Microwave absorption has attracted a considerable attention in the last decade. Various factors have effect on the microwave attenuation such as permittivity and permeability of absorbers. In this research, these properties were provided by multiwall carbon nanotube (MWCNT) as a conductive polymer and Zn0.25Co0.75Fe2O4 as a magnetic nanoparticle. MWCNTs were functionalized with carboxylic acid groups through the sonochemical method by the mixture of nitric and sulfuric acid, due to their better dispersion in the medium reaction and enhancing interfacial polarization, and then magnetic nanoparticles were formed base on the functionalized MWCNTs through the solvothermal method by use of ethylene glycol as a solvent. Finally, MWCNT/Zn0.25Co0.75Fe2O4 nanocomposite was blended in the silicone rubber as a polymeric matrix to investigation of microwave absorption properties. Zn0.25Co0.75Fe2O4 nanoparticles and MWCNT/Zn0.25Co0.75Fe2O4 nanocomposite were identified by the diffuse reflection spectroscopy (DRS), Fourier transform infrared (FT-IR), field emission scanning electron microscopy (FE-SEM), and investigation of microwave absorption properties was performed by vector network analyzer (VNA). Results indicated that magnetic nanoparticles and magnetic and dielectric MWCNT/Zn0.25Co0.75Fe2O4 nanocomposite have been prepared and absorbed more than 47% of microwave at x-band. Moreover, maximum reflection loss of this nanocomposite was 15 dB at 11.96 GHz.
Recently, barium ferrite nanoparticles have attracted substantial attention because of widespread applications in catalytic degradations, credit cards, storage hardwares, sensors, microwave devices, permanent magnets, high frequencies, photocatalytic catalysts, and etc. In this research, templated BaFe12O19 nanoparticles were prepared through the sol-gel method by use of cotton as a template in the sol step. Finally, templated nanoparticles were blended in the silicone rubber matrix and then prepared nanocomposite molded to investigate of microwave absorption properties at x-band frequency. Templated barium hexaferrite nanoparticles were characterized by Fourier transform infrared (FT-IR), diffuse reflection spectroscopy (DRS), vibrating sample magnetometer (VSM), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and microwave absorption characteristics were obtained by vector network analyzer (VNA). Microwave absorption curves showed that Templated BaFe12O19/silicone rubber nanocomposite absorbed 65.80% of microwaves at 9.87 GHz.