INFLUENCE OF LIGNIN CONCENTRATION ON VISCOELASTIC PROPERTIES OF ITS MODIFIED FORM OB-TAINED BY SOL-GEL METHOD IN THE PRESENCE OF ALUMINUM-SILICON COMPOUNDS

Abstract

The concept and flow model of a structured dispersed system obtained on the basis of sulfate lignin modified by Sol-gel method in the presence of aluminum-containing components in the form of nepheline concentrate are considered. The systems are mainly systems of non-Newtonian behavior, characterized by phenomena of destruction and formation of new structures in the shear flow, and the nature of the flow depends on the characteristics of interaction between system components, which are defined as their concentrations, and process conditions of the synthesis, at which the change of the adhesion forces between particles and at the moment cannot be generalized and described existing well-known equations of flow.As a result of the study, it was found that an increase in the concentration of sulfate lignin under various synthesis conditions, but with a constant amount of mineral component, leads to the formation of a new modified product, while there is a tendency to increase the parameters of kinematic viscosity and shear stress at the corresponding pH values of synthesis. Under conditions of excessive lignin concentrations of more than 400 mg/dm3, when self-organizing in the matrix of a new form, lignin dominance leads to a decrease in the strength characteristics of the polymer for all its forms obtained at different pH values. It is established that the kinematic viscosity and shear stress of water dispersions in this system depend on both the pH value of their synthesis and the concentration of the initial lignin, which determines the mechanisms of self-organization of the new modified structure.