Preparation and characterization of corn straw core-based composite films with excellent antioxidant, water vapor barrier, and mechanical properties

Corn straw core (CSC)/cellulose nanofibers (CNF) composite is researched as a food packaging material because of its better anti-ultraviolet (UV) and water vapor barrier properties. However, there are still some challenges, such as insufficient toughness, many gaps or pores inside the film, and a lack of antioxidant properties. To improve these properties, the composite films (CCP-VAE), with excellent anti-UV, antioxidant, blocking bacteria, water vapor barrier, and mechanical properties, were prepared by applying Vernonia anthelmintica (L.) Willd extract (VAE) and poly (ethylene oxide) (PEO). The interaction of the raw materials and the structure of composite films were analyzed by FTIR, XRD, SEM, TG, and DSC. Compared to LDPE, PBAT, or PBSeT, the tensile strength of CCP-VAE-1 composite film was improved by 1.17 times, 1.37 times, or 2.75 times, respectively; compared with CNF/CSC, PP, LDPE, PBAT or PBSeT, the puncture load of this film was advanced by 2.59 times, 0.72 times, 0.64 times, 0.81 times or 2.54 times, respectively; the tearing strength of this film, compared with CNF, PP, LDPE, PBAT or PBSeT, was enhanced by 1.49 times, 2.59 times, 4.00 times, 0.89 times or 3.48 times, respectively; furthermore, compared with CNF, PBAT and PLA, the water vapor transmission coefficient (P_wv) of CCP-VAE-1.5/2 films had a lower value. All CCP-VAE composite films also presented excellent UV barriers and wonderful antioxidant properties. In practical packaging tests with fresh garlic and milk, the weight loss and spoilage caused by external influences were effectively prevented by CCP-VAE composite films, which indicated the potential as food packaging.