bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physical Testing of Latex Films
Authors: Flint C. F. , Naunton W. J. S. 
Published: February 2011

Abstract
Determinations of the tensile strength of latex rubber involve difficulties which concern either the preparation of the sheets or the technic used in breaking them. Thick sheets of latex rubber may be cut into dumb-bell or ring test-pieces, which may then be broken on a tensile-testing machine of normal type. The preparation of thick sheets is, however, a matter of difficulty, owing to the fact that the complete drying-off of the water takes such a long time. Thus when ultra-accelerators are under test, vulcanization of the sheets may be advanced, or even complete, before the sheets are dry, so that investigation of the early stages of cure is impossible. Further, during the time that elapses before evaporation has gelled the whole thickness of latex, sedimentation of the compounding ingredients may occur in the mass of the fluid sheet, resulting in vulcanizates which are not uniform in composition or degree of cure. The use of devices such as porous tiles or the expedient of flowing the latex onto the surface of a gelatin jelly is objectionable because they absorb water-soluble components as well as water from the latex mix. Further, although they tend to prevent sedimentation by promoting more rapid gelling, the complete elimination of the water from a thick sheet is still a lengthy process, during which complete self-vulcanization may easily occur. The use of chemical coagulants is open to the same objection, which is of course overshadowed by the much more serious obstacle of their effect on the activity of accelerators and on the physical properties of the latex rubber.
Determination of Free Carbon in Rubber Goods
Authors: Oldham E. W. , Harrison J. G. 
Published: February 2011

Abstract
The carbon black analysis should not be made without a consideration of the nature of the original stock. The size of the sample must be related to the black content. To lessen time consumed in this analysis, preliminary extraction of the sample should be omitted. The correction factor for clay must be applied. By the revised method greater accuracy is obtained, although there is still a tendency for the results to be higher than calculated. Precision in this method seems to depend mainly upon accuracy of weighing and avoiding the loss of small particles of black.
The Preparation of Thin Films
Authors: Sager T. P. 
Published: February 2011

Abstract
VARIOUS means which have been suggested for the preparation of thin films of rubber and similar materials include their deposition on glass, porcelain, sheet metal, and mercury. The use of rigid surfaces is open to the objection that in the case of some materials the adhesion of the film may be troublesome. The removal from such surfaces, of films of materials which are subject to permanent deformation on stretching, tends to lessen the uniformity of their thickness. In connection with the study of the permeability to gases of thin films unsupported by fabric, a satisfactory and simple method was found for their preparation.
Colloidal Structure of Rubber in Solution
Authors: Gehman S. D. , Field J. E. 
Published: February 2011

Abstract
Analysis of the light scattered transversely by rubber solutions indicates that the units of structure responsible for the scattering are large compared to the wave length of light and possess a high degree of anisotropy. The scattering in many respects resembles that from a pure liquid more than that from a colloidal suspension. This is especially true for solvents of refractive index nearly the same as that of rubber and for high concentrations. In view of these facts the most probable view in regard to the structure appears to be that it is a loose structure of anisotropic groups with hindered rotation analogous to the cybotactic groups in a liquid.
The Absorption and Diffusion of Water in Rubber
Authors: Daynes H. A. 
Published: February 2011

Abstract
A new differential equation of diffusion is put forward to represent the movements of water vapor through rubber in accordance with the osmotic theory of absorption. Experiments are described which, together with the evidence quoted from existing knowledge, confirm a number of predictions as to differences between the absorption of a gas and of water vapor by rubber. These predictions deal with the shapes of the absorption- and desorption-time curves between narrow and wide limits of humidity, the relative times required for absorption and desorption, and the variation of absorption and desorption periods with thickness of the rubber sheet. The results are definitely inconsistent with the simple gas-diffusion theory, which is often assumed to apply to water in rubber. It is established that the shape of the humidity-absorption curve is a dominant factor in determining time-water content relations. Except for changes over very restricted ranges of humidity, the absorption- and desorption-time curves are of different shape, and desorption is much more rapid than absorption. The periods required for absorption and desorption are greater, the higher the humidity and the higher the hygroscopicity of the rubber. The law that the time required to reach a given stage of saturation varies as the square of the linear dimensions of the sample (the shape being constant) is equally true for diffusion, according to the old and new equations.
Nature of the Diffusion Process in Rubber
Authors: Barrer Richard M. 
Published: February 2011

Abstract
It is known that silica-gas diffusion systems exemplify a type of non-specific activated diffusion process, as opposed to the specific type of diffusion system, such as hydrogen-palladium. It seemed that the diffusion of gases through other “glass-like” materials such as some organic membranes, for example rubber, might offer further examples of non-specific activated diffusion. The data needed to test this hypothesis were available in papers by Edwards and Pickering, and by Dewar. Graham first noted the large temperature coefficient of the diffusion process through rubber, and that the diffusion velocities had no connection with the molecular weights.
The Oil Resistance of Rubber
Authors: Tanaka Yoshio , Kambara Shû , Hirakawa Kenji 
Published: February 2011

