Biodegradable PBAT films with in situ synthesized tannic acid/ZnS nanohybrids for active packaging, offering antioxidant, antibacterial, and UV-shielding properties

Active food packaging that provides antioxidant and antimicrobial protection can extend product shelf life, but adding such features to polymers often affects material performance. In this study, we developed a biodegradable poly(butylene adipate-co-terephthalate) (PBAT) film incorporating in situ synthesized tannic acid (TA)/zinc sulfide (ZnS) hybrid nanostructures to add antioxidant, antibacterial, and UV-shielding functions. The TA/ZnS nanohybrids were created using a green in situ co-precipitation method and evenly dispersed in the PBAT matrix to form nanocomposite films. The resulting films showed strong bioactivity, achieving 90.46% DPPH free radical scavenging and inhibition zones over 3.0 cm against both E. coli and S. aureus. They also offered about 97% UV blocking and improved moisture barrier properties, with a 40.9% decrease in water vapor permeability and a 13% increase in water contact angle (surface hydrophobicity). However, these improvements came with roughly a 30% reduction in tensile strength, highlighting a trade-off between added functionality and mechanical performance. Importantly, the composite kept enough flexibility and strength for practical applications. In conclusion, the organic–inorganic synergy between tannic acid and ZnS created a bioactive, UV-protective film that can help extend food shelf life while remaining biodegradable. This green, scalable method shows potential for sustainable next-generation active packaging.