COMPARATIVE STUDY OF THE RHEOLOGICAL BEHAVIOR OF SOLUTIONS OF THE CHITIN-GLUCAN COM-PLEX FROM THE FRUIT BODIES OF ARMILLARIA MELLEA IN ACETIC AND HYDROGENIC ACID

Abstract

The article is devoted to the study of the rheological properties of the chitin-glucan complex (CGC) in aqueous solutions of hydrochloric and acetic acids. The CGC sample was isolated from the fruiting bodies of the Armillaria mellea, biotechnologically obtained from an easily renewable plant material. The flow of solutions of chitin-glucan complex with a concentration of 1, 5, 10% (wt.) in hydrochloric acid and 1, 3, 5% (wt.) in acetic acid was studied by the method of rotational viscometry in the range from 10 s-1 to 1000 s-1 at temperatures from 20°C to 50°C. The values of the rheological coefficients of the Ostwald equation are determined. The phenomena of non-Newtonian viscosity anomalies are established. The high viscosity of solutions may be due to the presence of an internal supramolecular structure in solutions of the chitin-glucan complex. The predominantly pseudoplastic nature of the rheological behavior of the studied solutions is shown. The flow index in this case varies from 0,18 to 0,79 for solutions of the chitin-glucan complex in hydrochloric acid and from 0,01 to 0,47 in solutions of acetic acid with a concentration of 3 to 5% (wt.). The pseudoplastic flow mechanism of such solutions can be explained by the destruction of the internal structure of the solution with an increase in shear loads. The dilatant nature of the flow of CGC solutions in acetic acid at a concentration of 1% (wt.) at a shear rate of 10 to 100 s-1 was also revealed. The flow index in this case ranges from 1,28 to 1,57. The dilatant nature of the flow may be due to the predominance of the processes of formation of a new internal structure in solution over the destruction of the existing structure in solution at a low concentration of the chitin-glucan complex. The influence of temperature on the rheological behavior of solutions is strongly distorted by the influence of other factors.