Preparation and Characterization of Cellulose Acetate Film Reinforced with Cellulose Nanofibril.

In this study, cellulose acetate (CA)/cellulose nanofibril (CNF) film was prepared via solvent casting. CNF was used as reinforcement to increase tensile properties of CA film. CNF ratio was varied into 3, 5, and 10 phr (parts per hundred rubbers). Triacetin (TA) and triethyl citrate (TC) were used as two different eco-friendly plasticizers. Two different types of solvent, which are acetone and N-methyl-2-pyrrolidone (NMP), were also used. CA/CNF film was prepared by mixing CA and CNF in acetone or NMP with 10% concentration and stirred for 24 h. Then, the solution was cast in a polytetrafluoroethylene (PTFE) dish followed by solvent evaporation for 12 h at room temperature for acetone and 24 h at 80 °C in an oven dryer for NMP. The effect of solvent type, plasticizers type, and CNF amount on film properties was studied. Good dispersion in NMP was evident from the morphological study of fractured surface and visible light transmittance. The results showed that CNF has a better dispersion in NMP which leads to a significant increase in tensile strength and elastic modulus up to 38% and 65%, respectively, compared with those of neat CA. CNF addition up to 5 phr loading increased the mechanical properties of the film composites.