Dispersibility of Magnetic and Nonmagnetic Iron(III) Oxides in 2-Butanone

Abstract

Abstract The dispersion stability of needlelike and octahedral iron(III) oxides of magnetic or nonmagnetic particles in 2-butanone was studied. Two kinds of copolymers of poly(vinyl acetate-vinyl chloride-maleic acid) (VAVCCOOH) and poly(vinyl acetate-vinyl chloride-vinyl alcohol) (VAVCOH) were used as dispersants. The sedimentation of dispersions, the adsorption of copolymer dispersants on the particles and zeta potentials were measured. By polymer adsorption, the dispersion of nonmagnetic needlelike iron(III) oxide was stabilized and the dispersions of magnetic needlelike iron(III) oxides were somewhat stabilized, but the dispersions of magnetic octahedral iron(III) oxides were only slightly stabilized. This characteristic behavior of the sedimentation experiment was discussed in relation to the amount of polymer adsorption and zeta potential and was correlated with the observations by an electron microscope. The magnetic attractive force operating between the two magnetic particles was calculated to illustrate the dispersibility of magnetic oxides. It was suggested from the calculation that the strength of the magnetization and the volume of a particle are the main factors affecting the flocculation of the magnetic particles.