A Study on the Rheological and Magnetic Properties of Polymer-Bonded Magnets Using Polycarbonate as the Bonding Material

Abstract

The effect of three metal oxides on the magnetic properties of polymer bonded magnets (PBMs) was studied. The three PBMs, using polycarbonate (PC) as binder and 5 wt% of Fe3O4, Fe2O3, or CuO nanoparticles, were prepared by melt extrusion in a twin screw extruder followed by compression molding. Transmission electron microscopic (TEM) images showed a better dispersion for the PC/Fe3O4 nanocomposite compared with that of the other nanocomposites. The dynamic intersection frequency (ωc), which is related to the crossing of the G′ and G″ curves, showed that there was more homogeneity in the PC/Fe3O4 and PC/Fe2O3 nanocomposites. The curves of saturation magnetization for the three nanocomposites showed that there was a relationship between the magnetic properties and the homogeneity of the nanoparticles studied by rheometry. Because the magnetic strength of PC/Fe3O4 was greater than that of the other nanocomposites, it was concluded that not only the intrinsic magnetic property of the filler was an important factor to increase the magnetic property, but also the homogeneity of the filler within the matrix had an important role.