Dielectric and impedance properties of three dimension graphene oxide-carbon nanotube acrylonitrile butadiene styrene hybrid composites (original) (raw)
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Ac-Electrical Conductivity and Dielectric Properties Behaviour of MWCNT/Abs Nanocomposite
International Journal of Advanced Research, 2017
AC-Electrical conductivity and dielectric properties of MultiWalled Carbon Nanotube-Acrylonitrile Butadiene Styrene composite (MWCNT/ABS) has been investigated with MWCNT additive of different concentration percentage. The study showed that electrical conductivity σ, obeys power law with the frequency exponential factor S less than one and indicate dielectric loss, ε'' not equal to constant. At lower concentration of Carbon Nanotubes, the dielectric constant ε' and dielectric loss ε'' remain constant with increase in frequency but at high concentration, ε' and ε'' decrease with an increase in frequency of which indicated that high concentration Carbon Nanotubes play a vital role in increasing dielectric constant and dielectric loss.
Dielectric Properties of Multi-Wall Carbon Nanotubes / Polystyrene Composites
Multi-Wall Carbon Nanotubes (MWCNTs)/Polystyrene (PS) composites were prepared by solution casting method. The effects weight percentage of carbon nanotubes on dielectric properties of the composites studied using (LCR)meter as a function of frequency over the range (50Hz-5MHz) at room temperature were studied. The experimental results showedthat dielectric constant, dissipation factor and dielectric loss of composites increased with increasing the weight percentage of carbon nanotubes and decreases with increase in frequencies.
Influence of carbon-nanotube diameters on composite dielectric properties
physica status solidi (a), 2013
The dielectric properties of polymethylmetacrylate (PMMA) composites filled with CVD made multiwalled carbon nanotubes (MWCNT) of different mean outer diameters (d $ 9 nm and 12-14 nm) were investigated in the temperature range from 300 to 420 K and in a wide frequency range (20 Hz to 1 MHz). Below the percolation threshold the temperature dependence of the complex dielectric permittivity of the investigated composites is mainly caused by b relaxation in pure PMMA matrix and the dielectric permittivity is found to be higher in composites with thicker nanotubes. The activation energy of b relaxation increases with carbon nanotube concentration. The percolation threshold is lower in composites with both thinner and oxidized carbon nanotubes. The established influence of both the MWCNT mean outer diameter and their oxidation on the broadband dielectric characteristics can be exploited for the production of effective low-cost electromagnetic and/or antistatic coatings working at different temperatures.
Study of low weight percentage filler on dielectric properties of MWCNT-epoxy nanocomposites
An attempt is made to study the effect of low weight percentage multiwall carbon nanotube (MWCNT) powder on dielectric properties of MWCNT reinforced epoxy composites. For that MWCNT (of different low weight percentage) reinforced epoxy composite was prepared by dispersing the MWCNT in resin. Samples were prepared by solution casting process and characterized for their dielectric properties such as dielectric constant (" 0), dielectric dissipation factor (tan) and AC conductivity (ac). The main objective is the investigation of the dielectric properties of the prepared samples at the low weight percentage of the filler at different temperatures and frequencies. From the two mechanisms of electrical conduction, first the leakage current obtained by the formation of a percolation network in the matrix and the other by tunneling of electrons formed among conductors nearby (tunneling current); here we are getting conduction by the second mechanism. Generally, leakage current makes more contribution to conductivity than tunneling current. Dielectric dissipation factor at 250 Hz frequency is greater than all other frequencies and starts increasing from 60 C. The peak height of the transition temperature decreases with increasing frequency. This study shows that the addition of a low weight percentage of MWCNT can modify considerably the electrical behavior of epoxy nanocomposites without chemical functionalization of filler.
