bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of Zinc Oxide in Compounding Government Synthetic Rubber
Authors: Havenhill R. S. , Rankin J. J. 
Published: February 2011

Abstract
A comparative analysis of some of the factors involved in road tests on tires and laboratory flexometer tests indicates that not enough attention has been paid to heat dissipation and the role of the thermal conductivity of stocks in increasing heat dissipation. Flexometer tests currently used, in which samples are flexed between insulated plates, measure mainly heat generation. A modified St. Joe flexometer test is described, using metal-faced plates, which takes into account not only heat generation but heat dissipation, and should more nearly simulate road tests on tires when comparing GR-S (Buna-S) synthetic rubber stocks having different thermal conductivities. Using the new type test, mixtures of easy-processing channel black and zinc oxide are shown to have higher tensile strength and lower heat generation than soft blacks or mixtures of soft blacks and easy-processing channel blacks. The data given in this report indicate the need of further work along this line in the way of road tests on actual GR-S (Buna-S) tires containing zinc oxide in both tread and carcass.
Properties of Some Synthetic Rubbers
Authors: Sebrell L. B. , Dinsmore R. P. 
Published: February 2011

Abstract
X-RAY STRUCTURE OF SYNTHETIC RUBBER In presenting a series of x-ray diagrams of various types of synthetic rubber in comparison with natural rubber, in both the stretched and the unstretched condition, it is our purpose to bring out the fact that the molecular structure of synthetic rubbers is entirely different from that of natural rubber. It is proposed also to review briefly the theories which have been advanced, based on the x-ray analysis of rubber, to account for the elasticity of natural rubber, and to advance the possible reason for the difference shown by the x-ray diagrams of synthetic rubber. At the present time, from the most general point of view, the molecular structure of a rubberlike material is envisaged as a sort of brush-heap structure of entangled long chain molecules. x-Ray diffraction patterns show that, for some rubberlike materials, notable regularities of structure sometimes occur in the tangle of long-chain molecules. It is now realized that these regularities are not essential for rubberlike behavior. Nevertheless their observation and study is important because they afford a unique opportunity for studying the molecular structure of the chains and the molecular rearrangements which occur with the application of stress.
Statistical Thermodynamics of Rubber
Authors: Wall Frederick T. 
Published: February 2011

Abstract
The entropy change for the stretching of rubber is calculated by statistical methods, neglecting intermolecular attractions and deformation of bonds and bond angles. The calculation involves the probability of finding the system with a given distribution of molecular configurations. An equation of state relating the tension, length, and temperature of a rubber band is then derived. Following this a discussion of the applicability and the limitations of the theory is presented.
Solvents and Plasticizers for Chlorinated Rubber. Critical Data
Authors: Raynolds J. W. , Radcliffe M. R. , Vogel M. R. 
Published: February 2011

Abstract
1. No particular solvent may be classified as the best for use with chlorinated rubber. On the contrary, the solvent must be chosen with a view to its general properties and, where other ingredients are to be compounded with chlorinated rubber, the solvent strength as measured by the dilution ratio is of considerable importance. 2. The compatibility of blown castor oil with chlorinated rubber, some other blown oils, and some alkyds, depends on the strength of the solvent used. Strong solvents as measured by their dilution ratio enhance compatibility. 3. No particular plasticizer is best for use with chlorinated rubber. Different plasticizers impart totally different results at different loading percentages. The choice of plasticizers is dictated by the ultimate properties desired. More frequently than not, the use of two or more plasticizers will be necessary to obtain the optimum properties for any given application. 4. Consideration of the fundamental principles and trends presented in this paper will be helpful in the formulation of chlorinated rubber finishes for a wider variety of uses, and products of an improved nature will be the result.
Further Electron Microscope Studies on Colloidal Carbon, and the Role of Surface in Rubber Reenforcement
Authors: Wiegand W. B. 
Published: February 2011

Abstract
(1) Based on preliminary electron microscope analysis, rubber carbons are assigned tentative surface values, ranging from one to upward of 12 acres per pound. (2) In all cases particles are of essentially spherical habit. (3) Indications of chain and network structure have appeared in acetylene carbon and lampblack plates (conclusion not final). (4) Physical properties of carbons in rubber are reviewed, and the advantages of “soft” carbons enumerated. (5) Differences in chemical compositions are found not to square with reënforcing differences in rubber. (6) When colloidal properties, tinctorial properties, and rubber properties are plotted against acres per pound, it is found, as anticipated, that surface is, in general, the dominating influence; subject, however, to important and sometimes controlling anomalies. (7) These anomalies appear to be largely resolved on the assumption that three broad types of carbon behavior exist. (I) Carbon-rubber complexes (reënforced rubber) are formed (examples— semireënforcing carbons, Statex and carbon blacks). (II) Carbon-carbon complexes or networks are formed in addition to (I). Examples, acetylene carbon and lampblack. (III) Carbons are inert—neither (I) nor (II) occurs. Examples—thermal carbons. These relations are brought together in Table 1.
Heats of Combustion and Specific Heats of Buna-S Treated in Various Ways
Authors: Roth W. A. , Wirths Gerhilde , Berendt Hildegarde 
Published: February 2011

