Magnetic nanoparticles – polymer matrix nanodielectrics: Manufacturing, characterization and functionality

Abstract

In the present study, series of nanocomposites consisting of magnetic hexaferrite (BaFe12O19, SrFe12O19) nanoparticles as reinforcing phase and an epoxy resin acting as matrix were manufactured and characterized by multiple techniques. The morphological characterization was conducted via Scanning Electron Microscopy (SEM). The thermomechanical properties were studied using Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA) and tensile tests. The dielectric response of the nanocomposites and the related relaxation phenomena were examined by means of Broadband Dielectric Spectroscopy (BDS). Finally, the magnetic characteristics of the nanocomposites were investigated by employing a Superconducting Quantum Interference Device (SQUID) magnetometer.Experimental data demonstrate fine dispersions of nanoinclusions in all types of nanocomposites and an improvement in both the electrical and the mechanical properties of nanocomposites, increasing the filler concentration. Three different relaxation processes were observed: Interfacial Polarization, glass to rubber transition of the matrix and re-orientation of small polar side groups of the polymer chain. Furthermore, the specimens present ferromagnetic behaviour at room temperature and magnetization increases with filler content.