scholarly journals Fine Tuning of Electrical Transport and Dielectric Properties of Epoxy/Carbon Nanotubes Composites via Magnesium Oxide Additives

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2044 ◽  
Author(s):  
Povilas Bertasius ◽  
Darya Meisak ◽  
Jan Macutkevic ◽  
Polina Kuzhir ◽  
Algirdas Selskis ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Dielectric Properties ◽  
Electrical Transport ◽  
Hybrid Composites ◽  
Relaxation Times ◽  
Dc Conductivity ◽  
Fine Tuning ◽  
Electromagnetic Properties ◽  
Different Temperatures ◽  
Multi Walled Carbon Nanotubes

The dielectric properties of epoxy/MWCNT (multi-walled carbon nanotubes)/MgO hybrid composites with a fixed MWCNT amount of 0.12 vol.% (0.2 wt.%) and varying MgO concentrations up to 3 vol.% were investigated in broad frequency (20–40 GHz) and temperature (20–500 K) ranges. The composites with up to 2 vol.% MgO nanoparticles concentration showed a significant increase of DC conductivity in relation to their non MgO-containing counterparts. The optimal content of MgO was found, i.e., 0.46 vol.%, which gave up to 2.5 orders of magnitude larger DC conductivity than those of the samples prepared without MgO additives. Using various amounts of MgO, it is possible to predictably vary the broadband electromagnetic properties of the composites, even entirely eliminating the electrical percolation. Electrical transport at different temperatures can be substantially controlled by the addition of given amounts of MgO. The broadband properties are discussed in terms of the distribution of relaxation times, which are proven to be an effective, noninvasive, and simple tool for checking composite fabrication issues, such as the distribution of MWCNT aggregates within the epoxy matrix.

Electrical Transport Behavior in Phenolic Resin-based Composites Doped with Multi-walled Carbon Nanotubes

2007 ◽  
Vol 1006 ◽  
Author(s):  
Renato Amaral Minamisawa ◽  
Bopha Chhay ◽  
Daryush ILA
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Electrical Transport ◽  
Chemical Structure ◽  
Phenolic Resin ◽  
Structure Characterization ◽  
Electromagnetic Properties ◽  
Transport Behavior ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

AbstractThe reported electromagnetic properties of carbon nanotubes (CNT) make them a promising material for nanoelectronic applications [1,2]. Addition of CNT has recently been shown to enhance mechanical properties of phenolic-resin polymers [3]. We are attempting to control the electrical transport behavior of phenolic-based polymers doped with CNT as a function of the different nanopowder concentration added to the polymer. In that regard, we developed a technique to obtain a material with homogenous dispersion of nanopowders, an important factor that influences the transport behavior. The chemical structure characterization was also evaluated using optical techniques.

scholarly journals Synergy Effects in Electromagnetic Properties of Phosphate Ceramics with Silicon Carbide Whiskers and Carbon Nanotubes

2019 ◽  
Vol 9 (20) ◽  
pp. 4388 ◽  
Author(s):  
Artyom Plyushch ◽  
Jan Macutkevič ◽  
Polina Kuzhir ◽  
Aliaksei Sokal ◽  
Konstantin Lapko ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Silicon Carbide ◽  
Wide Frequency Range ◽  
Electromagnetic Properties ◽  
Aluminium Phosphate ◽  
Silicon Carbide Whiskers ◽  
Synergy Effects ◽  
Multi Walled Carbon Nanotubes ◽  
The Difference ◽  
Walled Carbon Nanotubes

Hybrid composite materials based on an aluminium phosphate matrix with silicon carbide whiskers and multi-walled carbon nanotubes were studied in a wide frequency range (20 Hz to 36 GHz). It was demonstrated, that the addition of the silicon carbide whiskers enhances the dielectric permittivity and conductivity. This was explained by the difference in tunnelling parameters. Hybrid ceramics with nanotubes and whiskers also exhibits substantially improved electromagnetic shielding properties. The hybrid ceramics with 10 wt. % silicon carbide whiskers and a 1 mm thick 1.5 wt. % carbon nanotube layer, show higher than 50% absorption of electromagnetic radiation.

Kinetics and thermodynamics of the sorption of furaltadone from aqueous solutions on magnetic multi-walled carbon nanotubes

2014 ◽  
Vol 70 (6) ◽  
pp. 964-971
Author(s):  
Xu Chen ◽  
Zhen-hu Xiong
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solutions ◽  
Sorption Data ◽  
Multi Wall Carbon Nanotubes ◽  
Adsorption Behaviors ◽  
Different Temperatures ◽  
Multi Walled Carbon Nanotubes ◽  
Pseudo Second Order ◽  
Experimental Data Analysis ◽  
Walled Carbon Nanotubes

