bluuebunny/crossref_metadata_2025_split huggingface dataset:
Natural and Synthetic Rubber. XVI. The Structure of Polystyrene
Authors: Midgley Thomas , Henne Albert L. , Leicester Henry M. 
Published: February 2011

Abstract
Styrene treated with sodium and alcohol gives 75% of ethylbenzene and 25% of 1,4-diphenylbutane. This shows that polystyrene should be represented by formula II, in opposition to the heretofore accepted formula I. Only formula II is consistent with Mack's explanation of the rubber-like elastic properties of polystyrene.
The Mode of Action of Disulfide Accelerators of Vulcanization
Authors: Langenbeck W. , Rhiem H. C. 
Published: February 2011

Abstract
The catalytic power of organic compounds in general has up to the present time been studied much less extensively than that of inorganic compounds. For about the last ten years, however, the first author has, in collaboration with a number of his students, attempted to fill this gap, though so far efforts have been confined to explaining the mode of action of natural enzymes by means of comparative experiments with organic catalysts. As a result of this work, a theory based on experimental facts has been developed to explain in a satisfactory way the action of enzymes. The other phase of organic catalysis is, strictly speaking, a technical problem. Why for instance should it not be practicable to utilize organic catalysts more extensively than heretofore in industry? If this problem is to be attacked, it seems reasonable to start with the particular industry which already uses organic catalysts to the greatest extent. This is, of course, the rubber industry. The important accomplishments of the chemical industry with respect to the development of vulcanization accelerators is already common knowledge, and the important task at present is not simply to increase the great number of accelerators already known. A problem of more practical value would seem to be to study the mechanism of the acceleration of vulcanization, about which relatively little has been known heretofore.
Specific Properties of Artificial [Buna] Rubber
Authors: Koch Albert 
Published: February 2011

Abstract
Developments in the Synthesis of Rubber Because of the peculiar properties of natural rubber, its usefulness is somewhat limited, and in many fields of application it is quite unsuitable. In contact with oils and fats it swells rapidly and loses almost completely its good mechanical properties, and besides this natural rubber has poor resistance to heat. Again it is attacked rather easily by oxygen, and on exposure to oxygen and light simultaneously there is a particularly strong tendency to develop cracks within a short time; it is for such reasons that the chemical industries of various countries have been looking for an artificial or synthetic product which is free from the shortcomings of natural rubber or exhibits them to only a relatively small extent. Experimentation on artificial rubber has depended fundamentally on the discovery of Harries that the natural rubber molecule is constructed of isoprene units. Isoprene and its allied hydrocarbons were prepared by Hoffmann and his coworkers at the Elberfeld dye works, and these compounds were in turn polymerized to masses similar to rubber. These experiments were carried out before the World War. Because of a shortage of raw materials during the War, it was necessary to adapt the laboratory results to a factory scale sooner than should logically have been done. At that time the most readily available technical raw material was dimethylbutadiene, a compound which differs from isoprene by the presence of an extra methyl group, as may be seen in Table I.
Nonsolvents in Rubber Cements
Authors: Ford T. Foster 
Published: February 2011

