bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rubber Photogels
Authors: Stevens Henry P. 
Published: February 2011

Abstract
When a rubber sol is exposed to light in an air-tight vessel, it sooner or later gels, provided the concentration of the rubber is not too low and the air space above the surface of the sol is not too large. The first published observation of the gelling of a rubber sol in light was made by Porritt. Finding that the exposure of a rubber sol containing sulfur did not induce vulcanization, he repeated the experiment with the removal of oxygen, providing also a control tube without sulfur. Nothing happened with the tube containing the sulfur, but the control tube “after a few days suddenly set to a gel without any obvious preliminary increase in viscosity.” This gel on exposure (to air) was found to be rapidly transformed to a liquid. From the context it seems that the solvent used was benzene, but no information is given as to the type of rubber, whether raw or milled, concentration or other details, or how the removal of air or oxygen was accomplished. This observation of Porritt's is referred to in two or three subsequent publications by chemists who have noted similar occurrences. Thus, Smith reported the gelling of a sol of ether soluble rubber; and Meyer and Ferri found that, although rubber in solution is readily degraded in light and air, it polymerizes to an elastic jelly when exposed to ultraviolet light. But previous to the publications of Smith and of Meyer and Ferri, the subject had been examined in detail by Pummerer and Kehlen. This paper seems to have been overlooked.
Distribution of Non-Rubber Substances in Preserved Latex
Authors: Baker H. C. 
Published: February 2011

Abstract
The properties of latex depend, not only on its chemical components, but also on the distribution of these components between the rubber and aqueous phases and at the boundary between them. Therefore, to appreciate the function of different components in affecting the behavior of latex, it is necessary not only to know their nature and quantity, but also how they are distributed. For example, a component dispersed in the aqueous phase is not likely to affect coagulation or stability in the same way as the same substance concentrated in the boundary between rubber globules and water. Moreover, a component dissolved in the rubber phase is not likely to have marked effects on the properties of the liquid latex, although it may be of considerable technical importance when the rubber phase has been separated and dried. This paper records experiments made to obtain a satisfactory technique for measuring the distribution of the non-rubber substances in latex; its application in particular to nitrogen, acetone- and alcohol-soluble substances, water-soluble acids and long-chain fat acids; the influence of various factors such as particle size, dilution, pH, the addition of alkalies, enzymes, soaps, storage in the dark; finally, conclusions are drawn relating to the composition of the boundary layer between rubber and serum and of the interior of the rubber globule.
New Development in Rubber Reclaiming
Authors: Essex W. G. 
Published: February 2011

Abstract
The history of rubber reclaiming has been given by Alexander, and it is therefore intended only to make a brief reference to the well-known acid and alkali processes, the latter having proved to be by far the most successful method of reclaiming vulcanized rubber. The alkali process, introduced by Marks in 1899 had the outstanding advantage of simultaneously removing, from the waste, free sulfur, of which from 3 to 5 per cent was present, of destroying the fabric and of plasticizing the waste, this being accomplished by heating in a closed vessel under steam pressure with caustic soda. The acid process destroyed only the fabric, and plasticization by heat was performed in another operation in a separate vessel: by this method little or no free sulfur was removed from the waste. This latter disadvantage has since disappeared, for, with modern rubber compounding, there is little free sulfur left in vulcanized rubber. In recent years there have been widespread changes in the manufacture of rubber goods, particularly in the case of pneumatic motor tires, which are now the main source of raw material for reclaimed rubber. Organic accelerators, anti-oxidants and carbon black have made vulcanized rubber a very tough, resilient article, extremely resistant to aging and to heat, one of the chief agents used in rubber reclaiming. For example, modern motor tire treads, which are heavily reinforced with carbon black, are not so amenable to alkali and heat treatment, and tire treads reclaimed by this process have finally to be plasticized and made homogeneous by a much longer mechanical milling and refining treatment than was formerly necessary; in spite of this the treads still produce a proportion of rough, unrefinable material which has to be separated and rejected from the final reclaim. This increase in milling time, combined with lower finished production due to rejected unrefinable material, has had the effect of greatly increasing the manufacturing cost of the reclaim. Research was therefore started with the object of evolving a process which would successfully offset these difficulties caused by the changes in the properties and characteristics of the initial waste. The result of this work has been the creation of reclaimed rubber from which the disadvantages mentioned have been largely eliminated.
Vulcanization of Rubber by Nitrogen Compounds
Authors: Margaritov V. B. , Guchkova N. 
Published: February 2011

