The Effect of Mold Pressure on the Electrical Resistivity of Elastomers

1994 ◽  
Vol 67 (1) ◽  
pp. 107-118 ◽  
Author(s):  
Corley M. Thompson ◽  
J. Scott Allen
Keyword(s):  
Electrical Resistivity ◽  
Carbon Black ◽  
The Other ◽  
Molding Pressure ◽  
Large Decrease ◽  
Pressure Data ◽  
Electrical Resistivities

Abstract Elastomers are commonly used as electrical insulators in marine acoustic devices. A previous paper discussed the very large decrease in electrical resistivity of a Neoprene GRT formulation when subjected to moderately high molding pressures. In the present paper, data will be presented showing similar dependencies on mold pressure for natural, polybutadiene, 39%-acrylonitrile NBR, and chlorobutyl elastomers and the absence of the effect for an EPDM, and a 27%-acrylonitrile NBR elastomer. These data are not easily explained. The previous paper also discussed that increasing the carbon-black loading caused the electrical resistivity to decrease at even lower molding pressures. Similar trends are presented here for the other elastomers whose electrical resistivities are dependent on molding pressure. Data will also be presented that show that the addition of poly-para-dinitrosobenzene (Poly DNB®) to a CR formulation will eliminate the mold pressure vs. electrical resistivity effect.

Effect of Elongation on the Electrical Anisotropy of Natural Rubber and SBR Vulcanizates Containing ISAF Carbon Black

1962 ◽  
Vol 35 (2) ◽  
pp. 317-325 ◽  
Author(s):  
R. Chasset ◽  
P. Thirion
Keyword(s):  
Mechanical Properties ◽  
Electrical Resistivity ◽  
Carbon Black ◽  
Natural Rubber ◽  
The Other ◽  
Electrical Anisotropy ◽  
Ohm’S Law ◽  
Carbon Blacks ◽  
Ohm's Law ◽  
Current Flows

Abstract The electrical resistivity of testpieces under different elongations, both parallel and at right-angles to the axis of elongation, was measured for two vulcanizates, i.e. one of natural rubber and the other of SBR, compounded with 20 volume per cent of ISAF black (Vulcan 6). Within the range of validity of Ohm's law, the main results of this study are as follows: a) the resistivities of both vulcanizates increase considerably with elongation, in both directions. b) on the whole, both vulcanizates are electrically anisotropic, since current flows more easily longitudinally than it does transversely. The anisotropy increases at the start with elongation, then becomes practically constant. However, the latter level is much higher with natural rubber, for which it corresponds to an anisotropy of about 1,000 and an elongation of around 150%. For SBR this level is only 20 to 30 and is reached at only 50% elongation. Owing to the complexity of the problem, no interpretation can yet be given for these differences. It will first be necessary to examine other elastomers and carbon blacks. For the time being, it may merely be stated that the electrical anisotropy of natural rubber and SBR reinforced vulcanizates differs as much as their mechanical properties, especially their tearing behavior.

Resistivity of Rubber as a function of Mold Pressure

1988 ◽  
Vol 61 (5) ◽  
pp. 828-841 ◽  
Author(s):  
Corley M. Thompson ◽  
T. W. Besuden ◽  
L. L. Beumel
Keyword(s):  
High Pressure ◽  
Electrical Resistivity ◽  
Carbon Black ◽  
Kinetic Data ◽  
Careful Consideration ◽  
Molding Pressure ◽  
Covalent Bonds ◽  
Cure Cycle ◽  
Effect Of Pressure ◽  
Rubber Compounds

Abstract For this N550 carbon black, loaded over a narrow but typically used range, high molding pressure caused a decrease in electrical resistivity of several orders of magnitude. The earlier in the cure cycle the high pressure was applied, the greater was the decrease in resistivity. A suggested mechanism for the effect is the formation of covalent bonds between carbon-black particles that are pushed into closer proximity by the high mold pressure. This postulate is supported by the limited kinetic data available. Clearly, pressure applied to a rubber sample during molding must be given as careful consideration as the loading of carbon black when materials requiring high resistivities are prepared. Although it has not been pursued in this work, the effect of pressure on the electrical resistivity of conductive rubber formulations may be significant. Further work underway is addressing the effect of mold pressure on the electrical resistivity of other rubber compounds as well as loadings of some other types of carbon black.