European Polymer Journal, 2009
Conducting polymer composites should have a high dielectric constant and a high dissipation factor in the low and high frequency regions if they are to be used in charge storing devices, decoupling capacitors and electromagnetic interference shielding applications. Currently, extensive research is being carried out to enhance the dielectric constants of graphite-polymer, ceramic powder-polymer, metal powder-polymer and nanotube-polymer composites in the low frequency region. In this paper, we present the dielectric properties of styrene-acrylonitrile (SAN)-graphite sheets (GS) composites in the low and high frequency ranges. SAN-GS composites were prepared by the mixing process and by the hot compression mold technique. The composites showed a high dielectric constant and a high dissipation factor in the low and radio frequency region. Furthermore, the EMI shielding properties of these composites are evaluated in the radio frequency range. The conductivity and the dielectric constant of the SAN/GS composites increased with the addition of GS composites, and followed the power law model of percolation theory. The dielectric constant and the dissipation factor of the composites were analyzed according to the low and high frequency region.
The effect of filler alignment on conductive and shielding properties has been investigated in multiwall carbon nanotubes (MWCNTs)/polymer nanocompos-ites (NCs) containing 0.05–1 wt. % of the filler. The filler alignment was produced by applying external AC electric field during the whole process of hardening. MWCNTs network formation was detected by optic microscopy. The percolation thresholds that have been found for NC with MWCNTs aligned network are of two types. The higher threshold (at 1.45 wt% of MWCNTs) is described by the statistical percolation theory. The lower one (at 0.45 wt% of MWCNTs) is the dynamic or kinetic threshold which is determined not only by the MWCNTs parameters but also depends on the electric field characteristics and viscosity of polymer matrix. The influence of the character of MWCNTs distribution in epoxy resin on electrodynamic characteristics of the prepared NCs has been investigated in a wide frequency range (26–53 GHz). The experiment has revealed the anisotropy of permittivity: the permittivity in the parallel direction is higher than that in the direction perpendicular to MWCNTs axis. The analysis of the obtained results in terms of Maxwell-Garnett theory with taking into account the distribution function of MWCNTs in NCs shows that the anisotropy factor ¦ D 2. The investigation of microwave absorbing properties has shown that the absorption peak as well as the absorption bandwidth strongly depends not only on MWCNTs concentration in NCs, but also on the character of MWCNTs distribution with respect to the direction of electromagnetic wave propagation.
Effect of DC-Bias on the Dielectric Behavior of CNT/ABS Nanocomposites
Physica B: Condensed Matter, 2013
Several aspects of the dielectric behavior of multi-walled carbon nanotube (MWCNT)/acrylonitrilebutadiene-styrene (ABS) nanocomposites were studied. MWCNT/ABS nanocomposites with filler content between 2 wt% and 15 wt% were prepared by melt mixing and characterized by the impedance technique. The results showed that the dc and ac conductivities increase with increasing dc bias and MWCNT content. The effect of dc bias was more pronounced for nanocomposites with low MWCNT content. The bode diagram of the real impedance for nanocomposites containing 2 wt% MWCNT or higher exhibited a frequency independent plateau in the low frequency region revealing that dc conduction is the dominant conduction mechanism. The critical frequency at which ac conductivity becomes frequency dependent increased with increasing dc bias and MWCNT content.
Advanced Engineering Forum, 2013
The paper highlights the most important dielectric features for some nanocomposites polymer matrix based on polypropylene (PP) with insertion of carbon nanotubes multi-walled (MWCNTs). The dielectric characteristics analyzed are the real permittivity and dielectric losses of the sample based on PP with 5% insertion of MWCNTs. The measurements are made in a range of frequency between 1 MHz to 3 GHz. The composite form was also analyzed through computer modeling and simulation and electromagnetic properties for EMC shielding applications are also considered. PP/MWCNTs composite with shielding effectiveness of 15-20 dB was investigated through modeling and simulation at about 5% MWCNTs filling. Shielding mechanism was estimated by calculating the total shielding effectiveness (SE) into absorption and reflection loss. PP/MWCNTs composite indicates a shielding mostly by absorption mechanism; therefore it also can be used in other microwave applications or like a radar absorbing material....
Dielectric properties of composite materials containing aligned carbon nanotubes
Inorganic Materials, 2016
This paper presents a study of the electrodynamic properties of polymer-matrix composite materials containing a filler in the form of multiwalled carbon nanotubes. We have examined the effect of filler alignment in the composites on their interaction with electromagnetic radiation. The composite materials have an anisotropic electrical conductivity, dielectric permittivity, and electromagnetic radiation attenuation coefficient because an applied electric field produces a preferential filler alignment direction.