Interaction of a vinyl acetate—vinyl chloride based wetting binder with metal particles for magnetic recording

The interaction of two commercially available iron alloy particles with a wetting binder based on a vinyl chloride and vinyl acetate copolymer has been investigated. The interaction was studied using the techniques of flow microcalorimetry, X-ray photoelectron spectroscopy (XPS) and microelectrophoresis. The results obtained indicate that whereas both particles interact strongly with the wetting binder, particles of low nickel content are characterized by very high heats of interaction (about 37–47 kcal mol⁻¹). The adsorption on both particles appears to obey the Freundlich equation. Binder adsorption on particles results in the development of rather large zeta potentials in tetrahydrofuran solutions. XPS experiments are unable to provide any conclusive evidence for the interaction mechanism.