The Influence of Temperature on the Evolution of Hydrogen Sulfide from Vulcanized Rubber

1933 ◽  
Vol 6 (1) ◽  
pp. 46-55 ◽  
Author(s):  
A. D. Cummings
Keyword(s):  
Hydrogen Sulfide ◽  
Electrical Properties ◽  
Constant Temperature ◽  
Sulfur Compounds ◽  
Vulcanized Rubber ◽  
Measurable Amount ◽  
Wide Range ◽  
Long Time ◽  
Influence Of Temperature On

Abstract This paper presents the results of measurements of the evolution of hydrogen sulfide from rubber-sulfur compounds heated at various temperatures. Determination of the amount of hydrogen sulfide produced under different conditions was used to measure the degree of decomposition of the rubber. Two types of experiments were carried out: (1) Samples of vulcanized rubber containing 8 to 32 per cent sulfur were heated for 8-hour intervals at 13 temperatures between 105° and 265° C., and (2) samples having sulfur contents of 4, 10, 18, and 32 per cent were maintained for about 200 hours at constant temperature, one set of specimens at 136° and another group at 220° C. These measurements of deterioration were undertaken in connection with an investigation on the electrical properties of vulcanized rubber at relatively high temperatures. During these experiments, samples of rubber-sulfur compounds had been subjected to a wide range of temperatures. Time of exposure to each temperature had been about eight hours. The purpose of the present work was to determine when the sulfur content of a specimen had changed sufficiently to affect its dielectric constant and power factor by a measurable amount. In order to approximate the conditions under which the electrical tests were made, it was necessary to determine the amount of decomposition when rubber vulcanized with 8 to 32 per cent sulfur was heated for successive intervals of eight hours each at temperatures changed in unequal steps from 105° to 265° C. To make this information more complete and to obtain additional data which could be compared with previous investigations, the work was extended to include determinations of the loss of hydrogen sulfide from vulcanized rubber heated for a long time at constant temperature. The electrical properties of the whole series of rubber-sulfur compounds is the subject of a separate investigation at this bureau, and will be reported in another paper.

The Determination of Free Sulfur by a Volumetric Method Part II

1933 ◽  
Vol 6 (4) ◽  
pp. 512-517
Author(s):  
W. D. Guppy
Keyword(s):  
Hydrogen Sulfide ◽  
Organic Compounds ◽  
Sulfur Compounds ◽  
Acetone Extract ◽  
Volumetric Method ◽  
Organic Sulfur Compounds ◽  
Vulcanized Rubber ◽  
Volumetric Determination ◽  
Free Sulfur

Abstract 1. The method previously described for the volumetric determination of free sulfur in vulcanized rubber has been compared with the older gravimetric methods in cases where other organic compounds containing sulfur are present in the vulcanizate. 2. The volumetric method gave lower results than the methods involving oxidation of the acetone extract in the case of vulcanized rubber containing aldehydeamine condensation products of thiouram disulfide compounds. This indicated that the sulfur combined with some organic compounds was not reduced by the reagents used. 3. The results with the accelerator tetraethylthiouram disulfide showed that in some cases part of the sulfur in organic compounds was reduced under the conditions of the reaction. 4. The acetone-soluble and the acetone-insoluble portions of brown substitute contain organic sulfur compounds. Part of the sulfur in these compounds was reduced to hydrogen sulfide by the action of nascent hydrogen. 5. The sulfur compounds present in white substitute were stable toward the reducing agents used in the estimation of free sulfur. 6. The sulfur compounds formed by the vulcanization of ebonite were in part reduced to hydrogen sulfide with tin and acid. Variations in the composition of the mixing and in the vulcanizing conditions altered the amount of these reducible compounds. 7. The volumetric method previously described cannot be used for the determination of the free sulfur in ebonite, brown substitute or in vulcanized rubber containing brown substitute. In the case of vulcanized rubber containing brown substitute or of ebonite the method can be used to determine the amount of sulfur in the acetone extract. 8. The volumetric method can be employed for the determination of the free sulfur in soft vulcanized rubber containing white substitute and in reclaimed rubber.

Heats of Reaction of the System Rubber-Sulfur

1935 ◽  
Vol 8 (3) ◽  
pp. 456-469
Author(s):  
Archibald T. McPherson ◽  
Norman Bekkedahl
Keyword(s):  
Temperature Rise ◽  
Entire Range ◽  
Sulfur Compounds ◽  
The Other ◽  
Vulcanized Rubber ◽  
Heat Effects ◽  
Heats Of Reaction ◽  
Heats Of Combustion ◽  
Relative Measurements

Abstract PREVIOUS investigators have employed two methods for determining the heat effects when rubber is vulcanized. In one method the heats of vulcanization are found by subtracting the heats of combustion of vulcanized rubber—sulfur compounds from the heats of combustion of the corresponding mixtures of rubber and sulfur before vulcanization (1, 10, 11). This method is limited in precision by reason of the fact that the differences thus obtained are at most only a few per cent of the measured heath of combustion. The other method, which has been used previously, involves the determination of the temperature rise which occurs when mixtures of rubber and sulfur are vulcanized. This method has, for the most part, been used for relative measurements, but Blake (2) has recently employed it for quantitative determinations of the heats of reaction of rubber with proportions of sulfur up to about 8 per cent by weight. Recently Daynes (7) has employed a similar method for measurements over a wider range of composition. This investigation was undertaken for the purpose of measuring the heath of reaction of rubber with different percentages of sulfur over the entire range of composition in which combination takes place. The study was exploratory in character, the aim being to make the measurements by direct means with emphasis on simplicity rather than refinement of calorimetric procedure.

