Thermodynamic and physical behaviour of some water + polyethyleneglycol mixtures. II. Dielectric properties

1979 ◽  
Vol 57 (6) ◽  
pp. 608-613 ◽  
Author(s):  
Gérard Douhéret ◽  
Maurice Morénas
Keyword(s):  
Dielectric Properties ◽  
Composition Range ◽  
Dipole Moments ◽  
Partial Molar Volumes ◽  
Correlation Factor ◽  
Dielectric Constants ◽  
Treatment Results ◽  
Rich Region ◽  
Physical Behaviour ◽  
Water Lattice

Dielectric constants of water + glycol (mono-, di-, tri-, and tetraethyleneglycol) mixtures have been measured at 298.15 K over the entire composition range. The mixtures involving monoethyleneglycol have also been studied at temperatures from 308.15 to 288.15 K. Calculated deviations from ideality are always positive and show one maximum. Related properties have been computed: polarizability volume and excess polarizability volume, correlation factor of mixtures, and dipole moments of both components using the Mecke–Reuter treatment. Results support conclusions previously deduced from excess and partial molar volumes; they suggest that the addition of glycol molecules gives rise to a slight enhancement of the water-lattice in the water-rich region, followed by a progressive destructuring; the ether functions do not seem to play a prominent role.

Ultrasonic velocity and volumetric properties of isomeric butanediols plus water systems

1998 ◽  
Vol 76 (4) ◽  
pp. 464-468 ◽  
Author(s):  
Brent Hawrylak ◽  
Kim Gracie ◽  
R Palepu
Keyword(s):  
Ultrasonic Velocity ◽  
Infinite Dilution ◽  
Composition Range ◽  
Transfer Functions ◽  
Adiabatic Compressibility ◽  
Partial Molar Volumes ◽  
Water Systems ◽  
Ultrasonic Velocities ◽  
Rich Region ◽  
Liquid Solutions

Ultrasonic velocities and densities of binary aqueous solutions of isomeric butanediols were measured in the temperature range 298-318 K at 10 degree intervals over the entire composition range, and 5 degree intervals in the water-rich region. The experimental data in the dilute region, with mole fraction of water less than 0.1, was analysed to determine the partial molar volumes and adiabatic compressibilities of water at infinite dilution. The standard thermodynamic transfer functions were calculated to evaluate the environment of water at infinite dilution in these systems. From the compressibility isotherms, as a function of temperature in the water-rich region, the formation and the composition of clathrate-like structures in the liquid solutions was determined, and the nature of these structures was discussed.Key words: ultrasonic velocity, adiabatic compressibility, density, partial molar quantities, standard thermodynamic transfer functions.

Dielectric properties of hexafluoroacetone and hexachloroacetone

1969 ◽  
Vol 47 (12) ◽  
pp. 2253-2256 ◽  
Author(s):  
R. K. Chan
Keyword(s):  
Dipole Moment ◽  
Dielectric Properties ◽  
Liquid State ◽  
Dipole Moments ◽  
Dielectric Constants ◽  
Pure Liquid ◽  
Gaseous State ◽  
Vector Addition ◽  
Inductive Effects ◽  
Experimental Values

The dielectric constants of hexafluoro- and hexachloro-acetone are measured in the solid and liquid state. They show negligible association in the liquid state. The dipole moments are 0.648 D measured in the gaseous state and 0.63 D in pure liquid for hexafluoroacetone, and 1.24 D in carbon tetrachloride solution and 1.34 D in pure liquid for hexachloroacetone. If the differences between inductive effects due to CX3 and C=O groups can be ignored, the vector addition of bond moments gives values of dipole moment which are compatible with the experimental values.

Dielectric Properties of Binary Mixtures of 1,2-Dichloroethane+Ethane-1,2-diol and 1,2-Dichloroethane+2-Methoxyethanol

1995 ◽  
Vol 48 (9) ◽  
pp. 1541 ◽  
Author(s):  
F Corradini ◽  
A Marchetti ◽  
C Preti ◽  
M Tagliazucchi ◽  
L Tassi
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Binary Mixtures ◽  
Composition Range ◽  
Narrow Range ◽  
Static Dielectric Constant ◽  
Dielectric Behaviour ◽  
Rich Region ◽  
Stable Adduct ◽  
Fitting Procedures

