Physicochemical changes in degrading polylactide films

It has been suggested in the literature that 'large' size bioabsorbable aliphatic polyester devices degrade heterogeneously when exposed to an aqueous environment. That is, following saturation, the material degrades preferentially from the center to the exterior due to an auto catalytic effect. Oriented absorbable films were developed using a new solid state method in order to assess the influence of molecular orientation on degradation pattern. The method entails uniaxial deformation and thus is referred to as solid state uniaxial orientation (SS-UO). This work examines solely the physicochemical changes occurring in the degrading polylactide film and their relevance to changes in key molecular parameters, as part of a broad based study on the effect of orientation on absorption. The results indicate that the orientation has a large effect on the glass transition temperature and the heat of fusion.