Dielectric Measurements in the Study of Carbon Black and Zinc Oxide Dispersion in Rubber

1939 ◽  
Vol 12 (2) ◽  
pp. 317-331
Author(s):  
A. R. Kemp ◽  
D. B. Herrmann
Keyword(s):  
Particle Size ◽  
Dielectric Constant ◽  
Zinc Oxide ◽  
Dielectric Properties ◽  
Carbon Black ◽  
Water Soluble ◽  
Oxide Dispersion ◽  
Dielectric Measurements ◽  
Thermal Decomposition Process ◽  
Rubber Compounds

Abstract The dielectric constant, power factor, conductivity and d.c. resistivity of rubber compounds containing various types and quantities of zinc oxide and carbon pigments have been measured. It has been shown that the dielectric properties of rubber compounds having high loadings of zinc oxide depend on the particle size and purity of the zinc oxide used. The French process oxides with the smallest particle size were found superior to other grades. Water-soluble impurities in zinc oxide are shown to have a deleterious effect on dielectric properties, especially in the presence of moisture. The effect on dielectric properties of adding carbon black to a rubber compound has been shown to be dependent on the type and amount of black added, and on the nature of its dispersion in the rubber. The dielectric properties of rubber compounds containing “soft” black made by the thermal decomposition process are shown to be distinctly superior to, and widely different from, those of the same compounds containing equal amounts of channel process black. The general conclusion has been reached that the smaller the particle size and the better the dispersion of carbon pigments in the rubber, the greater will be the increase in the dielectric constant and conductivity, and the greater will be the decrease in resistivity.

Effect of Diameter and Surface Area of Carbon Black Particles on Certain Properties of Rubber Compounds

1944 ◽  
Vol 17 (2) ◽  
pp. 451-474
Author(s):  
D. Parkinson
Keyword(s):  
Particle Size ◽  
Tensile Strength ◽  
Carbon Black ◽  
Abrasion Resistance ◽  
Particle Diameter ◽  
Stiffness Modulus ◽  
Carbon Structures ◽  
Rubber Compounds ◽  
Regular Manner ◽  
Tear Resistance

Abstract Carbon blacks can be grouped into different classes according to the way in which their fineness of division relates to different properties in rubber. Within any one class the principal properties vary in a regular manner with particle size. The normal class consists of the furnace carbons, Kosmos (Dixie)-40, Statex, the rubber-grade impingement carbons, and possibly, the color-grade impingement carbons. The subnormal classes consist of thermal carbons and acetylene and lamp blacks. Irrespective of the above classification, the properties which depend more on fineness of division than on other factors are rebound resilience, abrasion resistance, tensile strength and tear resistance. The lower limit of particle diameter for best tensile strength and tear resistance appears to be higher than that for abrasion resistance. B.S.I, hardness and electrical conductivity are properties which depend at least as much on other factors as on particle size. Stiffness (modulus) depends more on other factors than on particle size. Factors modifying the effects of particle size (or specific surface) include the presence of carbon-carbon structures and a reduction in strength of bond in rubber-carbon structures. Carbon black is thought to exist in rubber in four states: agglomerated, flocculated, dispersed, and bonded to the rubber molecules (the reënforcing fraction). Abrasion resistance is regarded as providing the only reliable measure of reënforcement.

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.

Enhanced dielectric properties of conductive-dielectric composites by reducing particle size and core@shell method

2018 ◽  
Vol 11 (01) ◽  
pp. 1850010 ◽  
Author(s):  
Yuqiang Guo ◽  
Yifei Wang ◽  
Yaxuan Ren ◽  
Mingzhu Fu ◽  
Hongmei Ma ◽  
...  
Keyword(s):  
Particle Size ◽  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Mass Fraction ◽  
Core Shell ◽  
Particle Sizes ◽  
Conductive Particle ◽  
Threshold Theory ◽  
Conductive Polyaniline

Based on the percolation threshold theory of conductive-dielectric composites, the dielectric constant can be improved more by adding a certain mass fraction of conductive particle into polymer matrix. However, the dielectric loss increases with the increasing mass fraction of conductive particle. In this paper, conductive Polyaniline (PANI) with different particle sizes is utilized to illustrate that reducing particle size can improve the dielectric properties. The dielectric constant is increased from 319 to 540, and dielectric loss is decreased from 2.34 to 0.85 when PANI with smaller particle size is used. Moreover, PANI coated with an insulating surfactant layer can further improve the dielectric properties, the experimental results show that the dielectric constant of the composite could be more than 1000, while the dielectric loss is 0.35 at 1[Formula: see text]KHz.

