The Preparation and Properties of Titanium Dioxide Pigments with Acidic Surfaces

Titanium dioxide pigments used in commercial polymers are generally coated with a neutral, alumina/silica gel-coat to improve the pigment physical properties and also to reduce the chemical activity of the titania surface. Production of an acidic alumina/silica coating on titania pigments gives them a chemical activity similar to that previously found in dry clays. This activity is sufficient to increase greatly the bonding of basic organic materials to the pigment surfaces. The enhanced bonding can lead to materials with highly organophilic surfaces. The property changes in polymer composites brought about by these acidic pigments are discussed.