Acid-basic surface properties of dispersed fillers based on metal oxides TiO₂, Al₂O₃, CaO and Fe₂O₃

The dispersed oxide fillers of different chemical composition were investigated: rutile (TiO₂), alumina (Al₂O₃), calcite (CaO) and hematite (Fe₂O₃). The mineral composition, surface morphology, particle size and specific surface of the fillers were investigated using modern physicochemical methods. It has been established that the acid-alkaline properties of the active surface centers (ASC) and hydroxyl-hydrate layer (HHL) depend on the chemical and mineral nature of the fillers. It is established that with decreasing acidity of the oxide, the desire for its surface to adsorb water molecules from the air increases. As the alkalinity of the oxide increases, the thickness of both the hydroxyl and hydrate surface layers increases in proportion. It is shown that the acid-alkaline properties of the surface correlate with the acid-alkaline properties of the oxides included in the fillers. (paper)