Comparison of fibrillation characteristics of unbleached kraft pulp and organosolv pulp by Alkali Kneading process

This study evaluated the effects of the operating parameters on the fibrillation of the pulp during the kneading process. The effects examined two types of pulp and different pulp concentrations during the kneading with a fixed pulp volume concentration (PVC). Unbleached kraft pulp and organosolv pulp were first treated at different pulp concentrations (5.0%, 7.5%, and 10.0%) and then the morphological and physical characteristics of the treated fibers were compared and analyzed. Optical microscopy, Kajaani fiber analysis, particle size analysis, freeness, and the water retention value (WRV) showed that the alkali kneading accelerated the micronization and fibrillation of both types of pulp. These results also showed that the organosolv pulp was more effective in size reduction and hydration ability than unbleached kraft pulp. In addition, the higher pulp concentration of organosolv pulp significantly increased the fibril contents for a fixed kneading time, suggesting that the alkali kneading process of the organosolv pulp can be a potential precursor for lignin-rich microfibrillated cellulose and cellulose nanofibrils.