Abstract
ETHANOL has long been used for reducing the apparent viscosity of rubber cements. Other rubber nonsolvents, especially acetone and amyl acetate, are sometimes similarly employed. However, there are few data in the literature from which adequate comparisons among nonsolvents may be deduced, nor has any systematic study of the properties of a cement containing nonsolvents been reported. Whitby (2), studying a long list of chemicals as solvents, records comparative swelling power for rubber and nitrocellulose; Whitby and Jane (3) find the viscosity of dilute rubber solutions to be reduced by a number of these materials; and Kawamura and Tanaka (1) obtain the following order of decreasing precipitant value for a 0.25 per cent solution of rubber in xylene—methanol, ethanol, n-butanol, isobutanol. With the exception of the swelling experiments, these results, as is the case with practically all published cement studies, are for dilute solutions only and therefore are of little technical value. The present experiments were performed with a commercial cement and are the result of a wish to control particularly two properties—the thickness of rubber film deposited upon an article by dipping and the tendency of the wet film to break across small holes in perforated objects. The addition of a suitable nonsolvent to a cement improved the film-breaking property, and by changing the proportion of the nonsolvent, with proper regard for other factors, satisfactory control of both film breaking and film thickness was possible. As here reported, the results afford a basis for comparison among the more common nonsolvents in cements in which the solvents used are benzene, Varnish Makers and Painters' (V. M. & P.) naphtha, or ethylene dichloride; and for a benzene-isopropanol cement they show the nature of the effects upon the properties studied, of simultaneously varying the proportion of nonsolvent, the concentration of nonvolatile ingredients, and the degree of mastication of the rubber stock. Results on temperature and humidity control are included to illustrate the importance of these factors in dipping-room operations.
Rubber Latex for Road Surfacing
Authors: Wren W. G. , Faircloth A. T. 
Published: February 2011

Abstract
(1) Methods of preparing sections for microscopical examination have been developed in order to obtain information as to the structure of latex-cement mixtures. (2) A large range of protective colloids which act as stabilizers of rubber latex have been examined as to their effect on the physical properties of aluminous cement, particularly on the rate of setting and hardening and tensile strength. Important differences in the effects produced by these substances have been found. (3) The possibilities of preparing a rubber cement crumb for consolidation on the highway are under examination. (4) A few experiments on the effects of compounding ingredients on the tensile strength of dried latex (without mastication) have been made. Silica gel improves the tensile strength of the dried film.
Hardness of Vulcanized Rubber at Low Temperatures
Authors: Nagai Hiroshi 
Published: February 2011

Abstract
1. By means of a new apparatus which is described, it is possible to estimate the hardness of vulcanized rubber at low temperatures. 2. The hardness of rubber-sulfur vulcanizates increases hyperbolically with lowering of temperature and they become “frozen” and hard at −50° C. 3. Since ordinary softening agents having high viscosities solidify at −30° to −40° C., these are unsuitable for softening rubber to be exposed to temperatures below this range. 4. Softening agents which do not solidify at −50° C. are among those ordinarily used as solvents, and they have very low viscosities. Though their effect on the hardness of rubber at −50° C. is small when they are used in small percentages, they prevent the freezing of rubber at −50° C. when large proportions are used. They are, however, of no practical value, since they decrease the tensile strength of rubber. 5. Vulcanized rubber containing 30 per cent of reclaimed rubber also froze to a hard product at −50° C. 6. The relation between temperature and hardness of rubber vulcanized with organic accelerators is the same as that in the case of rubber vulcanized with sulfur alone.
The Viscosity Characteristics of Rubber Solutions
Authors: Philippoff W. 
Published: February 2011

Abstract
As is well known, solutions of rubber in organic solvents exhibit a variety of noteworthy properties which are characteristic of solutions of lyophilic colloids, to which rubber belongs. These properties, notably high viscosity even in dilute solution and structure viscosity, distinguish these solutions from those of normal substances of low molecular weights. In the present article, the attempt is made to assemble known facts about viscosity phenomena and at the same time to add certain experimental data, heretofore unpublished, to the available literature on the subject.
Studies on the Joule Effect of Rubber. II. Thermal Effect on Stretched Latex Vulcanizates
Authors: Tanaka Yoshio , Kambara Shû 
Published: February 2011

Abstract
Latex vulcanizates behave with regard to the Joule effect similarly to ordinary vulcanized rubber when heated and cooled in a stretched condition. The observed thermal effect is assumed to represent the Joule effect. This effect is reduced chiefly by depolymerization and disaggregation of the rubber, and is increased by vulcanization, which may be followed by polymerization of vulcanized rubber molecules and an increase of the polar affinity of each molecule and micelle.
Swelling and Solvation of Rubber in Different Solvents
Authors: Williams Ira 
Published: February 2011

