Investigation of microstructure, electrical behavior, and EMI shielding effectiveness of silicone rubber/carbon black/nanographite hybrid composites

Abstract

In this study, electrical properties and electromagnetic interference shielding effectiveness (EMI SE) of composites based on room temperature vulcanizing silicone rubber (RTV-SR) and hybrid conductive fillers (carbon black [CB]) and graphite nanoplate [GNP]) were studied. The role of GNP/CB ratio on developed conductive networks, electrical properties, as well as electromagnetic interference (EMI) shielding effectiveness of composites was investigated in comparison with SR/CB and SR/GNP composites. Dielectric properties of hybrid composites were controlled by the dominant filler phase. Nevertheless, all hybrid nanocomposites with a higher fraction of CB in GNP/CB hybrid systems showed a lower percolation threshold and higher EMI SE. The frequency dependency of the AC conductivity revealed tunneling conduction mechanism below the percolation threshold, while above the percolation threshold, the direct contact mechanism played the dominant role of transferring electrical current. EMI shielding measurements over X-band frequency demonstrated absorption loss as the main mechanism for the attenuation of the incident EM wave intensity in hybrid composites. POLYM. COMPOS., 40:4056-4066, 2019.

Hybrid carbonaceous materials for radar absorbing poly(vinylidene fluoride) composites with multilayered structures

“…Jeddi et al studied the EMI SE of composites based on silicone rubber and hybrid conducting filler constituted by graphite nanoplatelets and CB. [20] The EMI Se of poly-dimethylsiloxane loaded with reduced graphene oxide (rGO)/CB was also reported by Anooja et al [21] Song et al observed an increase of conductivity and an improvement of the EMI SE in the frequency range between 30 and 3000 Hz with the addition of CB in composite constituted by acrylonitrile-styrene-acrylate copolymer and graphite. [22] Recently, we reported a synergistic effect of carbon-based hybrid fillers constituted by CB and expanded graphite on the conductivity, EMI shielding effectiveness and absorbing properties of melt blended composites based on recycled PVDF.…”

Highly Deformable Porous Electromagnetic Wave Absorber Based on Ethylene–Propylene–Diene Monomer/Multiwall Carbon Nanotube Nanocomposites

“…This result is consistent with the increase in melt storage modulus and nonterminal behavior of the nanocomposites with 4 phr or more reported in the SI. For these samples, the dominant dielectric loss ( Figure S7) mechanism was conductance loss, which means that the electric charges transferred within the polymer matrix by direct contact between MWCNTs [10,38]. Further evidence of the existence of a percolated 3D network is the frequency-independent behavior of the AC conductivity at low frequencies, with an increase in conductivity values from 10 −13 up to 10 −3 S/cm.…”

“…In the high-frequency region, we observed an increase of the ε with filler content for both solid and foamed samples. This could be attributed to the volumetric effect of the filler and enhanced interfacial charge accumulation [38]. Meanwhile, in the low-frequency region, samples with high loading fractions exhibited negative permittivity.…”

Role of cobalt nanowire and graphene nanoplatelet on microwave shielding behavior of natural rubber composite in high frequency bands

“…The presence of high aspect ratio cobalt nanowire produces high hysteresis losses when a high‐frequency microwave hit and passes through the shielding material. [ 38 ] Thus, higher total shielding effect is observed in NR 4 composite designation. In all frequencies, the magnetic nanowire added composite alone seen giving larger attenuation than composites contains only conducting material.…”