CNC-reinforced regenerated cellulose coating: A novel approach to enhancing barrier and mechanical properties of cellulose-based packaging

Abstract

The broader application of cellulose-based packaging has been restricted by its inherent limitations in mechanical and barrier properties, despite the advantages of biodegradability and renewability. In this study, a cellulose-based composite packaging material was developed through the incorporation of an ultra-thin layer of silane-modified regenerated cellulose coating, which was reinforced with cellulose nanocrystals (CNCs), onto a cellulose-based substrate. This incorporation was achieved utilizing the practical and efficient Mayer bar coating technique. The composites, incorporating an ultra-thin coating, weighing just 0.4 g/m², demonstrated notable enhancements in hydrophobicity, gas barrier properties, and mechanical characteristics compared to the untreated cellulose-based materials. The water contact angle of the composites reached up to 110.4°, indicating a significant shift towards hydrophobic surfaces. Furthermore, the water vapor transmission rate was reduced from 393.8 g/m²·d to 73.8 g/m²·d, while the oxygen permeability decreased by tens of times. Notably, the dry tensile index increased by 74.4 %, the wet tensile rose by a factor of 17.8, the burst index improved by 32.5 %, and the internal bond strength was enhanced by 94.3 %. The composites developed in this study demonstrate excellent barrier and mechanical properties, thereby expanding their potential applications in functional packaging.