Investigation of temperature effect on the electrical properties of MWCNTs/epoxy nanocomposites by electrochemical impedance spectroscopy

Sanli, Abdulkadir

doi:10.1080/09243046.2019.1616409

Cited by 10 publications

(6 citation statements)

References 31 publications

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“…Identifying the role that each mechanism plays in the electrical properties of extremely low loading CNT composites and realizing an effective and straightforward model are challenging. Changes in resistivity with varying temperatures for CNT composites are impacted by CNT loading, matrix properties, changes to tunneling conduction at different temperatures, conductive properties of CNTs, contact resistance between CNTs, and other factors as demonstrated in this research and in others [15,30,31,33,35,42,44,46,47].…”

Section: Mechanisms Responsible For the Electrical Properties Trends supporting

confidence: 54%

“…An example is found in the properties reported for epoxy-CNT composites containing 0.05 wt%, 0.1 wt%, 0.3 wt%, and 0.5 wt% CNTs presented by Shen et al [30]. Work by Sanli et al examined the impact of temperature for thin film epoxy-CNT composites (MWCNTs in epoxy resin L20 with EPH-161 hardener) using electrochemical impedance spectroscopy for different CNT wt% finding that a 0.5 wt% sample showed an 11.40% decrease in resistance over a temperature range of 20 to 80 degrees Celsius [31]. The reported percentage decrease in resistance in the later, tested over a roughly similar temperature range as in Figure 3b, is comparable to our observed percentage change in resistivity.…”

Section: Imposed Temperature Alteration Using a Hot Platementioning

confidence: 99%

“…An increase in temperature could result in carrier thermal activation and overcoming of the barrier between filler materials which would result in a decrease in resistance. This thermal fluctuation induced tunneling [43] or hopping is proposed as the reason for decreases in impedance for epoxy-CNT composites with 0.5 to 1.0 wt% CNTs by Sanli [31] and as the dominant mechanisms for epoxy-CNT composites with 0.05 to 0.5 wt% by Shen et al [30]. While this mechanism certainly could aid in explaining the resistivity decreases observed with increasing temperature, this mechanism would likely be reversible at the time at which heat is removed.…”

Section: Mechanisms Responsible For the Electrical Properties Trends mentioning

confidence: 99%

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Impact of Current and Temperature on Extremely Low Loading Epoxy-CNT Conductive Composites

et al. 2020

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Carbon nanotube (CNT) conductive composites have attracted significant attention for their potential use in applications such as electrostatic dissipation and/or electromagnetic interference shielding. The focus of this work is to evaluate resistivity trends of extremely low loading (<0.1 wt%) epoxy-CNT composites that lack a connected CNT network, but still present electrical conductivity values appropriate for those uses. The impact of current, temperature, and cycle life on electrical properties are here identified and tied to possible performance limits. At extremely low loadings, the CNT content is not sufficient to form a completely interconnected grid, thus, electrons must travel through insulating media. While still in the semi-conductor range, resistivity values are observed to decrease with increasing direct current and demonstrate a non-ohmic behavior. CNT epoxy composites were subjected to elevated currents and/or temperatures over diverse periods of time to examine impacts on resistivity. Microstructural analyses of composite samples were conducted to observe signs of damage for specimens taken to extreme temperatures/currents. An understanding of the electrical conductivity characteristics of extremely low loading epoxy-CNT composites and their failure mechanisms will aid in understanding risks associated with their use in challenging environments that may include high temperatures, high currents, and/or high frequencies.

