Cellulose nanofiber/shellac nanocomposite films as coatings for packaging paper

This study evaluates the efficiency of nanocomposite films prepared from cellulose nanofibers (CNF) isolated from rice straw and different ratios of shellac in terms of film properties, in addition to using a CNF/shellac mixture for coating paper sheets. The CNF/shellac nanocomposite films were prepared by the casting procedure. The weight percentage of shellac in the composition of the nanocomposite films was varied from 0 to 40%. Scanning electron microscopy was used to show the films' morphological structure. Also, the films' air permeability, tensile strength and water vapour permeability (WVP) were investigated. The outcomes showed that adding shellac to CNF can improve the films' tensile strength, WVP and air permeability characteristics. The formulation chosen for coating paper contained 60% CNF and 40% shellac. Tests were done to assess the tensile and burst strength, water absorption, air permeability and water vapour permeability of coated paper sheets. SEM analysis was performed on the surface and cross-section of coated paper sheets. It was noticed that paper sheets coated with a 90-mu m thick film of CNF or CNF/shellac presented enhanced tensile strength, as well as lower water absorption, air permeability and WVP, while the burst strength properties were not affected. The addition of shellac to the composite coating produced coated paper sheets with better tensile strength compared to those of paper sheets coated with CNF alone, making them a viable choice for packaging materials.