Polyaromatic-hydrocarbon-based carbon copper composites for the suppression of electromagnetic pollution (original) (raw)
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Phys. Chem. Chem. Phys., 2014
There is an increased interest in the development of high performance microwave shielding materials against electromagnetic pollution in recent years. Barium ferrite decorated reduced graphene oxide (BaFe 12 O 19 @RGO) nanocomposite was synthesized by high energy ball milling technique and its electromagnetic properties were investigated in the frequency range of 12.4-18 GHz (Ku band). The results showed that barium ferrite (BaFe 12 O 19 ) nanoparticles with an average particle size of 20-30 nm were well distributed and firmly anchored onto the surface of the reduced graphene oxide sheets. The obtained nanocomposite exhibited a saturation magnetization of 18.1emu/g at room temperature. The presence of BaFe 12 O 19 nanoparticles in the nanocomposite enhances the space charge polarization, natural resonance, multiple scattering and the effective anisotropy energy leading to a high electromagnetic interference shielding effectiveness of 32 dB (~99.9% attenuation) at a critical thickness of 3 mm. The results
J. Mater. Chem. C, 2015
We report detailed study on the electromagnetic interference (EMI) shielding effectiveness (SE) properties in La 0.7 Sr 0.3 MnO 3 (LSMO) nanomaterials. The samples were prepared by solution chemistry (Sol-Gel) route with different sintering temperatures. The single-phase samples with grain size 22 and 34 nm showed dc electrical conductivity variation from 0.65 to 13 S/cm at room temperature. An application of high magnetic field resulted in higher conductivity values. The electrical conductivity variation with 15 temperature could be fitted with variable range hopping mechanism in limited range of temperature. The variation of frequency dependent electromagnetic parameters measured at room temperature within the X-band region is consistent with electrical conductivity behavior. The complex permittivity and permeability parameters were determined in line with Nicholson-Ross and Weir algorithms. The LSMO nanomaterial samples showed EMI shielding effectiveness value up to 19 dB (96.3 % attenuation) over 20 X-band frequency range suitable for microwave radiation shielding in commercial and defense appliances. 65 etc motivated us to study them for electromagnetic radiation shielding. An epoxy composite of bulk LSMO has been reported
Journal of Materials Chemistry A, 2014
Microwave shielding properties of chemically synthesized MnO 2 decorated graphene nanoribbons (GNRs) are reported for the first time. The nature of MnO 2 decoration on the GNRs has been investigated using scanning electron microscopy, X-ray diffraction, Raman spectroscopy and high resolution transmission electron microscopy. The electromagnetic interference (EMI) shielding effectiveness of this material was investigated in the microwave region . The presence of MnO 2 on GNR enhances the interfacial polarization, multiple scattering, natural resonances and the effective anisotropy energy, which leads to absorption dominated high shielding effectiveness of À57 dB (blocking >99.9999% radiation) by a 3 mm thick sample. Dielectric attributes (3 0 and 3 00 ) were evaluated to understand the mechanism of the excellent shielding effectiveness. The material will be an excellent choice for radar absorbing applications. † Electronic supplementary information (ESI) available. See
Nanoscale, 2014
The multiphase approach was adapted to enhance the electromagnetic interference (EMI) shielding effectiveness (SE) of polyaniline (PANI) based nanocomposites. The natural graphite flakes (NGF) incorporated modified PANI was used for the development of multi-walled carbon nanotubes (MWCNTs) based nanocomposites. In PANINGF-MWCNTs composites, multilayer graphene was synthesized in situ by ball milling. The resultant PANINGF-MWCNTs nanocomposites were characterized by different techniques. It was revealed from the transmission electron microscope (TEM) observation that in situ derived multilayer graphene acts as a bridge between PANI and MWCNTs, and plays a significant role for improving the properties of multiphase nanocomposites. It was observed that EMI-SE increases with increasing the MWCNTs content from 1 to 10 wt% in the multiphase nanocomposites.
RSC Advances, 2014
Tin oxide nanoparticles architectured with a reduced graphene oxide composite (SnO 2 @RGO) have been synthesised by in situ reduction of graphene oxide in the presence of stannous chloride. The microwave shielding performance of SnO 2 @RGO has been evaluated over the X-band (8.2-12.4 GHz) range. XRD and TEM studies show that the tin oxide nanoparticles are anchored uniformly onto the surface of the reduced graphene oxide sheets. A total electromagnetic interference shielding effectiveness in the order of 62 dB was achieved, which is more than the required values ($30 dB) desired for techno-commercial applications.
Journal of Materials Chemistry C , 2017
The quick advancement in wireless information technology, especially in the high-frequency range, has led to a new kind of pollution; electromagnetic interference (EMI). This issue has been of increasing criticality and importance in worldwide consideration. One key answer is to fabricate materials that can constrict the undesirable electromagnetic waves. The coveted properties of these materials include low reflection loss, wide attenuation band, lightweight and economic viability. In this critical review, we endeavoured to condense a logical guide to different methodologies derived in the last few years to improve EM retention utilizing multi-layered sandwich designs. The prime focus of this review is to highlight the crucial and fundamental scientific necessities and preferred standpoint of using such designs. We likewise attempt to provide the necessary outlook and direction in which the future research will continue to thrive.