Cellulose Nanowhiskers Isolation and Properties from Acid Hydrolysis Combined with High Pressure Homogenization

This study focused on cellulose nanowhiskers (CNWs) isolation using a combination of acid hydrolysis and high pressure homogenization, and investigated the effects of acid concentration (20, 40, and 60 wt%), hydrolysis temperature (20, 40, and 60 o C), and hydrolysis time (2, 4, and 6 h) on the geometry and chemical properties.After the combined treatment, nanoparticles were rodlike with a diameter of 11 to 33 nm, a length of 199 to 344 nm, and aspect ratio of 10 to 18, which are characteristic properties of CNWs.Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) analyses showed that some breakages of intramolecular hydrogen bonds and glycosidic bonds occurred during the hydrolysis reaction of MCC.An increase in acid concentration from 20 to 60 wt% could effectively accelerate these breakages in cellulose molecules, leading to narrower, less polydisperse nanowhiskers with lower crystallinity.