Magnetic multi-wall carbon nanotubes (M-MWCNTs) were used as an adsorbent for removal of furaltadone from aqueous solutions, and the adsorption behaviors were investigated by varying pH, sorbent amount, sorption time and temperature. The results showed that the adsorption efficiency of furaltadone reached 97% when the dosage of M-MWCNT was 0.45 g · L−1, the pH was 7 and the adsorption time was 150 min. The kinetic data showed that the pseudo-second-order model can fit the adsorption kinetics. The sorption data could be well explained by the Langmuir model under different temperatures. The adsorption process was influenced by both intraparticle diffusion and external mass transfer. The experimental data analysis indicated that the electrostatic attraction and π–π stacking interactions between M-MWCNT and furaltadone might be the adsorption mechanism. Thermodynamic analysis reflected that adsorption of furaltadone on the M-MWCNT was spontaneous and exothermic. Our study showed that M-MWCNTs can be used as a potential adsorbent for removal of furaltadone from water and wastewater.

scholarly journals Impact of Synthesis Parameters of Multi-Walled Carbon Nanotubes on their Thermoelectric Properties

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3567 ◽  
Author(s):  
Bogumiła Kumanek ◽  
Grzegorz Stando ◽  
Paweł S. Wróbel ◽  
Dawid Janas
Keyword(s):  
Carbon Nanotubes ◽  
Thermoelectric Properties ◽  
Synthesis Temperature ◽  
Injection Rate ◽  
Optimum Synthesis ◽  
Synthesis Parameters ◽  
Different Temperatures ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
The Impact

Carbon nanotubes have been intensively researched for many years because of a wide array of promising properties that they have. In this paper, we present the impact of synthesis parameters on thermoelectric properties of nanocarbon material. We conducted a number of syntheses of multi-walled carbon nanotubes (MWCNTs) at different temperatures (800 and 900 °C) using various amounts of catalyst (2%, 5.5%, and 9.6%) to facilitate the process. We also tested the influence of injection rate of precursor and the necessity of material purification on thermoelectric properties of MWCNTs. The electrical conductivity, thermal conductivity, and Seebeck coefficient were measurement for all samples. Based on these parameters, the values of Power Factor and Figure of Merit were calculated. The results show that the most important parameter in the context of thermoelectric properties is purity of employed MWCNTs. To obtain appropriate material for this purpose optimum synthesis temperature and appropriate content of the catalyst must be selected. The study also reveals that post-synthetic purification of nanocarbon is essential to produce an attractive material for thermoelectrics.

Study on Dielectric and Magnetic Properties of MWCNTs/Polyester Composites

2015 ◽  
Vol 815 ◽  
pp. 188-192
Author(s):  
Y.S. Lee ◽  
F. Malek ◽  
E.M. Cheng ◽  
Wei Wen Liu ◽  
Kok Yeow You ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Magnetic Properties ◽  
Dielectric Properties ◽  
Rectangular Waveguide ◽  
The Real ◽  
Multi Walled Carbon Nanotubes ◽  
Polyester Composites ◽  
Walled Carbon Nanotubes ◽  
Ku Band ◽  
Dielectric Conductivity

This paper is to study the dielectric properties, magnetic properties, and dielectric conductivity of Multi-walled carbon nanotubes (MWCNTs) and polyester (PE) composites. The composites with different amount of MWCNTs (5-15%) have been studied in the Ku-Band range (12.4-18 GHz). The rectangular waveguide (WR-62) was used to measure the dielectric properties and magnetic properties of the samples. The results show the dielectric properties and conductivity of MWCNTs/PE composites is increasing with the MWCNTs filler increases. The real part of dielectric properties values increase from 5.5 to 26.6 with increasing the MWCNTs loading from 5 % to 15 %. The increasing of MWCNTs filler in the MWCNTs/PE composites does not effects on magnetic properties, the real part and imaginary part of magnetic properties are approximate to 1 and 0. The highest conductivity of 15 % MWCNTs loading is reach to 11.02 (S/m) at 18 GHz. Keywords: composites, dielectric properties, magnetic properties, conductivity

scholarly journals Electromagnetic Properties of Cold-Cure Silicone Mixtures Containing Multi-Walled Carbon Nanotubes

2020 ◽  
pp. 043-046
Author(s):  
A.G. Tkachev ◽  
◽  
N.R. Memetov ◽  
R.A. Stolyarov ◽  
N.A. Chapaksov ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Physical Properties ◽  
Electromagnetic Radiation ◽  
Nanocomposite Materials ◽  
Electromagnetic Properties ◽  
Frequency Range ◽  
Concentration Dependences ◽  
Multi Walled Carbon Nanotubes ◽  
Properties Of Materials ◽  
Walled Carbon Nanotubes

Nanocomposite materials based on a cold-cure silicone mixture containing multi-walled carbon nanotubes were obtained. The concentration dependences of the radio-physical properties of materials were investigated. An increase in the efficiency of shielding electromagnetic radiation in the radio frequency range of wavelengths with increasing concentrations of multi-walled carbon nanotubes up to 10 wt. % was verified.

Sign in / Sign up

Export Citation Format

Share Document