The effect of crystalline morphology on the degradation of polycaprolactone in a solution of phosphate buffer and lipase

The degradation of polycaprolactone (PCL) in a solution of lipase and phosphate buffer has been characterized using a combination of differential scanning calorimetry (DSC) and electron microscopy. The molecular weight of the polymer initially appeared to determine the degradation rate while the degree of crystallinity was found to increase with time. Samples of PCL were also conditioned using DSC to specify a known degree of crystallinity. This approach enabled the effects of molecular weight and degree of crystallinity on the degradation to be separated. It was observed that an increase in either molecular weight or degree of crystallinity reduced the rate of degradation. The work presented in this paper addresses a significant limitation associated with the characterization of “as received” samples and provides a more detailed understanding of the effect of polymer morphology on the degradation process.