scholarly journals Characterization of percolation behavior in conductor–dielectric 0-3 composites

2014 ◽  
Vol 04 (04) ◽  
pp. 1450035 ◽  
Author(s):  
Lin Zhang ◽  
Patrick Bass ◽  
Zhi-Min Dang ◽  
Z.-Y. Cheng
Keyword(s):  
Dielectric Constant ◽  
Percolation Threshold ◽  
Frequency Dependence ◽  
Experimental Results ◽  
Effective Dielectric Constant ◽  
Filler Concentration ◽  
Percolation Behavior ◽  
The Matrix ◽  
The Relationship

The equation ε eff ∝ (ϕc - ϕ)-s which shows the relationship between effective dielectric constant (εeff) and the filler concentration (φ), is widely used to determine the percolation behavior and obtain parameters, such as percolation threshold φc and the power constant s in conductor–dielectric composites (CDCs). Six different systems of CDCs were used to check the expression by fitting experimental results. It is found that the equation can fit the experimental results at any frequency. However, it is found that the fitting constants do not reflect the real percolation behavior of the composites. It is found that the dielectric constant is strongly dependent on the frequency, which is mainly due to the fact that the frequency dependence of the dielectric constant for the composites close to φc is almost independent of the matrix.

scholarly journals Electrophysical Properties of Epoxy Composite Materials Filled with Carbon Black Nanopowder

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Andriy Buketov ◽  
Serhii Smetankin ◽  
Eduard Lysenkov ◽  
Kyrylo Yurenin ◽  
Oleksandr Akimov ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Constant ◽  
Carbon Black ◽  
Percolation Threshold ◽  
Structural Features ◽  
Electrically Conductive ◽  
Percolation Behavior ◽  
The Matrix ◽  
Electrical And Dielectric Properties ◽  
Nanofiller Content

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.

An Analytical Model for the Effective Dielectric Constant of a 0-3-0 Composite

2010 ◽  
Author(s):  
K. A. Cook-Chennault ◽  
S. Banerjee
Keyword(s):  
Dielectric Constant ◽  
Aspect Ratio ◽  
Analytical Model ◽  
Experimental Results ◽  
Effective Dielectric Constant ◽  
The Third ◽  
Third Phase ◽  
Three Phase ◽  
Phase 0 ◽  
Experimental Values

An analytical expression for prediction of the effective dielectric constant of a three phase 0-3-0 ferroelectric composite is presented. The analytical results are verified with the experimental results from Nan et al [1]. We extend the analytical model, so that the influence of the shape of the third phase inclusion, on the effective dielectric constant of the composite, can be investigated. The results indicate that the dielectric constant increases ∼7 times, when the aspect ratio of the conductive inclusion is increased from 1 (sphere) to 10 (spheroid). The analytical predictions compare favorably with the experimental values.

scholarly journals Simulation of Percolation Threshold, Tunneling Distance, and Conductivity for Carbon Nanotube (CNT)-Reinforced Nanocomposites Assuming Effective CNT Concentration

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 114 ◽  
Author(s):  
Yasser Zare ◽  
Kyong Yop Rhee
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Percolation Threshold ◽  
Experimental Results ◽  
Filler Concentration ◽  
Experimental Measurements ◽  
Tunneling Conductivity ◽  
Tunneling Distance

This article suggests simple and new equations for the percolation threshold of nanoparticles, the tunneling distance between nanoparticles, and the tunneling conductivity of polymer carbon nanotubes (CNTs) nanocomposites (PCNT), assuming an effective filler concentration. The developed equations correlate the conductivity, tunneling distance, and percolation threshold to CNT waviness, interphase thickness, CNT dimensions, and CNT concentration. The developed model for conductivity is applied for some samples and the predictions are evaluated by experimental measurements. In addition, the impacts of various parameters on the mentioned terms are discussed to confirm the developed equations. Comparisons between the calculations and the experimental results demonstrate the validity of the developed model for tunneling conductivity. High levels of CNT concentration, CNT length, and interphase thickness, as well as the straightness and thinness of CNTs increase the nanocomposite conductivity. The developed formulations can substitute for the conventional equations for determining the conductivity and percolation threshold in CNT-reinforced nanocomposites.

Preparation and Characterization of Textured CaBi4-XLaXTi4O15 Ceramics

2011 ◽  
Vol 492 ◽  
pp. 218-221
Author(s):  
Guo Xi Jin ◽  
Xiao Bo Wu ◽  
Ling Di Chen ◽  
Yan Xue Tang ◽  
Ben Xue Jiang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Electric Field ◽  
Sintering Temperature ◽  
Tape Casting ◽  
Particle Method ◽  
Textured Ceramics ◽  
The Relationship

La3+ doped textured ceramics CaBi4-xLaxTi4O15were prepared by oriented consolidation of anisometric particle method with tape casting. The orientation was improved by modifying sintering temperature. The doping of La3+in orientated CaBi4-xLaxTi4O15ceramics increased the dielectric constant. The higher dielectric constant was obtained in the direction which tropism parallels to the electric field. The relationship between dielectric constant and orientation was discussed.

