Frequency and density dependencies of the electromagnetic parameters of carbon nanotube and graphene nanoplatelet based composites in the microwave and terahertz ranges

Шуба, М. В.; Yuko, D I; Gorokhov, Gleb; Meisak, Darya; Bychanok, D.; Kuzhir, P.; Maksimenko, S. A.; Angelova, Polya; Ivanov, Evgeni; Kotsilkova, Rumiana

doi:10.1088/2053-1591/ab2edf

Cited by 6 publications

(7 citation statements)

References 44 publications

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“…When an electromagnetic wave impacts on a surface, a part of it is absorbed by the material, another part is reflected, and the rest is transmitted through the material, in agreement with the following power balance: A + R + T = 100%, where A, R, and T are the absorption, reflection, and transmission power counterparts, respectively [ 28 , 29 , 30 ]. In our previous studies, it was found that the inclusion in the PLA matrix of the conductive fillers, such as MWCNT-a and GNP-a, in concentrations around and above the percolation threshold can attenuate the penetrating wave thanks to the effective conductive network, established in the material [ 10 , 13 , 31 ]. Recently, researchers reported for polyethylene composites with segregated carbon nanotubes network, which show high electromagnetic interference shielding efficiency [ 7 , 32 ].…”

Section: Resultsmentioning

confidence: 99%

Essential Nanostructure Parameters to Govern Reinforcement and Functionality of Poly(lactic) Acid Nanocomposites with Graphene and Carbon Nanotubes for 3D Printing Application

Kotsilkova

Ivanov

Georgiev³

et al. 2020

Polymers

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Poly(lactic) acid nanocomposites filled with graphene nanoplatelets (GNPs) and multiwall carbon nanotubes (MWCNTs) are studied, varying the filler size, shape, and content within 1.5–12 wt.%. The effects of the intrinsic characteristics of nanofillers and structural organization of nanocomposites on mechanical, electrical, thermal, and electromagnetic properties enhancement are investigated. Three essential rheological parameters are identified, which determine rheology–structure–property relations in nanocomposites: the degree of dispersion, percolation threshold, and interfacial interactions. Above the percolation threshold, depending on the degree of dispersion, three structural organizations are observed in nanocomposites: homogeneous network (MWCNTs), segregated network (MWCNTs), and aggregated structure (GNPs). The rheological and structural parameters depend strongly on the type, size, shape, specific surface area, and functionalization of the fillers. Consequently, the homogeneous and segregated network structures resulted in a significant enhancement of tensile mechanical properties and a very low electrical percolation threshold, in contrast to the aggregated structure. The high filler density in the polymer and the low number of graphite walls in MWCNTs are found to be determinant for the remarkable shielding efficiency (close to 100%) of nanocomposites. Moreover, the 2D shaped GNPs predominantly enhance the thermal conductivity compared to the 1D shaped MWCNTs. The proposed essential structural parameters may be successfully used for the design of polymer nanocomposites with enhanced multifunctional properties for 3D printing applications.

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Section: Resultsmentioning

confidence: 99%

Essential Nanostructure Parameters to Govern Reinforcement and Functionality of Poly(lactic) Acid Nanocomposites with Graphene and Carbon Nanotubes for 3D Printing Application

Kotsilkova

Ivanov

Georgiev³

et al. 2020

Polymers

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“…The fact that the Maxwell Garnett approximation is still applicable for 6 % GNP may indicate that in spite of the concentration being higher than previously reported percolation thresholds for GNPs [ 40 ], the impact of insulated filler particles still prevails. In the next subsection, we will try to explain the low-frequency shift of

maximum.…”

Section: Resultsmentioning

confidence: 96%

“…According to the low-frequency measurements described before (see Figure 4 in [ 40 ]), the percolation threshold for MWCNTs lies between 1.5 and 3 wt.%, while GNP-based composite experiences percolation between 3 and 6 wt.%. Therefore, the set of samples under investigation contains both pre- and post-percolated composites.…”

Section: Methodsmentioning

confidence: 91%

“…This fact allows making composite materials without expensive fillers through the introduction of low-cost ones into the hybrid percolation network [ 33 , 34 ], or even enhancing the electromagnetic properties due to the synergistic effect [ 35 , 36 , 37 ]. Recently, bi-filler composites containing graphene nanoplatelets and carbon nanotubes have attracted great interest due to the possible synergistic effects in their mechanical, thermal and electric properties [ 38 , 39 , 40 , 41 ]. Besides the filler morphology, the percolation threshold value strongly depends on the composite preparation technology, the filler dispersion in the dielectric phase (matrix) and the filler–polymer interfacial interactions.…”