Polymer composites as sensing materials for liquid organic solvents – preliminary results

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Stanislaw Frackowiak ◽  
Monika Maciejewska ◽  
Andrzej Szczurek ◽  
Marek Kozlowski
Keyword(s):  
Electrical Resistivity ◽  
Carbon Black ◽  
Polymer Composites ◽  
Percolation Theory ◽  
Liquid Mixtures ◽  
Organic Liquids ◽  
Volumetric Fraction ◽  
Factors Influencing ◽  
Benzene Toluene ◽  
Main Factors

AbstractCarbon black-filled polymer composites were investigated as sensing materials for organic liquids. Polypropylene and polystyrene which were selected as matrices and various amounts of carbon black were considered as the main factors influencing sensitivity of the composites in view of the percolation theory. Disposable filaments were produced of these materials. Change in their electrical resistivity was measured upon immersion in benzene, toluene, xylene, ethylbenzene and their mixtures. It has been found that studied materials were sensitive to the composition of liquid mixtures of organic solvent. Relationships between the filament response and volumetric fraction of the components were presented. The studied materials have shown promising sensing properties, which suggest their applicability for identification and quantification of multicomponent organic liquids.

The electrical resistivity of lithium-6

1961 ◽  
Vol 263 (1314) ◽  
pp. 407-419 ◽  
Keyword(s):  
Electrical Resistivity ◽  
Isotopic Composition ◽  
Specific Heat ◽  
Room Temperature ◽  
Natural Isotopic Composition ◽  
Square Roots ◽  
Conduction Electrons ◽  
Ionic Mass ◽  
Theoretical Predictions ◽  
Electrical Resistivities

The electrical resistivities of lithium -6 and lithium of natural isotopic composition have been studied between 4°K and room temperature. In addition, their absolute resistivities have been carefully compared at room temperature. These measurements show that the effect of ionic mass on electrical resistivity agrees with simple theoretical predictions, namely, that the properties of the conduction electrons in lithium do not depend on the mass of the ions, and that the characteristic lattice frequencies for the two pure isotopes are in the inverse ratio of the square roots of their ionic masses. A comparison with the specific heat results of Martin (1959, 1960), where the simple theory is found not to hold, indicates the possibility that anharmonic effects are present which affect the specific heat but not the electrical resistivity.

scholarly journals The influence of thermal fixation of interlining on the quality of woven clothing fabrics evaluated from the aspect of their electrical resistance

2020 ◽  
Vol 68 (4) ◽  
pp. 4-11
Author(s):  
Koviljka Asanović ◽  
Tatjana Mihailović ◽  
Mirjana Kostić ◽  
Iva Gajić ◽  
Aleksandra Ivanovska
Keyword(s):  
Electrical Resistivity ◽  
Ambient Air ◽  
Polyester Fabric ◽  
Woven Fabrics ◽  
Plain Weave ◽  
Weave Fabric ◽  
Polyester Fibers ◽  
Electrical Resistivities ◽  
Twill Weave

In this paper, the influence of thermal fixation of woven interlining on the quality of woven fabrics, evaluated from the aspect of their dc volume electrical resistivity, was investigated. The plain weave fabrics made from cotton, flax, viscose, polyester, and cotton/polyester blends and 3/1S twill weave fabric obtained from cotton and polyester fibers blend were investigated. A cotton fabric with a point-applied thermoplastic binder was used as an interlining. The obtained results showed that the dc volume electrical resistivity of fabrics is influenced by their chemical composition, type of weave, type of yarn, fabric density which is especially pronounced in the interlining, the process of thermal fixation of the interlining, and ambient air humidity. The thermal fixation of the woven interlining greatly reduces the dc volume electrical resistivity of polyester fabric (499 times in the warp direction and 860 times in the weft direction), and increases the resistivity of other fabrics in the range of 1.3 times for viscose fabric and fabric obtained from cotton and polyester fibers blend in plain weave to 3.9 times for twill weave fabric. Based on the conducted investigation, it can be concluded that the quality of the tested fabrics evaluated from the aspect of their electrical resistivities, was significantly improved in the case of polyester fabric i.e worsens in the other investigated fabrics after thermal fixation of the woven interlining.

