Highly Efficient Preparation of Functional and Thermostable Cellulose Nanocrystals via H2SO4 Intensified Acetic Acid Hydrolysis.

A highly efficient and sustainable strategy for the production of functional and thermostable cellulose nanocrystals (CNCs) was developed in this work. In which, the acid hydrolysis system composed with small doses of H2SO4 (5-10%) and large amounts of easily recoverable acetic acid (70-90%) was used to hydrolyze cellulose pulp at 80 °C for several hours. The rod-like CNCs were obtained with the length of 150-500 nm and diameter of 5-20 nm in high yield (Ymax = 81%). The resulted CNCs showed high thermal stability and excellent dispersion stability in both aqueous and organic phases. The acetic acid in the hydrolysis system can be completely recovered by vacuum distillation, and the dosage of sulfuric acid can be reduced significantly compared with the traditional sulfuric acid hydrolysis. Thus, this approach is promising for the large-scale and sustainable preparation of CNCs with excellent water dispersibility and good thermal stability, with less environmental issues.