scholarly journals Broadband Dielectric Properties of Fe2O3·H2O Nanorods/Epoxy Resin Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Darya Meisak ◽  
Jan Macutkevic ◽  
Dzmitry Bychanok ◽  
Algirdas Selskis ◽  
Juras Banys ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Percolation Threshold ◽  
Epoxy Resin ◽  
Polymer Matrix ◽  
Finite Conductivity ◽  
Resin Composites ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold ◽  
Percolation Network ◽  
Properties Of Composites

A series of polymer composites based on epoxy resin with a 5–40 vol.% concentration of goethite (Fe2O3·H2O) nanorods was produced. The electrical percolation threshold in these composites was determined as 30 vol.% of nanorods. The dielectric properties of the composites both below and above the percolation threshold were studied in a wide temperature (200 K–450 K) and frequency (from Hz to THz) ranges. The dielectric properties of composites below the percolation threshold are mainly determined by the relaxation in a pure polymer matrix. The electrical properties of composites above the percolation threshold are determined by the percolation network, which is formed by the goethite nanorods inside the polymer matrix. Due to the finite conductivity of the epoxy resin, the electrical conductivity at high temperatures occurs in the composites both above and below the percolation threshold.

Dielectric Properties of Epoxy Resin Composites Based on Magnetic Nanoparticles

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940018 ◽  
Author(s):  
D. Meisak ◽  
J. Macutkevic ◽  
J. Banys ◽  
D. Bychanok ◽  
P. Kuzhir
Keyword(s):  
Dielectric Properties ◽  
Percolation Threshold ◽  
Epoxy Resin ◽  
Wide Frequency Range ◽  
Finite Conductivity ◽  
Resin Composites ◽  
Manganese Ferrite ◽  
Frequency Range ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold

Dielectric properties of composite materials made of epoxy resin filled with different concentrations of goethite (Fe2O[Formula: see text] H2O) nanorods and manganese ferrite (MnFe2O4) are presented in a wide frequency range. The electrical percolation threshold in these composites is close to 30[Formula: see text]vol.%. Electrical conductivity in the composites occurs both below and above the percolation threshold due to the finite conductivity of the epoxy resin under high temperatures.

scholarly journals A Numerical Study on Electrical Percolation of Polymer-Matrix Composites with Hybrid Fillers of Carbon Nanotubes and Carbon Black

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yuli Chen ◽  
Shengtao Wang ◽  
Fei Pan ◽  
Jianyu Zhang
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Black ◽  
Percolation Threshold ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Matrix Composites ◽  
Electrical Percolation ◽  
Hybrid Fillers ◽  
Nonlinear Relation ◽  
Electrical Percolation Threshold

The electrical percolation of polymer-matrix composites (PMCs) containing hybrid fillers of carbon nanotubes (CNTs) and carbon black (CB) is estimated by studying the connection possibility of the fillers using Monte Carlo simulation. The 3D simulation model of CB-CNT hybrid filler is established, in which CNTs are modeled by slender capped cylinders and CB groups are modeled by hypothetical spheres with interspaces because CB particles are always agglomerated. The observation on the effects of CB and CNT volume fractions and dimensions on the electrical percolation threshold of hybrid filled composites is then carried out. It is found that the composite electrical percolation threshold can be reduced by increasing CNT aspect ratio, as well as increasing the diameter ratio of CB groups to CNTs. And adding CB into CNT composites can decrease the CNT volume needed to convert the composite conductivity, especially when the CNT volume fraction is close to the threshold of PMCs with only CNT filler. Different from previous linear assumption, the nonlinear relation between CB and CNT volume fractions at composite percolation threshold is revealed, which is consistent with the synergistic effect observed in experiments. Based on the nonlinear relation, the estimating equation for the electrical percolation threshold of the PMCs containing CB-CNT hybrid fillers is established.

scholarly journals Dielectric Properties and Electrical Percolation in MnFe 2 O 4 /Epoxy Resin Composites

2020 ◽  
Vol 217 (6) ◽  
pp. 1900526 ◽  
Author(s):  
Darya Meisak ◽  
Jan Macutkevic ◽  
Algirdas Selskis ◽  
Juras Banys ◽  
Polina Kuzhir
Keyword(s):  
Dielectric Properties ◽  
Epoxy Resin ◽  
Resin Composites ◽  
Electrical Percolation ◽  
Epoxy Resin Composites

Electrical conductivity and rheological properties of carbon black based conductive polymer composites prior to and after annealing

2021 ◽  
pp. 096739112110012
Author(s):  
Qingsen Gao ◽  
Jingguang Liu ◽  
Xianhu Liu
Keyword(s):  
Electrical Conductivity ◽  
Carbon Black ◽  
Percolation Threshold ◽  
Rheological Properties ◽  
Network Formation ◽  
Loss Modulus ◽  
Conductive Polymer ◽  
Complex Viscosity ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold

The effect of annealing on the electrical and rheological properties of polymer (poly (methyl methacrylate) (PMMA) and polystyrene (PS)) composites filled with carbon black (CB) was investigated. For a composite with CB content near the electrical percolation threshold, the formation of conductive pathways during annealing has a significant impact on electrical conductivity, complex viscosity, storage modulus and loss modulus. For the annealed samples, a reduction in the electrical and rheological percolation threshold was observed. Moreover, a simple model is proposed to explain these behaviors. This finding emphasizes the differences in network formation with respect to electrical or rheological properties as both properties belong to different physical origins.

A promising approach to low electrical percolation threshold in PMMA nanocomposites by using MWCNT-PEO predispersions

2016 ◽  
Vol 111 ◽  
pp. 253-262 ◽  
Author(s):  
Seyed Mohammad Mir ◽  
Seyed Hassan Jafari ◽  
Hossein Ali Khonakdar ◽  
Beate Krause ◽  
Petra Pötschke ◽  
...  
Keyword(s):  
Percolation Threshold ◽  
Electrical Percolation ◽  
Electrical Percolation Threshold

scholarly journals Dielectric Spectroscopy and Tunability of Multi-Walled Carbon Nanotube / Epoxy Resin Composites

2010 ◽  
Vol 19 (6) ◽  
pp. 096369351001900 ◽  
Author(s):  
Z Špitalský ◽  
S N Georga ◽  
C A Krontiras ◽  
C Galiotis
Keyword(s):  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Epoxy Resin ◽  
Temperature Region ◽  
Dielectric Response ◽  
Effective Dielectric Constant ◽  
Free Energy Barrier ◽  
Resin Composites ◽  
Multi Walled Carbon Nanotube ◽  
Epoxy Resin Composites

The dielectric response of oxidized multi-walled carbon nanotube / epoxy resin composites, is investigated with respect to filler content concentration, over a wide temperature and frequency range. Specimens, below the percolation threshold, exhibit similar behaviour to that of the neat epoxy. Two relaxation modes are observed in the low temperature region, attributed to the re-arrangement of small parts of the polymer chain (γ-mode) and the reorientation of polar side groups (β-mode) respectively, where in the high temperature region the evolution of the α-mode is present. Direct current (DC) conduction follows the Vogel – Tamann - Fulcher equation as expected. The dielectric response of specimens, above the percolation threshold, follows the “Random Free Energy Barrier Model”. DC conductivity exhibits Arrhenius temperature dependence with two distinct regions. The activation energies of both regions were evaluated. The contact resistance between two adjacent carbon nanotubes was also calculated. The effective dielectric constant as well as the capacitance of the specimens, above the percolation threshold, can be modulated by means of an applied DC bias voltage.

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