Tixotropic Properties of Solutions of Some Polysaccharides

摘要

The thixotropic properties of aqueous solutions of the following polysaccharides are studied: chitosan, its water-soluble derivative the sodium salt of chitosan succinamide, and the sodium salt of carboxymethyl cellulose. These polymers have been selected due to their physiological activity and the possibility of using them for biomedical purposes. Studying the effect of the polymer concentration on rheological behavior shows that if a dilute polysaccharide solution is taken for research, then the flow curve does not actually depend on the time of exposure to the shear strain; i.e., the system is thixostable and in equilibrium, in contrast to semidiluted solutions, which clearly demonstrate nonequilibrium and thixotropy. The solutions of the studied polysaccharides behave like thixotropic systems only in the concentration region where supramolecular structures are uniquely formed and the time required for their destruction is comparable with the experiment's time.