Dielectric Studies of Admicelled Natural Rubber with Poly(3-Trimethoxysilylpropyl Methacrylate)

2013 ◽  
Vol 844 ◽  
pp. 373-376
Author(s):  
Suparat Nooma ◽  
Rathanawan Magaraphan
Keyword(s):  
Dielectric Constant ◽  
Composite Materials ◽  
Dielectric Properties ◽  
Chemical Modification ◽  
Natural Rubber ◽  
Microwave Frequency ◽  
Dielectric Studies ◽  
Frequency Range ◽  
Admicellar Polymerization ◽  
Methoxy Groups

In this work, 3-trimethoxysilylpropyl methacrylate (MPS) was used as a substrate for coating on natural rubber (NR) particles by admicellar polymerization. The incorporation of MPS monomer, consisting of silicon element and 3 reactive methoxy groups (R-Si(OCH3)), is expected to increase dielectric properties of NR. Under the admicellar polymerization, the R-Si(OCH3) groups can be hydrolyzed and condensed into polysiloxane existed on NR particles. This method aims to prepare composite materials from NR and MPS with various amounts of MPS. The effects of microwave frequency and chemical modification by admicellar polymerization were studied. The dielectric properties of admicelled natural rubber (adNR) with PMPS were investigated at 20 °C in a frequency range extended from MHz to GHz. The results showed that the dielectric constant of adNR increased with PMPS contents. To study the effect of crosslinking on the dielectric properties of adNR, the dielectric spectroscopy measurements were performed on prevulcanized and non-prevulcanized adNR. The investigation showed that the dielectric constant of non-prevulcanized adNR was less than prevulcanized adNR.

scholarly journals Dielectric studies and microwave emissivity of alkaline soil of Alwar with mixing of gypsum

2010 ◽  
Vol 7 (2) ◽  
pp. 519-524
Author(s):  
V. K. Gupta ◽  
R. A. Jangid ◽  
Seema Yadav
Keyword(s):  
Dielectric Constant ◽  
Soil Moisture ◽  
Dielectric Properties ◽  
Soil Moisture Content ◽  
Microwave Frequency ◽  
Alkaline Soil ◽  
Dielectric Studies ◽  
Horizontal Polarization ◽  
Microwave Emissivity ◽  
Percentage Concentration

The real and imaginary parts of dielectric constant (ε' and ε") of alkaline soil of Alwar with mixing of gypsum (0.0% to 10.0%, gravimetrically) determined at 34.50C temperature and at a single microwave frequency 9.78 GHz by wave guide cell method. Mixture of soil and gypsum is prepared at various moistness of soil varying from 0.0% to 12.0%. The ε' and ε" of gypsum are also determined. It was observed that ε' and ε" increases as percentage concentration of gypsum in the soil increase. It was observed that the effect of gypsum mixing on dielectric properties is more significant at higher level of soil moisture content. Further, microwave emissivities are estimated from measured values of ε' and ε" for dry and wet mixture of, soil and gypsum at various observation angles (00-800) for horizontal polarization. It was observed that emissivity of soil decreases as the percentage concentration of gypsum in the soil increases.

The Formation of New Critical System by Electric Breakdown in Percolation System

1990 ◽  
Vol 195 ◽  
Author(s):  
V.A. Garanov ◽  
A.A. Kalachev ◽  
A.M. Karimov ◽  
A.N. Lagar´kov ◽  
S.M. Matitsin ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Dielectric Constant ◽  
Composite Materials ◽  
Dielectric Properties ◽  
Density Current ◽  
Critical Percolation ◽  
Frequency Range ◽  
Critical System ◽  
Current Action ◽  
Binary Composite

ABSTRACTA new way of obtaining binary composite materials having some properties of the critical percolation system is presented..These materials can be obtained by high-density current action on an initially well conducting mixture.This action destroys part of contacts between adjacent conducting granules bringing the system to the quasi-critical state.It is shown that quasi-critical s stems may have high values of dielectric constant ε′ ∼ 102-106 101 in the frequency range 0<f<1010Hz.Formation and dielectric properties of the systems are studied both by computer simulation and experi mentally.

