bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vulcanization Characteristics of Mercaptobenzothiazole Derivatives
Authors: Harman M. W. 
Published: February 2011

Abstract
WITHIN the past few years much progress has been made in the development of rubber vulcanization accelerators of the semi-ultra type which exhibit no prevulcanization or scorch during the preliminary processing. Most of the commercially important members of this class are derivatives of mercaptobenzothiazole in which the hydrogen atom of the mercapto group is replaced by an organic substituent. The increasing use of these products can be attributed to their favorable curing characteristics and to the valuable physical properties which they impart to the cured stock. Naunton and his co-workers (4), Twiss and Jones (8), and Shepard (6) discussed a number of these compounds in recent papers. Numerous references to their preparation and use also appear in the patent literature (1,2,3,5,7,10).
Latex Battery Separators. Preparation and Properties
Authors: Greenup H. W. , Olcott L. E. 
Published: February 2011

Abstract
THE commonly used electrical storage battery consists of alternate negative plates of sponge lead and positive plates of lead peroxide immersed in an electrolyte, sulfuric acid; the whole is enclosed in a hard rubber or bituminous composition case. These plates are ordinarily separated from one another by ribbed sheets of wood called “separators.” The separators prevent short circuiting of the plates caused by actual contact of the plates with each other or by “treeing” (formation of lead crystals between the plates). The separators must be thin, in order to make the battery as compact as possible, and yet must be durable. It is necessary that they be highly porous so that their electrical resistance will be low, but the pores must be sufficiently fine so that “treeing” does not take place. Wood separators are ordinarily made of Port Orford cedar. They are usually given a preliminary treatment in warm, dilute sodium hydroxide solution to swell them, thus increasing their porosity, and to remove injurious substances which cause self-discharge and corrosion of the plates. Wood separators have the advantage of being inexpensive and of having fairly low electrical resistance, but they are not so resistant to the action of sulfuric acid and the oxidizing action in the cell as is desirable. They are, in many cases, the first part of the storage battery to fail and must then be replaced if the battery is to give further service.
Kaysam. A Casting Process for the Manufacture of Rubber Products from Latex
Authors: Cutler David Roy 
Published: February 2011

Abstract
Various practicable methods of applying the solids of latex and latex mixtures in the manufacture of various types of products have been employed in this country during the past years. While meritorious within their respective fields, these processes, except that for the production of sponge rubber, all have the common limitation of being applicable only to comparatively thin articles of relatively uniform thickness. The recent introduction into this country of an important English invention, Kaysam, supplies the positive three-dimensional shrinkage control and accelerated drying method, which now opens new fields to all types of products with superior strength, stretch, tear-resistance, aging, and advantages characteristic of articles made directly of latex. The Kaysam Development Confronted with the conflicting problems of distressing competition and the necessarily wasteful and uneconomic methods of producing crepe rubber soles, Walter Kay, of Sam Kay & Co., Bury, England, despaired, of meeting the problem except by some workable substitution of latex for crepe rubber. The result of his experimental effort was a workable process of casting liquid latex into rubber articles without limitation of size or shape. This process became known as “Kaysam,” a contracted inversion of his company's name. This process has been applied in England during the past several years, and in various continental European countries to the volume production of many types of soles, metal-inserted heels, cloth-inserted boots, and various kinds of molded articles, including those of solid and hollow construction. More recently still, Kaysam, supplemented by other important inventions of prominent American technologists relating to the fundamentals of latex compounding and use, has been made available to manufacturers in this country by the Kaysam Corporation of America.
Physical Testing Procedure for Latex Stocks
Authors: Wohler L. A. 
Published: February 2011

Abstract
Adjustment of stabilizers may be necessary in order to produce a smooth surface on an air-dried latex test slab. A combination of 1 per cent of casein and 1 per cent of Aquarex D on the rubber gave a satisfactory dried slab. Reproducible results cannot be obtained unless the test strips are conditioned at controlled relative humidity conditions. Zero per cent humidity gave highest tensile and modulus figures. Batch-to-batch accuracy of latex stocks using methods described herein was comparable to that of mill-mixed pure gum stock.
Examination of Rubber Latex and Latex Compounds. Part II. Chemical Testing Methods
Authors: Fowler D. E. 
Published: February 2011

