Hydrophobic-modified cellulose nanofibrils (CNFs)/chitosan/zein coating for enhancing multi-barrier properties of heat-sealable food packaging materials

Paper-based packaging materials have drawn increased attention under the rising awareness of environmental issues, whereas the barrier properties of paper are inadequate for food packaging. This study aimed to improve the barrier properties of paper by multi-coating method. Chitosan was coated as the first layer primarily to improve the oil resistance of the paper, whereas hydrophobic modified nanocellulose was applied as the second layer to render the paper water-repellent as well as to further enhance its oil resistance. Finally, zein was coated as the third layer to achieve the heat-sealing property of paper, and further enhance the water and oil resistance of paper. The obtained triple-layer paper had a high kit number of 12 and a low Cobb 60 value of 2.6 g/m2, and exhibited heat-sealing ability without any adhesive agent, which has a peel strength of 372.6 N/m. The triple layers also effectively improved the mechanical properties, and decreased the moisture and oxygen permeability of the paper substrate. Moreover, the triple-layer paper possesses good antibacterial activity and cytocompatibility. This study may provide inspiration for improving the barrier properties of food packaging paper and endowing it with heat-sealing property.