Dielectric characterization and microwave absorption of expanded graphite integrated polyaniline multiphase nanocomposites in X-band

A very efficient microwave absorption characteristic of conducting polymer (polyaniline or PANI) incorporated fly ash cenosphere (FAC), which is a waste of thermal power plant, is revealed in this work with materials data‐driven approach. The different loading (wt%) of PANI‐FAC hybrids to a polymer such as polyvinyl butyral (PVB) results in different reflection loss (RL). However, RL performances do not improve by simply increasing the PANI‐FAC hybrid loading (wt%) to PVB. Herein, PANI‐FAC loading to PVB is optimized through the electromagnetic data‐driven methodology. A remarkable RL ≤ − 40 dB with entire X‐band (8.2–12.4 GHz) absorption bandwidth (RL ≤ −10 dB, RL value −10 dB corresponds to 90% absorption) is predicted for 8.5 wt% PANI‐FAC hybrid loaded PVB‐PANI‐FAC composite. The predicted RL matched with experimental data (minimum RL value −44.5 dB with X‐band absorption bandwidth), confirming the proposed proof of concept of data‐driven methodology to obtain broadband and robust microwave absorption characteristics of polymer‐FAC composites.

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“…The RL of PANI‐FAC composite for different thicknesses ( d ) were calculated using following equation, 8–10,15,25–32

Reflection loss ((), RL) goodbreak= 20 italiclog (||, \frac{Z_{italicin} - Z_{0}}{Z_{italicin} + Z_{0}}) ((), dB)

Z in is the input impedance and can be written as,

Z_{in} goodbreak= Z_{0} \sqrt{\frac{μ_{r}}{ε_{r}}} italictanh ((), j \frac{2 italicπfd \sqrt{μ_{r} ε_{r}}}{c})

Z 0 is the characteristic impedance of free space (= 377 Ω),

ε_{r} = ε' - italiciε ″

μ_{r} = μ' - italiciμ ″

, and c is the velocity of light. For nonmagnetic material,

μ_{r} = 1 - i . 0

35,15–25 . The RL value −10 dB corresponds to 90% absorption and RL ≤ −10 dB is preferred for real‐time application 8–29 .…”

Section: Resultsmentioning

confidence: 99%

Data‐driven methodology to realize strong and broadband microwave absorption properties of polymer‐fly ash cenosphere composite

Bora

Mahanta

Kishore

et al. 2021

J of Applied Polymer Sci

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“…The imaginary part e r // (v) of the complex permittivity responsible for the dissipation of EM energy in the form of heat (relaxation and ohmic loss) also increases with fillers concentration in the samples, which can be attributed to the improvement in electric conductivity of the samples with higher amount of rGO. Both the polarizations orientational and interfacial leads to the energy loss mechanism of irradiated radiation due to formation of huge dipoles with the associated relaxation phenomenon [40]. As the dipole density and their orientation determine the polarizability of the composite material which in turn depends on the fillers concentration, so increase in frequency of the applied field results dipole relaxation because the large number dipoles present in the sample C unable to match their reorienting frequency with that of applied electric field in order to resist the oscillating field and as a result, complex permittivity of sample C declines with increasing frequency as in Figures 3a and 3b.…”

Section: Microwave Characterizationmentioning

confidence: 99%

“…As the dipole density and their orientation determine the polarizability of the composite material which in turn depends on the fillers concentration, so increase in frequency of the applied field results dipole relaxation because the large number dipoles present in the sample C unable to match their reorienting frequency with that of applied electric field in order to resist the oscillating field and as a result, complex permittivity of sample C declines with increasing frequency as in Figures 3a and 3b. Also interfacial polarization provides good support at lower frequency [40], with increase in frequency of applied field the tendency for the interfacial polarization [41] is also expected to be decreased resulting in decrease in polarizability and hence permittivity and loss factor. Because of high conductivity and polarization at RGO-SiC interfaces make it possible for electron transfer process [38] through dipole-dipole interactions by allowing electron hopping and transferring between the fillers and matrix, which also assists for microwave absorption.…”

Section: Microwave Characterizationmentioning

confidence: 99%

X-band metamaterial absorbers based on reduced graphene oxide-silicon carbide-linear low density polyethylene composite

Bora

Mahanta²,

Sarmah

et al. 2020

EPJ Appl. Metamat.

