In sealants and adhesives, fumed silica plays a major role in rheological control and viscosity strength.
When fumed silica is added and dispersed in adhesives and sealants, a silica agglomerates network is formed, agglomerates react with SI-OH and result in hydrogen bonds, thus flowing property is restricted and viscosity increased, thickening property promoted; but,when shear thinning is applied, hydrogen bonds and silica network breaks,viscosity decreases, this allows adhesives and sealants to be applied smoothly; when shear thinning is removed, network restored,viscosity increases, this prevents adhesives and sealants from sagging during curing process.
