bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diffusion of Sulfur in Rubber. Relation to Vulcanization
Authors: Kemp A. R. , Malm F. S. , Winspear G. G. , Stiratelli B. 
Published: February 2011

Abstract
A survey of the literature failed to disclose any previous attempt to determine the. rate of diffusion of sulfur through rubber. The present paper is intended to fill this gap and to show the importance of diffusion and solubility of sulfur in rubber on control of the vulcanization reaction. The vulcanization of rubber cannot be considered as a homogeneous chemical reaction since the reactants, i. e., sulfur, accelerators and activators, are seldom completely in solution or uniformly dispersed. The limited solubility of sulfur, many accelerators, and zinc soaps in rubber leads to the presence of these substances partly in solution and partly in the dispersed state during vulcanization. Local high concentrations of these substances occur in solution around the dispersed phase, owing to their increased solubility which results from the temperature rise during vulcanization, coupled with their slow rate of diffusion through rubber. This paper presents the results of a detailed study of the effects of solubility, diffusion, and crystallization of sulfur on heterogeneity of vulcanization. Results showing the effect of various methods of mixing and handling on the physical properties of certain rubber compounds are presented. The diffusion of sulfur into rubber to form a solution during vulcanization, followed by the separation of globular sulfur on cooling, and its transition into dendritic and finally into rhombic sulfur on standing, was observed under the microscope by Loewen and Endres. Several factors which influence the migration and crystallization of sulfur internally and as a surface bloom on rubber were studied by Rimpel, Endres, Twiss, Loewen, and Graffe. The absorption of sulfur by rubber at elevated temperatures was studied by Skellon and by Venable and Green, and the solubility of sulfur at various temperatures was investigated by Venable and Green, Endres, Kelly and Ayers, Loewen, Morris, and Williams.
Synthetic Rubber from Acetylene. III. The Preparation of Butadiene by Catalytic Hydrogenation Of Monovinylacetylene in the Gaseous Phase
Authors: Hurukawa Zyunzi , Nakaguti Kôhei 
Published: February 2011

Abstract
Of the various technical methods for the preparation of butadiene from monovinylacetylene, the present authors chose to make first of all a thorough investigation of the continuous hydrogenation process, utilizing gaseous monovinylacetylene with various catalysts. As a result of this work the following conclusions were reached. The chief fault of this continuous hydrogenation process lies in the fact that, in addition to butadiene, large quantities of butene and oily polymerization products of monovinylacetylene are formed, as a result of which the yield of butadiene is small. This disadvantageous course of the reaction is attributable to the great heat of reaction which is evolved locally on the surface of the catalyst. In the experiments carried out by the present authors, the chief efforts were directed toward overcoming this drawback. As may be seen in Table II, a series of experiments were carried out with palladium as catalyst, which was used with excess carrier having a low heat conductivity, e. g., diatomaceous earth and Japanese acidic earth. This catalyst was expected to have a weakening effect on the activity, for this effect is very pronounced in the hydrogenation of acetylene to ethylene. In the present case, however, the results were unsatisfactory; dilution of the reaction gas with water vapor, a change in the gas current, and a change in the proportion of hydrogen to monovinylacetylene, were all tried. The maximum yield of butadiene at 80° C was 33.7 per cent, based on the monovinylacetylene.
A New Method of Determination of Fillers in Vulcanized Rubber
Authors: Hublin R. A. 
Published: February 2011

Abstract
A new reagent, o-nitroanisol, makes it possible to determine the total filler content of vulcanized rubber much more rapidly and more precisely than heretofore. In addition, the procedure is easier than that of the classic method. It would therefore be desirable if the method of determining fillers by solution of the rubber, which can now be carried out so easily, were to be used in many cases in place of incineration methods, which, in spite of being rapid, are very inaccurate, and also if the new method were to be used in place of the ordinary, relatively inconvenient solution methods.
Buna in the Manufacture of Cables
Authors: Roelig H. 
Published: February 2011

Abstract
The production on an increasingly large industrial scale of the synthetic rubberlike material, Buna, has led to its steadily expanding use in all branches of industry. The cable industry in particular has become interested in the properties of the various types of Buna in a large way in some of its extensive development problems. Buna S and Buna SS (formerly Levulkan), which have excellent aging, heat-resistant and insulating properties, are for example being used for insulating the metallic conductors of the various types of cables and cords for heavy current and low current service. Vulcanized Buna S as well as vulcanized Perbunan (formerly Buna N), the latter having the character of a semiconductor, are being used for the protective jackets of portable cables, ship cables, mine cables and telephone cables. Cable coverings made with Buna are characterized by their high stability over a wide range of temperatures, and by their great resistance to mechanical forces, which is manifest for example in a resistance to abrasion greater than that of natural rubber. In addition, Perbunan has much greater resistance to oils, fats and benzine than does natural rubber. Not only does cable manufacture require a material with high insulating properties and a cable covering of high mechanical quality, but also it is desirable that Buna, if used, have properties which make it process satisfactorily. Most Buna mixtures designed for insulation can be processed in strip-covering machines, Buna mixtures for coverings in ordinary extrusion machines. An extensive experimental program has been necessary to find a way of meeting all these frequently conflicting requirements with a new raw material like Buna. It seems advisable, therefore, to describe in a brief way the electrical and mechanical properties which can be obtained in cable manufacture with Buna as a result of these prolonged experiments.
The Standardization of Durometers
Authors: Larrick Lewis 
Published: February 2011

