Enhanced strength, antioxidant and barrier properties of chitosan-based film by bentonite and lignosulfonate

The application of chitosan (CS) film in active food packaging fields is greatly limited by their poor strength , antioxidant and barrier properties. Two nanoparticles , lignosulfonate (SLS) and bentonite (BT), were used together to enhance the food packaging properties of CS composite films in this work. A dense and robust multifunctional bio-based nanocomposite film with a pearl-like structure was successfully prepared. Results indicated that the introduction of SLS substantially better the strength, antioxidant, and UV-shielding capacities of CS composite film. The maximum tensile strength of the obtained nanocomposite film (SLS/BT/CS) reached 1.9 times of pure CS film. The SLS gave the composite film an excellent UV-shielding property (between 6.18–0.14% (T UVA ) and 0.32–0.06% (T UVB ) at 10–40 wt% SLS). The total phenolic hydroxyl group content of the composite film was significantly increased after adding SLS, and the DPPH· scavenging ability of SLS/BT/CS film was 5 times better than that of BT/CS film. The addition of BT bent the water vapor transport path in the film and created a hydrophobic surface , which in turn led to a significantly better water vapor barrier performance of SLS/BT/CS than pure CS films. The results of this work showed the great application potential of SLS/BT/CS nanocomposite film in the food packaging fields.