Abstract
Measurements of the heats of combustion and specific heats (between 20° and 50° C) of crude untreated Buna-S, highly degraded Buna-S, and cyclized Buna-S are reported. The heats of combustion are then discussed. A well defined relation exists between thermal data and changes which take place in Buna-S. In the case of specific heats, the values of which are less precise, the relation is not so clearly defined.
A Simplified Hot Tensile Test for GR-S
Authors: Braendle H. A. , Valden E. , Wiegand W. B. 
Published: February 2011

Abstract
In September, 1942, the hot-iron test developed by E. Valden, of these laboratories, was demonstrated as a simple rapid method of evaluating the heat embrittlement of GR-S. The test-specimen, a T-50 test-piece, may be cut from the remnants of test sheets cured for stress-strain determinations. for GR-S treads a convenient set of conditions is 200 per cent elongation and an iron temperature of 400° F. The iron is fastened to the test-block at a sufficient height to assure positive contact of the specimen with the iron, and the screws in the spacer blocks are set to give a 200 per cent elongation. The iron, a “patch heater”, for spotting or dry-mounting photo prints, has a built-in thermostat. The time in seconds between contact of the specimen with the iron and its failure due to heat is recorded. The relative behavior of various elastomers with 27.8 volumes of carbon is illustrated in Figure 1. The excellence of Hevea at both optimum and prolonged overcure is apparent. The hot-iron test does not serve to pick best cure. It does provide an effective warning against overcure and a means of recognizing compounding changes which benefit heat stability, as, for example, the use of high carbon high softener ratios.
Reactions of Iodine, Iodine Chloride and Thiocyanogen with the Hydrocarbons of Natural Rubber and Synthetic Rubber
Authors: Medvedchuk P. I. , Aldoshin F. D. , Marovich V. P. , Repman A. V. 
Published: February 2011

Abstract
The reactions of iodine, iodine chloride and thiocyanogen with solutions of natural rubber and of synthetic sodium-butadiene rubber were studied. The experimental results show that the chemical properties of these two hydrocarbons are in general similar, although there are also certain differences which can be explained by the peculiarities of their structures. The products of the reactions of iodine chloride and of thiocyanogen with natural rubber and sodium-butadiene rubber were isolated, and their compositions and some of their properties are described.
Structural Features of Buna-S. Relation to Physical Properties
Authors: Kemp A. R. , Straitiff W. G. 
Published: February 2011

Abstract
The low tensile strength of Buna-S gum stocks is generally believed to be due to failure to obtain effective cross-linkage as the result of vulcanization with sulfur and accelerators. Combined with this is the complete absence of crystallization of Buna-S on stretching which, in the case of natural rubber, reinforces and strengthens the vulcanized gel structure. The absence of crystallization in Buna-S can be explained on the basis of nonsymmetry along the polymer chains. Strictly speaking, Buna-S is not a true polymer, for ozonolysis shows that the styrene units are not spaced evenly in the chain but are grouped together in some locations. Ozonolysis also has proved the presence of vinyl groups attached to the chain, resulting from the polymerization of butadiene in the 1,2 instead of the 1,4 position. These vinyl groups must be unevenly spaced along the chain, and mixed trans and cis isomers must be present. Figure 1 illustrates the chemical units present in Buna-S, rubber, and gutta-percha hydrocarbons. In a Buna-S copolymer containing 24.5 per cent of styrene, there are six butadiene to one styrene units. It appears that about one butadiene in five polymerizes in the 1,2 position in the chain. It should be emphasized that, in Buna-S, ozonolysis has shown that no regular order exists in the location of A, B, and C units in the polymer. An entire lack of symmetry in the positioning of these units in the chain would be expected in view of the nature of the polymerization reaction.
A New Approach to the Theory of Rubberlike Elasticity
Authors: Huggins Maurice L. 
Published: February 2011

Abstract
It has been shown that for a simple hypothetical model substance, containing like independent systems, each capable of existing in two alternative orientations, stress-strain curves may be computed which are similar in form to those ordinarily obtained from rubber and rubberlike materials, provided one introduces a certain dependence of the volume shift per rearrangement on the elongation. With this model, the dependence of the initial elastic modulus and that of the shape of the stress-strain curve on various characteristics of the rearranging systems are readily studied. More detailed comparison of these theoretical results with experimental data and with other theoretical treatments will be postponed until a later date.
Qualitative Spot Tests for Rubber Polymers
Authors: Burchfield H. P. 
Published: February 2011

