bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Curing Temperature on Quality of Vulcanized Rubber
Authors: Shepard Norman A. , Street John N. 
Published: February 2011

Abstract
A review of the literature permits no definite conclusion concerning the influence of temperature of vulcanization on the ultimate quality of a rubber product. Some investigators claim equal properties at different curing temperatures, others superior properties at low temperatures, while still others believe superior qualities are obtainable at higher temperatures. Concerning the influence of temperature on aging, no conclusive data are available. The temperature of cure has no influence on the tensile properties at maximum, in the case of the di-o-tolylguanidine stock. In the case of the mercaptobenzothiazole stock, there is a trend toward slightly higher tensile strength as the temperature is decreased. Natural, as well as artificial, aging of the di-o-tolylguanidine slock shows that the lower the temperature of cure, the better the aging will be. The results are clean-cut, probably owing to the fact that this is a stock which ages rapidly and hence shows differences in comparatively short periods of aging. The data on the mercaptobenzothiazole stock containing an antioxidant are far from conclusive, though they show a trend toward belter aging with lower temperatures of curing.
Grit in Carbon Black. Effect on Flexing Resistance of Vulcanized Rubber
Authors: Street John N. 
Published: February 2011

Abstract
Rubber channel black has been found to contain amounts of grit retainable on a 325-mesh screen varying from 0.05 to 1.7 per cent. This residue is shown to be objectionable from the standpoint of the flexing resistance of the resulting rubber compounds, higher concentrations being correspondingly more harmful than lower concentrations. The coarser fractions appear to give rise to larger cracks and earlier appearance of cracking than the finer material. Even that which passes a 200-mesh screen but is retained on a 325-mesh is objectionable.
A Method for the Purification of Rubber and Properties of the Purified Rubber
Authors: McPherson A. T. 
Published: February 2011

Abstract
Purified rubber was prepared by the digestion of crude rubber or latex with water at about 190° C., followed by extraction with water and with alcohol, and drying in an atmosphere of inert gas. The digestion hydrolyzed the proteins, and the extraction removed the hydrolysis products, resins, and other impurities. The purified rubber contained about 99.5 per cent of rubber hydrocarbon. Properties of the rubber hydrocarbon at 25° C. were: density, 0.9060; refractive index, 1.5184; dielectric constant at 1000 cycles per second, 2.37; power factor at 1000 cycles per second, 0.0015; conductivity at the end of 1 minute, 2.2×10−7 mho. The electrical properties measured on 14 samples were apparently independent of the botanical source or the kind of crude rubber.
Natural and Synthetic Rubber. IX. The Products of Destructive Distillation of Ebonite
Authors: Midgley Thomas , Henne Albert L. , Shepard Alvin F. 
Published: February 2011

Abstract
The following compounds have been identified in the products obtained from ebonite by destructive distillation: 2-methylthiophene, 2,3-dimethylthiophene, 2,4-dimethylthiophene, 2,5-methylethylthiophene and m-xylene. These results will be used to derive the structural formula of ebonite.
Natural and Synthetic Rubber. XI. Constituents of the Milled Rubber Hydrocarbon
Authors: Midgley Thomas , Henne Albert L. , Renoll Mary W. 
Published: February 2011

Abstract
The composition of milled rubber has been investigated by a method based on fractional precipitation from a benzene—alcohol mixture. This has shown that milled rubber is made of a continuous series of undefined components, without a single predominating individual. The same method had previously shown that one single individual constituted more than one-half of unmilled rubber.
Studies of Polymers and of Polymerization. VI. The Vulcanization of Methyl Rubber
Authors: Whitby George Stafford , Katz Morris 
Published: February 2011

