Effect of oxidized chitin nanocrystals isolated by ammonium persulfate method on the properties of carboxymethyl cellulose-based films

Oxidized chitin nanocrystals (ChNCs) were isolated from crab shell chitin using ammonium persulfate (APS) method. The oxidized ChNCs were in needle shape with a diameter of 15 nm, the length of 400-500 nm, and crystallinity index of 93.5%. Carboxymethyl cellulose (CMC)-based films reinforced with the ChNCs (0, 1, 5, and 10 wt.%) were flexible and transparent. The mechanical strength of the CMC film increased significantly (p < 0.05) after blending with the ChNCs. The tensile strength (TS) and elastic modulus (EM) increased by 88% and 243% when 10 wt.% of ChNCs were incorporated. Water vapor barrier property of the composite films decreased and the hydrophilicity increased compared with the neat CMC film. The oxidized ChNCs obtained using the APS method have a high potential for being used as a reinforcing filler to improve the mechanical properties of nanocomposite films for the application in food packaging, nano-papers, hydrogels as well as biomedical applications.