Abstract
The hardness test is one of the most useful and convenient physical tests which can be made on vulcanized rubber. It is easily made because the equipment can be simple, compact and portable. It is particularly useful in that the test sample may be a production article which can be put into service, undamaged, after the test. Consequently the test appears in the industry in several modifications, and the tester in diverse styles. Several more or less readily portable hardness testers are available commercially. The Shore Instrument and Manufacturing Co. has its line of Durometers, types A, B, C, D, etc.; Schopper, through Testing Machines, Inc., has marketed a tester similar to the Shore type A; the U. S. Gauge Co. has an instrument of the same type using the case of their pressure gage; the Firestone Penetrometer is another well-known tester of the spring-load type, as is the Adams Densimeter. At the present time the Society's Committee D-11 on Rubber Products is studying four portable hardness testers which are based on the specifications of the Standard Method of Test for Hardness of Rubber (D314-39), three of these being spring-operated instruments, the fourth, a dead-load type. In addition to the testers mentioned above, there is the Pusey-Jones Plastometer, which is a dead-weight hardness tester rather than a plastometer.
The Application of Latex to Highway and Floor Surfacing
Authors: Wren W. G. 
Published: February 2011

Abstract
Investigations on the development of latex mixtures for roadways were carried out in Malaya by Hastings during the period 1931 to 1933. Of the different mixtures tried, those containing aluminous cement gave the most promising results. Considerable progress of a practical character in working out the details of a suitable cement-latex mixture was then made, culminating in the laying in 1933 of an experimental section of road 4.5 miles from Kuala Lumpur on the Kuala Lumpur—Port Swettenham Road, where the traffic is fast and fairly heavy. In view of the promising results obtained in these experiments, it was agreed that the subject should be studied further in London, and that particular attention should be given to obtaining a better understanding of the fundamental principles involved in the preparation of latex mixtures for road and floor surfacing. As the economic factors are less exacting for flooring than for highways, it was decided that the application of latex mixtures to flooring should receive prior attention. The main purpose of the investigation has now been fulfilled, and this paper presents a summary of the work carried out and the results obtained. Mixtures of aluminous cement and latex have been in use for some time, both for flooring and other purposes; as early as 1923–4 patents were obtained for mixing cement with specially treated latex. The theory underlying this process is that the cement combines with the water of the latex and becomes hydrated, the latex losing its water and coagulating. How far this occurs in practice was not established at the outset of the work in London, and attempts were made to determine the extent of hydration of the cement and to examine the microstructure of the mixtures. During the course of this work it became apparent that the structure and physical characteristics of the products were largely dependent on the materials used in compounding and especially on the latex stabilizer. A systematic study of the principles underlying the compounding of the mixtures was then undertaken, and the relationship between compounding and physical properties determined. It thus became necessary to develop a series of tests to measure the physical properties, as no suitable methods were available. As a result of these experiments, a number of cement-latex compositions were developed and the most suitable selected for small scale trials. A summary of the work carried out and the conclusions reached are given in the following sections.
Influence of Moisture Content of Carbon Black on Rubber Properties
Authors: Cohan Leonard H. , Johnson C. R. 
Published: February 2011

Abstract
The moisture content of carbon black should be kept approximately constant if maximum accuracy in rubber testing is to be attained. In this laboratory we have found it convenient to equilibrate blacks at about 30 per cent humidity, under which condition most rubber channel blacks adsorb 1.5 to 2.0 per cent water. In the case of most of the properties of tread stocks, this precaution decreases the average deviation from the mean value in any series of experiments. In the case of extrusion tests, the effect of adsorbed moisture is so great that the use of a standard moisture content, or at least the determination of moisture content at the same time as the black is milled for extrusion, is necessary if reproducible results are to be expected.
Hydrodepolymerization of Rubber
Authors: Zelinsky N. D. , Rapoport J. B. 
Published: February 2011

