bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extraction of Water-Soluble Accelerators in Water Cure
Authors: MacKay J. W. 
Published: February 2011

Abstract
No measurable quantity of the water-soluble accelerators tested was extracted from the rubber during the water extraction. Therefore, these accelerators will not be extracted during vulcanization in water. The softening action observed in water-cured latex products is due to the extraction of water-soluble nonrubber components from the rubber film. The water-soluble accelerators tested have a selective solubility for rubber which is many times greater than their solubility in water.
Control Tests of Uniformity in the Manufacture of Carbon Black
Authors: Grote H. Walter 
Published: February 2011

Abstract
Twenty-five years ago, a pneumatic tire for an automobile cost twenty-five dollars and gave service of about 3500 miles. Today a pneumatic tire costs only one-half as much and can be relied upon to give service of about 25,000 miles. These improvements are the result of various factors, such as the use of cord fabric, organic accelerators, antioxidants, and other carefully chosen raw materials. Among these latter, it is safe to say that carbon black is unquestionably the raw material which has contributed most of all to the increased mileage of pneumatic tires. Years ago when the reënforcing properties imparted to rubber by carbon black first became recognized, this product was furnished without any particular requirements other than freedom from impurities. Later, as the percentage of carbon black incorporated in rubber mixtures continued to increase, certain measures were taken to control the grit content. Ultimately, with the aim of furnishing the rubber industry with a product of the highest quality and greatest uniformity, the most important producers of carbon black, in coöperation with the laboratories of rubber factories, proceeded to develop a series of check tests and various other tests, which have led in turn to the development of the present-day specifications of carbon black.
The Creaming of Hevea Latex by Colloids
Authors: Vester C. F. 
Published: February 2011

Abstract
Hevea latex is generally considered to be a suspension of rubber particles of various dimensions up to about 3 µ. The rubber hydrocarbon contains no “ionogenic groups,” and it is believed that part of the serum components imparts a negative charge to the rubber particles. Almost all latex imported into Europe is preserved by means of 0.5 to 0.7 per cent of ammonia. This ammonia plays a three-fold part: (1) it prevents premature souring of the latex; (2) it increases somewhat the charge on the particles; and (3) it attacks all types of serum components so that within a short time the “preserved” latex is hardly comparable with natural latex. As with all suspensions in which the dispersed phase is lighter than the dispersing medium, rubber latex exhibits the phenomena of creaming. The density of the rubber particles is approximately 0.914, that of the medium, 1.020. By means of creaming, it is possible to obtain a latex (1) which has a higher rubber content, whereby transportation space and cost are saved, and (2) which contains no components having a tendency to deposit a sediment. The natural creaming of latex, which is of no importance technically, was observed by Faraday as early as 1825.
The Behavior of Raw Rubber When Stretched Isothermally
Authors: Hintenberger H. , Neumann W. 
Published: February 2011

Abstract
The S-shaped form of the stress-strain curve of rubber is today explained in a quite satisfactory way. In the first part of the curve, i. e., the gradual ascent, work must be expended because of the van der Waals forces of attraction of the molecules; in the second part, i. e., the steep ascent, the elasticity is chiefly an entropy effect, which is finally exceeded by crystallization phenomena. The phenomenon of crystallization itself has been the subject of extensive investigations, but in most cases vulcanized rubber has been employed, and because of the various accelerators and fillers which the rubber has contained, the products have been rather ill-defined. It is evident that the phenomena involved in crystallization would be much more clearly defined if the substance under investigation were to be in a higher state of purity. If experiments are carried out with raw rubber, a flow effect is added to the various other phenomena. As a result of this flow effect, Rosbaud and Schmidt, and Hauser and Rosbaud as well, found that the stress-strain curve depends on the rate of elongation at very low extensions, with a greater stiffness at high rates of elongation. As found recently by Kirsch, there is no evidence of any flow phenomena in vulcanized rubber at room temperature. Most investigations have been so carried out that the stress has been measured at a definite elongation. It was therefore of interest to determine the elongation at constant stress, and the changes in this relation with time and with temperature, of various types of raw rubber.
The History of Rubber. Franz Carl Achard's “Experiments on Elastic Resin”
Authors: Eck Leo 
Published: February 2011