Abstract
LATEX compounds are purchased either on the basis of total solids content or the so-called dry rubber content. The total solids probably furnish a more reliable basis of evaluation, as the determination can be made with a high degree of accuracy. The dry rubber content is not a precise determination, as the proteins, fatty acids, and other non-rubber constituents are included, and in the case of compounded latices some of the compounding materials are included in the value and some are not. Hauser (8) and Noble (9) include in their books useful chapters on testing latex. Total Solids The total solids are determined by weighing about 2 grams of the sample in a low covered weighing dish about 6.25 cm. (2.5 inches) in diameter on an analytical balance. A metal weighing dish is preferred for more rapid drying. Tinned 60-ml. (2-ounce) ointment cans are satisfactory and so inexpensive that they may be thrown away if they are at all difficult to clean. The sample is dried, preferably in a vacuum oven. The temperature may be increased to 120° C. in a vacuum without any apparent oxidation or deterioration of the rubber. A sample of normal latex may be completely dried in about 10 minutes if the drying arrangement is right. Results are accurate to better than 0.1 per cent. Methods involving the use of specific gravity are worse than useless when applied to preserved latex as a concentration control. Even in the case of unpreserved, unwatered normal latex on the plantations, the hydrometers must be calibrated especially for the latex from the estate on which they are to be used.
An Air-Bomb Aging Test for Tread Compounds
Authors: Booth E. W. , Beaver D. J. 
Published: February 2011

Abstract
Data here presented demonstrate that study of tread compounds by the air-bomb aging method must include modifications of the conditions followed in the comparison of inner-tube compounds. Data are presented which show the effect of air pressure, temperature, elongation, oxygen concentration, time, and pigment variation on the aging of rubber compounds. The air-bomb aging conditions suggested for the study of tread compounds, consisting in testing at 0 elongation, 50 pounds air pressure per square inch (3.5 kg. per sq. cm.), and 220° F, (104.4° C.) temperature, have provided a shorter laboratory teat which parallels the Geer-oven aging test in its effect on carbon black compounds.
Determination of Diarylamines in Rubber Compositions
Authors: Craig David 
Published: February 2011

Abstract
THIS paper deals with semi-quantitative methods for the determination of certain typical diarylamine age resisters—namely, diphenylamine, phenyl-α-naphthylamine, and N,N′-diphenyl-p-phenylenediamine. It serves as an essential feature of a study of the general behavior of these materials in rubber to be discussed in a subsequent communication. Previous methods for the detection and estimation of rubber age resisters have been of limited though of useful application. Thus Endo^ (3) described the colors produced by the action of sulfuric acid on a large number of commercial age resisters unmixed with rubber. Later Endo^ (4) published papers dealing with the action of concentrated nitric acid and Erdman reagent (solution of 0.5 ml. of concentrated nitric acid in 100 ml. of concentrated sulfuric acid) as well as of Mandelin reagent (solution of 1 gram of ammonium vansdate in 200 grams of concentrated sulfuric acid) and of concentrated sulfuric acid containing 1 per cent of arsenic acid.
Change of Volume of Rubber on Stretching: Effects of Time, Elongation, and Temperature
Authors: Holt William L. , McPherson Archibald T. 
Published: February 2011

Abstract
1. Two dilatometers have been described which are suitable for measuring the change of volume of rubber on stretching. 2. The volume of pure gum rubber remains constant up to a critical elongation, above which it decreases. Coarse fillers and other inhomogeneities tend to increase the volume because of the formation of vacuoles on stretching. Carbon-black compounds, however, decrease in volume above a critical elongation, which is lower than for pure gum. 3. The decrease in volume of rubber on stretching is greater the higher the elongation, the lower the temperature, or the longer the time the rubber is kept stretched. 4. After the first few minutes the volume of stretched rubber decreases at an approximately uniform rate with the logarithm of the time. No final or equilibrium state was attained in periods up to 3 or 4 weeks. 5. Stretched rubber shows a greater coefficient of expansion than unstretched rubber. 6. Poisson's ratio for rubber in the absence of coarse fillers is 0.5 or greater, the numerical value being a function of the composition, the elongation, the temperature, and the time after stretching.
Isoprene and Rubber. Part 46. Viscosity Measurements of Gel Solutions of Rubber and Hydrorubber
Authors: Staudinger H. , Mojen H. P. 
Published: February 2011

