Food packaging is one of the most commonly used materials today due to its affordability and convenience. However, this type of packaging is challenging to handle after use, leading to significant environmental waste since it is often made from petrochemical polymers that take a long time to decompose. Polyvinyl alcohol (PVA) is a low-cost, safe, and biodegradable polymer with high potential for food packaging, offering a solution to waste issues in the polymer industry. However, its limited hydrophilicity, bactericidal properties, and poor performance in humid conditions hinder its practicality. Enhancing the mechanical properties and water resistance of PVA-based composite films can significantly improve their applicability, particularly in food packaging. In this study, nanocomposite films based on PVA were reinforced with nanocellulose fiber (CNF) and Ag nanoparticles (AgNPs), and cross-linked using citric acid (CA) through the film casting method. The incorporation of CNF and AgNPs improved the structural integrity and thermal stability of the film, while CA crosslinking significantly enhanced water resistance and mechanical properties. The (PVA/CNF/Ag)-CA film exhibited the highest tensile strength (89.44 MPa), Young's modulus (3.29 GPa), and water contact angle (similar to 90 degrees), alongside the lowest water absorption (78.6 %) and a reduced water vapor transmission rate of 6.62 g x h(-1) x m(-2). Compared to pure PVA film, the resulting crosslinked nanocomposite films showed a 32.3 % increase in modulus and a 22.64 % increase in tensile strength. Additionally, the (PVA/CNF/Ag)-CA film exhibited higher thermal stability with 13 % more residue content than uncrosslinked counterparts, reduced moisture absorption, minimal swelling, and water insolubility. However, the CA crosslinking process promoted AgNP aggregation, reducing the antibacterial activity of the (PVA/CNF/Ag)-CA film against Staphylococcus aureus and Escherichia coli, and slowed down its biodegradation in soil. Nevertheless, after seven days of storage under both aerobic and anaerobic conditions, the nanocomposite coatings effectively minimized mass loss and microbial growth on fresh chili peppers. These results highlight the synergistic contribution of CNF/Ag reinforcement and CA crosslinking in enhancing the mechanical strength, thermal stability, and water resistance of PVA-based films for potential food packaging applications.

来源平台：INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES