Preparation, characterization, and permeability of novel poly (lactic acid)-based blends filled with thymol and ZnO

Novel thin sheets based on poly (lactic acid)/poly (caprolactone)/thermoplastic starch ternary blends were fabricated by incorporating thymol, zinc oxide nanoparticles (ZnO-NPs) and thymol/ZnO-NPs at different concentrations (6, 9, 12 wt% thymol and 1, 3, 5 wt% ZnO). The gas/water vapor barrier properties of the nanocomposites comprising the effects of polar and non-polar molecules and their leading mechanisms were thoroughly discussed. Moreover, the localization preference of ZnO-NPs, morphology along with mechanical, and thermal properties of the nanocomposites were investigated. A significant improvement of 58% in the water vapor impermeability by 5 wt% ZnO and 12 wt% thymol loading was achieved. Finally, the fitting of the Maxwell model on the experimental data revealed that this model cannot correctly predict the permeation behavior of ZnO-filled nanocomposites. Results suggested that these nanocomposites could be capable of being used as the packaging materials with high barrier performance.