Section: Introductionmentioning

confidence: 99%

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THz Spectroscopy as a Versatile Tool for Filler Distribution Diagnostics in Polymer Nanocomposites

et al. 2020

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Polymer composites containing nanocarbon fillers are under intensive investigation worldwide due to their remarkable electromagnetic properties distinguished not only by components as such, but the distribution and interaction of the fillers inside the polymer matrix. The theory herein reveals that a particular effect connected with the homogeneity of a composite manifests itself in the terahertz range. Transmission time-domain terahertz spectroscopy was applied to the investigation of nanocomposites obtained by co-extrusion of PLA polymer with additions of graphene nanoplatelets and multi-walled carbon nanotubes. The THz peak of permittivity’s imaginary part predicted by the applied model was experimentally shown for GNP-containing composites both below and above the percolation threshold. The physical nature of the peak was explained by the impact on filler particles excluded from the percolation network due to the peculiarities of filler distribution. Terahertz spectroscopy as a versatile instrument of filler distribution diagnostics is discussed.

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“…Mostly, the electrical conductivity improvement of a multiphase composite is accompanied by a decrease in the percolation threshold compared to single-filler composites. A considerable number of papers have been published with successful detection of synergy effects of different carbon allotropes [ 6 , 7 , 8 , 9 ]. Composites with the combination of particles of different natures (carbon and non-carbon) can have optimal dielectric and magnetic properties [ 10 , 11 , 12 , 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Dielectric Relaxation Spectroscopy and Synergy Effects in Epoxy/MWCNT/Ni@C Composites

et al. 2021

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The dielectric/electric properties of the Ni@C (carbon-coated Ni)/epoxy composites and Ni@C/MWCNTs (multi-walled carbon nanotubes)/epoxy composites loaded with fixed MWCNTs amount just below the percolation threshold (0.09 vol.%) and Ni@C at different concentrations up to 1 vol.% were investigated in broad frequency (20 Hz–40 GHz) and temperature (30 K–500 K) regions. In composites with the only Ni@C nanoparticles, the electrical percolation threshold was determined between 10 and 15 vol.%. Above the percolation threshold the dielectric permittivity (ε’) and the electrical conductivity (σ) of the composites loaded with Ni@C only are high enough, i.e., ε’ = 105 and σ = 0.6 S/m at 100 Hz for composites with 30 vol.% Ni@C, to be used for electromagnetic shielding applications. The annealing to 500 K was proved to be an effective and simple tool to decrease the percolation threshold in epoxy/Ni@C composites. For hybrid composites series an optimal concentration of Ni@C (0.2 vol.%) was determined, leading to the conductivity absolute values several orders of magnitude higher than that of a composite filled with MWCNTs only. The synergy effects of using both fillers have been discussed. Below room temperature the electrical transport is mainly governed by epoxy resin compression in all composites, while the electron tunnelling was observed only in hybrid composites below 200 K. At higher temperatures (above 400 K), in addition to the nanoparticles redistribution effects, the electrical conductivity of epoxy resin makes a significant contribution to the total composite conductivity. The dielectric relaxation spectroscopy allows estimating the nanoparticles distributions in polymer matrix and could be used as the non-destructive and fast alternate to microscopy techniques for general polymer composite fabrication control.

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Frequency and density dependencies of the electromagnetic parameters of carbon nanotube and graphene nanoplatelet based composites in the microwave and terahertz ranges

Cited by 6 publications

References 44 publications

Essential Nanostructure Parameters to Govern Reinforcement and Functionality of Poly(lactic) Acid Nanocomposites with Graphene and Carbon Nanotubes for 3D Printing Application

Essential Nanostructure Parameters to Govern Reinforcement and Functionality of Poly(lactic) Acid Nanocomposites with Graphene and Carbon Nanotubes for 3D Printing Application

THz Spectroscopy as a Versatile Tool for Filler Distribution Diagnostics in Polymer Nanocomposites

Dielectric Relaxation Spectroscopy and Synergy Effects in Epoxy/MWCNT/Ni@C Composites

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