Adsorption of silane coupling agent on Co-?-Fe2O3 a nd its effect on dispersibility

Abstract

The adsorption of a new type of silane coupling agent containing polyethylene oxide (EOS) on cobalt-modified iron oxide (Co-γ-Fe2O3) particles and its effect on dispersibility are examined by measuring the surface chemical properties. The EOS is adsorbed on Co-γ-Fe2O3 in the form of a monolayer and reduces the hydrophilicity of the surface of the particles with the adsorption. The surface hydrophilicity of EOS-treated iron foil (the iron foil has an ideal iron oxide surface) becomes lower with the increasing heat-treatment temperature. Heat treatment at 80°C or higher is required to achieve chemical bonding between EOS and the iron foil. By the same heat treatment, EOS polymerizes on the iron foil resulting in the formation of a polysiloxane network. The dispersibility of the particles in vinyl chloride-vinyl acetate-vinyl alcohol copolymer solution is improved dramatically by the surface treatment with EOS. The improvement in dispersibility is explained by considering the increase of the wettability of Co-γ-Fe2O3 for the solvent due to EOS treatment.[/p]