Key factors for tuning hydrolytic degradation of polylactide/zinc oxide nanocomposites

AbstractThe hydrolytic degradation of thin films of polylactide/surface treated zinc oxide [poly(lactic acid) (PLA)/ZnOs] nanocomposites was investigated in phosphate buffer solution at the temperature of 37°C for more than 10 months. To produce PLA/ZnOs nanocomposites, the previously silanized metal oxide nanofiller has been dispersed into PLA by melt blending using twin screw extruders and the resulting dried pellets were shaped into thin films of about 70 μm thickness. For sake of comparison, pristine PLA was processed and investigated under similar conditions. The evolution of molecular weights of the PLA matrix, as well as of crystallinity and thermal parameters of interest, with the hydrolysis time, has been recorded by size exclusion chromatography (SEC) and differential scanning calorimetry (DSC), respectively. Accordingly, at longer hydrolysis time, the nanocomposites revealed better resistence to the hydrolytic degradation (lower weight loss, smaller decrease of molecular mass, no dramatic incre...