bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Free Carbon in Rubber. The Cresol Method
Authors: Roberts J. B. 
Published: February 2011

Abstract
A simple, accurate method for the determination of free carbon in either raw or vulcanized rubber is presented. It has replaced the nitric acid method entirely in the laboratory of the United States Rubber Company, Detroit, Michigan. A study of the effects of interfering substances, and numerous comparisons of results by the cresol and the nitric acid methods, are given. Results by the cresol method, in the absence of interfering substances, are within 1 per cent of the calculated free carbon content. The method requires only simple apparatus readily available.
Creaming of Rubber Latex
Authors: Hauser E. A. , Dewey Bradley 
Published: February 2011

Abstract
The creaming of rubber latex was first observed as far back as 1824 when Hancock, working with what was probably Castilloa latex, observed that if this latex is well shaken with three or four times its volume of water and then allowed to stand, a separation into two layers will take place which thus effects a purification of the dispersion. This phenomenon, reported again by Faraday in 1825, is a spontaneous creaming which takes place with latices of large particle size. Latex of Hevea brasiliensis will not cream spontaneously in this manner and, although other methods of inducing creaming, such as the addition of caustic alkali, were previously known, it remained for Traube in 1924 to patent the first method which would prove satisfactory for commercial concentration. Rahn had reported in 1922 that the natural creaming of milk could be greatly accelerated and made more complete if small amounts of gelatin or of similar hydrophilic colloids, such as gum tragacanth, gum arabic, peptone or albumen, were added to the milk before allowing it to stand. Recognizing the similarity between milk and rubber latex, Traube applied this knowledge to the development of the creaming of latex. He found such substances as carrageen moss, Iceland moss, and other vegetable mucilages to be effective in causing separation of the latex dispersion into two layers—the upper one rich in rubber and the lower one, generally termed serum, almost free of rubber.
Formation of Compounding Ingredients in Rubber
Authors: Twiss D. F. , Neale A. E. T. , Hale R. W. 
Published: February 2011

Abstract
In 1923, dealing with compounding ingredients for rubber, one of the authors, with particular reference to compounding rubber with carbon black, commented on the attractiveness of the possibility of producing a compounding ingredient immediately inside the rubber colloid medium, to assure its formation in a state of uniform and intimate distribution with reinforcing effect, and with incidental avoidance of the economic and technical disadvantages attendant on mechanical mixing. Numerous experiments, however, with this aim, have given disappointing results. For instance, all attempts to produce amorphous carbon by means of chemical reaction in a rubber medium have been frustrated, either by the special conditions, so that the expected reaction proceeded in an unexpected and undesired direction, or by the carbon separating outside the rubber medium provided for it. A number of endeavors with the same aim, i.e., the improved compounding of rubber, but based on other possible compounding ingredients, was described in another paper in 1933, in which the ideal conditions for compounding in situ were reviewed. Two of the more important of these conditions were that the compounding ingredient must be formed in the rubber phase and must be as nearly insoluble therein as possible. More recent investigations into the mechanism by which carbon black exercises its beneficial influence on the mechanical qualities of rubber in which it is dispersed admittedly indicate that mere dispersion of ultrafine particles in the rubber phase may not be the only important factor. At present, however, such dispersion of fine particles appears to be an essential first step in the compounding process for eventual reinforcement, so that compounding by formation of reinforcing agents in situ may still provide a valuable or even essential step in methods for the production of rubber with exceptionally enhanced physical or mechanical characteristics.
Experiments on the Degradation of Buna-S. Part I
Authors: Reiner St. 
Published: February 2011

Abstract
In this first communication on the subject, an apparatus is described, with the aid of which experiments on the degradation of Buna S and Buna SS can be carried out on a laboratory scale. The experiments thus far completed show that the volume of air, at least above the range of very low quantities, has no marked influence on the degree to which Buna is degraded under otherwise constant conditions. Likewise the viscosities are hardly influenced by a change in the rate of flow of air. Only the elastic components increase with reduction in the volume of air supplied to the sample. With slightly degraded Buna (see Table 2), the effect of low rates of flow of air can be observed clearly. From a practical point of view, the experiments show that a minimum quantity of air, i. e., a definite rate of flow, is necessary for degrading Buna-S. On the basis of the experiments described, a minimum of approximately 20 liters of air per hour may be assumed to be necessary to degrade 50 grams of Buna-S in crumb form. Converted to a large-scale basis, this would mean that at least 40 cubic meters of air per hour would be necessary to degrade 100 kilograms of Buna-S in uniform crumb form, provided the air is distributed uniformly throughout the reaction vessel. Electric drying chambers and vulcanizers which have no continuous supply, but only a stationary volume of air, are not suitable, since the quantity of air is far from sufficient to bring about homogeneous degradation. Most factories which use Buna have suitable equipment with a supply of air under pressure, so that the volume of oxygen necessary for degradation can be supplied to the Buna.
Rubber in the Automotive Industry. From the Viewpoint of the Rubber Technologist
Authors: Cadwell S. M. , Merrill R. A. , Sloman C. M. , Yost F. L. 
Published: February 2011

