bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of the Absorption of Oxygen by Vulcanized Rubber in Air
Authors: Milligan A. G. , Shaw J. E. 
Published: February 2011

Abstract
It is generally agreed that oxidation is the controlling factor in the decay of rubber compounds. Measurements of the decay of any physical properties—commonly tensile strength—can be made in a convenient time only if the decay is greatly accelerated, and there is always a grave doubt about the equality of the acceleration for different materials. There is also a difficulty in selecting a universally suitable aging period, since the decay of the physical properties is not linear. A direct measure of the rate of oxidation is, in our view, more fundamental and less equivocal. It can, moreover, be made in a reasonable time at a temperature not far removed from service temperatures. Again, whereas tensile tests require several samples of each point in the timecurve to give acceptable mean values, here a single sample suffices for the whole test, and this sample can be simply prepared from a specimen of any form by rasping. The merits and simplicity of the method should commend it to rubber technologists.
The Direct Determination of Oxygen in Rubber. The Adaptation of the Ter Meulen Method to Rubber and Its Application to the Study of Aging
Authors: Cramer H. I. , Sjothun I. J. , Oneacre L. E. 
Published: February 2011

Abstract
The ter Meulen method for the direct determination of oxygen has been adapted, with modifications, to the analysis of raw and vulcanized rubbers. Raney nickel has been found to be quite effective as the reducing catalyst and to be satisfactorily resistant to sulfur poisoning. The method has been applied to the study of the aging of vulcanized rubber in the Geer oven and oxygen bomb. From this study the following conclusions may be drawn: (1) The increase in combined oxygen is greater in the oxygen bomb than in the Geer oven. (2) Deterioration of rubber in the oxygen bomb involves oxidation primarily, whereas that occurring in the Geer oven involves not only oxidation but also thermal decomposition followed by volatilization of oxidation products. (3) The effectiveness of an antioxidant in retarding the absorption of oxygen in oxygen-bomb aging agrees well with its ability to maintain the physical properties of the stock in which it is present. (4) The deterioration in physical properties of a rubber stock in the oxygen bomb during the early stages of aging is a linear function of the increase in combined oxygen. For stocks containing antioxidants and diphenylguanidine as the accelerator, an increase in combined oxygen of approximately 1.2% corresponds to a decrease in tensile strength of 50%. (5) The relationship of increase in combined oxygen to decrease in tensile strength seems to be affected not only by antioxidants, but also by accelerators of vulcanization.
A Proposed New Method of Retarding the Aging of Vulcanized Rubber by Means of Peroxides and Nitro Compounds
Authors: Minatoya S. , Ando^ T. 
Published: February 2011

Abstract
(1) Considering that low-sulfur vulcanization gives high resistance to aging, because vulcanization does not go beyond the primary stage, it has been sought to effect this control in stocks accelerated with diphenylguanidine. m-Dinitrobenzene has been selected from a number of possible agents as a reliable controller; other agents which retard vulcanization and have weak control effect or active oxidizing effect were rejected. (2) From a comparison of m-dinitrobenzene and aldol-α-naphthylamine in diphenylguanidine stocks, successful aging resistance has been observed. Mechanical tests were carried out before and after bomb aging, and chemical analyses were made of the vulcanized rubbers to throw light on the vulcanization mechanism and the reasons for improved resistance to aging. (3) Parallel experiments with other accelerators failed to reveal improved aging resistance, and in the presence of mercaptobenzothiazole in particular, m-dinitrobenzene acts as an oxidizing agent. (4) Tests of the stability of m-dinitrobenzene, alone and when mixed with various reagents, by the Abel test for stability of explosives have shown that the stability depends on the purity of the compound. Diphenylguanidine is effective as a stabilizer of m-dinitrobenzene, while other accelerators act as decomposers, thus providing a reason for the age resistance observed with diphenylguanidine. As a result of the stability tests, it has been found that various amines, soaps and mineral oils are effective as stabilizers of m-dinitrobenzene. As an instance of their application, aging tests have been carried out on rubber compounds accelerated with mercaptobenzothiazole and containing m-dinitrobenzene stabilized with diphenylamine. It has been found that the age resistance is much improved and is comparable with that obtained in the presence of aldol-α-naphthylamine.
Fatigue in Rubber. Part II
Authors: Naunton W. J. S. , Waring J. R. S. 
Published: February 2011