The dielectric behaviour of binary mixtures of 1,2-dichloroethane (DCE)/ethane-1,2-diol (ED) and DCE/2-methoxyethanol (ME) has been studied at 19 temperatures in the range from -10 to +80°C. The DCE/ED system is immiscible, except in a narrow range near the ED-rich region. The DCE/ME system, which is completely miscible, has been investigated over the whole composition range. Fitting procedures have been applied in order to check the suitability of empirical or semiempirical functions of the type є(T), є(XI) and є(T,XI). Furthermore, the excess static dielectric constant, єE, has been evaluated in order to investigate the possibility of the existence of complex entities. A DCE.2ME species appears to be the only stable adduct.

Dielectric properties of the hydrates of argon and nitrogen

1968 ◽  
Vol 46 (10) ◽  
pp. 1673-1681 ◽  
Author(s):  
S. R. Gough ◽  
E. Whalley ◽  
D. W. Davidson
Keyword(s):  
Dielectric Properties ◽  
High Frequency ◽  
Dielectric Constants ◽  
Water Molecules ◽  
Circular Arc ◽  
Circular Arcs ◽  
In Series ◽  
Temperature And Pressure ◽  
Water Lattice ◽  
Static Dielectric Constants

The dielectric relaxation of water in the structure I clathrate hydrates of argon and nitrogen was studied over a range of temperature and pressure. Hydrates were slowly grown at pressures of 1 to 2 kbar in a coaxial cell enclosed in a pressure vessel. The complex permittivity loci resemble circular arcs with static dielectric constants of ~56 at 0 °C and high-frequency dielectric constants of 2.85 ± 0.05. Relaxation near 0 °C is about as slow as in ice I, but activation energies and entropies are much smaller. Formation of Bjerrum defects probably takes place preferentially near the occasional sites at which argon and nitrogen molecules have replaced water molecules in the lattice. The much faster relaxations found previously in the isostructural hydrates of ethers arise from orientational defects induced in the water lattice by the encaged molecules, a small proportion of which may form hydrogen bonds with water. The effect of small gaps in series with samples showing circular-arc dispersion behavior was evaluated.

scholarly journals Dielectric Properties of Wood-Polymer Composites: Effects of Frequency, Fiber Nature, Proportion, and Chemical Composition

2021 ◽  
Vol 5 (6) ◽  
pp. 141
Author(s):  
Imen Elloumi ◽  
Ahmed Koubaa ◽  
Wassim Kharrat ◽  
Chedly Bradai ◽  
Ahmed Elloumi
Keyword(s):  
Dielectric Properties ◽  
Polymer Composites ◽  
Wide Frequency Range ◽  
Dielectric Constants ◽  
Cellulose Content ◽  
Wood Fibers ◽  
Low Frequencies ◽  
Wood Polymer ◽  
Wood Polymer Composites ◽  
New Applications

The characterization of the dielectric properties of wood–polymer composites (WPCs) is essential to understand their interaction with electromagnetic fields and evaluate their potential use for new applications. Thus, dielectric spectroscopy monitored the evolution of the dielectric properties of WPCs over a wide frequency range of 1 MHz to 1 GHz. WPCs were prepared using mixtures of different proportions (40%, 50%, and 60%) of wood and bark fibers from various species, high-density polyethylene, and maleated polyethylene (3%) by a two-step process, extrusion and compression molding. Results indicated that wood fibers modify the resistivity of polyethylene at low frequencies but have no effect at microwave frequencies. Increasing the fiber content increases the composites’ dielectric properties. The fibers’ cellulose content explains the variation in the dielectric properties of composites reinforced with fibers from different wood species. Indeed, composites with high cellulose content show higher dielectric constants.

