Modification of rheological properties of cellulose nanofibrils suspension by additives

The CNF film can impart excellent barrier property to paper-based packaging material. However, uniform coating of CNF suspension onto paper sheet is not easy because of high viscosity of CNF suspension. Therefore, understanding and modifying of the rheological properties of CNF suspension is necessary. In this study, we investigated the rheological properties of CNF suspension under various conditions and tried to find a proper approach for the modification of rheology. The effect of additives such as surfactant and lubricant was examined. Suspension rheology was evaluated using Brookfield viscometer and oscillatory rheometer. The viscosity of the CNF suspension was decreased with an increase in addition level of surfactant at the low shear condition. In particular, nonionic surfactant and lubricant were effective for reduction in the viscosity of CNF suspension. At the high shear rate, however, the viscosity was not changed. The rheological properties of the CNF suspension could be modified by addition of additives or by control of consistency.