Dielectric properties of barium titanium niobates

1997 ◽  
Vol 12 (2) ◽  
pp. 526-530 ◽  
Author(s):  
G. L. Roberts ◽  
R. J. Cava ◽  
W. F. Peck ◽  
J. J. Krajewski
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Low Temperature ◽  
Dielectric Constants ◽  
Partial Substitution ◽  
Dielectric Measurements ◽  
Niobium Oxides ◽  
Polycrystalline Ceramic ◽  
Barium Titanium ◽  
Very Low Temperature

The results of measurements of dielectric constants, in the vicinity of ambient temperature, are presented for eight barium titanium niobium oxides (BaTi1+2nNb4O13+4n for n = 0, 1, 2, 3, 4; Ba3Ti4Nb4O21, Ba3Ti5Nb6O28, and Ba6Ti2Nb8O30) in polycrystalline ceramic form. The dielectric constants are in the range of 30 to 70. The results of dielectric measurements on solid solutions obtained by partial substitution of Ta for Nb are also reported. These substitutions do not dramatically increase the dielectric constants. One material, Ta-substituted Ba3Ti5Nb6O28, has a very low temperature coefficient of dielectric constant at K ≈ 45.

Effect of Temperature and Frequency on the Dielectric Constant, Power Factor, and Conductivity of Compounds of Purified Rubber and Sulfur

1934 ◽  
Vol 7 (2) ◽  
pp. 342-370 ◽  
Author(s):  
A. H. Scott ◽  
A. T. McPherson ◽  
Harvey L. Curtis
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Power Factor ◽  
Water Soluble ◽  
Effect Of Temperature ◽  
General Character ◽  
Soluble Salts ◽  
Electrical Measurements ◽  
Separate Paper ◽  
Rubber Compounds

Abstract The electrical measurements given in this paper differ from those previously reported by the authors and by other investigators in that they were made on specimens prepared from purified rubber. The purification, which involved the removal of proteins, resins, and water-soluble salts, affected all the electrical properties to some extent, but did not alter the general character of the variation in electrical properties with composition, temperature, or frequency. The results of the present investigation afford comprehensive data on the electrical properties of rubber-sulfur compounds, and may form a basis for designing rubber compounds for specific electrical uses. They also demonstrate the inadequacy of the simple numerical coefficients that are sometimes employed to evaluate the changes in the electrical properties with temperature and frequency. A discussion of the results from the standpoint of modern dielectric theory is not included in the present paper, but is contemplated for a separate paper.

scholarly journals Preparation and electrostrictive properties of polyurethane filled with polypyrrole-carbon black for the energy harvesting application

2021 ◽  
Vol 2145 (1) ◽  
pp. 012044
Author(s):  
K Hirunchulha ◽  
K Jehlaeh ◽  
C Putson
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Carbon Black ◽  
Polymer Composites ◽  
Electrical Breakdown ◽  
Casting Process ◽  
Weibull Model ◽  
Lcr Meter ◽  
High Dielectric ◽  
Electrostrictive Properties

Abstract The polymer composites based on electrostrictive materials with high polarization are attracting scientists because of the prospect of application in energy conversion and electromechanical performance. Polyurethane is one of a good flexible dielectric polymers which is more interesting in electromechanical applications due to its easy fabrication, high dielectric constant, and high electrostrictive coefficient. This work focuses on the dielectric properties and electrostrictive properties of Polyurethane (PU) filled with Polypyrrole-Carbon Black (PPy-CB) various the different concentrations. All polymer composites were prepared by using a film-casting process in solution with DMF solvent. The dielectric properties and conductivity of thin films were investigated by using LCR meter at 1-105 Hz. The results showed that the dielectric constant of composites significantly increases when the concentration of PPy-CB was increased. Moreover, the electrostrictive coefficient of composites also increases when the concentration of PPy-CB was increased. Furthermore, the electrical breakdown stretches were analyzed by using the Weibull model, this result will discuss the relationship when the PPy-CB fillers were used.

Reënforcing Action of Pigment Mixtures on Rubber Compounds

1931 ◽  
Vol 4 (2) ◽  
pp. 248-255
Author(s):  
D. J. Beaver ◽  
J. W. MacKay
Keyword(s):  
Tensile Strength ◽  
Zinc Oxide ◽  
Carbon Black ◽  
Physical Properties ◽  
Chemical Reaction ◽  
Rubber Compounds ◽  
Soft Carbon ◽  
Acidic Compounds

Abstract Mixtures of varying ratios of either channel black or a soft carbon black with whiting, lithopone, or clay show additive physical properties. Mixtures of soft carbon with zinc oxide also show additive properties, while mixtures of channel black and zinc oxide show poorer resistance to abrasion, higher modulus, and higher tensile strength than would be shown by purely additive mixtures. The explanation of these results appears to be found in the chemical reaction between the basic zinc oxide and the acidic compounds in the rubber or on the black. These results have been applied to the formulation of a solid-tire stock which will give a better resistance to abrasion and blow-out when using a soft black than when using a channel black.

