Synergism of Zinc Oxide/Organoclay-Loaded Poly(lactic acid) Hybrid Nanocomposite Plasticized by Triacetin for Sustainable Active Food Packaging

The synergistic effect of organoclay (OC) and zinc oxide (ZnO) nanoparticles on the crucial properties of poly(lactic acid) (PLA) nanocomposite films was systematically investigated herein. After their incorporation into PLA via the solvent casting technique, the water vapor barrier property of the PLA/OC/ZnO film improved by a maximum of 86% compared to the neat PLA film without the deterioration of Young’s modulus or the tensile strength. Moreover, the film’s self-antibacterial activity against foodborne pathogens, including gram-negative (Escherichia coli, E. coli) and gram-positive (Staphylococcus aureus, S. aureus) bacteria, was enhanced by a maximum of approximately 98–99% compared to the neat PLA film. Furthermore, SEM images revealed the homogeneous dispersion of both nano-fillers in the PLA matrix. However, the thermal stability of the film decreased slightly after the addition of the OC and ZnO. The film exhibited notable light barrier properties in the UV-Vis range. Moreover, the incorporation of a suitable biodegradable plasticizer significantly decreased the Tg and notably enhanced the flexibility of the nanocomposite film by increasing the elongation at break approximately 1.5-fold compared to that of the neat PLA film. This contributes to its feasibility as an active food packaging material.