Studies of Dielectric Constant, Dielectric Loss, Loss Tangent and Dielectric Relaxation Time of Some Halobenzene and Nitrobenzene at X-Band Microwave Frequency

The relaxation time and dipole moment of cis-dichloroethylene has been determined in the X-band microwave-frequency region from its dilute solutions in a nonpolar solvent. The dielectric loss tangent δ is found to vary linearly with concentration only for very dilute solutions.

Download Full-text

Dielectric Relaxation of Natural Rubber Vulcanizates

Rubber Chemistry and Technology ◽

10.5254/1.3543061 ◽

1951 ◽

Vol 24 (2) ◽

pp. 320-327 ◽

Cited By ~ 2

Author(s):

A. Schallamach

Keyword(s):

Relaxation Time ◽

Dielectric Loss ◽

Natural Rubber ◽

Dielectric Relaxation ◽

Loss Tangent ◽

Dielectric Loss Tangent ◽

Dielectric Relaxation Time ◽

Different Types ◽

Cross Links ◽

Natural Rubber Vulcanizates

Abstract The dielectric loss tangent of different types of vulcanizates of natural rubber has been measured as function of the frequency. Comparisons of the losses in different vulcanizates containing the same amount of combined sulfur show that they decrease with increasing modulus, and it is suggested that the dielectric loss is mostly due to sulfur which has been combined in forms other than cross-links. The dielectric relaxation time is approximately an exponential function of the percentage of combined sulfur. It has been found that moisture increases the audiofrequency losses in rubber more than the radiofrequency losses.

Download Full-text

Dielectric Relaxation Studies of Ternary Mixture of Dimethyl Phthalate and Heptanol in Benzene Solution in the Microwave Region

Zeitschrift für Naturforschung A ◽

10.1515/zna-2014-0304 ◽

2015 ◽

Vol 70 (7) ◽

pp. 507-512

Author(s):

A. Mushtaq Ahmed Khan ◽

M. Subramanian

Keyword(s):

Dielectric Constant ◽

Dipole Moment ◽

Relaxation Time ◽

Dielectric Relaxation ◽

Benzene Solution ◽

Microwave Frequency ◽

Viscous Force ◽

Dimethyl Phthalate ◽

Flow Process ◽

Relaxation Studies

AbstractThe molecular structure and molecular forces in liquids and solutions, in particular, have been investigated by dielectric relaxation studies. The nature and strength of the molecular interactions have been established as the main cause for the chemical behaviour of compounds. The dielectric behaviour of dimethyl phthalate with heptanol in benzene solution has been studied at a microwave frequency of 9.36 GHz at different temperatures 303, 308, and 313 K. Different dielectric quantities such as dielectric constant (ε′), dielectric loss (ε″), static dielectric constant (ε0), and dielectric constant at optical frequency (ε∞) have been determined. The relaxation time τ has been calculated by both Higasi’s method and Cole–Cole method. The dielectric relaxation process can be treated as a rate process just like the viscous flow process. The complex system investigated shows the maximum relaxation time values at high temperatures by both Higasi’s method and Cole–Cole method. The molar free energies of activation of dipole moment (ΔFτ) and viscous force (ΔFη) have also been reported. The excess dipole moment is also determined. The excess dipole moment is a qualitative index for the presence of a hydrogen bond in the ternary system. The value of Δμ obtained in our study indicates the presence of hydrogen bonds between the components of the mixture. The system investigated shows that the relaxation time value increases with the increase in the concentration of solute.

Download Full-text

An Empirical Relation for the Evaluation of the Dielectric Relaxation Time of Certain Polar Liquids Using a Single Microwave Frequency

Australian Journal of Physics ◽

10.1071/ph740087 ◽

1974 ◽

Vol 27 (1) ◽

pp. 87 ◽

Cited By ~ 2

Author(s):

BS Sarma ◽

V Venkateswara Rao

Keyword(s):

Experimental Data ◽

Relaxation Time ◽

Dielectric Relaxation ◽

Concentration Factor ◽

Empirical Relation ◽

Microwave Frequency ◽

Dielectric Constants ◽

Dielectric Relaxation Time ◽

Polar Liquids

An empirical relation is proposed for the determination of the dielectric relaxation time .. of polar liquids with nearly spherical molecules from measurements of the dielectric constants at a single microwave frequency. The relation is obtained by introducing a concentration factor as a parameter in the expression for .. derived by Eyring et al. (1941). Its validity for suitable polar liquids is demonstrated by comparison of results with previously reported values. Thermodynamic parameters for a number of liquids at various concentrations have also been evaluated from experimental data using the relation.

