocatalysis of carboxylic endgroups formed by ester bond cleavage. Nevertheless, the copolymers present various degradation behaviors depending on the initial composition. The PCL component appears the most resistant to degradation, and the PGA one the most degradable according to compositional changes. Terpolymers could crystallize during degradation even though they were amorphous initially. Degradation induced increase of crystallinity was also found during hydrolysis.