Abstract
The active influence of nitrogen compounds on the structure of the sols of bivinyl polymers, with consequent colloidization of the system, would lead one to assume that films obtained by evaporation of the treated sols would have better mechanical properties and greater elasticity than films of the unmodified polymers. The considerable activity of nitrogen compounds in rubber was first observed by Buizov, who directed attention to the vulcanizing action of diazoaminobenzene. Ostromislensky pointed out that nitrogen compounds are capable of producing phenomena in rubber similar to normal vulcanization with sulfur. Alessandri carried out a reaction of rubber with nitrosobenzene, which was later similarly studied by Bruni and Geiger, and by Pummerer and Gündel. In 1937 Levi observed the transformation of rubber which is brought about by brief heating with diazo compounds and leads to a condition outwardly resembling vulcanized rubber. Levi called particular attention to the fact that the most active agent, diazoaminobenzene, when heated to 150° C, produces free nitrogen amounting to two-thirds of the entire quantity of nitrogen, with the formation of o- and p-aminobiphenyl.
Studies of the Amorphous State. XVII. Dielectric Losses in Swollen Rubbers
Authors: Aleksandrov A. , Dzhian J. 
Published: February 2011

Abstract
1. The maximum of tan δ in rubber and the range of Ε-bending are displaced towards lower temperatures when plasticizers are incorporated. 2. The system: rubber—nonpolar plasticizer possesses the same time-constant, which indicates that the plasticizer affects the whole system and not only a definite part of it. 3. The system: rubber—polar plasticizer possesses the same time-constant, which indicates that one and the same activation energy U is required for orientation of the dipoles, regardless whether they are tied together by chemical bonds or by van der Waals forces.
The Proteins of Hevea Brasiliensis. II. Analysis of a Product Isolated from Crepe Rubber
Authors: Tristram G. R. 
Published: February 2011

Abstract
A protein (2) has been isolated from crepe rubber and analyzed for amidenitrogen, tyrosine, tryptophan and basic amino-acids. The dicarboxylic acids have been shown to be present. The results indicate that preparation 2 is of the same composition as preparation 1. It is now suggested that preparation 1 is a representative fraction of the total protein of latex. Loss of tryptophan has been observed from the protein found in crepe rubber and a reason for this loss has been suggested.
Buna for Hard Rubber Linings
Authors: Gartner E. 
Published: February 2011

Abstract
On the basis of the investigations described in the present paper, certain rules or directions for obtaining the most desirable properties with the various types of artificial rubbers can be laid down. Brinell hardness.—The higher the proportion of vinyl component in a mixed butadiene polymer, the harder is the resulting vulcanizate within the relatively narrow range of percentages of sulfur which were tested. In this respect, acrylonitrile has a greater effect than does styrene. Mechanical properties.—As far as mechanical properties are concerned, Perbunan-Extra is an extraordinarily good material for, in addition to giving high Brinell hardness and tensile strength, it also shows good shock resistance and impact strength. Buna-SS and Perbunan-Extra give, within the range of hardnesses tested, high Martens values. Compared with natural rubber, their resistances to dynamic bending are particularly good.
Investigations of Rubber Fillers. I. Particle Size and Characteristic form of Carbon Blacks and Their Influence on the Properties of Rubber Mixtures, as Judged by Ultra-Microscopic Photographs
Authors: Schoon Th. , Koch H. W. 
Published: February 2011

Abstract
The particle sizes and characteristic shapes of the particles of eighteen blacks used in the rubber industry were determined. The values which were obtained are compared with the physical properties of rubber mixtures prepared from these blacks. The characteristic shape of the particles has the greatest effect on the extensibility and the rigidity at 200 per cent elongation, i.e., on the modulus. When the particle size of a black is over 100 mµ, relatively poor resistance to tearing of vulcanizates containing the black is obtained. In general, the particle size of a black has far less influence on the other physical properties than has been believed in the past. With the aid of electron microscopic photographs, it is possible to estimate the value of a black as a filler in rubber.
Chemical Reactions of Rubber
Authors: Sibley R. L. 
Published: February 2011

Abstract
Most of the literature descriptive of the various known derivatives of rubber is found published as patents rather than as technical papers, thus indicating the commercial possibilities that may be expected from these developments. Fisher, Schidrowitz and, more recently, Jones have summarized and discussed the chemistry of rubber and its commercial derivatives. The decomposition of rubber by heat has been studied by several investigators. Williams showed that isoprene is one of the main products formed by the destructive distillation of either caoutchouc or gutta percha. Later investigators have shown that slow heating in vacuo at 300° C converts somewhat more than one-half of rubber hydrocarbon into a solid, thermoplastic, isomeric product, which has a high molecular weight and less unsaturation than that of the original hydrocarbon. Rapid heating, especially in vacuo, converts almost all the rubber into volatile products. The most complete investigation of the products obtained by the heat decomposition of rubber apparently was carried out by Midgley and Henne. These investigators destructively distilled 200 pounds of pale crepe rubber in 16-pound batches by raising the temperature as rapidly as possible to 700° C at atmospheric pressure in an iron kettle. The condensate was fractionally distilled, and cuts were made every degree between 50 to 176° C. Each cut was then separately examined. Twenty-three different hydrocarbons were identified in the distillate.
Theory of Filler Reinforcement in Rubber
Authors: Weiss Joseph 
Published: February 2011

