Chitosan/Graphene Oxide/Ag Nanocomposites Loaded in Polyvinyl Alcohol Films as Biodegradable, <scp>UV</scp>‐Blocking, and Antibacterial Film for Fruit Packaging
Nhung Thi Tran, Giang Tien Nguyen, Tam Minh Le, Anh Tuan Nguyen Huynh
Abstract
ABSTRACT The polyvinyl alcohol/chitosan/graphene oxide/Ag composite films are facilely fabricated as active multifunctional food packaging materials. The AgNPs of less than 10 nm immobilized onto CS/GO matrices are in situ synthesized by using NaBH 4 as a reductant. The effect of different amounts of Ag and CS:GO weight ratios on the mechanical properties, water resistance, optical properties, thermal stability, and antibacterial activities of various films are systematically investigated. The composite film obtained at 0.5 wt% AgNP loading and a CS:GO ratio of 5:1 demonstrates significantly improved tensile strength (33.07 MPa, 1.7 times higher), reduced water swelling (2.4 times lower), increased contact angle (71.08° vs. 53.54°), and enhanced thermal stability compared to the neat PVA film. Additionally, these composite films exhibit excellent bacterial killing and inhibition activities against Escherichia coli and Staphylococcus aureus , with zones of inhibition of 10.09 nm and 12.66 mm, respectively. Interestingly, no viable bacteria were found with the film‐forming dispersion at 10 μg/mL. Furthermore, the fabricated films exhibit excellent UV‐blocking effects, sufficiently protecting exposed green plums from UV damage for 10 days. The membrane‐packed acerola fruits also demonstrate better freshness, slower ripening rate, and no signs of microbial growth as compared to those packed with commercial polyethylene film.