Abstract
Samples of synthetic rubber prepared by the polymerization of dimethylbutadiene at room temperature and at 45° C., respectively, were subjected to vulcanization tests in comparison with natural rubber. In an accelerated gum stock containing 3% sulfur the cold polymer gave at best vulcanized products less than one-third as strong and only about one-third as extensible as natural rubber; the heat polymer gave products as extensible but only one-tenth as strong as natural rubber. The incorporation of carbon black greatly increased the strength of the synthetic rubbers, rendering both about one-half as strong as natural rubber in a similar stock. The vulcanized synthetic rubbers were less “snappy” than natural rubber at room temperature. Increase of temperature improved their speed of retraction, but seriously reduced their breaking strength. Products from the cold polymer showed a greatly increased stiffness and strength at 5° C. as compared with room temperature, and at about 1° C. were non-retractible. In general the synthetic rubbers were much more sensitive than natural rubber to change of temperature. A 50:50 mixture of the heat and cold polymers was also subjected to tests.
The Oxidation of Rubber Gutta-Percha and Balata with Hydrogen Peroxide
Authors: Mair John A. , Todd John 
Published: February 2011

Abstract
The behavior of rubber toward hydrogen peroxide was studied first by Boswell, McLaughlin, and Parker (Trans. Roy. Soc. Can., 16, 27 (1922)) and more recently by Robertson and Mair (J. Soc. Chem. Ind., 46, 41t (1927)). The earlier workers, using a solution of rubber in carbon tetrachloride, isolated a compound, C30H48O, which they found to absorb atmospheric oxygen and yield another compound, C25H40O2. The later workers adopted a modification of the usual method of hydrogen peroxide oxidation of terpene hydrocarbons and employed a chloroform solution of rubber, to which glacial acetic acid was added. They obtained a product, alcoholic in character, of the empirical formula C59H102O16. The present work was commenced with the object of extending the latter work to include gutta-percha and balata. Certain changes were introduced and new avenues of investigation opened up, and it was thought desirable to extend the scope of the work to include rubber so that each of the three substances, rubber, gutta-percha, and balata, and corresponding derivatives of them, might be submitted to as nearly as possible identical reaction conditions.
The Law of Absorption of Carbon Dioxide by Rubber as a Function of the Time
Authors: Cheneveau C. 
Published: February 2011

Abstract
1. As the form of the curves shows, factice does not appear to obey the law for rubber. Calculations give values which, in relation to the observed values, show deviations of 8.5 per cent for brown factice and 13.7 per cent for white factice, whereas Table I gives smaller deviations for the different rubbers. 2. Crude rubber absorbs more than the same rubber cut into pieces, which indicates that the latter has become less porous. The absorption measurements can therefore give an idea of the porosity. It is a curious fact that if crude or cut-up rubber is boiled with alcohol the same value for the coefficient of absorption is obtained. 3. Vulcanized rubber or rubber mixed with mineral or organic fillers absorbs carbon dioxide in the same way. 4. Although Reychler has assumed that carbon dioxide dissolves in rubber, it should be noted that the law of the phenomenon of absorption is identical to that of monomolecular chemical combination. Might there not be formed therefore a compound with one of the components of the rubber? In any case, it is extremely difficult to remove the carbon dioxide from rubber, even after subjecting it to a vacuum for a long time. Moreover, if successive experiments are repeated on a single sample, it is found that the coefficients of absorption become smaller and smaller. This indicates that more and more carbon dioxide remains in the rubber. The coefficient of absorption for plantation rubber at the end of four tests changed from 0.165 to 0.141 and did not regain its value at the end of 50 days' standing. Upon washing the rubber at this stage, traces of carbon dioxide were detected in the wash water by means of lime water. 5. The study of the k coefficients, which may be called diffusion coefficients, likewise gives information about a rubber. 6. A sample left for one whole day in carbon dioxide did not appear to have altered, as judged by its elongation and tensile strength. 7. Without desiring to draw any definite conclusions from this work, it is believed that more complete tests such as those described would doubtless be of value in obtaining information about the constitution or the quality of different rubbers.
Studies on Rubber in Solution. I. Studies on the Aging of Rubber Solutions
Authors: Fujihara Takeo 
Published: February 2011