Abstract
There are many active filler substances capable of improving to a considerable extent the mechanical properties of rubber mixes. The reinforcing effect of fillers is rather a complex problem and is known to depend, not only on the surface area and size of the particles involved, but also the nature and shape of the particles and the nature of the material in which they are situated. The influence of the surface forces between the filler and matrix has been discussed from a theoretical point of view, particularly by Hock and his collaborators. However, a closer perusal of the available experimental material reveals that the surface energy cannot be the only important factor in the reinforcing effect. It is clear that a particle of a foreign substance embedded within the bulk of the rubber will, in general, have a different volume from the actual space in the material available for it. If it is held firmly enough by the surface forces, the particle will either compress or expand the surrounding medium, depending on whether its size is larger or smaller than the hole in the matrix available for it. Consequently, this particle will become the center of a more or less symmetrical stress (compressional or tensional) field. In a discussion of filler reinforcement, the elastic energy generated by the particles must be taken into account. In the following it will be attempted to give a brief discussion of this effect and its relation to the previously treated surface effect of the particles. Although this should not be considered a complete theory, it introduces a new feature into the discussion of this subject, provides a basis for further experiments, and might be helpful in assessing the usefulness of fillers in rubber mixes.
Thermal Decomposition of Natural and Synthetic Rubber Stocks
Authors: Prettyman Irven B. 
Published: February 2011

Abstract
The factors responsible for failure of natural and synthetic rubber stocks in tires in service are primarily thermal in nature. They govern the temperature attained by the stock and the ability of the stock to withstand this temperature. The factors which determine the temperature attained include those dependent upon the stock itself and those dependent upon attendant conditions. In the first group may be mentioned thermal conductivity, internal friction, and elastic modulus. In the second are included the construction and design of the tire, the speed at which it is run, the load to which it is subjected, its inflation pressure, and the temperature of the road and surrounding air. Therefore, assuming a fixed set of conditions for the second group, the problem resolves itself into a determination of the amount of heat generated within the stock, the rate at which the generated heat is conducted away from it, and the temperature it may attain without undergoing chemical degeneration. These characteristics can be investigated independently in the laboratory.
Action of Organic Accelerators in Buna-S
Authors: Vila George R. 
Published: February 2011

Abstract
Buna-S is an unsaturated polymer capable of undergoing vulcanization. This may be effected by the application of heat in the presence of sulfur. The process is accelerated by certain organic substances which are used widely for a similar purpose in natural rubber. Preliminary teats have indicated that most of them are applicable to Buna-S, and appear superior to any other chemicals yet investigated. This is fortunate in view of the present emergency, as plants for their manufacture already exist and the industry is familiar with their use. In spite of superficially similar effects, more careful study has indicated that it is an oversimplification to assume various accelerators will produce ideptical effects in both polymers. A wide range of materials is now available to the industry, and the task of accurately evaluating all of them is complex. In addition, an indefinite number of combinations are theoretically possible. The present investigation was undertaken to determine what effect different chemical types of organic accelerators were likely to have on properties of fundamental importance.
Technical Microscopy in the Rubber Industry
Authors: Allen R. P. 
Published: February 2011

Abstract
For supplying information not obtainable by the usual methods, the microscope is useful and often essential; not only will it disclose details which would otherwise be unseen, but by its unique methods of examination measurements of certain properties of materials can be readily secured which are not otherwise obtainable. When one considers the value of the microscope to the rubber industry specifically, the study of the size of particles is usually the first and frequently the only application which comes to mind, although other uses have been suggested and described. The present paper not only describes the importance of the microscope in determining particle size and shape, but also covers its applications in the solution of other problems which ordinarily are not considered to lie in the field of microscopy. [Chamot describes many interesting applications in different industries which indicate the unusual capabilities of microscopic methods.] In a well-organized industrial laboratory, the microscope is used to supplement and aid other methods for examination of raw materials, control of factory processing, correlation of physical properties with service performance, and solution of factory difficulties. The specific examples cited in this paper represent uses which have originated in connection with the manufacture of rubber goods, but they serve also to illustrate methods applicable to problems of the same type originating in other industries.
The Course of Autoöxidation Reactions in Polyisoprenes and Allied Compounds. II. Hydroperoxidic Structure and Chain Scission in Low-Molecular Polyisoprenes
Authors: Farmer Ernest Harold , Sutton Donald A. 
Published: February 2011

