HYDRODYNAMIC BEHAVIOR OF AQUEOUS-SOLUTIONS OF ALKALI SILICATES AND STRUCTURIZATION EFFECTS AT EARLY STAGES OF GEL FORMATION

Within the frame of the scaling approach, expressions were obtained fo r the hydrodynamic behavior of aqueous solutions of alkali metasilicat es (''liquid glasses,'' LG). These expressions involve the relationshi ps between the efficient hydrodynamic volume of D-dimensional fractal clusters consisting of s simple particles, the mean concentration of c lusters c(S), and the relative viscosity eta(rel) of LG. Full agreemen t between calculated and experimental values eta(rel) for LG samples ( Na+, K+, module m = 2.8 - 3.84) was obtained. The calculation of eta(r el) was performed by modeling the changes in the hydrodynamic volume o f fractal clusters with the dimension D = 2.50 +/- 0.05 for a varying number of single particles in the solution. The description of volume percolation in LG was reduced to the analysis of the dependences p ([e ta]0c), where p is the probability of cluster formation, and [eta]0c i s the multiplicity of the filling of the hydrodynamic volume. Under th e condition p almost-equal-to p(c) (p(c) almost-equal-to 0.31, [11]0c = 0.5) sBAR = exp(p - p(c)); near the values p almost-equal-to 1 - p(c ) in accordance with the theory of critical phenomena, the scaling rel ationship NBAR is similar to (DELTAp)-1.63 +/- 0.01 was found, where N BAR is the mean polymerization degree of a cluster.