POLYMERIZATION OF SILICIC-ACID .2. KINETI C-ANALYSIS

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