Development and characterization of biodegradable PLA-based food packaging films enriched with natural antioxidants

Abstract

The main objective of this study was to develop biodegradable and active packaging films based on poly(lactic acid) (PLA) for sustainable food packaging applications. To improve the inherent brittleness of PLA, it was blended with polycaprolactone (PCL) and plasticized using polyethylene glycol (PEG). Natural antioxidants, thymol and Rosemarinus officinalis extract, were incorporated to provide antioxidant activity. The microhardness results showed that the addition of PCL, PEG, and natural additives reduced the of PLA and significantly enhanced its flexibility while the tensile tests revealed improved ductility, characterized by higher elongation at break and lower Young’s modulus, particularly for the PLA/PCL20/PEG15 formulation, by increasing polymer chain mobility. However, high concentrations of natural additives led to a decrease in tensile strength. Structural analysis by XRD demonstrated a progressive reduction in PLA crystallinity from 42.97% to 22.26% and 19.75% in the modified formulations, indicating increased flexibility of polymer chains. Furthermore, AFM observations confirmed these structural changes through increased surface roughness and altered surface morphology. Overall, the developed PLA/PCL/PEG films containing natural antioxidants show strong potential as sustainable and active food packaging materials.