Polymer-iron tungstate-reduced graphene oxide nanocomposites for microwave absorption

Three polymers were used in the preparation of three-component nanocomposites. Sulphonated poly(ether-ether-ketone) (SPEEK) was synthesized by sulphonation of powdered poly(ether-ether-ketone) (PEEK) using concentrated sulphuric acid. Polyvinyl alcohol (PVA) was used as purchased. Polyaniline (PANI) was synthesized using aniline, hydrochloric acid and ammonium persulphate. Three nanocomposite films based on SPEEK, PVA and PANI were synthesized through solution casting from N-Methyl-2-pyrrolidone (NMP) solutions with a magnetic filler, iron tungstate (FeWO₄) and a conductive filler, reduced graphene oxide (RGO) dispersed in them. The synthesized PANI was characterized by X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-vis), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) and the nanocomposites (RGO/PANI, FeWO₄/PANI, FeWO₄-RGO/PANI) were characterized by FTIR, TGA, DSC and SEM. The nanocomposite films based on SPEEK and PVA containing 2% RGO and 2% FeWO₄ showed the electromagnetic interference (EMI) reflection loss of only -0.5 dB for a 0.1 mm thick sample. The PANI based nanocomposite film containing 2% RGO and 2% FeWO₄ showed the maximu m EMI reflection loss of -4.5 dB for a 0.1mm thick sample. (paper)