Analytical formulation for electrical conductivity and percolation threshold of epoxy multiscale nanocomposites reinforced with chopped carbon fibers and wavy carbon nanotubes considering tunneling resistivity

2019 ◽  
Vol 126 ◽  
pp. 105616 ◽  
Author(s):  
M. Haghgoo ◽  
R. Ansari ◽  
M.K. Hassanzadeh-Aghdam ◽  
M. Nankali
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Percolation Threshold ◽  
Carbon Fibers ◽  
Analytical Formulation

scholarly journals Segregated network polymer/carbon nanotubes composites

2004 ◽  
Vol 2 (2) ◽  
pp. 363-370 ◽  
Author(s):  
A. Mierczynska ◽  
J. Friedrich ◽  
H. Maneck ◽  
G. Boiteux ◽  
J. Jeszka
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Network Formation ◽  
Processing Parameters ◽  
Low Grade ◽  
Single Walled Carbon ◽  
Conductive Composites ◽  
Grade Material

AbstractIn this work we present the preparation of conductive polyethylene/carbon nanotube composites based on the segregated network concept. Attention has been focused on the effect of decreasing the amount of filler necessary to achieve low resistivity. Using high- and low-grade single-walled carbon nanotube materials we obtained conductive composites with a low percolation threshold of 0.5 wt.% for high-grade nanotubes, about 1 wt% for commercial nanotubes and 1.5 wt% for low-grade material. The higher percolation threshold for low-grade material is related to low effectiveness of other carbon fractions in the network formation. The electrical conductivity was measured as a function of the single-walled carbon nanotubes content in the polymer matrix and as a function of temperature. It was also found that processing parameters significantly influenced the electrical conductivity of the composites. Raman spectroscopy was applied to study single wall nanotubes in the conductive composites.

Improving the Electrical Conductivity of Composites Comprised of Short Conducting Fibers in a Nonconducting Matrix: The Addition of a Nonconducting Particulate Filler

1995 ◽  
Vol 390 ◽  
Author(s):  
Pu-Woei Chen ◽  
D. D. L. Chung
Keyword(s):  
Electrical Conductivity ◽  
Percolation Threshold ◽  
Silica Fume ◽  
Carbon Fibers ◽  
Volume Fraction ◽  
Filler Volume Fraction ◽  
Conducting Filler ◽  
Particulate Filler

ABSTRACTThe addition of a second discontinuous filler (silica fume) that is essentially nonconducting to a composite with a comparably non-conducting matrix (cement) and a conducting discontinuous filler (carbon fibers) was found to increase the electrical conductivity of the composite when the conducting filler volume fraction was less than 3.2%. The maximum conducting filler volume fraction for the second filler to be effective was only 0.5% when the second filler was sand, which was much coarser than silica fume. The improved conductivity due to the presence of the second filler is due to the improved dispersion of the conducting filler. The silica fume addition did not affect the percolation threshold, but the sand addition increased the threshold.

Enhanced electrical conductivity and piezoresistive sensing in multi-wall carbon nanotubes/polydimethylsiloxane nanocomposites via the construction of a self-segregated structure

Nanoscale ◽  
2017 ◽  
Vol 9 (31) ◽  
pp. 11017-11026 ◽  
Author(s):  
Ming Wang ◽  
Kai Zhang ◽  
Xin-Xin Dai ◽  
Yin Li ◽  
Jiang Guo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Percolation Threshold ◽  
Multi Wall Carbon Nanotubes ◽  
Segregated Structure

Self-segregated PDMS/MWCNT nanocomposites exhibit high piezoresistive sensitivity, low percolation threshold and an enhanced mechanical properties.

scholarly journals Incorporation of Functionalized Multiwall Carbon Nanotubes into a Polyurethane Matrix

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Martin Michálek ◽  
Michael Bredol
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Percolation Threshold ◽  
Aqueous Suspension ◽  
Sodium Dodecyl ◽  
Multiwall Carbon Nanotubes ◽  
Glass Substrates ◽  
Functionalized Mwcnts ◽  
Multiwall Carbon

Functionalized and raw multiwall carbon nanotubes (MWCNTs) were investigated colloid-chemically in order to study the role of polar versus nonpolar interaction with a polyurethane (PU) matrix. Both kinds of MWCNTs were dispersed by ultrasonication in the presence of a surfactant (sodium dodecyl sulphate) in aqueous solution. Functional groups on the nanotube surface were characterized by infrared spectroscopy and by theζ-potential in aqueous suspension. Such suspensions were added to waterborne PU dispersions, drop-cast on glass substrates and cured. The percolation threshold for electrical conductivity with polar (functionalized) MWCNTs was reached at 0.24 wt.%, whereas at concentrations as high as 2 wt.%, PU films with nonpolar MWCNTs stayed below the percolation threshold. With an addition of 0.4 wt.% polar MWCNTs, the electrical conductivity increased to >10−6 S/cm in the cured coating layer. These results are interpreted with respect to the chemical nature of the PU matrix.