Abstract
The large variation of the fractional increase in viscosity of rubber sols and its lack of relation to the viscosity of the solvent indicates that the increase in viscosity is not due to rigid filiform molecules. The ability to interchange solvents and obtain a viscosity characteristic of the solvent shows the existence of a reversible equilibrium between solvent and rubber. The close relation between the maximum swelling and the fractional increase in viscosity of rubber in different solvents suggests that rubber sols contain swollen micelles of rubber. The extent of swelling and the viscosity depend on the equilibrium between solvent and rubber which, in turn, depends on the state of oxidation (or other suitable chemical attack) of the rubber. A rubber sol becomes a gel at the concentration which immobilizes essentially all the solvent. The relative viscosity of rubber sols of equal concentration in the same solvent is probably some function of the degree of solvation of the dispersed particles which is influenced by the degree of oxidation of the rubber. Viscosity is not a measure of the molecular weight.
The Fine Structure of Crystallized Rubber
Authors: Lotmar W. , Meyer K. H. 
Published: February 2011

Abstract
Whereas in the unstretched state rubber gives on examination by x-rays the diagram of a liquid, in the stretched state it gives a well-defined fiber diagram. This was first described by Katz in 1925. Since that time the crystalline interferences of rubber have been studied by several investigators. The first classification of these interferences was undertaken by Hauser and Mark, who arranged them in the form of a rhombic lattice. Later, working with a thin film of highly stretched rubber, Mark and von Susich succeeded in obtaining preparations with a higher degree of orientation. According to whether it was irradiated parallel or perpendicular to the surface of the film, such a preparation showed different intensities of the reflections. In this way Mark and von Susich succeeded in obtaining a different and more reliable indication of the reflections than did Hauser and Mark. Mark and von Susich found a rhombic elementary cell with axes of 8.3 ± 0.1 A. U., 8.1 ± 0.1 A. U. (fiber axis), and 12.3 ± 0.1. A. U. On the basis of their better established elementary cell, Mark and von Susich developed a space model of rubber which agreed fairly well with the largest intensity effects. In constructing this model they relied on the assumption expressed by Meyer and Mark that primary valence chains of the formula:
A Survey of Latex Coagulants Used by Malayan Small-Holders
Authors: Rhodes Edgar 
Published: February 2011

Abstract
A survey was made of the coagulants employed by Malayan small holders. Though in the main these small holders are employing formic and acetic acids, sulfuric acid is employed to a much greater extent than has been supposed. Propaganda against the use of this coagulant was commenced recently through the Small-Holders' Advisory Service, and reports from the districts are encouraging.
Soft Vulcanized Rubber. Effect of Temperature and Oxygen Pressure on Aging Rate
Authors: Ingmanson J. H. , Kemp A. R. 
Published: February 2011

Abstract
IMPORTANT to the manufacturer and consumer of rubber goods are suitable accelerated aging tests for predicting readily the life of rubber articles under the variable storage and service conditions encountered. Since service conditions may involve the exposure of rubber to wide variations of temperature, light, and atmosphere under various types of mechanical strain, there is obviously need for a variety of tests, each designed to emphasize factors which are most important in any given set of service conditions. Since the primary cause of failure of soft vulcanized rubber in service is oxidation, emphasis has been placed on tests which accelerate the oxidation effect. The most widely adopted and generally satisfactory procedure of this type is the Bierer and Davis oxygen bomb method which involves heating the rubber under oxygen pressure. In Bierer and Davis' original publication (2), results were shown on the effect of increasing oxygen pressure in increments of 28.1 kg. up to 112.5 kg. per cm. on the aging of two different rubber compounds at the three temperatures, 50°, 60°, and 70° C. Their results showed that in some cases there was a uniform increase in aging rate with increased pressure and in other cases the rate increased rapidly up to a pressure of 28.7 kg. per sq. cm. but more slowly with further increases in pressure. In a later investigation (3) the same authors employed a pressure of 21.1 kg. per sq. cm. and 60° C. throughout. For the past ten years most laboratories have used an oxygen pressure of 21.1 kg. per sq. cm. and a temperature of 70° C., which may therefore be considered as standard.
Determination of Sulfur in Rubber. Use of Tetrahydroxyquinone as a Titration Indicator
Authors: Sheen Robert T. , Kahler H. Lewis , Cline Delbert C. 
Published: February 2011

