Preparation of highly filled super-paramagnetic PMMA-magnetite nano composites using the solution method

The effect of super-paramagnetism is limited to magnetite particles at the nano scale [1–5]. Agglomerated particles exceeding a diameter of 20 nm do not show super-paramagnetism any longer. To transfer this special nano property to a bulk material it is necessary to ensure maximum dispersion of the fine particles within the polymer matrix. The focus of this paper is on the production process for super-paramagnetic magnetite PMMA nano composite material. The polymer PMMA is highly filled up to 50 mass-% with magnetite particles. The solution process uses a stabilized magnetic fluid, in which the polymer is dissolved. This solution/dispersion is atomized and dried in a spray tower to produce a fine powder of composite material. This powder is characterized (SAXS, XRD, VSM, AGM) and further processed e.g. in an injection moulding machine to manufacture structural parts. The structural parts still show super-paramagnetic properties. C 2006 Springer Science + Business Media, Inc.