The impact of manufacturing technology, of the polypropylene matrix and iron oxide nanoparticles based magnetodielectric nanocomposites on electrophysical parameters

Abstract

PP + Fe3O4 nanocomposite films were produced by two technological ways, namely hot pressing and extrusion techniques. It was found that depending on the production methods, the proportion of absorbed EM waves by the composite films differs. It is known that the EM waves absorbing properties of materials depend on the electrophysical parameters. Therefore, the frequency dependence of dielectric permittivity and dielectric loss were investigated for both type samples. The polarization properties and the frequency dependence of the dielectric losses of the nanocomposites obtained by different methods vary both quantitatively and qualitatively. It was also studied the influence of an external permanent magnetic field on the electrical resistivity of the nanocomposite samples. It was found that independent of the production techniques the electric resistivity of both polymer nanocomposite samples decreases under the influence of an external magnetic field, and the negative magnetoresistive effect was observed. The proportions of EM waves absorption and also differentiation of other electrophysical properties of these nanocomposites, which consist on same components but were produced throughout different methods, could be explained by the fact that the diamagnetic anisotropy, defects density and also interphase layer on the boundary of nanoparticles and matrix in these materials are quite different from each other.