Dielectric Properties of SiAlON Ceramics

2008 ◽  
Vol 403 ◽  
pp. 125-128 ◽  
Author(s):  
Do Kyung Kim ◽  
Ha Neul Kim ◽  
Young Hoon Seong ◽  
Seung Soo Baek ◽  
Eul Son Kang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Microwave Frequency ◽  
Tangent Loss ◽  
Hot Press ◽  
Frequency Range ◽  
Cationic Species ◽  
Press Method ◽  
Resonator Method

The dielectric properties of -SiAlON and various cations doped -SiAlON bulk ceramics prepared by a hot-press method were investigated. The dielectric properties (dielectric constant and tangent loss) were characterized by a post-resonator method (Hakki-Coleman method) at room temperature in the microwave frequency range. The effect of z-values about -SiAlON was examined, and also the effects of various interstitial cations on dielectric properties of -SiAlON were studied. Dielectric properties of -SiAlON were compared with those of Si3N4 and -SiAlON and their relationship between the dielectric properties and the cationic species of SiAlON were discussed.

CANDIDATES FOR μ<0, ∊<0 NANOSTRUCTURES

2001 ◽  
Vol 15 (24n25) ◽  
pp. 3258-3265 ◽  
Author(s):  
G. DEWAR
Keyword(s):  
Magnetic Field ◽  
Dielectric Constant ◽  
Composite Materials ◽  
Applied Magnetic Field ◽  
Microwave Frequency ◽  
Index Of Refraction ◽  
Frequency Range ◽  
Left Handed ◽  
Negative Index Of Refraction ◽  
Recent Interest

Recent interest has been generated in composite materials for which both the dielectric constant and the magnetic permeability are negative. These composites behave as if they possess a negative index of refraction, although the broader, less specific adjective "left-handed" has also been applied to them. Such composites possess two sets of structures which are separately responsible for the negative ∊ and μ. However, materials having a negative μ are common in the microwave frequency range and such a material can replace one set of structures in the composite. An example of a simple composite is a YIG medium (μ<0) penetrated by sets of metallic strips or wires which give rise a negative dielectric constant in the appropriate frequency range. The index of refraction of the composite can be modulated by adjusting the applied magnetic field.

Modeling The Microwave Frequency Dielectric Properties of Thermoplastic Composite Materials

1992 ◽  
Vol 269 ◽  
Author(s):  
Mitchell L. Jackson ◽  
Curtis H. Stern
Keyword(s):  
Composite Materials ◽  
Dielectric Properties ◽  
Volume Fraction ◽  
Perturbation Technique ◽  
Resonant Cavity ◽  
Microwave Frequency ◽  
Thermoplastic Composite ◽  
Fiber Volume ◽  
Thermoplastic Matrix ◽  
Rotation Procedure

ABSTRACTMixture models were studied in an effort to predict the microwave frequency permittivities of unidirectional-fiber-reinforced thermoplastic-matrix composite materials as a function of fiber volume fraction, fiber orientation relative to the electric field, and temperature. The permittivities of the constituent fiber and plastic materials were measured using a resonant cavity perturbation technique at 9.4 GHz and at 2.45 GHz. The permittivities of the composite specimens were measured using a reflection cavity technique at 9.4 GHz and at 2.45 GHz. Simple “rule-of-mixtures” models that use the fiber and plastic permittivities have been found to approximate the complex dielectric properties of the composite for varied fiber volume fractions. The permittivities of oriented composites were modeled using a tensor rotation procedure. Composite permittivities were modeled with temperature up to the glass transition temperature of the thermoplastic matrix.

The Dependence of Dielectric Properties on Crosslink Density of Rubbers

1978 ◽  
Vol 51 (1) ◽  
pp. 72-80 ◽  
Author(s):  
R. Bakule ◽  
A. Havránek
Keyword(s):  
Dielectric Properties ◽  
Natural Rubber ◽  
Crosslink Density ◽  
Unit Volume ◽  
Volume Distribution ◽  
Dicumyl Peroxide ◽  
Frequency Range ◽  
Polar Groups ◽  
Main Transition ◽  
Macroscopic Parameters

Abstract The dielectric properties of natural rubber, synthetic polyisoprene, andpolybutadiene samples crosslinked with sulfur and of natural rubber samplescrosslinked simultaneously with sulfur and dicumyl peroxide were studied. Inthe investigated systems, the number of polar groups in unit volume and thecrosslink density may be changed independently over relatively wide ranges.The measurements were performed in the frequency range from 101 to 105 Hzat various temperatures, and macroscopic parameters describing the dielectricproperties of the samples were evaluated. The position and intensity of thedielectric dispersion peak in the main transition zone is only slightly dependenton the crosslink density of the samples. These two values are mainly influencedby the amount of combined sulfur, or more generally, by the number and thedipole moments of polar groups in the sample. The influence of crosslink densityon the width of the absorption curve is very strong; the width increases withincreasing crosslink density. The possibility of explaining this effect in termsof the dependence of the free volume distribution function on crosslink densityis discussed.

