Zinc oxide enhanced the antibacterial efficacy of biodegradable PBAT/PBS nanocomposite films: Morphology and food packaging properties

Enhancing the antimicrobial functions of biodegradable polyesters facilitates the utilization of sustainable food packaging. Poly(butylene succinate) (PBS) and polybutylene adipate terephthalate (PBAT) blends were compounded with zinc oxide (ZnO) nanoparticles (up to 4.5%) into a master batch via twin-screw extrusion. Biodegradable films were produced via cast extrusion, and the morphologies and packaging properties were determined. Adding ZnO nanoparticles up to 2.7% modified the film's surface topography, causing non-homogeneity and voids. ZnO tended to form aggregates at higher loading, while phase separation of metal oxide from PBAT/PBS matrices occurred. Dispersion of ZnO nanoparticles reduced water vapor permeability, with the lowest effects on oxygen permeability. Adding ZnO in combination with the molecular orientation of the polymer effectively reinforced the matrices and improved the mechanical properties of PBAT/PBS blends. PBAT/PBS/ZnO films exhibited antimicrobial capacity against Escherichia coli and Bacillus cereus. PBAT/PBS with ZnO >2.7% delayed discoloration of red pigments in packaged minced pork due to efficient inhibition of microbial growth and UV blocking. ZnO-loaded polyester enhanced antimicrobial functions, producing sustainable active nanocomposite packaging.