Abstract
The thermal effects of benzene on various rubber films are correlated with the polar and oil-resisting properties of rubber. By means of quantitative experiments on these effects, natural crude rubber was proved to be a non-polar material; purification, vulcanization, mastication, irradiation by ultra-violet rays, and chlorination increase the polarity of rubber. Synthetic films show small thermal effects because of the high polar properties and the compactness of structure of the films.
The Evolution of Heat during Vulcanization
Authors: Oberto S. 
Published: February 2011

Abstract
An experimental apparatus has been developed by means of which it is possible to measure with a high degree of precision the heats of vulcanization of rubber mixtures containing even very low percentages of sulfur, at temperatures as low as 110° C. Studies of vulcanization on a strictly thermochemical basis now appear both practicable and promising. An evolution of heat of vulcanization is accompanied by an improvement in the mechanical properties of a rubber mixture. The quantity of heat evolved does not seem to be a linear function of the percentage of combined sulfur, at least for low percentages.
The Brittleness of Ebonite
Authors: Ariano R. 
Published: February 2011

Abstract
The results of tests of the brittleness of ebonite are described. Resilience is influenced chiefly by the moment of inertia of the cross section of the test-specimen, but it seems also to be affected by the form of the specimen. The state of vulcanization has considerable influence on these mechanical properties within the undercured range, but with thorough vulcanization the state of cure plays no appreciable part. Notching of test-specimens is not of great importance. It diminishes the resilience, but when the tests are compared on a basis of equal moments of inertia of the resistant cross sections, this diminution becomes inappreciable in the case of brittle ebonites. On the other hand, the shape of the notch in ebonites containing no loading ingredients does influence the resilience. With V-shaped notches, the depth of the notch and its angle of aperture influence considerably the resilience of this latter type of ebonite, and notches of minimum depth are sufficient to have an appreciable effect.
Studies of Hard Rubber Reactions. III. Changes in Acetone-Extractable Substances during Vulcanization
Authors: Numajiri Seiiti 
Published: February 2011

Abstract
1. To explain chemically the fundamental hard rubber reactions which take place during the vulcanization, changes in the acetone-extractable substances, as well as in tensile strength, elongation, and hardness, during vulcanization were studied. 2. Preliminary experiments on acetone extraction with the author's apparatus indicated that a 20-hour extraction was ideal for the purposes of the investigation, and extractions extending to extremely long periods were unsuitable in the present experiments. 3. The corrected acetone extract or organic acetone-soluble substances do not either increase or diminish steadily throughout vulcanization, but show a maximum value at a definite period of vulcanization. The appearance of this maximum value, which also corresponds to characteristic changes in tensile strength, elongation, and hardness (cf. the preceding Communication) is a turning point where the hard rubber reaction diminishes rapidly. 4. To explain chemically the appearance of a maximum value and consequent increase and decrease in the percentage of acetone-soluble substances (corrected) it may be considered that the rubber or rubber compounds with different degrees of vulcanization are polymerized at a certain period of vulcanization, depending on the action of heat, accelerators and agencies, and that the amount of acetone-soluble substances is governed by these factors.
Studies of Hard Rubber Reactions
Authors: Numajiri Seiiti 
Published: February 2011

Abstract
As shown in Fig. 1, all the compounds containing 5 to 150 per cent of sulfur (based on the rubber) indicated a gradual loss of total sulfur, with a relatively rapid loss after about 90 minutes, which corresponds to the period of the hard rubber reaction. Some investigators hold the view that the loss of total sulfur is the result of liberation of hydrogen sulfide by the interaction of sulfur with rubber, resins, and proteins, and sublimation of sulfur. In the present experiments, the cause of the comparatively marked loss of total sulfur seems to be related to the hardening or polymerization reaction in hard rubber. No good mixture could be obtained from which the maximum loss of total sulfur was reached, with reference to the content of rubber, i. e., rubber resins, proteins, and that of sulfur. The loss of sulfur by sublimation was restricted as far as possible by enveloping the samples with cellophane. It appears from these facts that the depolymerization phenomena of soft or semi-hard rubber products may occur during the initial stage of vulcanization and those of the hard rubber after 90 minutes. Considering again the vulcanization curves in the previous report (Part IV), there is no loss of sulfur in the initial stage of vulcanization but considerable losses of sulfur are seen in the present curves of total sulfur; in other words, during the whole course of vulcanization the combined sulfur increases to a certain extent, accompanying the loss of sulfur on one side. In Fig. 2, the relationship between the loss of total sulfur and the tensile strength of the hard rubber product is shown. Of all the hard rubber compounds, the samples containing 70–80 per cent of sulfur showed the maximum loss of sulfur, coinciding with the maximum tensile strength after vulcanization for 90 minutes. It may be assumed that the polymerization and the depolymerization reactions occur simultaneously and are closely related.
Expanded Chlorinated Rubber
Authors: Schidrowitz P. , Redfarn C. A. 
Published: February 2011

