RHEOLOGICAL PROPERTIES OF AQUEOUS ACID SOLUTIONS OF CHITOSAN: EXPERIMENT AND CALCULATIONS OF THE VISCOMETRIC FUNCTIONS ON THE BASIS OF A MESOSCOPIC MODEL

The rheological properties of chitosan solutions in acetic acid at 20^oC in the range of polymer concentrations from 0.5 to 8 mass% and acid concentrations from 2 to 70% have been investigated. With the use of a modifi ed Vinogradov–Pokrovskii model based on the microstructural approach to the description of polymer fluid dynamics, numerical solutions of gradient dependences of viscometric functions of aqueous acid solutions of chitosan have been obtained. It has been established that the numerical solution describes with good accuracy the experimental viscosity rheograms. The values of the highest Newton viscosity η_max have been calculated. The concentration modes of semidiluted and concentrated solutions have been determined by the dependence of η_max on the polymer concentration, and the range of concentrations in which the mass transfer mechanism changes and a fluctuation network is formed has been found. It has been shown that the concentration of acetic acid practically does not infl uence the structure and character of flow of chitosan solutions, the formation concentration of a network, and the efficiency of its labile nodes
   
Author:  A. B. Shipovskaya, A. Yu. Abramov, G. V. Pyshnograi, and Al Joda Hyder Nadom Aziz
Keywords:  chitosan, acetic acid, solutions, rheological properties, shear viscosity, concentration mode, fl uctuation network, mesoscopic model, viscometric functions
Page:  642