Fabrication of recyclable high-barrier water- and oil-proof paper by sodium alginate/cellulose nanofiber/ethyl cellulose/ polyvinyl butyral

Paper-based packaging materials have seen explosive growth in recent years as consumers become more aware of the environmental and health hazards created by traditional food packaging materials. Even yet, there is a significant opportunity for improvement in the production of fluorine-free, water- and oil-proof, recyclable food packaging papers made from ecologically friendly polymers. In this study, we used sodium alginate (SA), cellulose nanofibers (CNF), ethyl cellulose (EC), and polyvinyl butyral (PVB) to create coatings that are impervious to water and oil. The paper was first impregnated with CaCl2 solution before SA and CNF were evenly mixed and applied to the paper. Ca2+ ion cross-linking strengthened the connection between the SA/CNF coating and the paper, which increased its oil-proof properties. The hydrogen bonding force in EC/PVB solution enhanced the water-proof performance and mechanical qualities of the paper. Finally, the water- and oil-proof paper showed excellent water repellency (Cobb value: 1.1 g/m2), oil repellency (kit rating: 12/12), low air permeability (0.2 µm/Pa·s), and stronger mechanical properties (4.21 kN/m). There is a great need for this fluorine-free, biodegradable, and recyclable paper-based material in the food packaging market due to its excellent barrier qualities.