Abstract
To eliminate processing difficulties and ensure the production of standard natural and synthetic rubber reclaims, the scrap used as the raw material must be carefully segregated. When mold markings are lost, or large consignments of miscellaneous scrap are received, methods for distinguishing between the basic polymers are necessary. This paper describes a new color reaction which will serve to characterize natural rubber, GR-S, and Perbunan. Confirmatory tests included in the same operation distinguish between the remaining commercially important types. The procedure is sufficiently rapid to be practical in the testing of representative samples from carload shipments, or for establishing the identity of materials on which indecisive results are obtained by less specific methods. For the routine assortment of scrap, spot tests are proposed, which are carried out by holding impregnated filter paper strips in the smoke emitted when the sample is branded with a metal rod heated to redness. Color changes take place which indicate the nature of the polymer. One test distinguishes between natural rubber and GR-S ; a second is specific for Butyl ; a third differentiates Neoprene-GN, Neoprene-ILS, and Perbunan from one another and from the hydrocarbon rubbers. The spot reactions can be carried out very rapidly, and are particularly useful when large numbers of samples must be examined.
A Comparison of Different Types of Rubber Obtained from the Same Field Latex
Authors: Van Der Bie G. J. 
Published: February 2011

Abstract
Several comparative investigations of various types of raw rubber have been published, but most of these refer to products of different origin, hence it is not known to what extent the results depended on natural variations in the rubber. Moreover, the investigators, who prepared their own material, worked either with old latex in Europe, in the United States or in the tropics, where the work was confined to only a few types of rubber. The present investigation was conducted with the following objects in view : (1) A comparison of various types of commercial rubber, i.e., smoked sheet, crepe and whole-latex rubber. (2) A comparison of these rubbers with those obtained from different types of latex (or cream latex). (3) The influence of storage of latex (cream latex) on the properties of the rubber. (4) The influence of storage on various types of, rubber. (5) A comparison of the accelerated aging tests of Geer and Evans and of Bierer and Davis.
Natural Rubber from Russian Dandelion
Authors: Eskew Roderick K. 
Published: February 2011

Abstract
A great deal has been published during the past three years regarding the various sources of natural rubber which have been called upon to supplement this nation's stockpile and to meet those special needs for which commercial synthetic rubbers are not entirely satisfactory. We have read of wild rubbers being brought in under great difficulty from Central and South America; of the 32,000 acres of guayule grown by the government, largely in California, and now nearly ready for harvest; and of the large experimental plantings of Cryptostegia in Haiti. Almost nothing, however, has appeared regarding a plant which is known to be potentially rich in high-grade rubber and which has been extensively cultivated outside this country. This is the Russian dandelion, or Taraxacum kok-saghyz. In the course of a systematic investigation instituted in Russia in 1929 to determine the possibilities of producing natural rubber in that country, the kok-saghyz was found near Tien Shan, Kazakstan, near the border of China. By 1932 more than 2,000 acres of this plant were under cultivation in Russia, and it is reported that at the time of the German invasion of Russia approximately 200,000 acres of kok-saghyz had been planted for the production of rubber.
Studies on Deproteinized Rubber. V. Effects of Several Proteins
Authors: Ōkita T. 
Published: February 2011

Abstract
It has been reported that rubber cures slowly when the protein in the rubber is removed, and similar results have been obtained in the author's experiments (Reports 1 and 4). As the phenomenon has relation to evolution of hydrogen sulfide during vulcanization, several experiments were carried out concerning these points. Vulcanization Test 7.5 parts of sulfur were mixed with 92.5 parts of washed smoked sheet or deproteinized rubber, and 5 parts of albumin, glutamic acid, hemoglobin, and gelatin, respectively, were added to the latter. These 6 mixes were cured in sheets 1.2 to 1.4 mm. thick in a press at 148° C. Tensile strengths of these samples are shown inFig. 1. The curing velocity of rubber is accelerated by these proteins. The effect is most pronounced in the case of gelatin, followed by hemoglobin and albumin. Glutamic acid has a slight effect on cure. The deproteinized rubber mixed with gelatin cured in almost the same time as the mixture of washed smoked sheet.
Soluble and Insoluble Rubber
Authors: Staudinger H. 
Published: February 2011

