Preparation and characterization of the ribbon-like cellulose nanocrystals by the cellulase enzymolysis of cotton pulp fibers

Abstract

The enzymolytic preparation of cellulose nanocrystals (CNCs) has the unique advantages due to its green chemistry process. In this work, the cotton pulp fibers were enzymolyzed with the cellulase to prepare the ribbon-like CNC, and the samples were characterized by SEM, FTIR, XRD and DLS. The results indicated the CNC with the length 250-900 nm and width 30-45 nm could be produced from cotton pulp fibers at the lower cellulase concentration, the time 5-11 h and temperature 50 ºC. When the cellulase concentration rose up to 100 /ml, the granular CNC appeared, and at 300 μ/ml all of the formed CNC were granular. FTIR and XRD analyses proved that the ribbon-like CNC had the same crystal style and chemical structure with original cotton pulp fibers, but its crystallinity was weakened slightly. Despite the fact that there are the weakened crystallinity and aggregates, the as-prepared samples were still called as CNCs for simplicity. In addition, the article has discussed the mechanism for the forming ribbon-like CNC from the enzymolysis of cotton pulp fibers.

Keywords: Cellulose nanocrystals; Cotton pulp fiber; Enzymatic hydrolysis; Ribbon-like.