Abstract
It is well known that raw rubber in colloidal solutions with different dispersion mediums shows the general characteristics of aging such as a decrease in its viscosity, whether aged by natural or artificial methods, and especially when exposed to ultra-violet light. Whitby and Jane (Colloid Symposium Monograph, Vol. 2, page 16) pointed out this phenomenon, and Asano (Mem. Coll. Eng. Kyoto Imp. Univ., Vol. 3, page 267) noticed that dispersed rubber sols decreased in viscosity and the rubber depolymerized and became insoluble by exposure to ultra-violet light. This effect was particularly noticeable with light of 2250 A. U.; however, light of longer wave lengths caused oxidation of the rubber and formed a transparent insoluble substance. Recently Hada (Rubber Ind., 1931, 147) demonstrated the curves of decrease in viscosity of rubber sols by exposure to ultra-violet light, and pointed out that the sols reached a definite viscosity after long exposure. The theory generally accepted to explain the mechanism of the lowering of the viscosity of rubber sols on aging is that depolymerization results from the oxidation of rubber molecules, and thereby increases the degree of dispersion. The process as a whole involves the formation of a dispersed phase from the absorption of the dispersion medium, and after passing the stages of solvation the viscosity of sols thus formed decreases on aging. The principal cause of these phenomena is considered to be due to a change in the structure of the dispersed particles by a chemical change of the dispersed phase itself. Whether or not it is possible to obtain, in the laboratory, a stable rubber sol by the process of long aging is not certain. It is, however, no exaggeration to say that the oxidation of the dispersed phase causes a decrease in its affinity for the dispersed medium, i. e., the oxidation changes the emulsoid to a supersoid or, in other words, there is a decrease in the size of the particles in the dispersed phase if the theory of the aging of rubber sols is that there is an increase in the dispersity by depolymerization. The author subjected rubber sols to long exposure to ultra-violet light and measured the lowering of their viscosity. The results show that (1) rubber sols in benzene reached a constant viscosity, and (2) the use of different solvents causes marked differences in rubber sols. The Brownian movement of the particles in aged rubber sols was observed with a cardioid ultra-microscope. These experiments were made as a preliminary test to explain the mechanism of dispersion of raw rubber in solvents.
Investigations of Colloidal Solutions of Rubber. Part I. The Influence of the Precipitating Agent on Rubber Solutions
Authors: Kawamura Jiro , Tanaka Kunikiti 
Published: February 2011

Abstract
The nature of colloidal solutions of rubber is not yet fully explained in spite of the numerous investigations on the subject which have been carried out. It is well known that the viscosity of these solutions is diminished greatly by heating, by standing, by the action of oxygen and light, and by acids. In the present paper the influence of precipitating agents such as acetone and ethyl alcohol on the change in viscosity of rubber solutions at various temperatures was studied. Smoked sheet was used as the raw material. It was purified from its filtered benzene solution by precipitation once with alcohol and twice with acetone. An Ostwald viscosimeter of brown colored glass with a capillary diameter of 0.7 millimeter and 14.5 centimeters long was used.
The Nature of Vulcanization. Part V
Authors: Stevens H. P. , Stevens W. H. 
Published: February 2011

Abstract
(1) Diphenylguanidine, p-nitrosodimethylaniline, zinc isopropylxanthate, and benzoyl peroxide do not effect polymerization (vulcanization) of sulfur-free rubber in the presence of a small proportion of rubber sulfide. (2) In the presence of rubber sulfide, zinc diethyldithiocarbamate has a definite vulcanizing effect on rubber containing 1 per cent of combined sulfur. This effect is equivalent in magnitude to that produced by the presence of at least 0.5 per cent of free sulfur in the mixing, a much larger amount than could possibly have remained after exhaustive acetone extraction. The accelerator piperidine 1-carbothionolate has a similar but weaker effect. (3) The fact that a similar but lesser polymerization is induced by purified vulcanized oil, analogous to the “activation” of the accelerators by rubber sulfide and that the activities of the accelerators are in the same order in both cases, would indicate that vulcanization promoted by accelerators is partly a polymerization activated by the vulcanizing agent and its reaction product with the rubber medium. (4) It has been found that the smallest proportion of free sulfur to give a measurable vulcanizing effect in the presence of zinc diethyldithiocarbamate is of the order of 0.1 per cent.
Studies on the Combined Use of Two Different Accelerators. I. Diphenylguanidine and Mercaptobenzothiazole
Authors: Minatoya Shukusaburo , Kojima Kitaro , Nagai Izumi 
Published: February 2011

