On the effect of electric field application during the curing process on the electrical conductivity of single-walled carbon nanotubes–epoxy composites

Morais, Manuel V. C.; Oliva-Avilés, A.I.; Matos, Miguel A.S.; Tagarielli, V.L.; Pinho, S.T.; Hübner, Christof; Henning, Frank

doi:10.1016/j.carbon.2019.04.087

Cited by 29 publications

(18 citation statements)

References 46 publications

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“…Once a good level of matrix infiltration, dispersion and distribution in the CNT agglomerates is obtained, it was found that heat application during the curing process further decreased the electrical resistivity of the nanocomposites. This is expected to be due to a reduction in the matrix viscosity at higher temperatures, allowing more mobility of the particles and hence leading to more contacts between them, as investigated in [22]. This proved to be beneficial when combined with the application of an electric field between the electrodes, leading to a reduction in resistivity of up to one order of magnitude compared to the samples cured without the field.…”

Section: Discussionmentioning

confidence: 92%

“…This proved to be beneficial when combined with the application of an electric field between the electrodes, leading to a reduction in resistivity of up to one order of magnitude compared to the samples cured without the field. As explored in [22], the clear alignment of CNTs due to the electric field was not observed in scanning electron microscope (SEM) images of sample fracture surfaces. Instead, the reduction in electrical resistivity was attributed to an electric-field-induced increase in contact points between the nanoparticles.…”

Section: Discussionmentioning

confidence: 99%

“…A sinusoidal voltage of 60 Vpp at a frequency of 10 MHz was used to generate a sinusoidal alternating electric field strength of 400 Vpp/cm using a function generator Agilent 33250A and a high frequency power amplifier (Tabor 9260). The voltage and the frequency were chosen based on results presented in [22], where the procedure for electric field application is further described. After mounting the system together, two hose couplings (5 in Figure 2) were screwed on the top plate, each then connecting a feeding tube (6 in Figure 2) fastened with a tightening nut (7 in Figure 2).…”

Section: Electric Fieldmentioning

confidence: 99%

“…Moreover, by increasing the curing temperature, the electrical resistivity of the SWCNT/epoxy 0.1 wt.% composites appears to decrease around 50%. This is probably due to the fact that, at 80 • C, the resin matrix is less viscous than at room temperature, as it emerges from the rheological tests performed in [22]. A more liquid suspension provides less viscous resistance for the secondary agglomerates' network formation, under Van der Waals forces or intentional applied dielectrophoresis (useful consideration for alignment experiments described further on in this paper, which in fact were performed at 80 • C).…”

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confidence: 99%

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Process Chain Optimization for SWCNT/Epoxy Nanocomposite Parts with Improved Electrical Properties

et al. 2020

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Electrically conductive nanocomposites present opportunities to replace metals in several applications. Usually, the electrical properties emerging from conductive particles and the resulting bulk values depend on the micro/nano scale morphology of the particle network formed during processing. The final electrical properties are therefore highly process dependent. In this study, the electrical resistivity of composites made from single-walled carbon nanotubes in epoxy was investigated. Three approaches along the processing chain were investigated to reduce the electrical resistivity of nanocomposites-the dispersion strategy in a three-roll mill, the curing temperature, and the application of electric fields during curing. It was found that a progressive increase in the shear forces during dispersion leads to a more than 50% reduction in the electrical resistivities. Higher curing temperatures of the nanocomposite resin also lead to a decrease of around 50% in resistivity. Furthermore, a scalable resin transfer molding set-up with gold-coated electrodes was developed and tested with different mold release agents. It has been shown that curing the material under electric fields leads to an electrical resistivity approximately an order of magnitude lower, and that the properties of the mold release agent also influence the final resistivity of different samples in the same batch.

