Multifunctional lignocellulose nanofibrils-polyvinyl alcohol composite films with dual-crosslinked networks for UV-shielding and high-barrier food packaging applications.

The next generation of food packaging films should meet both sustainability requirements and performance requirements for multifunctional integration to accommodate the diverse packaging needs of the food industry. By preserving the natural interfacial chemistry between lignin and cellulose and combining it with the self-polymerization and covalent crosslinking of KH560 (γ-(2,3-epoxypropoxy) propyltrimethoxysilane) in the LCNF/PVA (Lignocellulose nanofibrils/ Polyvinyl alcohol) system, a composite film featuring dual crosslinking (lignin crosslinking/silane crosslinking) and triple barrier functions (oxygen barrier, water vapor barrier, and UV barrier) was successfully constructed. The resulting K-LCNF-1@PVA composite film exhibits outstanding gas barrier properties (water vapor transmission rate: 0.5613 g·m-2·day-1, oxygen transmission rate: 0.6111 cm3·m-2·day-1·0.1 MPa-1) and UV shielding capability (UVB region >90%), alongside synergistic improvements in mechanical properties (tensile strength: 102.25 MPa) and hydrophobicity (water contact angle: 105.22°). Fruit preservation experiments further confirmed the effectiveness of this film as a food packaging material. This study offers insights into the high-value utilization of lignin nanocellulose and the development of multifunctional bio-based food packaging films.