Bacterial Cellulose/Poly(vinyl alcohol)/Chitosan Films: Tuning Mechanical and Functional Properties for Sustainable Food Packaging

This work reports a novel, green, and scalable wet mixing approach to prepare bacterial cellulose (BC)/poly-(vinyl alcohol) (PVA)/chitosan (CH) composite films with precise control over barrier, mechanical, and antimicrobial properties, suitable for active food packaging. The resulting composites exhibit tunable water interaction, ultraviolet (UV) barrier, and mechanical properties dictated by the BC/PVA ratio. Increasing BC content reduces the water uptake, water solubility, water vapor permeability, and UV transmittance (<20%). Mechanical characterization reveals stiffness values up to 8.5 GPa and tensile strengths approaching 93 MPa, though excessive PVA content (>60 wt %) introduces interfacial defects limiting deformability. Soil burial tests demonstrated composition-dependent biodegradation, reaching a weight loss higher than 30 wt % after 15 days. Incorporation of CH (5 wt %) improves film homogeneity and imparts antimicrobial activity, effectively extending strawberry shelf life. This processing method eliminates harsh solvents while enabling precise compositional control, yielding renewable films with composition-dependent performance for sustainable packaging applications.