Improvement of microwave absorption for PAni/HA/TiO2/Fe3O4 nanocomposite after chemical treatment

In order to obtain efficient microwave absorbers that possess high conductivity, dielectric and magnetic properties, hexanoic acid doped polyaniline (PAni) nanocomposites which contain different ratios of ferum (II) oxide (Fe3O4) and titanium dioxide (TiO2) nanoparticles were successfully prepared by in situ chemical polymerization through template free method. Chemical structure, conductivity, morphology, thermal stability, magnetic properties, and amorphous/crystalline behavior of PAni nanocomposites were characterized by Fourier transform infrared spectrometer (FTIR), four point probe, field emission scanning electron microscope (FESEM), thermal gravimetric analysis (TGA), vibrating samples magnetometer (VSM), and X-ray diffractometer (XRD), respectively. From this study, conductivity was significantly improved from 8.48 x 10-4-1.23 x 10-2 S/cm for PAni nanocomposites without any chemical treatment (during addition of Fe3O4) to 3.58 x 10-2-4.77 x 10-2 S/cm for those with chemical treatment. PAni nanocomposites with chemical treatment show a narrow sharp reflection loss (RL) peak with high absorption (-48.9 dB) at lower frequency due to the limited individual Fe3O4 nanoparticles outside the nanorods/nanotubes as proved by the new proposed mechanism (Fig. ), while it shows a broad RL peak with poor absorption (-13 dB) at higher frequency for those without chemical treatment. The novelty of this research has been focused on PAni with chemical treatment which yield better microwave absorption property (99.999% absorption), combination of high conductivity (3.58 x 10-2-4.77 x 10-2 S/cm), high heterogeneity and moderate magnetization (Ms=8.87-28.49 emu/g) compare to the PAni without chemical treatment. POLYM. COMPOS., 34:1186-1194, 2013. (c) 2013 Society of Plastics Engineers