High-Barrier, Photothermal Conversion, and Antibacterial Composite Enabled by Kraft Lignin-Coated Cellulose Paper for Plastic Replacement

Paper-based materials demonstrate considerable potential as a substitute for plastic packaging. However, their limited barrier properties, singular functionality, and intricate preparation methods pose challenges to further advancement. Specifically, the inadequate barrier adversely impacts the preservation of paper-based packaging materials under conditions characterized by high humidity and prolonged exposure to sunlight. Herein, a refined preparation strategy is proposed for the direct and enhanced production of a biodegradable multifunctional barrier packaging paper. Lignin is deposited onto the surface of cellulose paper (CP) via vacuum filtration followed by conversion into lignin/cellulose paper (LCP) through a simple hot-pressing process. The resulting LCP exhibits outstanding barrier properties (Kit grade of 12, water vapor permeability of 197 g/(m²·24 h) at 37 °C and 90% RH) and wet strength (50.79 MPa). Moreover, the prepared LCP also exhibits rapid and stable photothermal conversion capability, along with remarkable photothermal antibacterial activity (photothermal antibacterial rate >99.9%). The overall prepared LCP exhibits numerous advantages, encompassing an intact biobased composition, degradability, environmental protection, and exceptional barrier properties. Therefore, it presents an optimal alternative to conventional plastic packaging materials, offering an efficient solution for product storage across diverse environments while also providing a sustainable and cost-effective approach to the production of barrier packaging materials.