Rheological Properties of Cellulose Nanocrystals Suspension at Different pH

The relationships between the microstructure and the rheological behavior of suspension of rod-like cellulose nanocrystals at different pH were investigated. The fluidity, creep and frequency responsibility of suspension systems were investigated by linear rheological methods, and the mechanism of structure change of suspension system caused by pH regulator was discussed. The flow data and creep data of suspension systems were fitted by Power-Law model and Burger model respectively. The experimental results show that the suspension system with pH=2 has typical liquid crystal structure and shows S type of flow curve. With the increase of pH, suspension systems form gel structure gradually and gel strength increases. The S type of flow curve becomes weakened. The creep elastic compliance decrease while the viscous complianc increase, and the suspension systems show elastic recovery when pH9. The storage modulus G′ and loss modulus G″ increase significantly while tanδ decrease first and then increase. The internal friction of suspension system at pH=7 is at minimum.