Abstract
In a previous publication (J. Soc. Chem. Ind., 54, 263T–267T (1935); Rubber Chem. and Tech., 8, 613 (1935)) some particulars were given regarding the production and development of a hard spongy material from chlorinated rubber (British Patent No. 424,561). Thermal and Electrical Properties Some preliminary tests on the thermal and electrical properties of the material have now been carried out, and these serve to confirm the view that expanded chlorinated rubber should prove to be a very good insulating material. Thermal Conductivity.—The details given herewith are taken from a report by the Research Association of British Rubber Manufacturers. The thermal conductivity was determined by comparison with cork, a good insulating material of which the thermal properties are fairly well known. The method used consisted in placing slabs of cellular rubber and of cork each between a pair of aluminum plates, and then interposing between the two sets of plates an electric heating plate made of wire enclosed between sheets of mica. The plates, heater, and sheets of expanded chlorinated rubber material and cork were all of the same size, namely, 20.3 by 10.25 cm. The aluminum plates were 0.625 cm. thick.
Impact Resilience in Testing Channel Black
Authors: Fielding J. H. 
Published: February 2011

Abstract
THE precise grading of carbon black has been a problem to rubber manufacturers for years. Empirical specification tests inherited from the paint and ink industries have been used extensively; although they may have great merit in predicting the behavior of a black in paint or ink, they generally tell very little of its value in rubber. Since neither these tests nor the usual stress-strain data showed any great differences that could be associated with type of carbon black, chemists have been inclined to believe in the past that the rubber grade of channel black was quite a uniform material, at least when used in mercaptobenzothiazole stocks. Among the tests which have been used recently in the grading of black is resilience of the cured stock as determined by an impact pendulum. Although superficially it seems to measure no fundamental property of the black, it is a very practical test from a laboratory standpoint and appears to be capable of at least rough correlation with more fundamental properties. It is not a new property; the fact that it is influenced by carbon black is not new; but its application to the separation of blacks within the range of rubber channel black is new, and this phase will be discussed here.
The Evaluation of Rubber and Rubberlike Compositions as Vibration Absorbers. Apparatus for Automatic Recording
Authors: Yerzley Felix L. 
Published: February 2011

Abstract
The equipment is simple and foolproof. It provides an autographic record in a few seconds, from which can be evaluated dynamic hardness, dynamic modulus, internal friction, static hardness, and drift. It can be used to test rubber and rubberlike compositions over a very wide range of temperatures—for example, from −40° to 150° C. —for testing compositions which have been exposed to solvents or gases, and in conjunction with a fatigue machine for evaluation at various stages in a life flexing test.
Scorch Retarders and Scorch-Retarding Materials
Authors: Thies H. R. 
Published: February 2011

Abstract
Softeners, such as pine tar, rosin oil, and mineral oil, are useful when scorching trouble is encountered, owing to their scorch-retarding properties as well as to the fact that they soften the rubber batch. Stearic acid functions as a scorch-retarding material as well as an activating material when used with mercaptobenzothiazole. A decided gain in scorching time is demonstrated by use of scorch-retarding material without alteration to a great extent of the physical properties of the compound used. There is a definite change in the temperature coefficient of scorching encountered between 82° and 130° C., this coefficient being greater when rated per 10° C. for the temperature change between 82° and 99.5° C. than it is either between 99.5° and 113.5° C., or between 113.5° and 130° C. There is a tendency on the part of the stocks containing some retarders to give a greater percentage decrease in temperature coefficient of scorching over the range studied than does the control stock. With other retarding materials this does not hold. A scorch-retarding material is best measured by its effect upon index numbers of a control stock rather than by its effect upon the temperature coefficient of scorching.
Behavior of Rubber under Repeated Stresses
Authors: Holt W. L. 
Published: February 2011

Abstract
The stress-strain relations of a sample of rubber are very markedly affected by the previous strain history. Rubber will recover to some extent from the effects of a strain, but not completely. In a rubber compound, such as tread stock, a series of increasing strains has a pronounced progressive action, each increase in strain producing added effects. The conventional stress-strain curve does not represent the permanent characteristics of a rubber compound.
Acetylene Polymers and Their Derivatives. II. A New Synthetic Rubber: Chloroprene and Its Polymers
Authors: Carothers Wallace H. , Williams Ira , Collins Arnold M. , Kirby James E. 
Published: February 2011

