Evaluation of the properties of gel, film and paper coated with nanocellulose and nanochitin

Bio-based nano-materials have great potential as films and as paper coatings to produce materials that are suitable for food packaging. However, more needs to be understood about the characteristics of the starting materials and how they influence the final film properties. The objective of this study was to comparatively investigate the structural, thermal, mechanical, rheological, and functional properties of nanocellulose and nanochitin films or gels and their application as bio-coatings for paper. The thermal behavior of nanocellulose and nanochitin samples was similar. The tensile strength and strain of the nanocellulose films were significantly higher than those of the nanochitin films. The viscosity of both nanocellulose and nanochitin gels decreased uniformly with increasing shear rate. The coating process was carried out at a speed of 5 cm/s for single-layer and double-layer coatings. Bio-coating of the paper with nanochitin significantly improved the barrier properties (resistance to water, air, and oil penetration). At similar coat weights, the nanochitin-coated papers always consistently exhibited a lower thickness than the nanocellulose-coated papers. The brightness of nanocellulose-coated papers was higher than that of nanochitin-coated papers. This study demonstrates the potential of these bio-based nanomaterials for sustainable and effective paper bio-coatings.