Study on the rheological properties of carboxymethyl chitosan aqueous solution

The effects of mass percentage, shearing speed, temperature and pH on the rheological behaviors of carboxymethyl chitosan(CMCS) aqueous solution were studied by measuring the apparent viscosity under different conditions. The results suggested that CMCS aqueous solution was a pseudoplastic fluid with a flowing curve in accordance with the power-law. The flow activation energy of the solution with the concentration ranging from 0.5% to 4.5% was 23.06 ± 2.23 kJ/mol (P = 0.95). pH had great impact on the solubility, but not on the apparent viscosity. The CMCS solution showed positive thixotropy. The empirical equations for the consistency coefficient K and the non-newton index n at 20 C were obtained by polynomial fitting, so the semi-empirical model of apparent viscosity was established. It provides a basis for the mutual calculation of the apparent viscosity and mass percentage of the CMCS solution.