Comparative Study and Characterization of Cellulose Nanowhiskers Extraction from Palm Fibers by Different Methods

Abstract

Cellulose nanowhiskers as one kind of renewable and biocompatible nanomaterials evoke much interest because of its versatility in various applications. Herein, palm based cellulose nanowhiskers were prepared by TEMPO oxidation and acid combined enzymatic hydrolysis combined with homogenization, respectively. With the increase of sodium hydroxide concentration, the crystal form of the prepared palm fibers will gradually change from cellulose I to cellulose II. The crystallinity of the nanocellulose prepared by the two TEMPO oxidation systems has little change, which were 63.87% and 60.65%, respectively. While the acid combined enzymatic hydrolysis method increased the crystallinity of palm nanocellulose to 66.59%. The nanocelluloses prepared by the two TEMPO oxidation methods had no obvious difference in shape and size, were all needle-like structures with a diameter of about 10–50 nm. The suspensions were transparent with the optical transmittance of about 90%. While the nanocellulose prepared by the acid combined enzymatic hydrolysis is rod-shaped with a diameter of 30 nm, and the optical transmittance is about 81%. The versatile palm cellulose nanowhiskers would be particularly useful for applications in the nanocomposites as reinforcing phase, as well as in tissue engineering, filtration, pharmaceutical and optical industries as additives.