Design and fabrication of bio-based functional composite materials with antibacterial, antioxidant, and improved mechanical properties based on poly (butylene adipate-co-terephthalate) (PBAT) for food packaging

The PBAT/epoxy chain extender (ADR-4468) film, with its competitive pricing, excellent biodegradability, and outstanding mechanical properties, stands out. Through experimental design, quercetin (QR) with antibacterial and antioxidant properties was effectively grafted onto the epoxy chain extender (ADR-4468), resulting in the successful synthesis of the functional modifier A-QR. PBAT composite films containing different weight percentages (0.2, 0.4, 0.6, 0.8, and 1% w/w) of A-QR were prepared using extrusion blow molding technology. QR and ADR are chemically bonded together, forming a strong and tightly knit composite. The composites exhibit excellent composite effects and outperform single-component blends, reducing A-QR migration, improving mechanical properties, and enhancing the barrier properties of the composite film. Structural, mechanical, and water barrier properties, antibacterial and antioxidant properties, as well as freshness preservation effects of the film, were analyzed. A-QR and PBAT formed a cross-linked network structure through chain extension reactions. Tensile strength increased from 19.7 MPa to 37.9 MPa, representing a 92.4% improvement. Antioxidant activity reached up to 65%. It exhibited excellent antibacterial activity against Staphylococcus aureus and Escherichia coli. The maximum total migration was only 0.7 mg/dm2, significantly below the specified overall migration limit (OML). PBAT/A-QR films successfully extended the shelf life of bananas, strawberries, apples, and oyster mushrooms due to their excellent antioxidant, antibacterial, and water barrier properties.