Abstract
1. The study of the effect of the combined use of mercaptobenzothiazole and methylene-aniline is based on its eutectic curve. 2. These two accelerators do not form a molecular compound on mixing, and they have only one eutectic point. The eutectic mixture gave a stronger accelerating action than did either of the ingredients alone, vulcanization proceeded smoothly, and the products were superior. 3. The scorching effect increased with increase in the proportion of mercaptobenzothiazole, but there was no evidence that the eutectic mixture gave any increased scorching. In general, the scorching effect was less when these two accelerators were used in combined form.
A Contribution to the Problem of the Impregnability of Cord Threads with Rubber
Authors: Hauser E. A. , Hünemörder M. 
Published: February 2011

Abstract
A review of the different methods employed today for preparing the carcass of tires will distinguish two main principles of working: 1. The direct treatment of dry fabrics (cord fabrics, weftless cords) with raw rubber compounds either by simply applying skim coats or by combining this operation with frictioning rubber on by calendering. 2. The pre-impregnation of the fabric or weftless cord either with a rubber solution or with latex. Latterly the direct application of latex (natural rubber milk) has found more and more favor in this industry also, and it is certainly possible to use latex for impregnation, instead of rubber solutions or cements. This is evident from the practice of the natives of Brazil in making their waterproof fabrics. The second category of processes may accordingly be divided into two subgroups: those which work with benzine rubber solutions and those which use latex. While comparatively simple tests enable us to find out with the greatest ease why the use of cord fabrics or weftless cords has other advantages over the use of closely woven fabrics, in addition to the higher degree of elasticity already referred to, it is much more difficult to decide whether it is more advantageous to use dry fabrics previously impregnated with benzine rubber solutions or fabrics that have been pre-treated with latex.
The Structure of Rubber and the Mechanism of Elastic Stretching
Authors: Mack Edward 
Published: February 2011

Abstract
A theory of the mechanism of elastic stretch in rubber is described. It is christened a “hydrogen-evaporation-condensation” mechanism. In an attempt to develop a unified theory of rubber behavior, some of the more important properties of the various forms of rubber are discussed, from the point of view of strict adherence to the principles of geometry and of structural organic chemistry. Among the topics discussed are: shape of the rubber molecule, the work of stretching rubber, the shape of the stress-strain curve, heat effects in rubber (including the Joule effect), Staudinger's hydrogenated rubber, factors controlling cis and trans addition, x-ray diffraction pattern, properties of synthetic rubbers, inversion, and sluggishness.
Vulcanization and Stress-Strain Behavior of Sol, Gel, and Total Rubber Hydrocarbon
Authors: Smith W. Harold , Holt William L. 
Published: February 2011

Abstract
The existence and significance of a soluble and an insoluble fraction in rubber hydrocarbon and the proportions in which they occur have long been the subject of conflicting reports, which have been summarized in a previous paper. They were the basis of a two-phase theory of rubber structure proposed by Fessenden. The history of the subject need not be reviewed here. Early knowledge of it was summarized by Engler and Herbst in 1887 and an excellent historical treatment has been given by Whitby. The differing solubilities and other characteristics of the two fractions suggested a study of their behavior when vulcanized. A sufficient quantity of rubber hydrocarbon for the purpose was purified and separated into the soluble and insoluble fractions by extraction with ethyl ether; suitable compounds of each were mixed and vulcanized, and comparative tests made.
The Influence of Certain Colored Substances on the Autoöxidation of Balata and of Rubber
Authors: Bondy H. F. 
Published: February 2011

