Corn straw core/cellulose nanofibers composite for food packaging: Improved mechanical, bacteria blocking, ultraviolet and water vapor barrier properties

Corn straw core (CSC) is considered as a promising biodegradable packaging material, owing to good ultraviolet (UV) and water vapor barrier properties. Nonetheless, if CSC will be used for packaging materials, some challenges, such as no mechanical strength (not-forming), poor water resistance, and lack of antimicrobial properties, still exist. To overcome these limitations, novel cellulose nanofibers (CNF)/CSC nanocomposites were developed, characterized, and demonstrated for potential food packaging applications. The reaction between CSC and CNF and the structures of CNF/CSC films were analyzed by FTIR, XRD, SEM, TG and DMA. Compared with CNF, polypropylene (PP), poly (butylene adipate-co-terephthalate) (PBAT) or poly (butanediol sebacate - butanediol terephthalate) (PBSeT), the tensile strength of CNF/CSC-100 film was advanced by 0.63 times, 1.25 times, 4.71 times or 8.04 times, respectively; the tearing strength of CNF/CSC-100 film, compared with PP, low density polyethylene or PBSeT, was improved by 19.79%, 66.96% or 49.61%, respectively; moreover, water vapor barrier property of CNF/CSC-100 film was enhanced by 57.69% or 46.59% than CNF and PBAT, respectively. The CNF/CSC films were also presented a superior UV barrier (UPF of 47.91–101.15) and wonderful bacteria blocking properties. In the bacteria blocking test, the growth of microorganisms using CNF/CSC-100 film was restricted to 12 days. In practical packaging tests with fresh garlic and milk, the weight loss and spoilage by external influences were effectively prevented by CNF/CSC films, which indicated the potential as food-packaging.