ABSTRACT
Pyrogenic silica is a finely divided amorphous silicon dioxide produced by high temperature hydrolysis of silicon tetrachloride in an oxygen–hydrogen flame. The most important thermal pyrogenic path is the flame hydrolysis of silanes, which gives access to pyrogenic silica, silica. Pyrogenic silica is widely used in industry as an efficient thickening agent, providing shear thinning and thixotropy to liquid media like sealants, adhesives, composite resins, coatings, and inks. Control over the rheological properties of liquid systems is of enormous industrial importance. In the case of pyrogenic silica, several general types of silica are commonly used to govern the rheological properties of liquid media such as paints or adhesives. In silica–resin mixtures, adsorption of resin oligomers due to the high surface energy of the silica particles has to be taken into account. The surface of a colloidal system influences most strongly on the viscosity of a fluid where the colloidal solid is dispersed.
