scholarly journals Dielectric Behavior of Ceramic (BST)/Epoxy Thick Films

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
N. Hadik ◽  
A. Outzourhit ◽  
A. Elmansouri ◽  
A. Abouelaoualim ◽  
A. Oueriagli ◽  
...  
Keyword(s):  
Experimental Data ◽  
Dielectric Constant ◽  
Composite Materials ◽  
Dielectric Loss ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Dielectric Behavior ◽  
Mixing Models ◽  
Dielectric Measurements ◽  
Best Fit

Composite materials were made by mixing powders ofBa1−xSrxTiO3(x=0.2and 0.4) ceramics and epoxy resin with various volume fractions (vol%). Dielectric measurements of these composites were performed as a function of filler ratio in the range 100–360°K at 10 KHz. The dielectric constant of the composite increased with increasing volume fraction varies slightly with temperature. The 20 vol% of BST(0.4)-epoxy composite had the highest dielectric constant of 19.4 and dielectric loss tangent of 0.027. Among the dielectric mixing models presented, the model of Lichtenecker shows the best fit to the experimental data for both composites.

scholarly journals Dielectric Behavior of Medical PMMA Polymer Filled With Copper Nanobud Particles

2019 ◽  
Vol 8 (3) ◽  
pp. 50-56
Author(s):  
I. I. Marhoon ◽  
A. H. Majeed ◽  
M. A. Abdulrehman
Keyword(s):  
Dielectric Constant ◽  
Composite Materials ◽  
Dielectric Loss ◽  
Average Particle Size ◽  
Weight Fraction ◽  
Dissipation Factor ◽  
Dielectric Behavior ◽  
Nano Particles ◽  
Average Particle ◽  
Vis Spectroscopy

In this paper, the effect of weight fraction and frequency on dielectric properties of polymethylmethacrylate filled with copper nanobud particles is studied. copper nano particles were synthesized by chemical reduction method. The resultant copper nano particles were characterized by UV-Vis spectroscopy and X-ray diffraction (XRD). Results show that the Cu Nps have bud shapes, and their average particle size obtained from the XRD study is 53.78 nm. For the resultant composite materials, such as the dielectric behavior of composite materials reinforced with 5%, 10%, 15%, and 20% weight fractions of copper nanobud particles and frequency ranges of 50, 250, 103, 104, 105, and 106 Hz at 25 °C were investigated. Results reveal that the dielectric constant, dielectric loss factor, and dissipation factor increased with the increase in weight fraction of copper nanobud particles due to their high conductivity. The dielectric constant, dielectric loss, and dissipation factor decreased with the increase in frequency.

Skin–core structured fluorinated MWCNTs: a nanofiller towards a broadband dielectric material with a high dielectric constant and low dielectric loss

2018 ◽  
Vol 6 (9) ◽  
pp. 2370-2378 ◽  
Author(s):  
Yang Liu ◽  
Cheng Zhang ◽  
Benyuan Huang ◽  
Xu Wang ◽  
Yulong Li ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
High Dielectric Constant ◽  
Dielectric Material ◽  
Epoxy Composite ◽  
Low Dielectric ◽  
High Dielectric

A novel skin–core structured fluorinated MWCNT nanofiller was prepared to fabricate epoxy composite with broadband high dielectric constant and low dielectric loss.

scholarly journals Effect of Terminal Groups on Thermomechanical and Dielectric Properties of Silica–Epoxy Composite Modified by Hyperbranched Polyester

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2451
Author(s):  
Jianwen Zhang ◽  
Dongwei Wang ◽  
Lujia Wang ◽  
Wanwan Zuo ◽  
Lijun Zhou ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Binding Energy ◽  
Epoxy Resin ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Mean Square Displacement ◽  
Mean Square ◽  
Hyperbranched Polyester ◽  
Free Volume Fraction

To study the effect of hyperbranched polyester with different kinds of terminal groups on the thermomechanical and dielectric properties of silica–epoxy resin composite, a molecular dynamics simulation method was utilized. Pure epoxy resin and four groups of silica–epoxy resin composites were established, where the silica surface was hydrogenated, grafted with silane coupling agents, and grafted with hyperbranched polyester with terminal carboxyl and terminal hydroxyl, respectively. Then the thermal conductivity, glass transition temperature, elastic modulus, dielectric constant, free volume fraction, mean square displacement, hydrogen bonds, and binding energy of the five models were calculated. The results showed that the hyperbranched polyester significantly improved the thermomechanical and dielectric properties of the silica–epoxy composites compared with other surface treatments, and the terminal groups had an obvious effect on the enhancement effect. Among them, epoxy composite modified by the hyperbranched polyester with terminal carboxy exhibited the best thermomechanical properties and lowest dielectric constant. Our analysis of the microstructure found that the two systems grafted with hyperbranched polyester had a smaller free volume fraction (FFV) and mean square displacement (MSD), and the larger number of hydrogen bonds and greater binding energy, indicating that weaker strength of molecular segments motion and stronger interfacial bonding between silica and epoxy resin matrix were the reasons for the enhancement of the thermomechanical and dielectric properties.

