Electrical properties of epoxy nanocomposites containing Fe₃O₄ nanoparticles and Fe₃O₄ nanoparticles deposited on the surface of electrochemically exfoliated and oxidized graphite

Electrical conductivity, electromagnetic interference shielding and microwave absorption properties of epoxy composites containing magnetite nanoparticles and modified electrochemically exfoliated graphite (mEEG) were described in this work. Different nanoparticles were prepared by co-precipitation method and electrochemical exfoliation. Structure of synthesized Fe₃O₄ NPs and graphite based nanostructures was described in detail. The X-ray diffractometry, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy as well as scanning and transmission electron microscopy were used in order to characterize samples. Fe₃O₄ nanoparticles with average crystallite size equal to 8.45 nm and 8.30 nm were obtained in highly agglomerated structure and on the surface of mEEG. Reconstruction of graphite structure during precipitation of Fe₃O₄ on the surface of oxidized, exfoliated graphite was observed. In order to describe dispersion of AC electrical conductivity, correlated barrier hopping model was used. It was noticed, that addition of nanoparticles changes the values of hopping energy and activation energy as well as electromagnetic interference shielding and microwave absorption properties. Epoxy composite containing Fe₃O₄ NPs had the highest value of activation energy of electrical conductivity. It was shown, that the addition of magnetite nanoparticles has also improved electromagnetic interference shielding and microwave absorption properties of epoxy resin.