Abstract
About 80 per cent of the rubber consumed in the United States is used in the automotive industry. Rubber was necessary for the development of the modern automobile, and the popularity of the automobile has, in turn, tremendously enlarged the rubber business. The parallel growth of the rubber and automotive industries is apparent in Figure 1, where the consumption of rubber is compared with the registration of motor vehicles in the United States for the past thirty years. The modern automobile contains about two hundred different parts made wholly or in considerable part of rubber. Including the tires and tubes, the weight of these materials is about 145 pounds per car. Rubber is used in the automobile in practically all of its available forms, either as latex, cements, soft rubber, hard rubber, or sponge rubber. Every important characteristic of rubber is utilized. Rubber has a wider range of properties than any other single material and automotive engineers are to be congratulated on their progressiveness in using these unique and valuable properties to improve their product.
Determination of Scorching of Rubber and Synthetic Compounds by Use of the Mooney Plastometer
Authors: Weaver John V. 
Published: February 2011

Abstract
There are in use today several methods for determining the scorching point of rubber and synthetic compounds. Some compounders use the Williams plastometer method, while others press-cure a thin slab of compound for increasing periods of time at 220° F or thereabouts until an examination of the slab shows that vulcanization has taken place. Another method consists of heating several pieces of the compound in an oven and removing at constant intervals until the compound scorches. The test-pieces in the latter method are quite often sheeted out on a mill to determine if any vulcanization has taken place. These methods all give good indications of the scorching point; however, each one is a rather long and tedious test. The Mooney plastometer scorch test cuts down the time considerably and gives a picture of the scorching rate, when the plasticity is plotted against the time. It is necessary, as a rule, to run this test only 10 or 12 minutes at 250° F to determine just how scorchy a compound really is, while the other methods cited sometimes require an hour or more to determine the scorching characteristics. It is desirable also to express the results of any test in the form of a graph or curve, so that one may make comparisons more easily without reviewing a lot of data. The Mooney scorch test gives results which can be plotted in the form of a curve, which also shows some very interesting facts aside from the scorching characteristics. The plasticity of the compound, the point at which vulcanization begins, and the rate of vulcanization after it begins, are shown. Summarizing the advantages of this test in a few words, one can say that it affords a quick, convenient method for determining scorching characteristics, and that it gives a clearer and more informative picture of scorching than other methods used today. Just a few illustrations demonstrating the use of the Mooney plastometer as an instrument for determining scorch have been given in this report. They do, however, point out the value of this test in the following ways: (1) The Mooney scorch test gives a quick method for studying the effect of various accelerators and accelerator combinations on the scorching characteristics of rubber compounds. It can also be used to show the effect of a retarder with various accelerators, and the effect of any other compounding change which might have a bearing on the scorching characteristics. (2) The Mooney scorch test may be used to show the relationship between scorching and rate of curing. As has been pointed out, there appears to be a definite relationship; however, before any general statements can be made, a considerable amount of work would be necessary. In the particular example cited here (Curve Sheet No. 2), one could visualize, from the shape of the Mooney scorch curves, the rate of curing of these compounds from the first signs of vulcanization to the peak cure.
Possibilities of Utilizing the Polarographic Method in Rubber Laboratories. I
Authors: Proske G. 
Published: February 2011

Abstract
Following a brief description of electrochemical principles and the experimental technique of the polarographic method, possible applications of this method in the rubber laboratory are discussed in some detail. In addition to its availability in many ways for the determination and the investigation of numerous inorganic materials which are so frequently analyzed in rubber laboratories, the polarographic method is of special importance in the determination of organic accelerators of vulcanization. The first investigations of the author in this field are described in detail.
Hysteresis in the Crystallization of Stretched Vulcanized Rubber. II. X-Ray Studies of the Effects of Sulfur Content and Method of Curing
Authors: Clark G. L. , LeTourneau R. L. , Ball J. M. 
Published: February 2011