Abstract
1. An apparatus is described for measuring the modulus and resilience of rubber over a wide range of frequencies. 2. These measurements can be made at any point in the stress-strain curve of the sample. 3. By increasing the power input, the same apparatus can be used to induce high frequency fatigue in the sample. 4. The earlier work with the torsion head apparatus has been confirmed, namely, that internal friction is greatest near zero strain. 5. High frequency resilience is more independent of degree of vulcanization than tripsometer resilience. 6. Modulus tends to increase with frequency. The effect is least with a rubber gum stock and is greater with compounds containing gas black. 7. Resilience decreases with frequency both in gum and gas black compounds. The decrease is more rapid in the gum compounds. 8. Viscous resistance decreases with frequency and becomes constant at higher frequencies. 9. The modulus of both rubber and Neoprene carbon black compounds decreases with fatigue. 10. The change in modulus with frequency in fatigued stocks is exactly analogous to the change before fatigue in rubber, but there is a slight divergence in the case of Neoprene.
Note on the Theory of Water Absorption by Rubber
Authors: Daynes H. A. 
Published: February 2011

Abstract
There is still a need for a quantitative theory of the form of curves describing the changes of water content of rubber with time of exposure to various conditions of ambient humidity. Although considerable progress has been made in recent years, both in our understanding of the factors which determine such curves and in the use of empirical relations, there is still no fundamental solution which will enable reliable predictions to be made either for practical purposes or for verification of theories of the mechanism of absorption. It has been shown that, although this problem has much in common with that of the conduction of heat in solids, the chief obstacle to the application of the latter theory is the great deviation from linearity in the relation between humidity and the concentration of water in rubber which is in equilibrium with that humidity. It was also realized that it could not be assumed that the diffusion constant was independent of concentration (Daynes, Trans. Faraday Soc., 33, 531 (1937)). Blake and Morss (Proc. Rubber Technology Conference, London, 1938, 868), making use of this analogy between diffusion and heat conductivity, applied the well known differential eauation:
The Ultra-Rapid Testing of Rubber. The Testing of its Oxidizability in One Quarter of an Hour
Authors: Dufraisse Ch , Bras J. Le 
Published: February 2011

Abstract
It is hardly necessary to go into further detail to demonstrate the great advantages of such a test when used in a practical way. In the control laboratory, it will supplement and confirm the various other routine tests and, most important, immediately detect an error which the other tests will not do, particularly the omission, insufficiency or incomplete distribution of antioxygen. It will also reveal the presence of harmful impurities. For specifications and in manufacture, it will enable the article itself to be tested, either by removing a small piece or by providing a cavity for this purpose in the mould. Of course it is not necessary to limit the testing time to a quarter of an hour. If greater differences in the manometric levels are desired, the oxidation curve may be continued for a longer period, one hour, for example. Finally this oxidizability test at 120° C. would appear to fulfill the requirements of rapidity and precision of control testing, at least in the present state of stability of rubber products. Only in case of greatly increased resistance to oxidation would it be necessary to prolong the test for more than one quarter of an hour.
Forced and Spontaneous Changes in the Arrangement of the Molecules in Stretched Rubber. Crystals and Fused Phase in Stretched Rubber
Authors: Thiessen P. A. , Wittstadt W. 
Published: February 2011