Abstract
A particularly striking property of unvulcanized rubber is that benzene-soluble rubber, which is a colloid capable of unlimited swelling, is transformed on standing into insoluble rubber—a colloid of limited swelling capacity. Scarcely any difference in composition can be found analytically between the two kinds of rubber, which differ so widely in solubility. Insoluble rubber can be reconverted into a soluble form by long standing or by mastication. These apparently reversible transformations between soluble and insoluble rubber were formerly ascribed to a micellar structure of rubber; it was assumed that the swelling phenomena, as also the high viscosity of rubber solutions, were connected with the solvation of the micelles. In contrast to such micellar theories it was shown, by the conversion of polymer-homologous rubbers into the polymer-analogous hydrorubbers, that the colloidal particles in dilute solutions are the macromolecules themselves. The high viscosity of rubber solutions is caused by the thread-like form of the macromolecules and not by a micellar structure; rubber thus belongs to the linear molecular colloids.
Heat of Dilution in the System: Rubber-Toluene
Authors: Meyer Kurt H. , Wolff Eberhard , Boissonnas Ch. G. 
Published: February 2011

Abstract
It is already known that the heat of dilution of a system can be derived from the temperature coefficient of the osmotic pressure. This method is an example of the indirect method supplementing direct calorimetric measurements which have been carried to a high degree of perfection by Swietoslawski. The present brief work is dedicated to this master of calorimetric research. It may be in keeping with the present work first of all to review the theoretical principles of the indirect method. The equation relating heat content to the temperature coefficient of free energy can be expressed thus:
A Machine for the Systematic Testing of Rubber Subjected to Repeated Flexings
Authors: Graffe Lucien 
Published: February 2011

Abstract
The machine which is described in this communication was designed, after due consideration from both the theoretical and practical points of view, to flex rubber samples repeatedly without subjecting them to longitudinal traction, i.e., to flex them at constant length. The test-piece, cut in the form of strips from a sheet or from some particular part of an article, is fastened at each end; one end is held immovable, the other is fastened to a movable support which undergoes reciprocal motion. There seems to be no record of the existence of a machine of this type, in fact most specifications call for tests involving repeated traction. At a recent international rubber conference F. Jacobs described a machine with which test-specimens of special shape can be alternately flexed and subjected to impact, which has an influence on the results. Moreover this machine requires moulded test-specimens, so that it is impossible to test samples prepared from articles in the particular forms in which they are designed for service. At first thought it might be assumed that this machine operates in such a way that the samples are not subjected to longitudinal traction during flexing. In reality, since every deformation of a solid body involves a change in the arrangement of the elementary fibers, and since rubber is apparently no exception to this rule, a sequence of tensions and compressions occurs, the frequency of which is the same as that of the reciprocating motion; the amplitude can be changed at will, and the intensity of the stresses depends on the particular conditions, as the brief analysis which follows will attempt to show.
Purified Latex and Rubber
Authors: Noble R. J. 
Published: February 2011

Abstract
Within the past ten years purified rubber has come to be a subject of considerable interest, particularly in the field of electrical insulation. Several papers have been published relating to methods of preparation and the properties of the resulting product. Numerous patents have been granted covering methods of preparation of purified rubber and its use in the manufacture of insulation, all such methods having as their object the removal of nitrogenous and water-soluble substances so that the final product may have a low degree of water absorption and high dielectric stability. Previous investigators in this field have arrived at somewhat divergent conclusions as to the cause of water absorption, the proper requirements of a purified rubber in this respect, and the efficacy of the various methods of purification. Inasmuch as different lots of rubber or latex with different compositions and properties were used in each case, it is difficult to correlate their results. The object of this paper, therefore, is to review the earlier work and to offer new data and conclusions resulting from the application of several different purification methods to one original latex.
Mechanical Properties of “Two-Dimensional” Rubber. The Micellar Structure of Rubber
Authors: Trapeznikov A. A. 
Published: February 2011

Abstract
It has been suggested by a number of authors that the enhancement in the mechanical properties of rubber by loading it with active fillers is connected with the transition of the rubber into a special state on the surface of the filler particles. Rehbinder and Margaretov, studying the mechanism of activation due to fillers, consider this change in the mechanical properties as a transition of the rubber into a two-dimensional film-state of solvate membranes which, similar to thin liquid layers, possess anomalous mechanical properties (elasticity in shear), as well as a peculiar colloidal structure. In the present investigation the mechanical properties of thin films of rubber were studied with the aim of discovering their anomalies, the appearance of which may be expected for sufficiently thin and, most probably, oriented films. The mechanical properties, characterized by deformation curves during stretching, were studied with an apparatus consisting of a paraffined trough containing water, on the surface of which was placed a film of rubber, spring balances (glass needle) to measure the tension, and two barriers to stretch the film. One barrier, in the form of a paraffined strip of paper floating freely, was joined by steel hooks to the lower ends of the balance; the other, a glass one, moved along the ends of the trough.