Effect of Polyvinyl Alcohol (PVA)/Chitosan (CS) Weight Ratio on Morphology, Mechanical Properties, Antibacterial and Biodegradability of the Composite Film for Food Packaging Applications

Despite being an effective material for food packaging, chitosan (CS) exhibited poor ductility when processed into film, which restricted its use in this industry. In this study, composite films with enhanced properties were developed by incorporating polyvinyl alcohol (PVA) into CS through a simple solution casting method. The effects of different PVA/CS weight ratios (70:30, 50:50, and 30:70 w/w) on the morphology, mechanical properties, antibacterial activity, and soil degradation of the composite films were analyzed. Compared to the pristine PVA film, increasing the CS content in the PVA/CS composite film enhanced thickness, stiffness, roughness, antibacterial efficiency, and degradation rate, while reducing tensile strength and elongation at break. Fourier transform infrared (FTIR) spectroscopy revealed the highest intermolecular interactions in the PVA/CS composite film with 70:30 w/w. Antibacterial activity tests and soil burial analysis demonstrated that the PVA:70/CS:30 composite exhibited significantly higher antibacterial activity toward Escherichia coli and Bacillus subtilis bacteria compared to the PVA film, along with a moderate degradation rate of 76.76% following 30 days of soil burial, effectively balancing biodegradability and material integrity. These findings suggest that the PVA: 70/CS:30 composite is a promising alternative for sustainable and functional biodegradable packaging solutions.