Flexible and sustainable PBAT@g-C3N4/MWCNT nanocomposite films for the packaging of green grapes.

Abstract

Packaging films were developed by reinforcing poly(butylene adipate-co-terephthalate) (PBAT) with graphitic carbon nitride/multiwalled carbon nanotubes (g-C3N4/MWCNTs) via solvent casting. Structural analyses confirmed improved interfacial interactions and uniform nanofiller dispersion within the PBAT matrix. The PBAT@g-C3N4/MWCNT films exhibited significantly enhanced mechanical performance, achieving a tensile strength of 36.1 MPa, representing a 43.5% improvement over neat PBAT. Barrier properties were markedly improved, with the oxygen transmission rate reduced from 1005.2 to 319.0 cc m-2·24 h-1 and water vapor transmission decreased by 67.7% at 5 wt% loading. The films demonstrated strong antibacterial activity against Escherichia coli and Staphylococcus aureus, achieving up to 98.0% antibacterial efficiency. Storage tests on green grapes showed that the optimal film extended shelf life from 1 to 18 days, reduced weight loss, and improved vitamin C retention. These results highlight the strong potential of g-C3N4/MWCNT-reinforced PBAT films as sustainable active food packaging materials.