Effect of pH on Rheological Properties of Microcrystalline Cellulose Dispersions

The size distribution and morphology of microcrystalline cellulose (MCC) particles and the effect of pH on the rheological properties of their dilute aqueous dispersion were studied. The 0.3 wt% aqueous dispersion of fine particles (89 nm) also showed solid‐like dynamic viscoelastic behavior at low pHs (below pH 3), in contrast to liquid‐like behavior at high pHs. These findings suggest that at lower pHs the electrostatic repulsion force between MCC particles decreases to induce the aggregation of particles into a three‐dimensional network structure. The minimum empty space in the network structure is expected to be 450 nm or more.