Phase behaviour, microstructure, and percolation of poly(ethylene glycol) filled by multiwalled carbon nanotubes and organophilic montmorillonite

2011 ◽  
Vol 45 (24) ◽  
pp. 2555-2566 ◽  
Author(s):  
N.I. Lebovka ◽  
E.A. Lysenkov ◽  
A.I. Goncharuk ◽  
Yu.P. Gomza ◽  
V.V. Klepko ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Ethylene Glycol ◽  
Percolation Threshold ◽  
Multiwalled Carbon Nanotubes ◽  
Phase Behaviour ◽  
Poly Ethylene Glycol ◽  
Multiwalled Carbon ◽  
Poly Ethylene ◽  
High Level

This work studies phase behavior, microstructure and percolation of the poly(ethylene glycol) (PEG), filled by multiwalled carbon nanotubes (MWCNTs), organo-modified montmorillonite (OMMT), and their mixtures, using differential scanning calorimentry (DSC), X-ray diffraction (XRD), electrical conductivity, and analysis of microscopic images. The DSC and XRD data showed a noticeable decrease of PEG crystallinity with increase of nanofiller content. Filling of PEG by MWCNTs was accompanied by a percolation threshold at ≈0.1 wt%, and the estimated electrical conductivity exponent ( t = 1.77 ± 0.07) was typical for the random percolation networks. The similar threshold behavior, but with higher percolation threshold ≈0.5–1.0 wt%, was observed for PEG filled by OMMT. The observed effect of OMMT-enhanced dispersion of MWCNTS in PEG at a high level of loading by nanoparticles offers good prospects for simultaneous improvement of the electrical and mechanical properties of PEG-based composites.

Investigation of dielectric relaxation phenomena and AC electrical conductivity in graphite/carbon nanotubes/engine oil nanofluids

2020 ◽  
pp. 073168442095185
Author(s):  
S Barnoss ◽  
BMG Melo ◽  
M El Hasnaoui ◽  
MPF Graça ◽  
ME Achour ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Complex Impedance ◽  
Engine Oil ◽  
Positive Temperature ◽  
Multiwalled Carbon ◽  
Remarkable Change ◽  
Ac Electrical Conductivity

In this paper, we report an investigation on electrical conduction mechanisms of nanofluids based on commercial engine oil loaded with graphite (Gt) and multiwalled carbon nanotubes, at different concentrations. The impedance spectroscopy technique was used to measure the resistance and capacity characterizing each sample in a frequency range 100 Hz–1 MHz and a temperature range 300–400 K. Two formalisms were used to analyze the data: (a) the electrical conductivity which has found to follow the Jonscher’s law with single and double exponents for carbon nanotube concentrations below and above the percolation threshold, respectively, and (b) the complex impedance that has permitted to identify the relaxation peaks according to the Cole–Cole model. Both the two formalisms showed that when the carbon nanotube concentration is higher than the percolation threshold, a positive temperature coefficient and a remarkable change in conductivity were observed, suggesting that the presence of the carbon nanotube greatly affect the electrical properties of the engine oil as a result of additional polarization effect induced by these nanoparticles. Furthermore, the analysis of the temperature dependence of dc conductivity and relaxation time using the Arrhenius equation indicated the addition of carbon nanotubes into engine oil increase the activation energies.

Assessment on the Electrical Conductivity of Additive Fillers into Carbon Fiber-Cement Based Composites

2011 ◽  
Vol 492 ◽  
pp. 185-188 ◽  
Author(s):  
Jun Jie Qin ◽  
Wu Yao ◽  
Jun Qing Zuo ◽  
Hai Yong Cao
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Carbon Fiber ◽  
Percolation Threshold ◽  
Electrical Conduction ◽  
Cement Matrix ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

