Green Preparation of Cellulose Nanocrystal and Its Application

A green method was used to prepare cellulose nanocrystals (CNCs) with no use of harsh chemicals or organic solvents. This method was simple via ball milling cellulose with water followed by centrifugation. The diameter and length of the CNCs were 3-10 nm and 120-400 nm, separately, with a aspect ratio of 20-60. The yield was about 20%. The thermal stability of the CNCs was the same as that of raw cellulose owing to lacking of chemical modification. So it was superior to CNCs prepared by acid hydrolysis. Then poly(vinyl alcohol) (PVA)/CNC composite film was made by solution casting. The results showed that the tensile strength of the composite film was 79% increased from neat PVA film when adding 5% CNCs to the PVA matrix. In addition, the composite films possessed good transparency and thermal stability.