POLYMERIZATION OF SILICIC-ACID .2. KINETIC-ANALYSIS

The theory of homogeneous nucleation is applied to a high shear rheological study of silicic acid in dilute aqueous solutions with pH = 8 and various temperatures. The radius of the colloidal particule, the number of silica molecules in a nucleus of critical size and the free energy of formation of the critical nucleus were evaluated for all conditions. The experimental data for DELTA-G(c) at 25, 30, 34 and 40-degrees were compared to the theoretical value of the activation free energy. These results show that the process of polymerization of silicic acid is dependent on homogeneous nucleation and is favoured at 30-degrees.