Influence of chemical treatment on the microstructure of nanographite

Ovsiienko, I. V.; Lazarenko, Oleksandra; Matzui, L. Yu.; Brusylovets, Oleksii; Normand, F. Le; Shames, Alexander I.

doi:10.1002/pssa.201431400

Cited by 7 publications

(4 citation statements)

References 19 publications

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“…For example, the functionalization can be used to provide oxygen-containing functional groups on the surface [43]. Functional groups are important for the use of EG for adsorption [25].…”

Section: Structure Of Exfoliated Graphitementioning

confidence: 99%

A review of exfoliated graphite

2015

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Exfoliated graphite (EG) refers to graphite that has a degree of separation of a substantial portion of the carbon layers in the graphite. Graphite nanoplatelet (GNP) is commonly prepared by mechanical agitation of EG. The EG exhibits clinginess, due to its cellular structure, but GNP does not. The clinginess allows the formation of EG compacts and flexible graphite sheet without a binder. The exfoliation typically involves intercalation, followed by heating. Upon heating, the intercalate vaporizes and/or decomposes into smaller molecules, thus causing expansion and cell formation. The sliding of the carbon layers relative to one another enables the cell wall to stretch. The exfoliation process is accompanied by intercalate desorption, so that only a small portion of the intercalate remains after exfoliation. The most widely used intercalate is sulfuric acid. The higher concentration of residue in unwashed EG causes the relative dielectric constant (50 Hz) of the EG to be 360 (higher than 120 for KOH-activated GNP), compared to the value of 38 for the water-washed case. An EG compact is obtained by the compression of EG at a pressure lower than that used for the fabrication of flexible graphite. Compared to flexible graphite, EG compacts are mechanically weak, but they exhibit viscous character, outof-plane electrical/thermal conductivity and liquid permeability. The viscous character (flexural loss tangent up to 35 for the solid part of the compact) stems from the sliding of the carbon layers relative to one another, with the ease of the sliding enhanced by the exfoliation process.

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“…For example, the functionalization can be used to provide oxygen-containing functional groups on the surface [43]. Functional groups are important for the use of EG for adsorption [25].…”

Section: Structure Of Exfoliated Graphitementioning

confidence: 99%

A review of exfoliated graphite

2015

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“…Therefore, the chemical modification of GNPs by Fe 3 O 4 not only reduces the percolation threshold significantly but also increases the value of electrical conductivity (see Figure 4 ). It is known that in the process of chemical modification, a significant delamination of GNP particles takes place [ 61 , 62 ], and as a result, there is a significant increase in the aspect ratio of GNPs. This leads to a decrease in the percolation limit and a decrease in electrical conductivity at the same concentration of fillers in the composite [ 63 , 64 ].…”

Section: Resultsmentioning

confidence: 99%

Segregated Conductive Polymer Composite with Fe3O4-Decorated Graphite Nanoparticles for Microwave Shielding

Matzui,

Syvolozhskyi,

Vovchenko

et al. 2024

Materials

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Graphite nanoplatelets (GNPs)—the segregated ultra-high molecular weight polyethylene (UHMWPE)-based composites with hybrid filler—decorated with Fe3O4 were developed. Using X-ray diffraction and scanning electron microscopy, it was shown that the decorated component has the shape of separate granules, or their clusters were distributed evenly over the GNPs surface. The individual Fe3O4 nanoparticles are predominantly rounded, with diameters of approximately 20–60 nm. The use of GNPs/Fe3O4 as a filler leads to significant decreases in the percolation limit φc, 0.97 vol% vs. 0.56 vol% for GNPs/UHMWPE- and (GNPs/Fe3O4)/UHMWPE segregated composite material (SCM), respectively. Modification of the GNP surface with Fe3O4 leads to an essential improvement in the electromagnetic interference shielding due to enhanced microwave absorption in the 26–37 GHz frequency range in its turn by abundant surface functional groups and lattice defects of GNPs/Fe3O4 nanoparticles.

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“…As‐prepared carbon nanotubes were produced by means of chemical vapour deposition (CVD) method with using nickel catalyst. More details concerning the structure characterization of as‐prepared and functionalized carbon nanotubes by scanning electron microscopy (SEM), X‐ray diffraction (XRD), as well as results of investigations of functional groups qualitative composition on the surface of carbon nanotubes are presented in previously published paper . According to electron microscopy data the outer diameter of carbon nanotubes varies from 10 nm to 20 nm while their length is about 15 μm, Fig .…”

Section: Methodsmentioning

confidence: 99%

Magnetoresistance of functionalized carbon nanotubes

Ovsiienko

Len

Matzui

et al. 2016

Materialwissenschaft Werkst

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In present work a novel method for the functionalization of carbon nanotubes is proposed. The magnetoresistance of carbon nanotubes specimens in temperature range from 1.6 K up to 85 K and in magnetic field up to 5 T was investigated. It was shown that the proposed functionalization method does not cause any new defects in structure of carbon nanotubes and does not essentially influence the resistivity of nanotubes. It is revealed the appearance of the charge carriers weak localization and interactions effects for as‐prepared and functionalized carbon nanotubes. On the basis of the experimental data, the explicit type of temperature dependence of wave function phase relaxation time and Fermi‐level energy value for as‐prepared and functionalized carbon nanotube are established.

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Influence of chemical treatment on the microstructure of nanographite

Cited by 7 publications

References 19 publications

A review of exfoliated graphite

A review of exfoliated graphite

Segregated Conductive Polymer Composite with Fe3O4-Decorated Graphite Nanoparticles for Microwave Shielding

Magnetoresistance of functionalized carbon nanotubes

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