Lignin-enhanced wet strength and UV-Blocking properties of nanocellulose-based composite films obtained by casting/hot-pressing methods

We composited nanocellulose, lignin and polyvinyl alcohol (PVA) by using borax as a cross-linking agent, and prepared nanocellulose-based composite films by two simple and convenient methods of the casting and hot-pressing. Results showed that the molding method affected the film properties. The hot-pressing composite film exhibited smoother surface and tighter structures, while the casting one exhibited better stretchability. The composite films showed a good tensile strength (casting: 149.56 MPa; hot-pressing: 179.68 MPa). Due to the addition of lignin, the composite films were endowed with good UV-blocking capabilities, wet strength, oxidation resistance and bacteriostatic properties. The composite film has good application prospects in the field of food packaging and UV-shielding.