Download Full-text

Dielectric Relaxation Studies Between Brompheniramine with 1-Butanol, 1-Pentanol and 1-Hexanol at 303K

Material Science Research India ◽

10.13005/msri/170305 ◽

2020 ◽

Vol 17 (3) ◽

pp. 230-235

Author(s):

Sampandam Elangovan ◽

Tilahun Diriba Garbi ◽

Senbeto Kena Etana

Keyword(s):

Dielectric Constant ◽

Relaxation Time ◽

Dielectric Relaxation ◽

Intermolecular Interaction ◽

Research Work ◽

Liquid Mixtures ◽

Time Domain Reflectometry ◽

Dielectric Relaxation Time ◽

Pharmaceutical Industries ◽

Relaxation Studies

The dielectric relaxation studies are vital in analyzing the strength of the inter molecular interaction between the binary liquid systems [1-4]. Jyostna et al. [5] reported thermodynamic parameters of isoamyl alcohols and mono clinic aromatic liquid mixtures. Shakila et al. [6] studied the dielectric properties of aromatic alcohols and aliphatic amines at different temperatures. In general, dielectric relaxation time varies with the inter molecular forces acting between the molecules in the selected liquid mixtures. Brompheniramine is one of the critical compounds of an amine group with spectacular applications, including pharmaceutical industries [7]. Higher carbon chain length alcohols are having self associated and proton donating ability in the liquid mixtures. The variations in the dielectric constant (є’), dielectric loss (є’’), static dielectric constant (є0) and the dielectric constant at an optical frequency (є∞) with a range of brompheniramine concentrations with 1-butanol,1-pentanol and 1-hexanol systems are useful in the applied research and chemical industries. Moreover, the variations in the dielectric constant and dielectric relaxation time should be useful in the analysis of intermolecular interaction between the functional group of the selected liquid mixtures. This research work attempts to analyse the intermolecular interaction between the brompheniramine and 1-butanol,1-pentanol and 1-hexanol at 303K using time domain reflectometry techniques.

Download Full-text

Dielectric Constant and Dielectric Relaxation Time of Rochelle Salt

Journal of the Physical Society of Japan ◽

10.1143/jpsj.31.1748 ◽

1971 ◽

Vol 31 (6) ◽

pp. 1748-1753 ◽

Cited By ~ 8

Author(s):

Ryuji Abe ◽

Yukuya Tokumaru

Keyword(s):

Dielectric Constant ◽

Relaxation Time ◽

Dielectric Relaxation ◽

Dielectric Relaxation Time ◽

Rochelle Salt

Download Full-text

Dielectric Loss Measurements on Nonpolar Liquids in the Microwave Region from 18 to 37 GHz

Canadian Journal of Physics ◽

10.1139/p72-317 ◽

1972 ◽

Vol 50 (20) ◽

pp. 2397-2401 ◽

Cited By ~ 16

Author(s):

I. R. Dagg ◽

G. E. Reesor

Keyword(s):

Dielectric Constant ◽

Carbon Tetrachloride ◽

Dielectric Loss ◽

Carbon Disulfide ◽

Loss Tangent ◽

Microwave Frequency ◽

Frequency Region ◽

Low Loss ◽

Microwave Region ◽

Nonpolar Liquids

The results of dielectric-constant measurements on a number of low-loss liquids in the microwave frequency region from 18 to 40 GHz are presented. Emphasis is placed on the value of the loss tangent. Liquids measured include carbon tetrachloride, carbon disulfide, cyclohexane, n-hexane, n-heptane, n-nonane, and n-decane. A wave guide method was used giving an accuracy for the loss tangent of ±0.3 × 10−4. Where possible, results have been fitted to a Debye expression. Comparisons have been made with available results of other workers.