The Determination of Free Sulfur in Soft Vulcanized Rubber by a Volumetric Method

1932 ◽  
Vol 5 (3) ◽  
pp. 360-362 ◽  
Author(s):  
W. D. Guppy
Keyword(s):  
Hydrogen Sulfide ◽  
Sulfuric Acid ◽  
Organic Compounds ◽  
Subsequent Oxidation ◽  
Vulcanized Rubber ◽  
Elementary State ◽  
Previously Treated ◽  
Mineral Sulfides ◽  
Free Sulfur

Abstract The methods so far proposed for the determination of the free sulfur in vulcanized rubber depend upon the removal of the sulfur by extraction of the rubber with hot acetone, and subsequent oxidation to sulfuric acid of the sulfur in the extract. The extract is liable however to contain, in addition to sulfur in the elementary state, organic compounds containing sulfur derived from the rubber resins, accelerator, or antioxidant. In the subsequent oxidation this sulfur will be oxidized to sulfuric acid to an extent which depends on the method of oxidation used. In the present work, a method of analysis has been developed which is more rapid than the existing methods, and in which it is considered that the determination of the sulfur present in the elementary state is less likely to be affected by organic compounds containing sulfur. It has been found that when vulcanized rubber placed in contact with a metal, such as tin or aluminum, is boiled in hydrochloric acid, hydrogen sulfide is generated by the action of the nascent hydrogen produced. This reaction occurred with rubber which had been previously treated with acid alone to decompose metallic sulfides, but no hydrogen sulfide was obtained from rubber which had been previously extracted with acetone and was free from metallic sulfides. As these results showed that the reactions were not due to the presence of mineral sulfides, or of sulfur combined with the rubber, it was concluded that the hydrogen sulfide was formed by the reduction of the free sulfur.

Voltammetric Determination of Low-Molecular-Weight Sulfur Compounds in Hydrothermal Vent Fluids - Studies with Hydrogen Sulfide, Methanethiol, Ethanethiol and Propanethiol

2010 ◽  
Vol 22 (10) ◽  
pp. 1066-1071 ◽  
Author(s):  
Daiane Dias ◽  
Paulo C. do Nascimento ◽  
Cristiane L. Jost ◽  
Denise Bohrer ◽  
Leandro M. de Carvalho ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Hydrogen Sulfide ◽  
Hydrothermal Vent ◽  
Sulfur Compounds ◽  
Voltammetric Determination ◽  
Low Molecular Weight

Comparison of Methods for the Sulfur Compounds and Elemental Sulfur Analysis in High-Sulfur Natural Gas

2013 ◽  
Vol 712-715 ◽  
pp. 688-700
Author(s):  
Qin Luo ◽  
Zhen Quan Tu ◽  
Zhong Li Ji ◽  
Xue Lan Xiao ◽  
Hong Gang Chang ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Natural Gas ◽  
Elemental Sulfur ◽  
High Accuracy ◽  
Sulfur Compounds ◽  
Sulfide Content ◽  
Good Repeatability ◽  
Hydrogen Sulfide Content ◽  
Gas Fields

Some gas fields with high hydrogen sulfide content, such as Luojiazhai, Dukouhe and Puguang Gas Fields, are found in Northeast Sichuan. For exploring and utilizing high sulfur natural gas reservoirs, it is essential to quantificational analysis of sulfur compounds and elemental sulfur in high sulfur natural gas. Determination of hydrogen sulfide content in natural gas with a laser method has many advantages, including on-site measurement, fast response, wide application scope, high accuracy, high reliability, and low maintenance. When the hydrogen sulfide concentration is 1% to 20%, the relative deviation of the analysis value to the standard value is less than 3% with repeatability of less than 1%. Determination of sulfur compounds in natural gas by gas chromatograph with sulfur chemiluminescence detector (SCD) also has many advantages, such as it is simple, fast, accurate and free from interference of most sample matrixes. The analysis method has good repeatability with lower limit of detection. Since SCD has liner equimolar response to sulfur atom, only one reference gas mixture of sulfur compound is used as external standard calibration. Determination of total sulfur content in natural gas with oxidative microcoulometry method has good repeatability and high accuracy. Determination of elemental sulfur by liquid chromatography has repeatability better than 3%, the detection limit is 10mg/m3, and recovery rate of over 90%, and is applicable for determination of elemental sulfur content in high sulfur natural gas.