Abstract
An unsaturated hydrocarbon of the formula (C5H8)2x is the basis of natural rubber. Although there are still differences of opinion about the size of the molecules, it may nevertheless be accepted as fairly certain that the parent substance, the unsaturated hydrocarbon, is composed of a mixture of various steps of polymerization. At ordinary temperatures and under no mechanical stress, both vulcanized and unvulcanized rubber are isotropic glasses. Exposed to x-rays they give the diagram of an amorphous substance, i.e., a broad, diffuse ring. As a result of mechanical deformation, especially stretching, rubber becomes anisotropic. This anisotropy is manifest by the appearance of optical double refraction, as well as by an x-ray fiber diagram, which replaces the amorphous ring. This indicates orientation of the molecules and rearrangement into a space lattice, measurements of which have been made repeatedly and which make probable a rhombic structure.
An Apparatus for Measuring Compressibility and Permanent Set of Rubber and Rubber-Like Materials at Various Temperatures
Authors: Hoekstra H. A. , Hoekstra J. 
Published: February 2011

Abstract
The importance of rubber and rubber-like substances for packings as shock-absorbers between parts of machinery, in short, the use of rubber under compression in mechanical construction is continually increasing. Several methods have already been proposed to investigate the behavior of rubber under these conditions, and the most ingenious method seems to be a two-dimensional stretching of rubber films in the form of balloons (Sheppard and Clapson, Ind. Eng. Chem., 24, 782 (1932)). This deformation is identical to homogeneous compression if volume changes by the deformation may be disregarded. The latter does not hold true if inactive fillers are used, which give rise to vacuoles in stretching but not in compression. However, in practice homogeneous compression is rare, as the material will never be able to glide without friction along the compressing parts to which in many cases the rubber is vulcanized. Because of the complicated deformation of rubber in practice, it is necessary to imitate the real conditions under which compression takes place. for these reasons a simple compression of cylindrical specimens between parallel plates was chosen as a first basis for the investigations.
A New Method of Investigation in the Evaluation of Fillers for the Rubber Industry
Authors: Behre Johannes , Göhde Karl 
Published: February 2011

Abstract
The busy technologist in the rubber industry is continually faced with the problem of choosing, by ready and simple means, the fillers best suited to his needs from the endless number offered him. In many cases there is no information at all about their composition or activity. In examining a filler it is necessary therefore to determine first of all whether it conforms to chemical requirements; whether for instance, it contains any substance poisonous to rubber. The degree of fineness must also be determined. Only if these tests are satisfactory is the filler given its final and conclusive test in a rubber mixing. Obviously there is little time to carry out such a series of tests in a systematic way, so in most cases a standard mixing is chosen to serve as a means of judging a filler. It is however well recognized that it is very difficult to reach any satisfactory conclusion by such a procedure, since only relative values are obtained, i.e., the values must be compared with those obtained with other fillers. Furthermore in such a test it is almost impossible to maintain the experimental conditions as constant as is necessary when it is intended to compare the results of two series of measurements with one another. It is readily understandable therefore that for a long time rubber technologists have wished for some kind of method which would make it possible to measure in absolute terms the activity of a filler in rubber.
A Mechanical Oscillograph for Routine Tests of Rubber and Rubber-Like Materials
Authors: Yerzley Felix L. 
Published: February 2011

Abstract
The oscillograph described has been developed primarily as a laboratory instrument to evaluate rubber and Neoprene compounds for mechanical applications. It is complete in itself as a means of measuring all of the quantities inherently involved in such service in units which are understandable to rubber technologists and mechanical engineers alike. It is hoped that it may serve its purpose by bringing into closer cooperation those who make and those who use rubber springs. The details of the test have been carefully developed, and it is expected that the machine and standard test-specimen described will not need essential modification for routine use. However, enough background has been given so that the machine may be modified in accordance with definite principles in order to gain greater load capacity if required. The test has been restricted thus far to compression. The author expects to adapt the machine to tests in shear, and by correlation between shear data and compression data to obtain figures capable of substitution in relationships already offered by other investigators for calculations in the applications and design of rubber springs. This field of calculation is complicated and in an early state of development, but by the use of the oscillograph it should be easier to obtain the quantities of information required to clarify our understanding of the mechanical characteristics of rubber-like materials within the range of deformation encountered in structural use.
Sol and Gel in Hevea Latex and Crude. Rubber Influence of Oxidation on Gel-Sol Transformation
Authors: Kemp A. R. , Peters H. 
Published: February 2011