Abstract
1. Improvements in technique make possible complete rubber patterns in only five minutes' exposure. 2. The extreme sensitivity of hysteresis in crystallization to changes in temperature at which the stock is investigated is demonstrated. 3. Hysteresis decreases with the time of cure for a given compound. 4. Crystallinity at a given elongation seems to decrease with increasing temperature of curing for equivalent cures over the range of 239–307° F. 5. For the stock studied, at a given time and temperature of cure, the proportion of sulfur giving the greatest crystallinity at 550 per cent is between one and three per cent. 6. Inhomogeneities in the disappearance of crystallinity have been clearly demonstrated, and shown to be an exaggerated localized hysteresis effect.
An X-Ray Study of the Proportion of Crystalline and Amorphous Components in Stretched Rubber
Authors: Field J. E. 
Published: February 2011

Abstract
A method is described for obtaining a quantitative measure of crystalline hydrocarbon present in stretched rubber samples by comparing the intensities of the diffraction spots and the amorphous halo appearing in the x-ray diagrams. This method has been applied to a study of the crystallinity of stretched vulcanized rubber as it is affected by different vulcanization accelerators, variations in extension, temperature, and cure. To illustrate a connection between the physical performance of a rubber vulcanizate and its degree of crystallization, measurements were made of the relation of crystallinity to creep when the rubber was stretched to different initial elongations under constant loads. The creep as a function of the elongation has a maximum value at the same intermediate elongation for which crystallization becomes appreciable. At higher elongations, increased crystallinity results in a diminution of the creep. The ultimate strength and extensibility generally associated with stretched vulcanized rubber is the result of the combined effect of primary valence cross-linkages formed by vulcanization and the formation of crystallites caused by stretching. Crystallization is an important factor in maintaining the relatively high strengths of vulcanizates having a greater range of extensibilities. In general, the physical properties and performance of vulcanized rubber is related to the amount of crystalline material formed on stretching, which depends on the structural characteristics of the vulcanizate.
Relation between Molecular Weights and Physical Properties of Rubber Fractions
Authors: Gee G. , Treloar L. R. G. 
Published: February 2011

Abstract
As high elasticity is a property possessed only by substances of high molecular weight, it is of interest to enquire into the relation between the elastic properties of a highly elastic material such as rubber and its molecular weight. An investigation on these lines has been made possible through the work of Bloomfield and Farmer, who have succeeded in separating natural rubber into fractions having different average molecular weights. The more important physical properties of these fractions have been examined with the object of determining which of the properties are dependent on molecular weight and which are not. Fairly extensive observations were made on the fractions from latex rubber referred to as Nos. 2, 3 and 4 by Bloomfield and Farmer, and some less extensive observations were carried out on the less oxygenated portion of fraction No. 1 obtained from crepe rubber (called hereafter 1b) . Before considering these experimental results, and their relation to the molecular weights of the fractions, it will be necessary to refer briefly to the methods used for the molecular-weight determinations, and to discuss the significance of the figures obtained.
Thermal Problems in Rubber Manufacture
Authors: Hahn Stuart H. 
Published: February 2011

Abstract
The threefold heat problems of the industry are, in order of their occurrence: (1) Controlled removal of heat generated in processing crude rubber. (2) Regulation of heating and cooling processes to give the most nearly uniform vulcanization in the shortest possible time. (3) Measurement and reduction of heat generation in products subject in service to cyclic stress conditions. Each of the three types of problems engages the attention of chemists and engineers as well as physicists. The chemist is constantly searching for new ingredients and combinations of materials which will promote rapid vulcanization at curing temperatures, that is, 240 to 320° F. The same rubber compounds, when unvulcanized, must be relatively insensitive to processing temperatures up to about 220° F; when vulcanized they must withstand prolonged use at temperatures above 200° F. The engineer must design curing equipment and related automatic controls. He also must design the combinations of rubber compounds and structural elements which make up the products of the industry. The physicist must measure and analyze the thermal properties of the raw materials, the rubber compounds and the finished products. He also must apply the methods of the physics laboratory to the study in the factory of thermal problems connected with production operations. The cooperation of all is essential in producing for the consumer better products at lower cost.
The Evaluation of Reclaimed Rubber
Authors: Hublin Roger A. 
Published: February 2011

Abstract
Examples have been given to illustrate a method of evaluation of reclaimed rubbers which takes into account the costs of the materials tested. When correctly applied, this method gives a rapid and, at the same time, precise answer to all questions of cost and quality which may arise in connection with the use of reclaimed rubber. In concluding this discussion, attention should be called to an important point, It has been proved fairly conclusively that, if an effort is made to define in a precise manner any problem to be solved, it is possible to apply rational methods to it. With these methods it is possible to avoid much futile experimentation, and to obtain directly results which are a quite satisfactory approximation to the correct ones. This is true, not only in studying and evaluating reclaimed rubbers, but also of problems in general which arise in connection with compositions and costs of various mixtures. In almost all cases it is possible, by making use of analogous methods of procedure, to save considerable time and effort. It appears to be certain that, thanks to progress in the technique and standardization of testing, it will be possible to make a truly systematic study of rubber compounding.
Hycar-OR. Properties of Typical Compounds
Authors: Garvey B. S. , Juve A. E. , Sauser D. E. 
Published: February 2011

