Conduction mechanism in Polyaniline-flyash composite material for shielding against electromagnetic radiation in X-band & Ku band

Abstract

β–Naphthalene sulphonic acid (β–NSA) doped polyaniline (PANI)–flyash (FA) composites have been prepared by chemical oxidative polymerization route whose conductivity lies in the range 2.37–21.49 S/cm. The temperature dependence of electrical conductivity has also been recorded which shows that composites follow Mott's 3D–VRH model. SEM images demonstrate that β–NSA leads to the formation of the tubular structure with incorporated flyash phase. TGA studies show the improvement in thermal stability of composites with increase in loading level of flyash. Complex parameters i.e. permittivity (ɛ* = ɛ′- iɛ″) and permeability (μ*=μ′- iμ″) of PANI-FA composites have been calculated from experimental scattering parameters (S11 & S21) using theoretical calculations given in Nicholson–Ross and Weir algorithms. The microwave absorption properties of the composites have been studied in X-band (8.2 – 12.4 GHz) & Ku–Band (12.4 – 18 GHz) frequency range. The maximum shielding effectiveness observed was 32dB, which strongly depends on dielectric loss and volume fraction of flyash in PANI matrix.

Multi-walled carbon nanotube–graphene–polyaniline multiphase nanocomposite with superior electromagnetic shielding effectiveness

“…During the past decade, improvements in EMI shielding effectiveness (SE) have been achieved by introducing carbon materials, such as carbon black, carbon ber, exfoliated graphite, graphite, yash, carbon nanotubes (CNTs) and even now multilayer graphene. 12,[15][16][17][18][19] To improve the properties of the PANI, Saini et al 15 developed PANI based composite by in situ emulsion pathway technique with a different ratio of graphite and PANI. It is reported that by incorporating 15.6 wt% of graphite in PANI, the ultimate composite possesses electrical conductivity 12.5 S cm À1 and total EMI-SE is reached up to À33.6 dB in the X-band frequency region .…”

Polyaromatic-hydrocarbon-based carbon copper composites for the suppression of electromagnetic pollution

“…7(a)-(c) for all samples. The SE T is the sum of contribution from SE A , SE R , and the transmission or multiple reection (SE M ), which can be simply be expressed as SE T (dB) ¼ SE A + SE R + SE M , where SE M can be neglected when SE T > 10 dB, 39 hence,…”

Synthesis of fly ash cenosphere/polyaniline and mullite/polyaniline core–shell composites

“…Consequently, it is reasonable to employ a silane coupling agent as a bridge-linking connector for homogeneously and completely coating FACs with PAN. The resultant FAC/polyaniline composites should possess the filling property of FAC and conductivity of PAN, thus, they can be potentially used as conducting fillers, and are applied in EMI shielding materials [26]. With proper treatment, the aluminosilicate-rich FAC core of FAC/polyaniline composites can be changed to porous mullite, which exhibits excellent properties, such as high melting point, thermal resistance, high surface area, and good chemical durability [27,28].…”