Abstract
I. RELATIONS BETWEEN VISCOSITY AND CONCENTRATION WITHIN THE RANGE OF SOL AND GEL SOLUTIONS Rubber and hydrorubber belong to that group of colloids known as lyophylic colloids. They are characterized by the fact that their solutions are extraordinarily viscous, even at low concentrations, and follow neither the Einstein nor the Hagen-Poiseuille law. It was pointed out in previous works that this abnormal behavior of rubber solutions, as well as of many other natural and synthetic high molecular substances, depends on the long, thread-like form of their macromolecules. All these compounds belong to that class known as linear colloids. With these solutions the relationships between viscosity, particle size, and number of particles are far different from those of solutions containing spherical particles (spherocolloids), for which the Einstein law is valid. Of the many attempts which have been made to derive some law relating the viscosity and concentration of rubber solutions, the formulas of Arrhenius, Bingham, and Fikentscher and Mark may be mentioned. It is difficult to derive any general relation, because the state of rubber solutions may vary considerably with the size of the molecules and the concentration. This point has not been sufficiently taken into account in deducing previous formulas. The following three states of solution are to be distinguished, but it is self-evident that there are intermediate states between these.
Isoprene and Rubber. Part 47. The Decomposition of Rubber by Acids
Authors: Mojen H. P. 
Published: February 2011

Abstract
The phenomena observed in the experiments which have been described can be explained in the following way. As already mentioned, raw rubber contains certain antioxygens which protect the rubber molecules from attack by oxygen. Very little is known about the nature of these antioxygens, but it is probably correct to assume that these substances are of a basic nature, like commercial antioxygens, which for the most part are complex organic bases. The activity of these anti-catalysts is stopped by the addition of organic or inorganic acids. As a result there is no longer any obstacle to an attack by oxygen, and decomposition can proceed under these conditions much more rapidly and much more extensively. The antioxygens are destroyed by the acids, even when oxygen is excluded during the experiments, but demolition of the fiber molecules does not then take place. The intense destructive effect of oxygen on rubber does not therefore depend on the action of acids on the fiber molecules of rubber, but is to be attributed solely to the fact that antioxygens which inhibit decomposition by oxygen are destroyed; destruction of the rubber itself is caused only by oxygen. It is not impossible that these phenomena bear a close relationship to the stickiness acquired by rubber. Rubber which has become sticky is composed of extensively decomposed rubber molecules. This phenomenon is noticeable at times in rubber goods which have been stored for a long time, and may be explained by the fact that atmospheric carbon dioxide destroys the natural antioxygens in the rubber. With their destruction, atmospheric oxygen then has free play to attack the rubber molecules. The acidic substances which are formed in this oxidation then destroy any remaining antioxygens, so that oxygen can destroy all of the rubber. Grateful acknowledgment is due Professor Staudinger, at whose instigation this work was carried out, who offered advice in various ways, and who took an active part in the investigation.
Some Physical Properties of Isoprene
Authors: Bekkedahl Norman , Wood Lawrence A. , Wojciechowski Mieczyslaw 
Published: February 2011

