Preparation of Nanocrystalline Cellulose from Corncob Acid-Hydrolysis Residue and Its Reinforcement Capabilities on Polyvinyl Alcohol Membranes

The sodium chlorite process was utilized successfully to remove the lignin from corncob acid-hydrolysis residue (CAHR), and the intermediate was used to prepare nanocrystalline cellulose (NCC) with a very mild ultrasonic treatment (600W). When the duration of the ultrasonic treatment increased, the absolute value of the zeta potential became stronger and the particle size smaller. When the duration reached 30 minutes, the zeta potential of the NCC reached −23mV, and the particle size was 28.7 nm. The FTIR, XRD, and TEM analysis results proved that the cellulose product was nanocrystalline in Type I structure with a high crystallinity index (79.74%), with a diameter less than 10 nm. The reinforcement of polyvinyl alcohol (PVA) membranes using NCC was also investigated. When the dosage of the NCC was 1.0 wt.%, the tensile strength increased from 34 MPa to 37 MPa. This work provides a novel and cost-effective way to utilize corncob acid-hydrolysis residue.