Preparation of composite magnetic microspheres by reactive blending

A novel method for preparation of polymer-based magnetic microspheres was proposed by utilizing melt reactive blending, which was based on selective location of Fe₃O₄ nanoparticles in PA6 domains of polystyrene (PS)/polyamide 6 (PA6) immiscible blends. The morphology of PA6/Fe₃O₄ composite magnetic microspheres was studied by scanning electronic microscopy (SEM). The composite magnetic microspheres were spherical with a diameter range of 0.5–8 μm; the diameter was sharply decreased with a very narrow distribution by adding terminal maleic anhydride functionalized polystyrenes (FPS) for reactive blending. Transmission electron microscopy (TEM) and thermogravimetry analysis (TGA) results showed that most of Fe₃O₄ was located in the PA6 microspheres. Magnetization data revealed the magnetite content of PA6/Fe₃O₄ microspheres was about 32 wt% and the saturation magnetization could be up to 17.2 Am²/kg.