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Section: Discussionmentioning

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: Electric Fieldmentioning

confidence: 99%

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confidence: 99%

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Process Chain Optimization for SWCNT/Epoxy Nanocomposite Parts with Improved Electrical Properties

et al. 2020

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“…First, the resin viscosity drops before gelation, allowing for a higher CNT re-agglomeration. 29 Second, the cured composite shrinkage also diminishes the CNT interparticle distance and enhances the conductivity of the epoxy-based CPC. Unfortunately, the heterogeneous resin behavior, due to lower wetting capabilities, leads to a reduction of mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Improving through‐thickness conductivity of carbon fiber reinforced polymer using carbon nanotube/polyethylenimine at the interlaminar region

Robert

Thitasiri

Mamalis

et al. 2020

J of Applied Polymer Sci

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The through-thickness conductivity of carbon fiber reinforced polymer (CFRP) composite was increased by incorporating multiwalled carbon nanotubes in the interlaminar region. Carbon nanotubes (CNTs) were dispersed in a polyethylenimine (PEI) binder, which was then coated onto the carbon fiber fabric. Standard vacuum-assisted resin infusion process was applied to fabricate the composite laminates. This modification technique aims to enhance the electrical conductivity in through-thickness direction for the purpose of nondestructive testing, damage detection, and electromagnetic interference shielding. CNT concentrations ranging from 0 to 0.75 wt% were used and compared to pristine CFRP samples (reference). The through-thickness conductivity of the CFRP exhibited an improvement of up to 781% by adopting this technique. However, the dispersion of CNT in PEI led to a viscosity increase and poor wetting properties which resulted in the formation of voids/defects, poor adhesion (as shown in scanning electron micrographs) and the deterioration of the mechanical properties as manifested by interlaminar shear strength and dynamic mechanical analysis measurements.

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Controlled Vertically Aligned Structures in Polymer Composites: Natural Inspiration, Structural Processing, and Functional Application

Lei

Xie

et al. 2021

Advanced Materials

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density, diverse processability, excellent flexibility, and high chemical resistance, have been attracting increasing research attention for practical applications. [5] Further, the combination of polymers with various functional fillers, such as graphene, carbon nanotubes (CNTs), [6] boron nitride nanosheets (BNNS), [7] and barium carbonate (BaTiO 3 ) [8] can help in developing bring polymer composites that have additional electrical, magnetic, thermal, or photonic functions that are not limited to the characteristics of the filler and the matrix; [9] this provides them with indispensable potentials in some emerging scenarios and sophisticated applications.The macroscopic performance and function of polymer composites depend on the polymer/filler composition and their morphological microstructure. In previous studies, polymer composites were fabricated via direct physical mixing, which appears as filler agglomeration in the polymeric matrix. [10] In this century, an increasing number of researchers have adopted structural manipulation, which focuses on the regulation of polymer/filler architecture, instead of homogeneous filler dispersion. For example, the number of uniform filler particles with random distribution in the polymer matrix can be controlled in the formation of interconnected filler morphology; [11] the filler can be selectively distributed (confined within one polymer phase or at the polymer-polymer interface) by structural processing procedures; [12] and the filler particles can be induced to be oriented along one specific direction by an intense shear field considering the anisotropy of the filler dimension. [13] These diverse processing strategies provide us with great opportunities to optimize the polymer/filler microstructure, performance and functionality, and to largely broaden their practical applications. Among the various structures in polymeric composites such as randomly distributed structures and horizontal structures, vertically aligned structures in polymer composites, which refers to the architectures with filler orientation, interconnection, or assembly in the thickness direction, have considerable significance and are gaining interest in scientific research and industrial applications, because of their distinctive throughplane functional properties. For instance, the reinforced filler in the polymeric matrix needs to be perpendicular to the Vertically aligned structures, which are a series of characteristic conformations with thickness-direction alignment, interconnection, or assembly of filler in polymeric composite materials that can provide remarkable structural performance and advanced anisotropic functions, have attracted considerable attention in recent years. The past two decades have witnessed extensive development with regard to universal fabrication methods, subtle control of morphological features, improvement of functional properties, and superior applications of vertically aligned structures in various fields. However, a systematic review remains to be attempted. Th...

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On the effect of electric field application during the curing process on the electrical conductivity of single-walled carbon nanotubes–epoxy composites

Cited by 29 publications

References 46 publications

Process Chain Optimization for SWCNT/Epoxy Nanocomposite Parts with Improved Electrical Properties

Process Chain Optimization for SWCNT/Epoxy Nanocomposite Parts with Improved Electrical Properties

Improving through‐thickness conductivity of carbon fiber reinforced polymer using carbon nanotube/polyethylenimine at the interlaminar region

Controlled Vertically Aligned Structures in Polymer Composites: Natural Inspiration, Structural Processing, and Functional Application

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