Rheological Behavior of Highly Filled EPDM Compounds with Calcium Carbonate, Carbon Black, Silica and Zinc Oxide

1996 ◽  
Vol 69 (4) ◽  
pp. 628-636 ◽  
Author(s):  
Li Li Li ◽  
James L. White
Keyword(s):  
Particle Size ◽  
Zinc Oxide ◽  
Calcium Carbonate ◽  
Shear Rate ◽  
Carbon Black ◽  
Shear Viscosity ◽  
Volume Fraction ◽  
Carbonate Carbon ◽  
Yield Value ◽  
Yield Values

Abstract The shear viscosity, creep and constant shear rate transients have been measured for 0.20 volume fraction compounds of an EPDM with calcium carbonate, carbon black, silica and zinc oxide of similar particle size at 100°C. Measurements have been made in a creep sandwich instrument, pressurized rotational rheometer and a capillary rheometer and cover nine decades of shear rate. All of the compounds exhibit enhanced viscosities and yield values; i.e. there are stresses below which there is no flow. The greatest yield values and increased viscosities are with the compounds with calcium carbonate and zinc oxide. More extensive studies were made with the EPDM-calcium carbonate system, where it was shown that, increasing particle size reduces shear viscosity and yield values. Further, surface treating calcium carbonate with stearic acid signifcantly reduces the shear viscosity and yield value of the corresponding EPDM compound.

Some Effects of Solid Fillers in Rubbers

1953 ◽  
Vol 26 (1) ◽  
pp. 156-165
Author(s):  
Ira Williams
Keyword(s):  
Tensile Strength ◽  
Zinc Oxide ◽  
Carbon Black ◽  
Abrasion Resistance ◽  
Volume Loading ◽  
Rubber Compounds ◽  
Before And After ◽  
The Matrix ◽  
The Many ◽  
Tear Resistance

Abstract The presence of pigments in rubber compounds produces physical properties which are of importance both before and after vulcanization. The ability of the unvulcanized mixture to calender or extrude smoothly with minimum swelling and to maintain shape during air cures, and the tensile strength, tear resistence, and abrasion resistance of vulcanized stocks all are affected. The methods by which these changes are brought about have been considered by many investigators and have been summarized by Parkinson1 and by Shepard, Street, and Park. Since carbon black is the most generally useful reinforcing pigment, it is natural that investigations have been directed particularly to this product. However, while it is recognized that differences exist in the final properties imparted by different pigments, all solid compounding ingredients have something in common. This point can be illustrated by the tear resistance imparted by such a variety of pigments as carbon black, zinc oxide, whiting, and clay. The effect of volume loading on the tear resistance of vulcanized stocks containing these materials, determined by the method of Zimmerman is shown in Figure 1. The effect of solid compounding ingredients can be studied only by considering the compound as a whole, since the properties are determined very largely by the relation between the solid particle and the matrix which surrounds it. Since the introduction of the many types of synthetic rubbers, the complexity of the problem has been greatly increased by the different states of polymerization, which affect the ability of the rubber to conform to the shape of the pigment particle and by the differences in polar nature which affect the type and the degree of adhesion between filler and matrix.

Vulcanization of Rubber Compounds

1940 ◽  
Vol 13 (4) ◽  
pp. 918-925 ◽  
Author(s):  
E. W. Booth ◽  
D. J. Beaver
Keyword(s):  
Zinc Oxide ◽  
Hydrogen Sulfide ◽  
Carbon Black ◽  
Physical Properties ◽  
Room Temperature ◽  
Appreciable Effect ◽  
Vacuum Oven ◽  
Rubber Compounds ◽  
Sulfide Content ◽  
Hydrogen Sulfide Content

Abstract 1. Rubber dissolves approximately one per cent of hydrogen sulfide when saturated at room temperature. 2. All types of commercial accelerators are retarded in rate of vulcanization as a result of treatment with hydrogen sulfide, and the retardation is directly proportional to the hydrogen sulfide content. 3. The physical properties of mercaptobenzothiazole types of accelerators and diphenylguanidine are not permanently affected by hydrogen sulfide, but dithiocarbamates, thiuram sulfides, aldehydeamines and litharge are permanently affected. 4. Rubber compounds containing mercaptobenzothiazole types of accelerators or diphenylguanidine, which have been treated with hydrogen sulfide and then degassed in a vacuum oven, show normal rate of vulcanization. Compounds containing aldehydeamines, litharge or carbon black show permanent retarding, even after degassing. 5. Increased zinc oxide or sulfur has no appreciable effect on the retardation. 6. Little or no zinc sulfide is formed as a result of treatment with hydrogen sulfide. 7. Hydrogen sulfide treatment of rubber compounds retards the rate of combination of sulfur with rubber. 8. In no case did hydrogen sulfide treatment improve the physical properties of the vulcanizate.

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