Precipitated silicas modified with 3-aminopropyltriethoxysilane

A comparison was made of the methods used to modify the surface of hydrated silicas employing aminosilane coupling agent. The so-called dry technique of modification and the newly elaborated technique of modification in the course of precipitation were applied. The extent of modification of precipitated silicas was determined on the basis of heats of immersion of silica surface and of spectrophotometric analysis. Morphology of silica particle surface and size distribution of silica particles were determined by transmission electron microscopy (TEM) and by ZetaPlus instrument using dynamic light scattering.