Crystallization and dielectric properties of SrO–BaO–Nb2O5–GeO2 tungsten–bronze glass–ceramics

2001 ◽  
Vol 16 (7) ◽  
pp. 2057-2063 ◽  
Author(s):  
Jiin-Jyh Shyu ◽  
Hsin-Wei Peng
Keyword(s):  
Heat Treatment ◽  
Dielectric Properties ◽  
Tungsten Bronze ◽  
Glass Ceramics ◽  
Dielectric Behavior ◽  
Dendritic Morphology ◽  
Dielectric Constants ◽  
Two Stage ◽  
Tetragonal Tungsten Bronze ◽  
Stage Heat Treatment

The crystallization and dielectric properties of SrO–BaO–Nb2O5–GeO2 glass–ceramics were investigated. One- and two-stage heat-treatment methods were used to convert the parent glass to glass–ceramics. Strontium barium niobate (SBN) with a tetragonal tungsten-bronze structure formed as the major crystalline phase. When the crystallizing temperature/time was increased, the secondary crystalline BaGe2O5 phase coexisted with SBN. BaGe2O5 formed as a surface layer grown from the surface into the interior of the sample. The dendritic morphology of SBN crystals was examined. The glass–ceramics crystallized by two-stage heat treatment have higher dielectric constants than those crystallized by one-stage heat treatment. The highest dielectric constant that was obtained in the present glass–ceramics was 320. The glass–ceramics showed relaxor-type dielectric behavior.

Epitaxial Growth and Anisotropic Dielectric Properties of La-Doped Bi4Ti3O12 Thin Films

2007 ◽  
Vol 124-126 ◽  
pp. 177-180
Author(s):  
Jang Sik Lee ◽  
Q.X. Jia
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Bottom Electrode ◽  
Dielectric Constants ◽  
The Other ◽  
Field Range ◽  
Anisotropic Dielectric ◽  
Dielectric Nonlinearity ◽  
La Doped

To investigate the anisotropic dielectric properties of layer-structured bismuth-based ferroelectrics along different crystal directions, we fabricate devices along different crystal orientations using highly c-axis oriented Bi3.25La0.75Ti3O12 (BLT) thin films on (001) LaAlO3 (LAO) substrates. Experimental results have shown that the dielectric properties of the BLT films are highly anisotropic along different crystal directions. The dielectric constants (1MHz at 300 K) are 358 and 160 along [100] and [110], respectively. Dielectric nonlinearity is also detected along these crystal directions. On the other hand, a much smaller dielectric constant and no detectable dielectric nonlinearity in a field range of 0-200 kV/cm are observed for films along [001] when c-axis oriented SRO is used as the bottom electrode.

Technique for Measuring the Dielectric Properties of Minerals as a Function of Temperature and Density at Microwave Heating Frequencies

1990 ◽  
Vol 189 ◽  
Author(s):  
Johanna B. Salsman
Keyword(s):  
Dielectric Properties ◽  
Microwave Heating ◽  
Research Effort ◽  
Coaxial Line ◽  
Dielectric Constants ◽  
Dielectric Constant And Loss ◽  
Electrical Conductivities ◽  
Natural Density ◽  
The Common ◽  
Method Of Measurement

ABSTRACTAs part of the research effort on investigating the effects of microwave energy absorption on the chemical and physical properties of minerals and ores, the Bureau of Mines, Tuscaloosa Research Center has developed a technique of measuring the dielectric constant and loss tangent of minerals at the common microwave heating frequencies. The objective was to establish a reliable data base to aid in predicting the effects of microwave heating on minerals.In this phase of microwave research, the Bureau measured the dielectric properties of powdered minerals with medium to high electrical conductivities (a ≥ 0.02 Mho/m) in the frequency range of 300 MHz to 3 GHz using an open-ended coaxial line probe connected to an HP 8753A network analyzer. Since the minerals were prepared as powders, techniques were used to relate the measured dielectric properties of the powdered minerals to the dielectric properties of the mineral at Its theoretical or natural density. Also, these measurements were performed as a function of temperature, from 25° to 325° C.The measured values of the dielectric constants and loss tangents using this method were accurate within ±5 percent. This report describes the method of measurement and discusses the results of the Bureau's investigations into dielectric properties of minerals.

A facile method for the preparation of aliphatic main-chain benzoxazine copolymers with high-frequency low dielectric constants

2018 ◽  
Vol 9 (21) ◽  
pp. 2913-2925 ◽  
Author(s):  
Ming Zeng ◽  
Jiangbing Chen ◽  
Qingyu Xu ◽  
Yiwan Huang ◽  
Zijian Feng ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
High Frequency ◽  
Main Chain ◽  
Polymerization Kinetics ◽  
Dielectric Constants ◽  
Low Dielectric

The effects of the reaction solvent on the preparation, polymerization kinetics, and high-frequency dielectric properties of aliphatic main-chain benzoxazine copolymers were investigated.

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