Simultaneous improvement of thermal stability and redispersibility of cellulose nanocrystals by using ionic liquids

Cellulose nanocrystals (CNCs) are predominantly obtained by the traditional sulfuric acid hydrolysis process. However, as-prepared CNCs powder features low thermal stability and poor redispersibility due to the existence of sulfonate groups and the hydrogen bond interaction among particles. Herein, by mixing the ionic liquid [BMIm][BF4] with freshly prepared CNCs without dialysis through a simple rotary evaporate procedure, the simultaneous improvement of thermal stability and redispersibility of CNCs has been achieved. By combining FTIR, TGA and DLS measurements, the critical role of rotary evaporates process for improving the thermal stability of CNCs has been discussed. Furthermore, the poly(lactic acid) (PLLA)/IL-CNC nanocomposites with enhanced mechanical properties were prepared by the melt-mixing method. This study provides a green and simple strategy for preparing dried CNC powders, which has a great potential in large-scale production of fully bio-based nanocomposites.