Abstract
An apparatus and procedure to determine the amounts of sol and gel rubber in dried latex films and crude rubber have been described. It is shown that whereas plantation smoked sheet and crepe contain large and varying quantities of rubber soluble in petroleum ether, dried rubber films from latex are practically free from sol rubber when oxidation has been avoided. Latex increases in sol rubber content when subjected to various treatments permitting oxidation of the hydrocarbon. It appears from this work that the rubber in the form of latex is very susceptible to oxidation, which however involves only minute quantities of combined oxygen. When latex film rubber is subjected to creeping, it shows an increased content of sol rubber corresponding to that of crepe. A short milling of crepe was found to convert it completely into sol rubber. This confirms the gel-sol transformation mechanism of breakdown. Gel rubber from dried latex films is swelled to a maximum of 1500 to 7800 per cent but is not dissolved when placed in benzene, chloroform, carbon tetra-chloride or carbon disulfide and allowed to stand for several days. Gel rubber becomes soluble and therefore diffusible in these solvents as a result of oxidation. It was found that dried latex film and various types of crude rubber swelled to a maximum of 1000 to 2400 per cent in petroleum ether and that this swelling was not proportional to the sol content. This investigation strengthens the belief that sol rubber is an oxidation product of gel rubber. The formula for sol rubber is suggested as (C5H8)nO2, and a relationship between the molecular weight and the oxygen content is postulated on the basis that oxygen acts as a molecular splitting agent for both gel and sol.
Composite Nature of the Stress-Strain Curve of Rubber
Authors: Williams Ira , Sturgis B. M. 
Published: February 2011

Abstract
The stress-strain curve of rubber can be imagined to consist of three curves which tend to approach straight lines. The first curve has a high elongation load ratio and intercepts the second portion at an elongation which depends on the temperature. The second curve is parallel to the elongation axis and represents a condition of flow. The third curve has a low elongation to load ratio and represents rubber with a high load carrying capacity. It is evident that the second curve must be avoided as much as possible in most industrial applications. Most industrial applications require the rubber to work only within the limits of the first curve. The first curve is lengthened when the temperature is increased and the rubber can work efficiently to a higher elongation. No evidence has been found regarding the nature of the change which occurs in rubber during the period of flow. Since the flow is reversible, it must be within the molecule and not between molecules.
The Resistance of Rubber to Dynamic Forces Part I
Authors: Ariano R. 
Published: February 2011

Abstract
The subject of the present paper, which is of great interest on account of the numerous service conditions under which rubber is subjected to dynamic forces, has received little attention, perhaps because of the complexity of the phenomena and the consequent difficulty of coming to any definite and significant conclusions from experimental data. It is a widespread belief, for instance, that in static tension plastic flow takes place and that this is responsible for the Joule effect and that it modifies the shape of the stress-strain curve. By working at high velocities of extension, Williams proved that at room temperature and also at 60° C the stress-strain curves are straight lines and that complete elastic recovery takes place. The importance of verifying such a conclusion as this is obvious. Since, in fact, the elongations for a given load found by Williams were in every case greater when the stress was static, one is led to the conclusion that the deformation brought about by a given load is the sum of two components; one a perfectly elastic component, which obeys Hooke's law and which therefore is applicable to the established science of construction; a second component, which, in contrast to the first, is plastic in character and consequently depends on the duration of application of the load and on the loads previously applied. In brief, the law of deformation should be capable of reduction to the laws of two types of systems, viz., an elastic system and a plastic system. Unfortunately however this assumption could not be confirmed.
Rubber Stretched by Forces in Two Directions Perpendicular to One Another
Authors: Ariano R. 
Published: February 2011