The Estimation of Thermal Conductivity for Alumina-Epoxy Composite Material with High Filling Volume Fraction

2014 ◽  
Vol 918 ◽  
pp. 21-26
Author(s):  
Chen Kang Huang ◽  
Yun Ching Leong
Keyword(s):  
Thermal Conductivity ◽  
Composite Material ◽  
Composite Materials ◽  
Physical Model ◽  
Electron Scattering ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
The Matrix ◽  
Transport Theorem ◽  
Good Agreement

In this study, the transport theorem of phonons and electrons is utilized to create a model to predict the thermal conductivity of composite materials. By observing or assuming the dopant displacement in the matrix, a physical model between dopant and matrix can be built, and the composite material can be divided into several regions. In each region, the phonon or electron scattering caused by boundaries, impurities, or U-processes was taken into account to calculate the thermal conductivity. The model is then used to predict the composite thermal conductivity for several composite materials. It shows a pretty good agreement with previous studies in literatures. Based on the model, some discussions about dopant size and volume fraction are also made.

Dielectric Behavior of Barium Titanate/Carbon Fibers Composites

2017 ◽  
Vol 898 ◽  
pp. 2101-2106
Author(s):  
Zhong Yang Wang ◽  
Xin Yan Li ◽  
Run Hua Fan ◽  
Pei Tao Xie ◽  
Kai Sun ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Barium Titanate ◽  
Carbon Fibers ◽  
Percolation Theory ◽  
High Dielectric Constant ◽  
Volume Fraction ◽  
Dielectric Behavior ◽  
Lower Volume Fraction ◽  
Lower Volume ◽  
High Dielectric

Conductor–insulator composites have been extensive researched for high dielectric constant. Most of them concentrated on metal polymers or metal ceramics. Barium titanate–carbon fibers composites were prepared by using a solid state reaction process with carbon fibers contents ranging from7 vol% to 23 vol%. Due to the high-aspect-ratio of carbon fiber, it was easy to produce a conducting network at much lower volume fraction. FESEM images illustrated that the carbon fibers influenced the densification and microstructure of the ceramics. Besides, addition of carbon fibers led to increase in dielectric permittivity, also had effects on the dielectric loss and ac conductivity. The dielectric and conductivity properties as a function of carbon fibers volume fraction were explained by the percolation theory.

scholarly journals Dielectric Behavior of Dysprosium Substituted Magnesium Ferrite

2018 ◽  
Vol 15 (1) ◽  
pp. 48-54
Author(s):  
Jeevan S. Ghodake
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Powder Diffraction ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Dielectric Behavior ◽  
Complex Dielectric Constant ◽  
Frequency Variation ◽  
Magnesium Ferrite ◽  
X Ray

Dysprosium substituted Magnesium ferrite weresuccessfully prepared by chemical combustion method. The as synthesized powder was presintered in air at 6000C for 1hr and finally sintered at 9500C for 1hr. From X-ray powder diffraction pattern of MgDy0.03Fe1.97O4, confirmed formation of single phase cubic spinel structure. The value of crystallite size obtained from X-ray powder diffraction (311) peak , it is found to be 46.38nm.The frequency and temperature variation of dielectric parameters such as real dielectric constant (ε′), complex dielectric constant (ε") and dielectric loss tangent (tanδ) were determined using Hioki LCR - Q meter. The frequency variation of dielectric constant shows a normal dielectric behavior of spinel ferrites. The dielectric loss tangent with frequency shows similar behavior as dielectric constant. The dielectric constant and dielectric loss tangent increases with increase in temperature

Characterization and dielectric properties of sodium fluoride doped talc

Clay Minerals ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 551-558
Author(s):  
S. Gümüştas ◽  
K. Köseoğlu ◽  
E. E. Yalçinkaya ◽  
M. Balcan
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Firing Temperature ◽  
Room Temperature ◽  
Dielectric Measurements ◽  
Frequency Range ◽  
Detailed Characterization ◽  
Circuit Element

AbstractThe purpose of this paper is to determine the effect of NaF and firing temperature on the dielectric properties (dielectric constant and dielectric loss) of talc, which is used in the electrical and electronic industries as a circuit element. A detailed characterization of the samples was made by XRD, FTIR, SEM and TG-DTG methods. Dielectric measurements were performed in the frequency range from 1 MHz to 80 MHz at room temperature. The dielectric constant value increased with an increase in firing temperature due to the removal of polarizable compounds from the talc structure. The higher dielectric constant values were obtained by addition of NaF. The dielectric loss of NaF doped talc decreased with the increase of firing temperature and increased with the increase of the amount of NaF.