Abstract
Thanks to the numerous investigations of Moureu and Dufraisse, a large number of substances are now known which retard the autoöxidation of oxidizable substances. These retarding substances were given the name of antioxygens by the authors. Dufraisse and his collaborators have studied, with special attention to rubber, a certain number of antioxygens which greatly retard autoöxidation and the changes which take place during aging. In a preceding work I showed, by a study of different portions of the acetone extract of rubber, that certain substances exercise an antioxygenic effect which is the greater the more highly colored they are. The question then arose whether, in addition to antioxygens which act chemically, there may not be colored substances capable of retarding the autoöxidation of rubber by physical means by absorbing active luminous radiation. I thus ignored completely spontaneous autoöxidation, which is quite a different phenomenon from the one I did investigate. In the work referred to above, some experiments on colored substances were described which showed, for example, that azobenzene and α-benzeneazo-β-naphthylamine had a very great antioxygenic action, whereas alizarin and carotene were almost inactive. The present work will show whether colored substances are capable, by purely physical means, of preventing the autoöxidation of rubber and of substances allied to rubber, such as balata and gutta-percha.
The Effect of Surface-Active Substances and Electrolytes upon the Crystallization of Sulfur from Rubber Solutions
Authors: Dogadkin B. , Margolina J. 
Published: February 2011

Abstract
1. If surface-active substances are added directly to rubber or to the solvent e. g., fatty acids and their salts, naphthenic acids, thionaphthenic acids, etc., there is after evaporation of the solvent a marked reduction in the size of the sulfur crystals which are formed in the rubber films. 2. The size of the sulfur crystals depends upon the concentration of the surface-active substances in the rubber solution. The precipitate with the greatest degree of dispersion is obtained at a definite optimum degree of concentration, e. g., one per cent of calcium oleate and fish oil, based on the rubber. A higher concentration of surface-active substances leads to an increase in the size of the sulfur crystals. 3. The dispersing action of capillary-active substances decreases with the age of rubber solutions, but this was not observed alter storage of the mixtures and films themselves. 4. Rubber softeners in the molecules of which there are no polar groups (e. g., vaseline oil) show no dispersing action. 5. Some electrolytes, added to the rubber solution, likewise promote the dispersion of sulfur in the form of small crystals. 6. The dispersing action of surface-active substances and electrolytes disappears with an increase in the temperature at which the film is formed (up to 70° C.). The sulfur is precipitated in the form of monoclinic dendrites and rhombic crystals.
The Measurement of the Plasticity of Rubber. A Reply to Dillon and Johnston
Authors: Behre J. 
Published: February 2011

Abstract
In a recent contribution Dillon and Johnston commence by criticizing my explanation of the dependence of the plasticity upon the pressure. They state that the shear dv/dx is dependent upon the shearing stress F and the slippage S, and that the pressure is not a criterion of the flow conditions of rubber. This is certainly true, and I have never maintained that the pressure is a criterion of the plasticity, but I certainly do use, as these authors also propose, .the shear as a measure of the degree of plasticity, that is, the volume extruded in fifteen minutes. Naturally this depends upon the pressure or its component, the shearing stress. The only difference in the methods of measurement seems to me to lie in the magnitude of the shear and in the pressure applied. I do not believe that this leads to results which differ essentially, but differ only in their order of magnitude. Furthermore, Dillon and Johnston believe that when I quoted my earlier publication an error was made. This is not the case, for the graph in the work by Bachmann, Behre, and Blankenstein shows clearly the dependence of the work expended upon the degree of plasticity for both cold and hot mastication, and also shows that in order to reach a given plasticity, the amount of energy consumed during hot mastication is less than during cold mastication. The graph shows at the same time, however, that hot mastication makes rubber soft more quickly, both with respect to the time and the energy consumed, than does cold mastication. In view of the fact that I was not so clear in the manner of expressing myself as the facts required, these statements may give rise to misunderstandings, and therefore I feel that I should explain this point in more detail. I meant to imply nothing more than that the rubber which was masticated on rolls at a temperature of 65° C., and which was also tested at this temperature, showed higher plasticity values than did rubber which was masticated and tested at 18° C. In spite of this, Dillon and Johnston, in checking this experiment, milled rubber at 73° and 112° C. and made their measurements in each case at 100° C.