Abstract
Isoprene (2-methyl-1,3-butadiene) has been for many years a substance of very considerable interest in the study of rubber, since it has been shown to be the fundamental unit in the constitution of the rubber hydrocarbon. Isoprene polymerizes to form a product which is chemically more closely related to natural rubber than any other synthetic product. Furthermore, the destructive distillation of natural rubber yields as its two major products isoprene and dipentene (dl-1-methyl-4-isopropenyl-1-cyclohexene) in amounts far exceeding those of any other constituents. Aside from its relation to rubber, isoprene is of interest, because it is thought to be the basic substance in the natural synthesis of terpenes and to play an important role in the formation of plant cells. An investigation of the chemical thermodynamics of rubber now in progress at the Cryogenic Laboratory of this Bureau includes a study of isoprene and its relationship to rubber. Measurements of heat capacity and heat of combustion are at present being made on isoprene for the purpose of calculating its entropy. A report covering these results is now being prepared. Similar measurements for rubber have already been reported. Since samples of high purity were desired for this work, care was taken in the preparation and purification of the isoprene, and the resulting product is thought to represent an improvement in purity compared with isoprene prepared by previous investigators. Furthermore, not all workers realized the importance of working with freshly purified samples. Also it is now possible to take advantage of recent important improvements in the technic of measuring physical properties, especially boiling point and related properties. In view of the wide divergence of values for many of the commonly measured physical properties, as reported in the literature, it seems worth while to report the values here obtained with samples of high purity.
Note on the Diffraction of X-Rays by Old Specimens of “Frozen” Rubber
Authors: Barnes William H. 
Published: February 2011

Abstract
The object of the present note is to make available in the literature a detailed comparison of the x-ray diffraction effects from old specimens of “frozen” rubber with available data for stretched fresh rubber. Several x-ray diagrams of “frozen” rubber have been published, and Ott has recorded measurements made on a photograph of apparently “frozen” crepe. Although Ott's values have been confirmed in Clark's laboratory, they appear to be the only values readily available in the literature, and are rather meagre.
Chlorination of Polymers of Chloroprene Rubber
Authors: Klebanskiĭ A. , Rakhlina M. 
Published: February 2011

Abstract
Products of the chlorination of α- and m-polymers of chloroprene were obtained. The chlorine content of the chlorinated polychloroprene depended on the conditions of chlorination, but corresponded to products formed by the addition of chlorine. A large excess and high concentration of chlorine resulted in the addition of chlorine to the double bonds, together with partial substitution of hydrogen by chlorine. Of the three basic types of chloroprene polymers, the α-polymer added chlorine most easily; m-polymer was chlorinated with more difficulty, giving a chlorination product of the composition, corresponding by analysis to the addition of chlorine at the double bond. All polymers of chloroprene chlorinated under these conditions contained saponifiable chlorine. Films of chlorinated polymers of chloroprene are characterized by a considerable stability to the action of various acids (nitric and sulfuric acids and aqua regia) in the cold and at moderately high temperatures. γ-Polymer of chloroprene is not chlorinated under the same conditions.
The Vulcanization of Rubber by Diazoamino Compounds
Authors: Levi T. G. 
Published: February 2011

Abstract
Vulcanizing agents for rubber can be classified in the following six types: (1) Sulfur, including α-sulfur, β-sulfur, γ-sulfur, precipitated sulfur, and nascent δ-sulfur. (2) compounds containing sulfur, e. g., sulfur chloride, sulfur iodide, sulfur dioxide, phosphorous sulfides, hydrogen persulfides, nitrogen sulfide, and alkaline polysulfides. (3) elements of the sulfur group and their compounds, e. g., selenium, tellurium, selenium sulfur chloride, and selenium diethyldithiocarbamate. (4) halogens and halogenated compounds, e. g., chlorine, bromine, iodine, hypochlorous acid, hypochlorites, and benzoquinone dichloride. (5) oxygenated compounds capable of liberating nascent oxygen at vulcanizing temperatures, e. g., persulfates (such as ammonium persulfate), peracids (such as perbenzoic acid), nitro compounds (such as 1,3,5-trinitrobenzene, tetranitronaphthalene, and nitrocyclohexane in the presence of metallic oxides), and organic peroxides (such as benzoyl peroxide). (6) derivatives of rubber, e. g., rubber ozonide, chlorinated rubber, brominated rubber, and rubber hydrochloride.
Tests on Crepe Soling. III. Water Absorption
Authors: Messenger T. H. , Scott J. R. 
Published: February 2011

