Green fabrication of high-performance chitosan-nanocellulose composite films using wood vinegar as a bio-based...

Wood vinegar (WV) can serve as both a solvent and a functional additive for chitosan (CS) due to its inherent weak acidity and richness in organic compounds. Based on this principle, we successfully prepared WV/CS films and further enhanced their performance by incorporating nanocellulose (NC). The resulting NCFs exhibited a tensile strength of 71.06 MPa, which is 30% higher than that of the WV/CS film (54.50 MPa). Furthermore, the NCFs had excellent UV shielding properties in the UVA (>70%) and UVB (>90%) regions and impressive antioxidant (more than 90% scavenging rates for DPPH and ABTS) and bacteriostatic properties (more than 20 mm circles of inhibition for E. coli and S. aureus). The ability of NCFs to release polyphenols in solvents of different polarities (10% and 95% ethanol systems) enables their use as antioxidant cling films in various food applications. The results indicated that NCFs reduced water evaporation and surface oxidation of fruits (apples) and retarded the peroxidation of edible oils during storage. This work presents a fully bio-based, biodegradable, and high-performance active packaging system composed of WV, CS, and NC, offering a sustainable alternative to petroleum-based plastics.