Analysis of Vulcanized Rubbers. Influence of Accelerators on the Determination of Free Sulfur by the Copper Spiral Method

1952 ◽  
Vol 25 (4) ◽  
pp. 956-958
Author(s):  
J. Mann
Keyword(s):  
Hydrogen Sulfide ◽  
Copper Sulfide ◽  
Acetone Extract ◽  
British Standard ◽  
Standard Methods ◽  
Vulcanized Rubber ◽  
Potential Source ◽  
Source Of Error ◽  
Free Sulfur

Abstract The copper spiral method is being inserted in a revised edition of the “British Standard Methods of Testing Vulcanized Rubber”, and this raises the question of what sulfur compounds react as “free” sulfur. In this method, “free” sulfur is considered to be that part of the sulfur which is present in the acetone extract and which reacts with a copper spiral, placed in the acetone during the extraction, with the production of copper sulfide, the amount of which can be estimated after its removal from the acetone. Since most accelerators contain sulfur, it is obvious that the presence of accelerators or accelerator fragments is a potential source of error. Fourteen accelerators of various types were therefore examined, and it was found that some react with copper, producing compounds which evolve hydrogen sulfide on treatment with hydrochloric acid.

scholarly journals Low frequency electric properties utilization in agriculture and food treatment

2012 ◽  
Vol 49 (No. 4) ◽  
pp. 125-136 ◽  
Author(s):  
Z. Hlaváčová
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Moisture Content ◽  
Measurement Techniques ◽  
Conductivity Measurement ◽  
Membrane Properties ◽  
Food Treatment ◽  
Wide Range ◽  
Agricultural Materials

Determination of electrical properties is utilized in a wide range of disciplines and industries. A brief compendium of agricultural materials and food electrical properties exploitation is presented in this paper. The measurement of electrical conductivity or resistivity can be utilized at investigation of cell membrane properties on microscopic level. Moreover the electrical conductivity have utilization at the salinity of soils and irrigation water determination. Biological material properties are determined from their leachates too. The conductivity measurement are applied for determination of various characteristics of agricultural materials and food, for example for determination of the frost sensitiveness, of chilling and freezing tolerance, of moisture content, of seeds germination, of mechanical stress, of pasteurization, of other properties of grains, seeds, meat, sugar, milk, wood, soil, fruit and vegetable, infected food, … The utilization of dielectric properties are also described; for example in agricultural materials and food quality sensing (moisture content, maturity of fruit, freshness of eggs, potential insect control in seeds, radio frequency heating, …). The classification of permittivity measurement techniques at the low frequencies is mentioned.

scholarly journals Electrical Characterization of Thin PEDOT:PSS Films on Alumina and Thiol–Ene Substrates

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3519
Author(s):  
Dalius Jucius ◽  
Rimantas Gudaitis ◽  
Algirdas Lazauskas ◽  
Viktoras Grigaliūnas
Keyword(s):  
Electrical Properties ◽  
Electrical Resistance ◽  
Room Temperature ◽  
Electrical Characterization ◽  
The Novel ◽  
Alumina Ceramics ◽  
Ceramic Substrates ◽  
Wide Range ◽  
Long Time

Transparent polymer layers that heal minor scratches and maintain the optical properties of the devices for a long time are highly desirable in optoelectronics. This paper presents the results of the electrical characterization of thin PEDOT:PSS films on the novel, optically transparent thiol–ene substrates capable of healing scratches under room-temperature conditions. Electrical properties of the PEDOT:PSS films deposited on the conventional alumina ceramic substrates were also tested for comparative purposes. This study demonstrated that the substrate can have a significant effect on the electrical properties of PEDOT:PSS films, and the electrical resistance of the films on thiol–ene substrates is not as stable as on alumina ceramics. However, the changes in electrical resistance of the films on thiol–ene are small enough over a sufficiently wide range of operating temperatures and relative humidities and allow the application of such bilayers in various polymeric optoelectronic devices.

The Problem of Identifying and Modeling the Relationship between Monetary Factor and Inflation in the Russian Economy

2008 ◽  
pp. 61-76
Author(s):  
A. Porshakov ◽  
A. Ponomarenko
Keyword(s):  
Money Supply ◽  
Money Demand ◽  
Russian Economy ◽  
Long Run ◽  
Complex Approach ◽  
Wide Range ◽  
Long Time ◽  
The Relationship ◽  
Supply Side Factors

The role of monetary factor in generating inflationary processes in Russia has stimulated various debates in social and scientific circles for a relatively long time. The authors show that identification of the specificity of relationship between money and inflation requires a complex approach based on statistical modeling and involving a wide range of indicators relevant for the price changes in the economy. As a result a model of inflation for Russia implying the decomposition of inflation dynamics into demand-side and supply-side factors is suggested. The main conclusion drawn is that during the recent years the volume of inflationary pressures in the Russian economy has been determined by the deviation of money supply from money demand, rather than by money supply alone. At the same time, monetary factor has a long-run spread over time impact on inflation.

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