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Section: Mechanisms Responsible For the Electrical Properties Trends supporting

confidence: 54%

Section: Imposed Temperature Alteration Using a Hot Platementioning

confidence: 99%

Section: Mechanisms Responsible For the Electrical Properties Trends mentioning

confidence: 99%

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Impact of Current and Temperature on Extremely Low Loading Epoxy-CNT Conductive Composites

et al. 2020

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“…59 In our case, all the formulations show an increase of electrical resistance increasing the temperature. According to the literature, 60,61 this behavior can be ascribed to the volume expansion of the polymer. As the temperature increases, it causes the polymer thermal expansion determining a larger distance between conductive particles.…”

Section: Preliminary Characterizationsmentioning

confidence: 97%

Graphene nanoplatelet, multiwall carbon nanotube, and hybrid multiwall carbon nanotube–graphene nanoplatelet epoxy nanocomposites as strain sensing coatings

Bragaglia

Paleari

Lamastra

et al. 2021

Journal of Reinforced Plastics and Composites

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Strain monitoring is of great interest in order to check components structural life, to prevent catastrophic failures, and, possibly, to predict residual life in case of unexpected events. In this study, strain sensing epoxy-based coatings containing carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), and a mix of the two (MWCNT+GNP) have been produced, with the same initial electrical resistivity, and applied on glass fiber reinforced composites. Morphological, mechanical, and electrical tests have been then performed evaluating the resistance variation and the strain sensing performance of the sensors. A theoretical model to relate the resulting gauge factors to the different types of nanofillers has been applied. The results showed that all systems present a strain sensing performance with different gauge factors (and hence sensitivity) at low strain: GNP samples showed the highest gauge factor (10.3), MWCNT samples the lowest (1.5), and the mixed system lies in the middle (4.3). From analytical analysis, the value of initial distance among conductive particles was found to be 0.3 nm in the case of MWCNT and 1.2 nm for GNP, explaining why the gauge factors of the produced sensors are different.

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“…Incorporation of conductive nanofillers, i.e. carbon black, 2,3 graphene, 4,5 nanowires 6,7 and carbon nanotubes (CNTs) [8][9][10][11] into a certain polymer matrix can enhance mechanical, electrical properties as well as sensing performance of the strain sensor significantly. [12][13][14][15][16][17][18][19][20] Among these nanomaterials, CNTs are widely used owing to their high aspect ratio, which enables the formation of the conductive paths within the nanocomposite network at very low CNTs concentrations.…”

Section: Introductionmentioning

confidence: 99%

Electrical impedance analysis of carbon nanotube/epoxy nanocomposite-based piezoresistive strain sensors under uniaxial cyclic static tensile loading

Sanli

Kanoun

2019

Journal of Composite Materials

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Carbon nanotubes-based nanocomposites have gained a great amount of attraction and play a key role in the realization of strain sensors owing to their remarkable physical properties. In this study, the piezoresistivity of multi-walled carbon nanotubes (MWCNTs)/epoxy-based nanocomposite-based strain sensor under static tensile load is examined using electrochemical impedance spectroscopy. Morphological examinations show that MWCNTs are randomly and homogeneously distributed in the epoxy polymer matrix. A simplified resistance constant phase element model is proposed and validated by impedance spectrum to fit the impedance spectra and the equivalent circuit parameters are extracted under uniaxial static load. Impedance results suggest that depending on the frequency regions, the sensor exhibits different responses under loading. Moreover, the proposed sensor gives high sensitivity, linearity and low hysteresis under cyclic quasi-static loading and unloading that makes the sensor a promising candidate for practical strain sensor applications.

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Investigation of temperature effect on the electrical properties of MWCNTs/epoxy nanocomposites by electrochemical impedance spectroscopy

Cited by 10 publications

References 31 publications

Impact of Current and Temperature on Extremely Low Loading Epoxy-CNT Conductive Composites

Impact of Current and Temperature on Extremely Low Loading Epoxy-CNT Conductive Composites

Graphene nanoplatelet, multiwall carbon nanotube, and hybrid multiwall carbon nanotube–graphene nanoplatelet epoxy nanocomposites as strain sensing coatings

Electrical impedance analysis of carbon nanotube/epoxy nanocomposite-based piezoresistive strain sensors under uniaxial cyclic static tensile loading

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