Degree of Silicic Acid Polymerization in Alkali-Metal Silicate Solutions

The degree of polymerization and the sizes of silicon-oxygen anions in liquid-glass solutions were studied as functions of the silicate modulus, silica density (concentration), and nature of the alkali cation by means of kinematic colorimetry. The degree of polymerization increased appreciably when the modulus increased above 2.6 and density above 1.3. In addition, the liquid glass modulus was the most important factor in the range of the studied characteristics. Above the critical values of the silicate modulus and concentration of the dissolved silicate the system transforms from the true solution of a polyelectrolyte, characterized by the presence of discrete polymer anions, into a coherent-disperse colloidal system with a high degree of volumetric polymerization.