Abstract
The main results obtained are summarized below: (1) The following observations made by previous workers are confirmed. The absorption by crepe immersed in pure water continues for a very long time, if not indefinitely; the initial rate of absorption and the amount absorbed after long immersion increase rapidly with rise of temperature. The influence of temperature is probably due largely to its effect on the mechanical properties of the rubber, the softening induced by heat facilitating the distension of the rubber. (2) Soling crepes vary enormously in rate of water absorption; this result is ascribable to a variety of causes, as there is direct evidence that water absorption is influenced by the number of plies and the ease of penetration of water between the plies, while the porosity (permeability) of the rubber and its content of water-soluble matter must also come into play; the rigidity of the rubber would be expected to have some influence, although this is not evident in the present experiments. (3) Water absorption does not differentiate sharply between estate and factory-prepared soling crepes, though there are indications that on the average factory crepes absorb water somewhat less rapidly. (4) Among the soling crepes examined, water absorption bears no obvious relationship to mechanical properties or solution viscosity. (5) Addition of solutes to the water in which rubber is immersed reduces the water absorption, and this occurs quantitatively in accordance with the osmotic theory of water absorption. These results indicate that water-absorption tests do not in general yield any information as to the mechanical or physical properties of crepe soling or its mode of manufacture, and are therefore of value only in relation to the water-absorbing properties of the material. Absorption at atmospheric temperatures is so slow that under normal conditions of use it probably does not affect more than a thin surface layer. This layer, however, is responsible for the grip of the soling on the pavement, and if absorption of water influences this gripping power, the control of water-absorbing capacity becomes important. The wide variation at present found between different crepes suggests that an investigation of the factors governing water absorption would enable this property to be closely controlled over a wide range. Penetration of water between the plies, which will occur especially when the soling is somewhat worn, may be more serious than absorption at the outer surface, since water cannot readily dry out from between the plies, and the absorption may therefore become cumulative and lead to weakening of the ply-adhesion.
Studies on Vibration Tests of Rubber
Authors: Saito Shohei , Ishiguro Katsumi 
Published: February 2011

Abstract
Experiments were carried out to determine the resistance of rubber products to vibration. There were no essential changes in mechanical properties as a result of vibration for 50 to 100 hours. There were on the other hand considerable changes in electrical properties, e. g., the insulation resistance decreased with increase in time of vibration. Further experiments in connection with this problem will be carried out to obtain data on the effects of vibration for prolonged periods. The authors wish to thank Messrs. Endo, Taguma, Hamono, and Wada for their aid in the experimentation.
Rubber-Lined Equipment. Fundamental Principles of Design
Authors: Hoover J. R. , Klein H. C. 
Published: February 2011

Abstract
IN 1924 a process known as Vulca-lock, discovered by chemists of The B. F. Goodrich Company, made possible the first successful steel tank car for hydrochloric acid service. The tank was lined with acid-resisting vulcanized rubber bonded to the steel shell with adhesion exceeding 500 pounds per square inch. A new material of chemical construction was thus made available in practical form. The resulting widespread and rapidly increasing use of rubber-lined equipment in the processing industries is well known. Basically, the value of such construction lies in properly combining the unique corrosion- and abrasion-resistant properties of rubber with the rigidity, strength, and adaptability of steel or other structural materials. It is essential, therefore, that chemical engineers be familiar with certain principles of design, upon which the successful use of rubber-lined equipment depends. No attempt will be made in this paper to define the broad field of usefulness or the limitations of rubber linings. The fact must be emphasized, however, that an extremely wide range of chemical and physical properties is available in commercial rubber compounds and that these compounds, like metals and alloys, are designed for specific uses.
Natural and Synthetic Rubber. XVII. The Separation of Sol Rubber and Gel Rubber
Authors: Midgley Thomas , Henne Albert L. 
Published: February 2011

Abstract
Sol rubber prepared by a single diffusion in ether can be separated into two components by fractional precipitation, whereas sol rubber prepared by a single fractional precipitation completely diffuses in ether, thus indicating the superiority of the fractional precipitation method as a means of preparing sol rubber.