Production and Characterization of Cellulose Nanofibrils from Different Chemical and Mechanical Pulps

In this study, mechanical fibrillation for the production of cellulose nanofibrils (CNF) from chemical and mechanical pulps with different chemical compositions was studied. To investigate the effect of nanofibrillation on wood pulps by the grinder, the nanofibrils obtained from grinded pulp were characterized with morphology, particle size distribution, apparent viscosity in aqueous solution, degree of crystallinity, and water retention capacity. The results showed that the low lignin-containing unbleached kraft pulp (UKP) exhibited good performance for fibrillation, resulting in CNF with high viscosity, high water retention value, and small particle size. However, the fibrillation of high lignin-containing chemi-thermomechanical pulp was the most inefficient which resulted in heterogeneous materials with relatively low viscosity, low water retention value, and large particle size compared to chemical pulps. Furthermore, bleached softwood pulp from radiata pine was found to be much faster and for easier fibrillation compared to the bleached hardwood pulp from acacia due to the more rigid structure of hardwood fibers.