Facile preparation of cellulose nanofibrils (CNFs) with a high yield and excellent dispersibility via succinic acid hydrolysis and NaClO2 oxidation.

ABSTRACT

An efficient and low-cost approach to preparing CNFs with succinic acid hydrolysis and NaClO2 oxidation is explored. High-temperature-short-time hydrolysis can depolymerize the cellulose, whereas the dispersibility of the CNFs is hugely enhanced by NaClO2 oxidation under alkaline condition. The degradation of cellulose in succinic acid hydrolysis follows first-order reaction kinetics and is severely influenced by the hydrolysis temperature, moreover, the molecular chains of the cellulose are seriously cracked under the optimized condition. The NaClO2 oxidation greatly improves the zeta potential (-36.2 mV) and the dispersibility of the CNFs. The obtained CNFs have an ultimate yield of 94.6%, and the diameter distribution is mainly within 20-40 nm. In addition, some amount of carboxyl groups in the cellulose will be instead of the hydroxyl groups, and the crystallinity of the CNFs is significantly increased.