Cellulose nanofibrils/polydimethylsiloxane double-layer coating for fabrication of high barrier and excellent water- and oil-resistance paper

Abstract

Paper-based packaging materials have attracted much attention due to their biodegradability, non-toxicity and renewability. However, traditional paper with poor water- and oil-repellency limits its application in food packaging. In this study, the traditional paper coated with cellulose nanofibrils (CNF) and a mixture of polydimethylsiloxane (PDMS) & CNF microparticles (CNFmp) became a hydrophobic and oleophobic paper-based material. The layer of CNF coated on paper can fill the porous on surface to improve the barrier, and the hydrophilicity of this layer contributed to resistance to oil. The coatings of PDMS@CNFmp provided the paper with good hydrophobicity. The effects of CNF concentration, coated thickness, and the second layer of PDMS@CNFmp on thermal stability, mechanical properties, water- and oil-resistance, and air barrier of the paper were investigated. When the concentration of CNF suspension for coating reached 2 wt%, the CNF layer's thickness was 16 μm and the coatings' thickness was 18 μm, the paper exhibited excellent tensile strength (35.02 ± 2 MPa), high hydrophobicity (WCA of 141° ± 3.2°), oil-resistance (91.8° ± 1.9°, kit rating 12/12) and gas barrier (1.38 ± 0.2 mL/min). The present work has great potential for preparing high barrier, fluorine-free, and water- and oil-resistant materials in the food packaging field.