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Graphene oxide obtained by Hummer's method is used to synthesize reduced graphene oxide (RGO) using chemical and thermal treatment method. Flexible composites of RGO-Silicon carbide (SiC)-Low density polyethylene (LLDPE) in different wt.% ratios of fillers are characterized for complex permittivity and permeability in X-band. A metamaterial design of ring shaped with four stripe structure is designed on developed substrate as well as standard FR4 substrate and simulated using EM simulator, CST Microwave Studio. Simulated results showed shifting of resonant peak frequency from C-band frequency for FR4 substrate to X-band for developed substrates signifying a role of microwave constitutive properties of the dielectric spacer. The fabricated metamaterial structure on RGO-SiC-LLDPE composite of thickness 0.7 mm shows a S11 ∼ −25 dB at 10.7 GHz with maximum absorption of 96.7%. Thus, the developed meta-material design showing a potential application in microwave applications.

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“…Therefore, it is important to select an absorber that has suitable EM properties for the required absorbing performance and used frequency. Materials such as carbon materials [ 4 , 5 , 6 ], carbonyl iron [ 7 , 8 , 9 ], and various ferrite materials [ 10 , 11 , 12 ] are mainly studied as absorbers because they are light, thin, and small but have a superior EM wave absorption performance. As for a magnetic absorber, soft magnetic spinel ferrite has mainly been studied and shown to modify the EM wave performance by substituting one or more divalent metal ions like Mn [ 13 , 14 , 15 ], Co [ 16 , 17 , 18 ], Ni [ 19 , 20 , 21 ], Cu [ 22 , 23 , 24 ], and Mg [ 25 , 26 ] at the site of Fe atoms.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Electrospun Ni0.5Zn0.5Fe2O4 Nanofibers Using Polyvinyl Pyrrolidone Precursors and Electromagnetic Wave Absorption Performance Improvement

Jang

Kim

et al. 2021

Polymers

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Ni0.5Zn0.5Fe2O4 nanofibers with an average diameter of 133.56 ± 12.73 nm were fabricated by electrospinning and calcination. According to our thermogravimetric—differential thermal analysis and X-ray diffraction results, the calcination temperature was 650 °C. The microstructure, crystal structure, and chemical composition of the nanofibers were observed using field-emission scanning electron, X-ray diffraction, and energy-dispersive X-ray spectroscopy. Commercial particle samples and samples containing 10 wt% and 20 wt% nanofibers were fabricated, and the electromagnetic properties were analyzed with a vector network analyzer and a 7.00 mm coaxial waveguide. Regardless of the nanofiber content, Ni0.5Zn0.5Fe2O4 was dominantly affected by the magnetic loss mechanism. Calculation of the return loss based on the transmission line theory confirmed that the electromagnetic wave return loss was improved up to −59.66 dB at 2.75 GHz as the nanofiber content increased. The absorber of mixed compositions with Ni0.5Zn0.5Fe2O4 nanofibers showed better microwave absorption performance. It will be able to enhance the performance of commercial electromagnetic wave absorbers of various types such as paints and panels.

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Dielectric characterization and microwave absorption of expanded graphite integrated polyaniline multiphase nanocomposites in X-band

Cited by 26 publications

References 21 publications

Data‐driven methodology to realize strong and broadband microwave absorption properties of polymer‐fly ash cenosphere composite

Data‐driven methodology to realize strong and broadband microwave absorption properties of polymer‐fly ash cenosphere composite

X-band metamaterial absorbers based on reduced graphene oxide-silicon carbide-linear low density polyethylene composite

Fabrication of Electrospun Ni0.5Zn0.5Fe2O4 Nanofibers Using Polyvinyl Pyrrolidone Precursors and Electromagnetic Wave Absorption Performance Improvement

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