Download Full-text

Dielectric Loss Measurements on Nonpolar Liquids in the Microwave Region 8 to 12 GHz

Canadian Journal of Physics ◽

10.1139/p74-004 ◽

1974 ◽

Vol 52 (1) ◽

pp. 29-32 ◽

Cited By ~ 12

Author(s):

I. R. Dagg ◽

G. E. Reesor

Keyword(s):

Dielectric Constant ◽

Carbon Tetrachloride ◽

Dielectric Loss ◽

Loss Tangent ◽

Microwave Frequency ◽

Frequency Region ◽

Low Loss ◽

Microwave Region ◽

Nonpolar Liquids ◽

Improved Accuracy

The results of dielectric-constant measurements on a number of low-loss liquids in the microwave frequency region from 8 to 12 GHz are reported. An improved wave-guide technique is described which gives precise values of the real part of the dielectric constant and improved accuracy in determining the dielectric loss. Liquids measured include the alkane series : n-pentane, n-hexane, n-heptane, n-nonane, n-decane, and n-dodecane. Results for cyclohexane and carbon tetrachloride are also given for comparison with those results of other workers. The data for the loss tangent for the alkane series of liquids are compared with previous results in the 18 to 37 GHz region.

Download Full-text

Dielectric relaxation, viscosity and freezing

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1957.0069 ◽

1957 ◽

Vol 240 (1220) ◽

pp. 101-107 ◽

Cited By ~ 21

Keyword(s):

Dielectric Constant ◽

Relaxation Time ◽

Solid State ◽

Dielectric Relaxation ◽

Simple Relation ◽

Experimental Results ◽

Organic Liquids ◽

Dielectric Relaxation Time ◽

Polar Liquids ◽

Molecular Radius

It is shown that polar liquids may be divided into two classes according to whether or not the rotation of the dipoles is prevented by solidification. For liquids belonging to the first class, and having rigid molecules, an equation similar to Debye’s can be used to relate the dielectric relaxation time and the viscosity. This equation does not involve the ‘molecular radius’ which has always made the interpretation of Debye’s equation uncertain, and it can, in consequence, be used to determine from the experimental results how the ratio of the microscopic to the macroscopic relaxation time ( ז/ז ') depends on the static dielectric constant. The theory has been applied to a number of organic liquids of rigid molecular structure, and indicates that the dependence of ז/ז ' on the dielectric constant is best expressed by Powles’s equation ז/ז ' = (2∊ 0 + ∊ ∞ )/3∊ 0 . For liquids belonging to the second class no simple relation between dielectric relaxation time and viscosity can be expected, but it may be possible to relate the relaxation time in some way to the transition which occurs in the solid state, in which the freedom of dipole rotation is lost.

Download Full-text

DIELECTRIC RELAXATION OF SOME NEARLY SPHERICAL MOLECULES IN THE LIQUID AND SOLID PHASES

Canadian Journal of Physics ◽

10.1139/p67-320 ◽

1967 ◽

Vol 45 (12) ◽

pp. 3815-3822 ◽

Cited By ~ 13

Author(s):

Abhai Mansingh ◽

David B. McLay

Keyword(s):

Dielectric Constant ◽

Melting Point ◽

Dielectric Relaxation ◽

Solid Phase ◽

Relaxation Times ◽

Microwave Frequency ◽

Debye Model ◽

Index Of Refraction ◽

Dielectric Relaxation Time ◽

Rotator Phase

The dielectric constant and loss at a microwave frequency of 9 GHz and also the static dielectric constant at either 10 kHz or 200 kHz have been measured for the nearly spherical molecules Br3CNO2, Cl3CNO2, BrC(CH3)3, ClC(CH3)3, and ClSi(CH3)3 over a range of temperature from below the respective melting point to above this melting point. The measurements combined with the tabulated values for the optical index of refraction allow a determination of the dielectric relaxation times at each temperature if it is assumed that either the Debye theory or the modification of this theory by Cole and Cole is valid. In the cases of the five liquids, the data are consistent with the Debye model. In the solid phase, however, only Cl3CNO2 and ClSi(CH3)3 do not exhibit solid rotator phases, while each of the other three molecules exhibits at least one solid rotator phase. The results are consistent with the interpretation that each liquid has a single dielectric relaxation time but that the transition to a solid rotator phase involves a distribution of relaxation times which are only slightly different in value from the appropriate single value in the liquid phase.

Download Full-text