Abstract
In a previous paper, one of the authors showed that the thermal decomposition of both natural and synthetic rubber proceeds easily and rapidly in the presence of aluminum chloride. The product so obtained is a mixture of hydrocarbons particularly rich in cyclic forms. One might, therefore, be led to believe that the polymerization of isoprene or butadiene, both in nature and under synthetic conditions, may be preceded by their dimeric or polymeric cyclization, with subsequent association of these unsaturated cyclic compounds, resulting in the formation of rubber. As a contribution to the knowledge of the chemical nature of highly polymeric substances such as rubber, we present here the results of our investigations on the depolymerization of rubber when subjected to hydrogen under high pressure in the presence of a catalyst. It was found that rubber, in the same way as oil or coal tar, is completely liquefied under such conditions. Experiments showed that, within the relatively short time of 1.5 to 2 hours, at a temperature of 400° C and a hydrogen pressure of 150 atmospheres, and in the presence of molybdenum sulfide or of nickel deposited on aluminum oxide, rubber is completely converted into a mobile liquid consisting of saturated and unsaturated hydrocarbons. The chemical nature of the resultant hydrocarbons casts light on the structure of rubber. It should be noted here that, in the absence of a catalyst, rubber cannot be converted into a mobile liquid when subjected to hydrogen under pressure.
A Manometric Test for Oxygen Absorption by Vulcanized Rubber
Authors: Johnson Robert H. 
Published: February 2011

Abstract
An apparatus can be set up in laboratory glassware that will confirm the results obtained by Dufraisse in his manometric test for oxygen absorption. It has been shown that different rubber compounds possess different tendencies to absorb oxygen. It has also been shown that the differences in the rate at which rubber compounds absorb oxygen are comparable with those differences found in the rate of tensile-strength deterioration of the same compounds aged in the oxygen bomb. This modified Dufraisse manometric method is convenient, efficient, accurate and, above all, a speedy method for measuring the relative aging behavior of vulcanized rubber compounds. Within two hours it is possible to have the results by this method, whereas it is necessary to wait from four days to two weeks for such information by the oxygen bomb method.
Industrial Progress in Synthetic Rubberlike Polymers
Authors: Cramer Howard I. 
Published: February 2011

Abstract
We may survey with some satisfaction the progress made in the development of synthetic rubber in the United States during the last decade. In this period four new types of synthetic elastic polymers have been developed: Neoprene, Thiokol, Koroseal, and Butyl Rubber. Extensive knowledge of the chemistry and engineering involved in the production of a large variety of types has been acquired. The plants in operation and under construction for the manufacture of these varied types are rapidly approaching such capacity as to justify the use of the expression “synthetic rubber industry”. True, it is an infant industry hardly out of the pilot-plant stage and far from ready to relieve the coolie in the Far East of his job; but it is growing rapidly, fed by a more than ample supply of cheap raw materials, and has already taken an important role in the defense program as a producer of vital war materials. Its growth is being stimulated at present by the emergency now facing the country, but it may be expected to continue to expand after the emergency is over because the synthetic rubbers as a group are outstandingly superior to natural rubber under certain severe service conditions.
Brittle Point of Rubber on Freezing
Authors: Selker M. L. , Winspear G. G. , Kemp A. R. 
Published: February 2011

Abstract
The need for a simple method of determining brittle points which would be adaptable to a large number of materials led the writers to develop the apparatus described below. There is presented here, for the first time, brittle point data on certain natural and synthetic rubber compositions. The study of the variation with temperature of the mechanical properties of elastomers is of immediate practical and theoretical interest. Recently Kistler attempted a correlation of temperature-strength data of polymers with their chemical structure. On the other hand, the increasing use of synthetic high polymers at low temperatures for insulation and mechanical purposes requires a more complete knowledge of their behavior under conditions of extreme cold. The determination of the brittle point offers a simple method for investigating the possible use of a new material at low temperatures. In 1928 Kohman and Peek described a method whereby a small strip of material at a known temperature was bent quickly through 90° by a hammer blow. They found that within rather wide limits the brittle temperature was independent of the sample dimensions and bending angle, but that a high rate of deformation was necessary for reproducible results. The brittle point was found to be definite and reproducible within ±2° C for the materials studied. Using this method, Kemp determined the brittle point range of crude and vulcanized rubber, balata, guttapercha, and paragutta.
Determination of Free Sulfur in Vulcanized Rubber
Authors: Mackay J. G. , Avons C. H. J. 
Published: February 2011

