Catalytic Transesterification of Cellulose Nanocrystals (CNCs) with Waste Oils: A Sustainable and Efficient Route to Form Reinforced Biofilms

Bioplastics are plastics derived from natural resources like corn starch, biomass, sugarcane bagasse, and food waste. Unlike fossil-fuel-based plastics, they are entirely or partially bio-degradable. Cellulose- and starch-based bioplastics are already used for applications like packaging, cutlery, bowls, straws, and shopping bags. With the aim of developing eco-friendly biofilms for various applications, cellulose nanocrystals (CNCs) were obtained by sulfuric acid hydrolysis of waste cellulose and functionalized by transesterification with exhausted oils. The resulting transesterified nanocellulose (TCNC) was used as a reinforced material of PLA at different concentrations to develop biofilms using the solvent casting method. The biofilms composed of PLA and TCNC were assessed through Fourier-transform infrared spectroscopy (FTIR), mechanical properties, moisture barrier property (water vapor permeability rate—WVTR), and measurements of the water contact angle (WCA). A scanning electron microscopy (SEM) analysis confirmed the high compatibility of the PLA blended with TCNC at 1% and 3%. The inclusion of transesterified cellulose nanocrystals (TCNCs) to PLA increased the hydrophobicity, the film tensile strength, and the water vapor barrier properties of the final composite films.