Abstract
One of the most astonishing phenomena connected with the chemistry of rubber is the ease with which it absorbs progressively very small percentages of oxygen, and suffers as a result drastic and progressive reduction of its molecular weight. The natural conclusion to be drawn is that the polyisoprene chains of the rubber are undergoing oxidative scission at one after another of their unsaturated centers, so that the original long hydrocarbon chains become divided into smaller and smaller fragments possessing oxygenated ends. Recent estimates of the molecular weight of rubber by viscosity and osmotic methods range from 240,000 to 360,000 for fractions of decreasing solubility in hydrocarbon solvents. If we accept these figures and assume for the moment that two atoms of oxygen are sufficient to sever the hydrocarbon chains at a double bond, then an absorption of only 0.009–0.013 per cent of oxygen (applied, of course, exclusively to scission reactions) should suffice to reduce the average molecular weight to one-half. If the observed reductions of molecular weight are to be ascribed solely to oxidative scission of the chains, then, provided oxygen-consuming side reactions are few, a fairly exact inverse proportionality may be expected to hold between the uptake of oxygen and the average molecular weight of the degraded rubber. The most striking reductions in the molecular weight per unit of oxygen absorbed must, of course, occur at the very early stages of oxidative fission, while the hydrocarbon chains are still very long, and to be able to follow effectively the quantitative relationship between these important reductions and the oxygen uptake, it is necessary to make experimental provision for the absorption, even distribution, and measurement of very minute quantities of oxygen. Minute though the overall proportion of oxygen necessary to produce a substantial reduction in molecular weight appears in practice to be, however, there is no evidence to indicate that the scission reaction ever follows the course most economical in oxygen, i.e.,
Unsaturation of Synthetic Rubberlike Materials
Authors: Cheyney La Verne E. , Kelley Everett J. 
Published: February 2011

Abstract
The quantitative determination of rubber unsaturation has concerned numerous investigators. The use of iodine chloride as a reagent for this purpose (the well-known Wijs method) has achieved favor in recent years. Under the proper experimental conditions, addition has been shown to be quantitative, and substitution reactions can be kept at a minimum. This procedure has likewise been rather extensively employed as a measure of the residual unsaturation of various rubber derivatives. This reagent does not, however, add quantitatively to all unsaturated compounds, regardless of structure. The presence of a negative substituent on one or more of the unsaturated carbon atoms inhibits the reaction; in fact, it may entirely prevent it, as in the cases of maleic or fumaric acids or dichloroethylene. In other compounds extensive substitution may occur along with addition, as in the case of the unsaturated terpenes. The unsaturation of the polymerized diolefins should be of considerable interest, especially in comparison with natural rubber. It should be of special interest to study the comparative reactions with iodine chloride, which has become practically a standard reagent for rubber. Kemp and Mueller mention that polychloroprene, to which they erroneously refer as polyvinyl chloride, adds iodine chloride to only 30 per cent of theory. This could be due to two causes—the negative influence of the chlorine attached to an unsaturated carbon, and/or possible cross-linkage between chains (cyclization). It is well established that polychloroprene is much less reactive chemically toward other reagents than is natural rubber. It is unfortunate that Kemp and Mueller did not state with more detail the history of the sample studied, as such a result might have shown some interesting correlation with the experiments reported in this paper.
Methylethyl Ketone Extraction of Rubber
Authors: Cheyney La Verne E. 
Published: February 2011

Abstract
The extraction of rubber samples with acetone as an analytical procedure is a classical method; its origin is almost lost in antiquity, at least from the viewpoint of the rubber technologist. It is a valuable procedure, not only for practical evaluation of rubber samples, but from theoretical considerations as well. Acetone is commonly regarded as a polar “nonsolvent” for rubber, although some slight swelling action on rubber samples has been reported. Various investigators have carried out the extraction under differing conditions, and the results have been shown to vary somewhat with the treatment of the sample. The procedure as commonly employed today is well standardized, and great reliance is placed by rubber chemists on the analytical data obtained. The standard procedure, however, suffers from one serious drawback—the length of time necessary to obtain the desired data. With a large number of samples this factor is enormously magnified. When applied to plant control determinations, the disadvantage is too readily apparent. One possible method of reducing this difficulty would be the substitution for acetone of some other solvent, perhaps of higher boiling point, which at the temperature of extraction would have a greater solvent action on the non-rubber components. It should therefore accomplish the desired extraction in a shorter time.