Abstract
Chloro-2-butadiene-1,3 (chloroprene) is described and its structure established through reactions leading to its conversion into butane-α, β,γ,δ-tetracarboxylic acid, and into β-chloroanthraquinone. Within ten days under ordinary conditions in a closed vessel containing a little air, chloroprene spontaneously changes into a transparent, resilient, strong, non-plastic, elastic mass resembling vulcanized rubber. This product is called μ-polychloroprene. By interrupting the polymerization before it has proceeded to completion one obtains a soft, plastic product (α-polymer) that resembles unvulcanized rubber. Under the action of heat the α-polymer rapidly changes to the μ-polymer. Other polymers of chloroprene described are volatile (β-) polymer, granular (ω-) polymer, and balata-like polymer. The structures of the polymers are discussed as well as the effect of conditions on the formation of each type. Unlike any previously described synthetic rubbers, μ-polychloroprene resembles natural rubber in the fact that when it is stretched its x-ray diffraction pattern shows a point diagram. The transformation of chloroprene into μ-polychloroprene occurs very rapidly in aqueous emulsion. The resulting product constitutes a synthetic (vulcanized) latex. It has a much smaller particle size than natural latex and it penetrates porous materials more readily. Chloroprene can also be polymerized in the pores of porous or bibulous materials. The materials thus become intimately impregnated with synthetic rubber. Compared with natural rubber the new synthetic rubber is more dense, more resistant to absorption or penetration by water, less strongly swelled by petroleum hydrocarbons and less permeable to many gases. It is much more resistant to attack by oxygen, ozone, hydrogen chloride, hydrogen fluoride and many other chemicals.
Some Factors Affecting the Resistance to Flexing
Authors: Neal Arthur M. , Northam Alfred J. 
Published: February 2011

Abstract
Failure on flexing has been shown to be due to oxidation rather than mechanical fatigue or the action of ozone. The action of secondary aromatic amines of the type of phenyl-β-naphthylamine in retarding the failure of rubber on flexing lies in their antioxidant properties. WITHIN the last few years the deterioration of vulcanized rubber under dynamic strain has received considerable attention from the rubber industry. The cracking of tire treads, carcass, and belting separation, the cracking of boot uppers and shoe soles are types of failure which come in this class. In order to study this type of deterioration it is necessary to have a quick method of laboratory evaluation. To meet this need, a large number of the rubber manufacturers have developed flexing machines, many of which are designed to make only specific tests. In addition, there are several general-duty flexing machines, for example, the De Mattia, the Torrence-Peterson, the du Pont, and the United States Rubber Company machines. All of these are designed to duplicate in the laboratory in a short period of time the same conditions which the article must withstand in service.
The Degradation of Rubber Solutions of Different Concentrations
Authors: Bary P. , Fleurent E. 
Published: February 2011

Abstract
Xylene solutions of rubber of the smoked plantation crepe type were placed in an atmosphere of nitrogen and maintained at a nearly constant temperature of 95° C. Solutions of five different concentrations were employed, namely, 5.12, 3.94, 2.88, 1.98, and 0.99 per cent, and measurements of the viscosity were made as before by the flow through a tube with an inside diameter of about 1 mm. In curves of the relative viscosity as a function of the time, the hyperbolic law already described (Comptes rendus 192, 946 (1931); Rubber Chemistry & Technology, 4, 505 (1931)) was again found to be true, but only for concentrations of 1.98 and 0.99%. With more concentrated solutions the curve presents a characteristic point, and can be separated into two distinct periods: (a) A period of disaggregation of the rubber swollen to the state of jelly in suspension in the xylene. The greater the concentration the more prolonged is this period (e. g., 320 hours for the 5.12 per cent solution and 110 hours for the 2.88 per cent solution). (b) A period of molecular degradation following that just described, during which the viscosity approaches more and more that of the solvent, while following the hyperbolic law observed previously.
The Plastic State
Authors: Antonoff G. 
Published: February 2011

Abstract
In the preceding article, Bary has shown a curve of the changes with time in rubber solutions of various concentrations, the interesting feature of which is the angular break which separates the curve into two sections. In a discussion of this paper, attention was called by de Meeus to the fact that it would be interesting to study the physical properties of rubber solutions as a function of the concentration without the complicating effect of aging. This brings up the question whether this curve would also have a similar break. Though data are not available on rubber solutions, it is considered that this is rendered probable by the following facts. Rubber solutions are true solutions or pseudo-solutions at great dilutions, while they become plastic at high concentrations. Experiments with certain plastic systems have shown a phenomenon which is characterized by the accompanying curve. A study of the physical properties of systems formed of various pigmente in suspension in unoxidizable oils, as a function of the concentration, showed that, in general, the properties change uniformly and continuously with increase in concentration of the pigment until a point is suddenly reached where a very pronounced break in the curve occurs.