scholarly journals Energy Recovery from Waste Tires Using Pyrolysis: Palestine as Case of Study

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1817 ◽  
Author(s):  
Ramez Abdallah ◽  
Adel Juaidi ◽  
Mahmoud Assad ◽  
Tareq Salameh ◽  
Francisco Manzano-Agugliaro
Keyword(s):  
Carbon Black ◽  
West Bank ◽  
The Other ◽  
Liquid Fuels ◽  
Pyrolysis Oil ◽  
Pyrolysis Gas ◽  
Heating Value ◽  
Waste Tires ◽  
High Heating Value ◽  
High Heating

The first industrial-scale pyrolysis plant for solid tire wastes has been installed in Jenin, northern of the West Bank in Palestine, to dispose of the enormous solid tire wastes in the north of West Bank. The disposable process is an environmentally friendly process and it converts tires into useful products, which could reduce the fuel crisis in Palestine. The gravimetric analysis of tire waste pyrolysis products from the pyrolysis plant working at the optimum conditions is: tire pyrolysis oil (TPO): 45%, pyrolysis carbon black (PCB): 35%, pyrolysis gas (Pyro-Gas): 10% and steel wire: 10%. These results are depending on the tire type and size. It has been found that the produced pyrolysis oil has a High Heating Value (HHV), with a range of 42 − 43   ( MJ / kg ) , which could make it useful as a replacement for conventional liquid fuels. The main disadvantage of using the TPO as fuel is its strong acrid smell and its low flash point, as compared with the other conventional liquid fuels. The produced pyrolysis carbon black also has a High Heating Value (HHV) of about 29 (MJ/kg), which could also encourage its usage as a solid fuel. Carbon black could also be used as activated carbon, printers’ ink, etc. The pyrolysis gas (Pyro-Gas) obtained from waste tires mainly consist of light hydrocarbons. The concentration of H2 has a range of 30% to 40% in volume and it has a high calorific value (approximately 31   MJ / m 3 ), which can meet the process requirement of energy. On the other hand, it is necessary to clean gas before the burning process to remove H2S from Pyro-Gas, and hence, reduce the acid rain problem. However, for the current plant, some recommendations should be followed for more comfortable operation and safer environment work conditions.

Reuse of carbon black from end-of-life tires in new pneumatic formulations and life-cycle assessment of the thermolysis process

2019 ◽  
Vol 51 (7-8) ◽  
pp. 740-754
Author(s):  
AD La Rosa ◽  
E Pergolizzi ◽  
D Maragna ◽  
G Recca ◽  
G Cicala
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Carbon Black ◽  
End Of Life ◽  
Market Price ◽  
Environmental Benefits ◽  
The Other ◽  
Assessment Methodology ◽  
Life Cycle Assessment Methodology ◽  
Main Attraction

Carbon black derived from end-of-life tires (ELTs) through thermolysis process was studied. The main attraction of this material is the low market price (€450 ton−1) compared with virgin carbon black (about €700 ton−1). Investigation was focused on the vulcanization reaction of rubber with the addition of both types of carbon black, that is, carbon black recycled (CBr) from the thermolysis of ELTs and carbon black virgin (CBv) from traditional oil process. The aim of the research was to verify that CBr has similar reactivity than CBv when blended with rubber and vulcanized. Furthermore, environmental benefits of recovering CBr and the other coproducts were evaluated by means of the life-cycle assessment methodology.

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