In vitro hydrolytic degradation of poly(para-dioxanone)/poly(d,l-lactide) blends

A series of biodegradable polymers were prepared by solution coprecipitation of poly(para-dioxanone) (PPDO) and poly(d,l-lactide) (PDLLA) in various blend ratios. Samples were compression molded into bars using a platen vulcanizing press. The in vitro hydrolytic degradation of PPDO/PDLLA blends was studied by examining the changes in weight, water absorption, tensile strength, breaking elongation, thermal properties, and morphology of the blends in phosphate buffered saline (PBS; pH 7.44) at 37 °C for 8 weeks. During the hydrolytic degradation, the weight loss and water absorption increased significantly for all samples, whereas the hydrolysis rate varied with the blend composition. The weight loss of PPDO/PDLLA 80/20, which showed the smallest degradation rate, was lower than that of pure PPDO for almost all of the hydrolytic degradation period. The results showed that the blend composition played an important role in determining the degradation behaviors of blends.