Abstract
In previous publications the author has defined by means of relatively simple expressions, the behavior of rubber under tension and under compression. However, as was mentioned in a book entitled “Finite deformations” by the author, it is not possible to develop a theory of elasticity for highly deformable objects, which have their prototype in rubber, unless it is known how they behave when each element is acted upon by the primary three forces which, according to the theory of finite deformations, as well as the ordinary theory of elasticity or again the theory of infinitesimal deformations, are sufficient to define each state of tension. With regard to the last theory, the linear relation between deformation and stress makes it possible to accept the principle of the superposition of simultaneous forces, i. e., to add algebraically all coexistent forces and deforma- tions. However, this is obviously impossible for finite deformations, for which the linear relation in question has not been confirmed. Rather than proceed on the basis of hypotheses to develop theories and to verify them by deductions, it seemed more reasonable to undertake an experimental investigation, which later would serve as a background for the theoretical development of the problem. As a beginning, the case of the coexistence of two principal stresses in a relatively thin film has been considered. The experimental results are described in the present paper and will be discussed in a forthcoming paper.
The Problem of Crude Rubber
Authors: Thomas A. 
Published: February 2011

Abstract
In recent years, rubber manufacturers have made tremendous progress in compounding and in methods of manufacture, yet they continue, as they always have done, to regard smoked sheet and crepe from the plantations as the essential raw material of their industry. As a matter of fact, however, latex is the essential raw material, and the changes which it undergoes on the plantations are among the factors which influence the quality of the final rubber and therefore play a part in its possible uses. In the face of this, it seems like a paradox to say that the processing of latex on the plantations is based on arbitrary methods, without any consideration taken of their effects on the properties of the finished rubber, whereas mixing and vulcanizing operations are scrupulously controlled by manufacturers. For what reason does this paradoxical situation continue to prevail? Only because of the way by which the broker still evaluates rubber. The plantations are obliged to classify their commercial product into different types, according to color, superficial appearance, cleanness and the presence or absence of bubbles in sheet rubber, with complete disregard to its intrinsic properties, the latter not even being measured. To be regarded as the best quality, commercial rubber must be of a uniform color, must have a regular surface and must contain neither impurities nor bubbles.
Specific Gravity of Latex and of Rubber
Authors: Smith H. Fairfield 
Published: February 2011

Abstract
From observations on specific gravity and dry rubber content of latex, of centrifugal concentrates, and of latex-water mixtures, a number of attempts have been made to deduce the specific gravity of the rubber phase. Such estimates, after allowing for criticisms and adjustments which have been put forward, range from 0.901 to 0.914. But writers have made no attempt to consider how their calculations would be affected by treatments of the latex such as ammoniating and centrifuging, by different ways of evaluating the results, and by variations in temperature. When consideration is given to such matters almost all observations published during the last 20 years are found to be in good agreement one with another. Specific gravity, the ratio of the mass of a certain volume of a substance, at temperature t2, to that of the same volume of water, at temperature t1 is commonly designated dt2t2. To avoid excess affixes, when the temperature of the substance does not require to be stated, let:
Second Report of the Investigation of the Crystallization of Crude Rubber
Authors: Park Chullchai 
Published: February 2011

Abstract
Very recently the writer observed a small residual elongation in a stretched ribbon of smoked sheet rubber brought about by freezing, and it was found that the maximum residual elongation occurred after stretching about 200–300 per cent of the original length, and also that there was almost no elongation after stretching higher than about 700 per cent. To explain the behavior of crude rubber by crystallization, including these facts, it was assumed that the long chain molecules of rubber are in the form of large irregular spirals.