Analysis of Percolation Behavior of Electrical Conductivity of the Systems Based on Polyethers and Carbon Nanotubes

Lysenkov, Е.А.; Klepko, V.V.

doi:10.21272/jnep.8(1).01017

Cited by 16 publications

(7 citation statements)

References 18 publications

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“…The crystallization temperature of the PEG polymer can be adjusted between 37.2 and 47.3 °C by changing the surface properties of the nanosubstrate. Carbon nanotubes have also been widely used to improve the thermal conductivity of PCMs . To investigate the role of the heat transfer medium, 5 wt % Al 2 O 3 (i), Al 2 O 3 (ii), Cu 2 O, and CuO nanoparticles were individually dispersed into the PEG.…”

Section: Resultsmentioning

confidence: 99%

Porosity reduction of polyethylene glycol phase change materials by using nanoscale thermal‐energy‐conducting medium during crystallization process

Zhang

Sun

Yuan

et al. 2017

J of Applied Polymer Sci

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Poly(ethylene glycols) (PEGs) are phase change materials (PCMs) that exhibit undesirable heat transfer properties, which restrict their industrial utility. Apart from the intrinsic material properties, a large quantity of micropores in the crystalline PEG polymers cause poor heat transfer performance. In this work, the formation and growth of micropores are reported through in situ characterization. The addition of a nanoscale thermal‐energy‐conducting medium into PCMs has been proposed for reducing their porosity. The mechanism for reducing porosity is reported for prepared composite PCMs. The intrinsic causes are thought to be the following. Metal oxide nanoparticles can migrate with the liquid PEG flow, which can reduce the thermal stresses in the crystal growth process. In addition, the nanoscale medium promotes heterogeneous nucleation. The results of this study show that reducing the porosity of the polymer crystals is an important approach for improving the heat transfer properties of the PEG PCMs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45446.

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Section: Resultsmentioning

confidence: 99%

Porosity reduction of polyethylene glycol phase change materials by using nanoscale thermal‐energy‐conducting medium during crystallization process

Zhang

Sun

Yuan

et al. 2017

J of Applied Polymer Sci

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“…For carbon nanomaterials introduced into a polymer matrix, the characteristic phenomenon of percolation, which consists in an abrupt increase in the properties of the material with the introduction of a critical filler content. For example, the introduction of CNTs into a polyethylene oxide matrix leads to an increase in electrical conductivity by more than two orders of magnitude [11]. In this case, percolation behavior is observed, in which clusters with CNTs at a content of 0.5 % form an electrically conductive network inside the polymer matrix.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Determination of the effect of carbon nanotubes on the microstructure and functional properties of polycarbonate-based polymer nanocomposite materials

Lysenkov

Klymenko

2021

EEJET

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Polymer nanocomposites are widely used in various high-tech industries. Due to the combination of the elasticity of the matrix and the strength of the inorganic filler, they have improved functional characteristics compared to unfilled polymers. The article is devoted to determining the effect of carbon nanotubes (CNT) on the microstructure and properties of polymeric nanocomposite materials for 3D printing based on polycarbonate. As a result of this work, a series of composite materials was manufactured using a piston extruder. Their microstructure and functional characteristics were investigated using methods of optical microscopy, thermophysical, electrical and mechanical analysis. It was found that CNTs form clusters in the polymer matrix, which form a percolation network at a content of 0.5–0.8 %. This feature of the structure formation of CNTs provided an abrupt increase in the functional characteristics of the materials obtained. It is shown that with an increase in the filler content in the system to 3 %, the thermal conductivity rapidly increases to 1.22 W/(m∙K). A similar effect is observed for the electrical conductivity, which increases by seven orders of magnitude from 10-12 to 10-5 S/cm at 3 % CNT content in the system, exhibiting percolation behavior. With the introduction of CNTs, the crystallinity degree of the polymer matrix decreases by almost 15 %, due to the fact that the developed surface of the nanotubes creates steric hindrances for polycarbonate macromolecules. This effect almost negates the reinforcing effect of nanotubes; therefore, the mechanical tensile strength with the introduction of 3 % CNTs increases by only 21 % compared to the unfilled matrix. In terms of their functional characteristics, the obtained materials are promising for the creation of filaments for 3D printing on their basis.

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“…where σ DC , σ m , and σ f are the electrical conductivity of the composite, matrix, and filler, respectively; φ c is the percolation threshold; and s is the critical conductivity exponent that characterizes the number of particles that form a percolation cluster (for a three-dimensional system, the theoretical value is s ≈ 0.73 [28]). is system of equations is universal and allows describing the electrical conductivity of filled polymer systems in the vicinity of a percolation transition with a high degree of accuracy [29,30]. As a result of modelling the (σ DC (φ)) dependence in the framework of equation 2, the following parameters are obtained: φ c � 8% and s � 0.81. e obtained value of the critical exponent s is very close to the theoretically calculated one, which indicates the formation of a three-dimensional percolation cluster.…”

Section: Features Of Conductivity Of Epoxy-carbonmentioning

confidence: 99%

Electrophysical Properties of Epoxy Composite Materials Filled with Carbon Black Nanopowder

Букетов

Smetankin

Lysenkov

et al. 2020

Advances in Materials Science and Engineering

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The effect of carbon black (CB) nanopowder on the electrical properties of polymer composite systems based on the epoxy resin is investigated using the method of impedance spectroscopy. It is established that the electrical and dielectric properties of the studied systems significantly depend on the nanofiller content. It is found that electrical conductivity and dielectric constant exhibit percolation behavior when the filler’s content increases. In this case, the electrical conductivity increases exponentially, indicating the formation of filler electrically conductive mesh inside the polymer matrix. A small jump in electrical conductivity when reaching the percolation threshold indicates the formation of indirect contacts between the particles. The value of the percolation threshold of conductivity is 8%. It is shown that the dielectric constant of epoxy nanosystems is almost unchanged in the frequency range of 102–105 Hz. It is related to the structural features of the filler particles, which ensure the existence of a minimal dielectric gradient between the matrix and the filler. It is found that the dielectric constant of the studied systems also shows percolation behavior. The obtained material based on the epoxy matrix is characterized by a high value of dielectric constant, which at a carbon black nanopowder content of 29% is 4680. This material is characterized by relative frequency invariance and a high value of dielectric constant, so it has great potential for practical application.

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Analysis of Percolation Behavior of Electrical Conductivity of the Systems Based on Polyethers and Carbon Nanotubes

Cited by 16 publications

References 18 publications

Porosity reduction of polyethylene glycol phase change materials by using nanoscale thermal‐energy‐conducting medium during crystallization process

Porosity reduction of polyethylene glycol phase change materials by using nanoscale thermal‐energy‐conducting medium during crystallization process

Determination of the effect of carbon nanotubes on the microstructure and functional properties of polycarbonate-based polymer nanocomposite materials

Electrophysical Properties of Epoxy Composite Materials Filled with Carbon Black Nanopowder

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