Abstract
The determination of sulfur in rubber by the precipitation of oxidized sulfur as sulfate by means of barium chloride and the back-titration of the excess barium has been shown to be as accurate as the gravimetric procedure in solutions of the characteristics described above, for the determination of sulfur, with the use of tetrahydroxyquinone as the indicator. The method is very rapid compared to the gravimetric procedure and after oxidation to the sulfate form in solution, a determination can be made on a single sample in 20 to 30 minutes; with groups of analyses this time can be greatly reduced when compared to the time required for a single analysis.
The Carbon Reinforcement of Rubber
Authors: Wiegand W. B. 
Published: February 2011

Abstract
Evolution Discovered in England in 1910 where, however, insufficient quantities were used, and developed commercially in Akron in 1912, its evolution may be roughly divided into three periods: 1913–1920, during which time the art led the science; 1920–1927, during which time science led the art, and 1927–1934, when the art once more overtook the science, leading to the empirical employment of 50 per cent or more of carbon on the rubber. At the present time there is needed a fresh theoretical approach. The Course The scope of carbon reinforcement may conveniently be defined as the region of positive Delta A values. The shape of the Delta A curve is in itself interesting as to symmetry, the presence of a well-defined maximum, and the extraordinary extent of positive values compared to other reinforcing pigments. Position of Maximum The published data on carbon Delta A functions have been assembled together with fresh data, the latter including both litharge and Captax accelerated mixings. Considerable discrepancies appear. A mean curve has been drawn to include the recent data, and previous work in which fatty acids were employed. This mean Delta A curve for carbon black shows a maximum at 26.3 per cent by volume of carbon on the rubber, corresponding to 51 per cent by weight. This mean curve cuts the base-mixing energy axis at 53.6 volumes of carbon, or approximately 105 per cent by weight.
The Use of Acetylene in the Rubber Industry
Authors: Walter Paul 
Published: February 2011

Abstract
Considering the advantages to be gained as a result of the favorable effect which acetylene has on rubber, it would be of still greater interest to study: (1) the coagulation of latex by acetylene, and (2) the fixation of acetylene by reclaimed rubber and by factice. Such studies should be of great significance, and if successful results were to be obtained, a large market for calcium carbide would be created. The use of calcium carbide in the rubber industry is of interest at present in three ways: (1) Its technical advantages, including the improvement to be gained in the quality of the rubber products, and the simplification of manufacturing operations. (2) Its economic advantages, i. e., the lower costs. (3) Its consumption, which, though impossible to foresee even in an approximate way, is possibly indicated by the following estimates: Balls and balloons 800 tons per year Sponge articles 200 tons per year Latex products 500 tons per year 1500 tons per year This total of 1500 tons per year is not of great significance, because it would be misleading to assume that all the manufacturing plants which make the articles described would use calcium carbide. To offset this, it has just been mentioned that there would be a very large consumption of calcium carbide if latex were to be coagulated by acetylene, or indirectly by calcium carbide, by some economical process, as seems possible. In conclusion, there are always unexpected uses for calcium carbide and acetylene in the rubber industry.
Mastication and Rate of Set-Up. Part I
Authors: Buchan S. 
Published: February 2011

Abstract
Until comparatively recently the importance of rate of set-up measurements in rubber compounding and in factory control testing received very little attention, but within the last few years various methods have been devised and used by different investigators. In many laboratories, the standard method of testing utilizes the change in physical properties which occurs when the rubber is converted from a plastic mass to an elastic solid under the influence of heat, the course of the reaction being traced by means of a plastometer. With a plastometer of the parallel plate type, such as the Williams instrument, a number of cylindrical test samples of known volume are cut from the mixed rubber under examination, and placed in the oven of the plastometer, maintained at a constant temperature. At definite intervals individual samples are tested on the plastometer and a note is made of their plasticities or, it may be, of their recoveries. When either of these sets of readings is plotted against the time of heating, it is usually observed in an accelerated mixing that the point at which vulcanization commences is shown by a steep inclination of the curve away from the time axis.
Secondary Changes during Vulcanization of Ebonite. Part I
Authors: Davies B. L. 
Published: February 2011

