Separation cellulose nanocrystals from microcrystalline cellulose using hydrated deep eutectic solvent and high shear force

Abstract

Cellulose nanocrystals (CNC) have been applied in many fields with excellent properties, however, efficient extraction of CNC from biomass materials remains a challenge. This study proposed and evaluated a method for preparing CNC from microcrystalline cellulose (MCC) by combining chemical hydrated deep eutectic solvent (DES) with mechanical high shear force methods. Specifically, when treatment time was increased, the yields of CNC increased from 27.2 % (0.5 h) to 65.2 % (2.5 h). The X-ray diffraction patterns indicate that the obtained CNC possesses the same type of crystal structure as the MCC (cellulose Ι). Transmission Electron Microscopy analyses determined that CNC has an average diameter of 25.1–33.3 nm and a length ranging from 281.3 nm to 404.2 nm. Moreover, the duration of treatment had no significant effect on the changes in morphology and dimension of CNC. This method is more eco-friendly than conventional hydrolysis, as well as faster than other DES treatments, which paves the way for CNC to be produced from MCC. • Combining chemical hydrated deep eutectic solvent and mechanical high shear force. • High yield of cellulose nanocrystals (up to 65.2 %). • Greener than acid hydrolysis and faster than other deep eutectic solvent methods.