Abstract
Hycar-OR is an oil-resistant synthetic rubber produced and sold by the Hydrocarbon Chemical and Rubber Company, which is jointly owned by The B. F. Goodrich Company and the Phillips Petroleum Company. Articles manufactured from Hycar by The B. F. Goodrich Company are sold under the trade name Ameripol. The object of this paper is to give a general view of the more important properties of a range of Hycar compounds and to illustrate the methods of compounding used. The recipes were selected, not to meet any particular specifications, but to include different types of stocks which might have commercial utility.
Wanted—A New Aging Test
Authors: Stevens W. H. 
Published: February 2011

Abstract
For many years rubber manufactures have been tested by artificial as well as natural aging tests. Of the former, the heat aging test by means of the Geer oven (an electric oven held at 70° C) was the first to be adopted and remains probably, the widest used. The correlation between the Geer oven and natural aging varies according to the type of goods and their conditions of service, but a rough and ready guide is that one day in the oven at 70° C is approximately equivalent to six months of natural life. Other heat-aging tests subject the rubber goods to air or oxygen at elevated temperature and pressure, with proportionate reduction of the time of test necessary for practical results. Apart from heat, light has a great deteriorating effect on rubber and some use has been made of this in testing rubber manufactures which are subject to light aging in service. The purpose of this article is to draw attention to the difficulty of accurately simulating natural light, particularly in reference to the conditions obtaining in direct summer sunlight, which has been found to have a far faster deteriorating action than that of ultraviolet light on rubber. For instance, it has been found that about 10 days of summer sunlight, partly deprived of its ultraviolet fraction by passage through window glass, is sufficient to completely destroy a plain rubber film which will stand up to weeks of light aging by a mercury vapor lamp or of ordinary heat aging at 70° C.
Color Measurements of Latices and of Rubber Films Prepared from Them
Authors: Van Nederveen G. 
Published: February 2011

Abstract
In the introduction to the present work, reasons for latex becoming discolored are reviewed, and the importance of color measurements are discussed. In addition, methods which have been developed for measuring the colors of various socalled white products, such as sugar, flour, paper, and the like, and methods for measuring the color of latex, are reviewed. Some of these methods are subjective; on the contrary, others utilize photocells so that subjective observations are eliminated. Measurements of the colors of different samples of latices were carried out with a Lovibond colorimeter, as a result of which it was found that this instrument is wholly unsuitable for this purpose. Measurements of the colors of both latices and films prepared from these latices were then made with a Hilger blancometer. The method of measuring and of calculating the intensity of the reflected light of a definite color is explained. The results obtained in measurements of the reflection of white light and of blue light from different samples of latex, using a Hilger blancometer, are compared with the results obtained with the same samples of latex estimated by simple visual examination. It was found that latices of good color reflect 80 or more per cent of white light and 78 or more per cent of blue light. The reflection of a yellow latex is considerably less in blue light than in white light. The reflection of a gray latex in white light does not differ much from that in blue light; in each case it is less than 80 per cent. It is proved conclusively that, judged by measurements of the colors of films, there is a close relationship between the color of a latex and the color of white-pigmented films made from the particular latex.
The Polarographic Determination of Organic Accelerators of Vulcanization
Authors: Proske Gerard 
Published: February 2011

Abstract
In spite of the great importance which vulcanization accelerators have attained in the rubber industry, there is still an almost complete lack of analytical methods, both for determining the accelerator contents of rubber mixtures and for identifying accelerators in vulcanized rubber. Apart from the wholly unsatisfactory and uncertain method of deciding the existence of organic accelerators in vulcanized rubber by a Kjeldahl nitrogen determination, there is little of value in the literature. Twiss and Martin have described a few qualitative reactions of accelerators. Recently Shimada described some color reactions of accelerators with cobalt oleate, but the analytical utility of these reactions is very doubtful. Of far more promise than these is the polarographic method, the value of which in the analytical determination of a series of important accelerators was proved in an investigation which will be described in the present paper. It had already been proved in earlier polarographic investigations that organic compounds containing nitrogen with a double bond can be reduced electrolytically, provided groups with a tendency to rupture are close to the double bond. Shikata and Tachi have shown this to be true of azobenzene, and Winkel and Proske of dimethylquinoxaline.