[Study of the hydrolytic degradation of a biodegradable copolymer]

The hydrolytic degradation of bioabsorbable Poliglactin 910 was studied in a phosphate buffer solution, pH = 7.4, at 37 degrees C. The degradation was evaluated by analyzing the changes in weight loss, pH, DSC, mechanical properties and morphological changes. After 10 weeks, the weight loss and pH changes suggested diffusion of low molecular weight chain segments into the reaction medium as a consequence of the breaking of ester bonds in the material. Breaking stress and Young Modulus decrease, indicating that chain scission proceeded in two steps: the first occurring in the amorphous regions within the intermicrofibrillar space; the second in the crystalline regions. Surface morphological changes suggest a heterogeneous degradation mechanism by layers.