Effect of moisture content on dielectric properties of banana leaves and peels in frequency range of 1–20 GHz

Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Soumya Sundar Pattanayak ◽  
Soumen Biswas
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Measurement Data ◽  
Banana Peel ◽  
Frequency Range ◽  
Proposed Model ◽  
Banana Leaves ◽  
Banana Leaf

Abstract The quality of agricultural products can be remotely sensed and enhanced by determining the dielectric properties. This paper studies the dielectric properties of banana leaf and banana peel over the frequency range 1–20 GHz using the open-ended coaxial probe (OCP) method. A new curve fitting model is proposed to characterize the dielectric properties of banana leaf and banana peel. The different moisture content (MC) levels are considered for both banana leaf and banana peel samples and, their dielectric properties are characterized. Further, the banana leaf and banana peel’s measurement data are compared with the data obtained using the proposed model. In addition, Root Mean Square Error (RMSE) and R-squared (R 2) are calculated to validate the performance of the proposed model. In case of banana leaf at 68.26% MC, the dielectric constant achieves the value of R 2 and RMSE of 0.98 and 0.0648, respectively. Similarly, dielectric loss achieves the value of R 2 and RMSE of 0.88 and 0.0795, respectively. Further, for banana peel at 80.89% MC, the dielectric constant achieves the value of R 2 and RMSE of 0.99 and 0.2989, respectively. Similarly, dielectric loss achieves the value of R 2 and RMSE of 0.96 and 0.6132, respectively.

Dielectric and Curing Properties of ZnFe2O4 Loaded Epoxidized Natural Rubber (ENR 25)

2020 ◽  
Vol 1010 ◽  
pp. 292-297
Author(s):  
Suziey Syamimi Sukri ◽  
Syifa' Muhamad Sharifuddin ◽  
Mohd Shukri Mat Nor ◽  
Fathin Asila Mohd Pabli ◽  
Piyawadee Luangchuang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Magnetic Properties ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Natural Rubber ◽  
Electronic Device ◽  
Epoxidized Natural Rubber ◽  
Cure Time ◽  
Device Applications

Electroceramic with high magnetic properties such as ZnFe2O4 is widely used in many electronic device applications. One of the major drawbacks of electroceramic is the difficulty in molding and processing into desired shapes due to its brittle nature. Flexible electroceramic with the superior process and mold abilities can be made by mixing magnetic ceramic with a flexible matrix, for instance, rubber. In this present study, the aims were to produce ZnFe2O4 loaded epoxidized natural rubber (ENR 25) as well as to determine its electrical and curing properties. The magnetic ceramic of ZnFe2O4 was blended with ENR 25 at different loadings varying from 0 to 120 parts per hundred of rubber (phr) in an interval of 20. The properties of produced composites include scorch time, cure time, torque and dielectric properties were characterised. The results demonstrated that the increase of ZnFe2O4 concentration in ENR 25 leads to a significant increase in the dielectric constant from 4.94 to 5.62 at 1.15 MHz, and decrease in the dielectric loss curves of the composites start from 0.0827 to 0.0586. Furthermore, the results of curing property studies exhibited an increasing pattern of the composite torques, starting from 1.43 to 1.76 dN.m.

Effect of Sintering Temperature on Dielectric Properties of CaCu3Ti4O12 Ceramics Prepared by Mechanochemical Process

2014 ◽  
Vol 974 ◽  
pp. 157-161
Author(s):  
Masturah Mohamed ◽  
Mahesh Talari ◽  
Mohd Salleh Mohd Deni ◽  
Azlan Zakaria
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Sintering Temperature ◽  
Processing Conditions ◽  
Dielectric Measurements ◽  
Frequency Range ◽  
Grain Sizes ◽  
Barrier Capacitance ◽  
Different Temperatures ◽  
Increasing Temperature

CaCu3Ti4O12(CCTO) is well known to have colossal dielectric constant in the range of 105.It is widely accepted that this phenomenon may be attributed to internal layer barrier capacitance (IBLC) model. The dielectric properties of CCTO were reported to be strongly dependent on the processing conditions and grain size. In this work, CCTO samples with different grain sizes were produced by varying sintering temperature in order to investigate IBLC effect on dielectric properties of CCTO. The samples were sintered at four different temperatures, (T=1100°C, 1050°C, 1000°C and 950°C). Dielectric measurements were carried out for the samples in the frequency range of 102– 106Hz using impedance spectrometer. Electron micrographs showed that increasing temperature promoted the grain growth of CCTO while sintering. The internal crystalline defects are seen to play major role by increasing the grain conductivity in dipole formation and increased the dielectric constant of the samples.

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