Abstract
(1) During the vulcanization in steam or water of sulfur-rubber mixes containing a high proportion of sulfur, there was a change of weight due to (1) loss of sulfur by volatilization, (2) loss of hydrogen sulfide, (3) absorption of moisture, (4) loss of soluble matter, (5) evolution of volatile products. (2) Loss of sulfur from the mix was high when vulcanization was carried out in steam, and low when vulcanized in water. In the former case, it produced an outer layer of appreciable thickness which was deficient in free sulfur. This layer was, however, not visibly different from the remainder. The sulfur was lost during the earliest stages of heating, and ceased when evolution of hydrogen sulfide became appreciable. The surface loss may or may not affect the vulcanization coefficient. (3) The mechanism of sulfur loss has been discussed. It was shown that sulfur reacts with steam or water under vulcanizing conditions, yielding a small quantity of hydrogen sulfide. The other reaction product could not be detected by the use of barium chloride in the case of steam heating, but in water some evidence of the presence of oxides of sulfur was obtained. It was concluded, therefore, that although a part of the sulfur lost probably results from successive oxidation and reduction, most of the sulfur is distilled from the surface of the sample. At the same time it was shown that water and steam, in the presence of iron, yield a reducing substance assumed to be hydrogen. (4) Absorption of water was much larger during vulcanization in water than in steam. In both cases the period necessary to attain a minimum weight on exposure to air was very long, the time depending upon the thickness of the slab. (5) After this period, oxidation proceeded at a velocity which was approximately constant for a given sample. This rate was therefore used to calculate the actual weight lost during vulcanization. (6) After allowing for oxidation and for water-absorption, it was found that the loss of weight sustained during vulcanization was not a pure function of the surface area, but increased with increasing volume. (7) The amount of water absorbed varied similarly.
Contributions to the Analysis of Rubber. I. Determination of the Water-Soluble Components of Rubber
Authors: Dekker P. 
Published: February 2011

Abstract
1. It is shown that the methods which are ordinarily used for determining water-soluble substances in raw rubber give low results, and are quite useless for vulcanized rubber. 2. New analytical procedures are developed for determining the water-soluble substances in raw rubber and in vulcanized rubber. These procedures are carried out in the following manner. (a) Raw Rubber.—Heat 2 grams of rubber in 80 cc. of xylene and 5 cc. of acetic acid on a water bath until the rubber is completely dissolved, add 5 cc. of acetic acid and 10 cc. of water, heat for 3–4 hours on the water bath with frequent agitation, transfer to a distilling flask (rinsing the first flask with 50 cc. of hot water), distill the xylene with steam, filter the residual solution, evaporate the filtrate on a water bath; and dry at 100° C. (b) Vulcanized Rubber and Rubber Mixtures.—First extract the sample with acetone, heat 2 grams of the acetone-extracted sample with 80 cc. of xylene on a water bath, add 5 cc. of acetic acid, reflux the mixture on an oil bath, after complete dissolution add 5 cc. of acetic acid and 10 cc. of water, heat the solution for 2 hours on an oil bath at 110–120° C., distill the xylene, as in the determination with raw rubber, filter the residue, evaporate the filtrate to dryness, take up the residue in 50 cc. of water, pass a current of hydrogen sulfide through the solution for 10 minutes to precipitate zinc as sulfide, filter, evaporate the filtrate, and dry the residue at 100° C. 3. In the presence of calcium compounds, magnesium compounds, glue and textiles, the method gives false results. Modifications of the method are therefore recommended, whereby these substances are eliminated.