Evaluating the Mechanical Properties of 3D Woven Carbon-Epoxy Composite Materials Using Experimental Data and FEA Methods

2011 ◽  
Author(s):  
Mahdi Farahikia ◽  
Sunilbhai Macwan ◽  
Fereidoon Delfanian ◽  
Zhong Hu
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Composite Materials ◽  
Epoxy Composite ◽  
External Pressure ◽  
Fiber Direction ◽  
Strain Gages ◽  
Element Analysis ◽  
Test Specifications ◽  
Dog Bone

A series of tensile, compression and shear tests were carried out on carbon-epoxy composite materials to evaluate their mechanical properties. The experiments were set upin accordance with ASTM standards that best corresponded to the test specifications. Specimens were categorized into groups according to their dimensions and shape. Based on testing requirements, some were cut into rectangular and others into dog bone specimens to determine the effects of stress concentration. A number of specimens were reinforced at both ends by means of tabs which were bonded on both faces to reduce the effects of the external pressure exerted on them through the grips of the testing machines, and the rest of them were tested without any reinforcement tabs. All the specimens were tested until failure. Load, elongation (displacement) and strain data were recorded by means of strain gages and data acquisition systems. The experimental results obtained from similar tests on different groups are compared to examine the conformity of the results regardless of dimension and geometry, and are also verified by Finite Element Analysis (FEA). In addition, FEA is used to study different conditions, such as geometry, that could affect the final results. The experimental data are analyzed and effects of fiber direction on failure method are studied. It was concluded that shape and geometry factors as well as fiber direction influenced the failure method. The work, however, is still in progress and tests under conditions, such as elevated temperature, will be conducted to study other effects on the mechanical properties of 3D woven carbon-epoxy composites.

Broadband Dielectric Relaxation of Polymer Composite Films

2000 ◽  
Vol 628 ◽  
Author(s):  
C.K. Chiang ◽  
Roman Popielarz ◽  
Ryusuke Nozaki ◽  
Jan Obrzut
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Composite Materials ◽  
Wireless Communication ◽  
Dielectric Relaxation ◽  
Polymer Composite ◽  
Electronic Devices ◽  
Composite Films ◽  
Dielectric Behavior ◽  
Complex Dielectric Constant

ABSTRACTThe broadband dielectric relaxation of a BaTiO3-polymer composite film was studied. The complex dielectric constant data from 10-4 Hz to 1010 Hz reveals the existence of relaxation process at frequency of 10 MHz in the polymer composite. On the basis of Cole-Cole analysis, the relaxation time of the system is of order of 10-8 s. The understanding of the broad dispersion in dielectric behavior of polymer composite materials is needed to support next generation electronic devices used in wireless communication and related applications.

Piezoelectric, Dielectric and Pyroelectric Property in Morphotropic Phase Boundary MnO2 Doped Bi0.5(Na0.82K0.18)0.5TiO3/P(VDF-TrFE) 0-3 Composites

2012 ◽  
Vol 535-537 ◽  
pp. 55-60
Author(s):  
Mao Yan Fan ◽  
Yang Yang Zhang ◽  
Qing Feng Zhang ◽  
Guang Zu Zhang ◽  
Lin Lu
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Phase Boundary ◽  
Morphotropic Phase Boundary ◽  
Figure Of Merit ◽  
Piezoelectric Coefficient ◽  
Volume Fraction ◽  
Ceramic Powder ◽  
Pyroelectric Coefficient ◽  
Pyroelectric Property

MnO2 doped Bi0.5(Na0.82K0.18)0.5TiO3/P(VDF-TrFE) 0-3 composites with high pyroelectric coefficient were prepared for different volume fractions of MnO2 doped Bi0.5(Na0.82K0.18)0.5TiO3 ceramic powder in P(VDF-TrFE) copolymer matrix. The dielectric constant, dielectric loss and the piezoelectric coefficient increased as MnO2 doped Bi0.5(Na0.82K0.18)0.5TiO3 ceramic volume fraction increased. The pyroelectric coefficient and figure of merit of Bi0.5(Na0.82K0.18)0.5TiO3/P(VDF-TrFE) with different MnO2 amount and 0.8mol% MnO2 doped Bi0.5(Na0.82K0.18)0.5TiO3/P(VDF-TrFE) as a function of ceramic volume fraction were studied respectively. The results indicated that 0.8mol% MnO2 doped Bi0.5(Na0.82K0.18)0.5TiO3/P(VDF-TrFE) in 20vol% ceramic volume fraction show the best pyroelectric properties with pyroelectric coefficient p= 7.8×10-5C/m2K and figure of merit FD=11.4×10-6Pa-0.5.

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