Abstract
The following comments pertain to a paper of the above title by Mackay and Avons, published in Transactions of the Institution of the Rubber Industry, Vol. 16, pages 117–122, October 1940, and reprinted in Rubber Chemistry and Technology, Vol. 14, pages 520–524, April 1941. H. P. Stevens draws attention to the penultimate paragraph on p. 522 in which it is pointed out that the bromine method of oxidation is tedious and the reagent unhealthful, whereas perchloric acid may be dangerous. As a result of many years experience he is of the opinion that neither reagent is necessary. After adding nitric acid to the acetone extract in the flask, which should be covered with a watch glass, and when the reaction has subsided, about 0.5 gram of potassium chlorate is added and the mixture kept warm at 50 to 60° C. The top of a water oven is convenient; but the heating must be limited, as the yellow oxides of chlorine are rapidly driven off near 100°, and the liquid changes back from yellow to orange. The flask can be left to itself for an hour or two, but further addition of chlorate may be necessary to complete the oxidation. The contents are evaporated to dryness and taken up twice with concentrated hydrochloric acid preparatory to precipitation with barium chloride. A volumetric method may be preferable when a large number of routine tests have to be made, otherwise the final estimation can be made as barium sulfate.
Improved Semimicrodetermination of Sulfur in Organic Materials. Peroxide-Carbon Fusion Followed by a Titration Using Tetrahydroxyquinone Indicator
Authors: Mahoney John F. , Michell John H. 
Published: February 2011

Abstract
Sulfur combined in a variety of nonvolatile organic compounds was oxidized to inorganic sulfate by a sodium peroxide-carbon fusion, and the sulfate ion was estimated by titration with standard barium chloride solution, using tetrahydroxyquinone as an internal indicator. No special apparatus was required, and 0.5- to 5-mg. quantities of combined sulfur were determined with speed and accuracy. The method should be especially useful for the routine analysis of materials like oil or rubber, with modification, if necessary, to remove interfering ions, and is apparently general for all types of sulfur-containing substances, including sulfonic acid derivatives.
The Compounding of Guayule Rubbers. Effect of Accelerator-Curing Agent Combinations
Authors: Morris Ross E. , James Robert R. , Werkenthin Theodore A. 
Published: February 2011

Abstract
The accelerator-curing agent combinations in most cases have the same effect on the three guayule rubbers as they have on smoked sheet. No accelerator-curing agent combination produces smoked-sheet stocks or guayule stocks excelling in every property; each rubber must be specially compounded for the purpose in mind. The authors conclude from the test data reported above that stocks prepared from domestic deresinated guayule rubber do not show sufficient advantages over similar stocks prepared from domestic resiniferous guayule rubber to justify the extra expense involved in the preparation of the former rubber. On the other hand, stocks prepared from Mexican resiniferous guayule rubber are definitely of poorer quality than similar stocks prepared from the domestic products.
Effect of Petroleum Products on Neoprene Vulcanizates Effect of Gasolines
Authors: Fraser Donald F. 
Published: February 2011

Abstract
The third paper of this series2 showed that the Diesel index may be used as a criterion of the swelling effect of kerosenes and kerosene-benzene blends on Neoprene. It was erroneously stated, however, that “swelling caused by kerosene is not a simple function of the … aniline point”. A recheck of the data, together with additional work, indicates that the aniline point may be used as a criterion of the swelling power of kerosenes, but this correlation is not so precise as with the Diesel index. This is particularly true in the case of kerosene-benzene blends when benzene predominates in the blend. As with kerosenes, the aniline point or Diesel index may be used as an indication of the swelling power of gasolines, and thus these constants may be used to specify standard immersion media of these types.
Influence of Exposing Vulcanized Rubber to Light on Its Subsequent Aging in the Dark
Authors: Scott J. R. 
Published: February 2011

Abstract
The present experiments confirm the observations of Morgan and Naunton by showing that exposure of vulcanized rubber to light may affect the results of oxygen-bomb aging tests made some days, or perhaps even weeks, afterwards. They show also that a few days' exposure to even diffused daylight may noticeably lower the tensile strength of unaged rubber. With normal, i.e., not transparent, rubbers the effect of light on subsequent aging is small, and indeed does not seem to be noticeable at all in relatively slow aging tests, such as that in the Geer oven. Nevertheless, it is clearly advisable, as a precaution, to avoid unnecessary exposure to light of rubbers that are to be subjected to accelerated aging tests.
Brittle Points of Natural and Synthetic Rubber Stocks
Authors: Morris Ross E. , James Robert R. , Werkenthin Theodore A. 
Published: February 2011

Abstract
The slow-bend brittle point test does not have the same practical significance as the Bell Telephone Laboratories brittle point test because most rubber articles which are exposed to low temperatures in service are required to withstand fairly rapid flexing. If the slow-bend brittle point test were used as a criterion of the cold resistance of these rubber articles, it might qualify the rubbers for a lower temperature than they could safely withstand in service. The brittle point test developed by the Bell Telephone Laboratories is simple and sensitive. It is believed that this test may advantageously be used to study all cold resistance problems where damage to the rubber itself and not increase in stiffness is the first consideration.