Filament Fragmentation Phenomena

1989 ◽  
Vol 170 ◽  
Author(s):  
Juan C. Figueroa ◽  
Linda S. Schadler ◽  
Campbell Laird
Keyword(s):  
Strain Energy ◽  
Stress Transfer ◽  
Fiber Surface ◽  
Yield Information ◽  
The Matrix ◽  
Two Parameters ◽  
The Relationship

AbstractThe effect of fiber surface treatments on the relationship between the tensile strength of a filament and the shear strength of its interphase is one of the central issues facing composite materials technologists today. We demonstrate here that analysis of fragmentation phenomena in monofilament composites can simultaneously yield information about these two parameters. Characterization of shear stress transfer zones in non-critical fragments has led us to the determination of interphase strength.A phenomenological treatment that highlights the role of the matrix in the fragmentation process is presented here. This analysis considers issues such as the strain energy exchange between a failing fiber and the matrix, as well as interphase relaxation due to the viscoelastic nature of the matrix. Our observations of the fragmentation phenomena in AU4/polycarbonate monofilament composites indicate that the fiber/matrix interaction in this system is governed by micromechanical locking.

scholarly journals Characterization of Polyvinylidene Fluoride (PVDF) Electrospun Fibers Doped by Carbon Flakes

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2766
Author(s):  
Pavel Kaspar ◽  
Dinara Sobola ◽  
Klára Částková ◽  
Alexandr Knápek ◽  
Daniel Burda ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Thermal Degradation ◽  
Polymer Material ◽  
Polyvinylidene Fluoride ◽  
Electrospun Fibers ◽  
Complex Structures ◽  
Crystalline Phases ◽  
Points Of View ◽  
The Relationship

Polyvinylidene fluoride (PVDF) is a modern polymer material used in a wide variety of ways. Thanks to its excellent resistance to chemical or thermal degradation and low reactivity, it finds use in biology, chemistry, and electronics as well. By enriching the polymer with an easily accessible and cheap variant of graphite, it is possible to affect the ratio of crystalline phases. A correlation between the ratios of crystalline phases and different properties, like dielectric constant as well as piezo- and triboelectric properties, has been found, but the relationship between them is highly complex. These changes have been observed by a number of methods from structural, chemical and electrical points of view. Results of these methods have been documented to create a basis for further research and experimentation on the usability of this combined material in more complex structures and devices.

Contribution to the Dielectric Behavior of Relaxers from the Surface of Nano-Order Cluster in the Materials

1997 ◽  
Vol 492 ◽  
Author(s):  
Z. -Y. Cheng ◽  
Aqiang Guo ◽  
R. S. Katiyar
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Frequency Dependence ◽  
Relaxor Ferroelectrics ◽  
Dielectric Behavior ◽  
Experimental Results ◽  
Time Analysis ◽  
Resonance Process

ABSTRACTBased on the analysis of the dielectric behavior of relaxor ferroelectrics, it is assumed that the material has two polarization processes. Thus, a formula, which can fit the experimental results very well, is proposed to describe the temperature and frequency dependence of the dielectric constant. The fitted results show that there is a resonance process in the material and the peak of the dielectric constant is determined with both the relaxation and resonance processes. The relaxation time analysis shows that the peak of the dielectric constant indeed consists of two parts.

NanoDielectric Theories

2021 ◽  
pp. 95-141
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Polymer Matrix ◽  
Power Law ◽  
Theoretical Models ◽  
Nanocomposite Materials ◽  
Effective Dielectric Constant ◽  
Filler Concentration ◽  
Polymer Filler ◽  
Exponential Power

This chapter sheds light on the recent nanotechnology theoretical models for interphase power law IPL model, inhomogeneous interphase, and multi-nanoparticles technique. Moreover, this chapter reviews deliberate hypothetical researches of the effective dielectric constant for polymer/filler nanocomposites and its reliance on “filler concentration, the interphase interactions, polymer filler dielectric constant, and interphase dielectric constant.” This chapter also investigates the prediction of the dielectric constant of new nanocomposite materials dependent upon exponential power law model. Thus, this work moves from the dielectric properties of beginning polymer matrix forward and predicts the dielectric properties of new nanocomposite materials to be utilized for high voltage and directing materials by adding specified nanoparticles with polymer matrix.

Synthesis and Characterization of TiO2 Reinforced Al6061 Composites

2017 ◽  
Vol 26 (1) ◽  
pp. 096369351702600 ◽  
Author(s):  
G B Veeresh Kumar ◽  
P S Shivakumar Gouda ◽  
R Pramod ◽  
C S P Rao
Keyword(s):  
Aluminum Matrix ◽  
Tribological Characteristics ◽  
Dry Sliding Wear ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Mechanical Characterisation ◽  
The Matrix ◽  
Mechanical And Tribological Characteristics ◽  
The Relationship

This article presents the investigative work carried out to study the relationship between the physical, mechanical and tribological characteristics of aluminum matrix composites reinforced with Titanium dioxide (TiO2). The powder metallurgy route of production was followed to produce the composites (Al6061 containing 3 wt% TiO2). The composites were subjected to sequences of physical, mechanical and tribological investigations. The outputs of the experiments done indicate that the increase in TiO2 fillers increase the density of the composite and the values accepted by the rule of mixtures. The result of mechanical characterisation of Al6061-TiO2 composites was noticed to increase significantly with higher TiO2 content in the matrix, with loss in ductility. The dry sliding wear studies of Al6061-TiO2 composite showed greater wear resistance than Al6061 matrix and the composite containing higher filler content displayed the superior physical, mechanical and tribological characteristics.

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