This paper gives an assessment on the electrical conductivity of different additive fillers (graphite, multi-walled carbon nanotubes) into carbon fiber-cement based composites (CFRC). Results show that cement matrix containing 0.4% carbon fiber (CF) and 0.5% multi-walled carbon nanotubes (MWCNTs) exhibits an excellent electrical conductivity of 33.65Ω·cm. When the content of CF is below the percolation threshold (0.4% CF), adding graphite is beneficial to the electrical conduction of CFRC, which has a tremendous drift from 3991.44Ω·cm to 524.33Ω·cm as the content of graphite varies from 0% to 30%. However, when the content of CF is above the percolation threshold, adding graphite makes no advantages in the electrical conductivity of CFRC because of leading to a porosity rising. MWCNTs are useful conductive constituents for CFRC and can increase electrical conductivity by two orders of magnitude. However, excessive adding MWCNTs into CFRC will have a rapid increase of electrical resistivity on the contrary.

scholarly journals Structure, thermophysical properties and electrical conductivity of nanocomposites based on epoxy polymer and carbon tubes

2021 ◽  
pp. 7-13
Author(s):  
V.V. Korskanov ◽  
O.M. Fesenko ◽  
V.B. Dolgoshey
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Percolation Threshold ◽  
Thermophysical Properties ◽  
Epoxy Polymer ◽  
Transition Range ◽  
Epoxy Polymers

The aim of this work was to find the optimal conditions for the formation of nanocomposites, study their structure and properties and conditions for the formation of multicomponent materials based on epoxy polymers and carbon nanotubes with predetermined performance properties. The basis for the formation of epoxy polymers was an epoxydian oligomer (EDO) based on bisphenol A. Polypox H354 was used as a hardener for EDO. Carbon nanotubes (CNT) were used as a nanofiller for the preparation of nanocomposites. The research methods were a diffractometer for measuring the intensity of X-ray scattering in the region of small angles and a differential scanning calorimeter for obtaining heating thermograms. The electrical conductivity of the samples at a temperature of 293 K was measured at direct current according to the two-electrode scheme. In this work the structure, thermophysical properties and electrical conductivity of nanocomposites based epoxy polymers and carbon  nanotubes have been studied. It was found that at low CNT content the formation of nanocomposites occurs by the mechanism of epoxy network growth, which is accompanied by the displacement of CNT particles to the periphery of the epoxy matrix. This process is accompanied by an increase in the scattering intensity of the SAXS, a rapid increase in the glass transition temperature and the degree of crosslinking of the epoxy polymer. When the critical concentration is reached, CNT particles form a continuous cluster, which leads to occurrence percolation threshold, reducing the glass transition temperature, expanding the glass transition range, occurrence of pores and reducing the degree of completion of the crosslinking reaction in nanocomposites relative to the epoxy polymer. It is established that the improvement of nanocomposite properties and the occurrence of the percolation threshold is due to the maximum specific energy of ER-CNT interaction and is achieved at a critical mass concentration of nanofiller from 0,1% to 0,4%.

Electrical Conductivity and Elastic Properties of Carbon Nanotube Reinforced Polycarbonate Nanocomposites

2011 ◽  
Author(s):  
Yves Ngabonziza ◽  
Jackie Li
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Conductivity ◽  
Percolation Threshold ◽  
Elastic Properties ◽  
Experimental Testing ◽  
High Strength ◽  
Effective Elastic Modulus ◽  
Injection Velocity ◽  
Micromechanics Models ◽  
Multi Walled Carbon Nanotubes

In the past years, carbon nanotubes and their composites have been intensively studied due to their extremely high strength and high electrical and thermal conductivities. However, to be able to use CNT-reinforced composites as structural materials in real applications, more cost-efficient processing methods should be adopted and the properties of such nanocomposites need to be further analyzed. Here we investigate the electrical and elastic properties of multi-walled carbon nanotubes (MWCNT) reinforced polycarbonate (PC) nanocomposites produced by injection molding which has been widely used in industrial plastic production. Nanocomposite samples with MWCNT ranging from 0 to 7wt% were tested for both electrical conductivity using a 2-probe measurement and mechanical properties under tensile loading. It has been found that the electrical conductivity depends on both injection velocity and the CNT content while the elastic properties of the nanocomposites only depend on the CNT content. Besides the experimental testing, a percolation theory and micromechanics models have been applied to determine the electrical conductivity percolation threshold and the effective elastic modulus of the nanocomposites in terms of CNT contents. The results are compared with our experimental data. It shows that a percolation threshold is around 1.8wt% of MWCNT. The evaluation of elastic properties using micromechanics models not only indicates the influence of MWCNT on elastic properties but also the presence of an interphase between the CNT and PC matrix.

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