Study on the surface modification of pulp with cationic polyelectrolyte for the manufacture of cationic cellulose nanofibril

Abstract

In this study, we evaluated the effect of modifying the surface of hardwood bleached kraft pulp (HwBKP) on the zeta potential of CNF. Modification of the surface of HwBKP was conducted using C-PAM and poly-DADMAC before mechanical isolation. After the surface of the pulp had been modified, micro-grinding was carried out to make CNF with surface-modified HwBKP. Then the particle size and the zeta potential of the CNFs were analyzed. The average particle size of the CNFs decreased as the pass number of the micro-grinder increased, regardless of the type of polyelectrolytes used. However, the zeta potential of the CNFs manifested different aspects depending on the type of polyelectrolytes used. CNFs made from HwBKP surface-modified with poly-DADMAC showed a charge reversion, but C-PAM could not modify the zeta potential of the CNFs. This result is thought to be due to the different adsorption mechanism, which depend on the type of polyelectrolytes, on the fiber surface. It may be concluded that polyelectrolytes with relatively low molecular weight and high charge density effectively make cationic CNFs by modifying the surface of pulp. ? 2019 Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.