Abstract
It is a curious fact that it is in the history of rubber that extreme difficulty is encountered in altering current beliefs. This is attributable in part to the fact that the history of rubber is usually treated in a cursory way in the introduction to a work, and an investigation of the original sources is ordinarily omitted. It is also attributable to the general belief that everything has been settled in this field, and therefore that it is sufficient merely to refer to this or to that original work. The present writer has plenty of evidence at his disposal to support this contention. Although of great value in its day, the compilation of scientific publications on the entire history of rubber by A. Slingervoet Ramondt is today out of date in many respects. Unfortunately too, much that is of value in this work has been forgotten. Slingervoet Ramondt cites, for example, Gmelin's “Handbuch der Chemie” to the effect that Achard studied the action of nitric acid on rubber. As a matter of fact the original work of Achard is not mentioned, either in any notes in the text or in the chronological list of references to the literature. The present author has therefore deemed it a pleasant task to make better known the contributions of a German chemist to the earliest investigations of rubber, a chemist whose name is already held in high esteem for his work in another field, the production of beet sugar.
Chemistry of Soft Rubber Vulcanization. Reversion and Nonreversion in Low-Sulfur Compounds
Authors: Garvey B. S. , Forman D. B. 
Published: February 2011

Abstract
ACCUMULATION of evidence in recent years has led to a wide acceptance of the view that, chemically, vulcanization is the establishment of cross bonds between the fiber molecules of unvulcanized rubber. The usual concept is that of a chemical cross bond typified by the sulfur bridge (4). It was recently proposed (2) that “mechanical cross bonds” might be formed by the interlocking of the molecules as they become kinked as a result of cis-trans isomerization at some of the double bonds. It was also suggested that free rotation around single bonds might unkink the molecules. This straightening of the molecules would result in reversion of the vulcanized structure. This theory suggested that a study of reversion would be of value. For this purpose low-sulfur compounds are most suitable because the number of chemically stable sulfur bridges is small. Consideration of the experiments reported here suggests the interesting possibility that in vulcanized compounds there exists a sort of dynamic equilibrium between the formation of cross bonds and their destruction, which results in the maintenance of an adequate number of cross bonds although the individual cross bonds are not permanent. The general methods of mixing, curing, and testing were previously described (3). Since PBA and Altax gave the most clear-cut distinctions between reverting and nonreverting types of acceleration, the complete data are given for these two accelerators. Similar tests were made with the other accelerators, but only the conclusions from them are reported here.
The Rubber-like Behavior of an Artificial Substance (Oppanol) when Irradiated with X-rays
Authors: Brill R. , Halle F. 
Published: February 2011

Abstract
As is known, natural rubber has the property of giving, when stretched, an x-ray fiber diagram, whereas in a normal state the same rubber is amorphous. Numerous other natural substances such as hair and tendon, and artificial substances such as polychloroprene, behave in the same way. However, this effect is not confined to purely organic substances, and it is to be found, for example, in the case of so-called amorphous sulfur and polyphosphornitryl chloride (PNCl2)x. All these substances have the property in common with one another of exhibiting a rubber-like elasticity within a definite temperature range, and of being composed of long-chain molecules.
Determination of the Resistance of Vulcanized Rubber to Tearing
Authors: van Wijk D. J. 
Published: February 2011

Abstract
By the resistance to tearing of a material is meant the resistance shown by the material, while under tension, to tearing completely apart after a split has been made in the surface by any means whatsoever. Without question, the destruction of rubber articles can in many cases be traced to tearing. The initial tears can be regarded as the result of a splitting of the inelastic oxidized skin or of injury to the surface. Tears on the side walls of a tire, for example, can be attributed to the first cause; the wear on the tread is attributable to the second cause mentioned above. Resistance to tearing should therefore be regarded as one of the most important properties of rubber. The numerous and widely different methods which have been proposed and used for determining resistance to tearing are proof of this. A complete survey of the literature to 1932 was published by Lefcaditis and Cotton. These authors described about twelve different methods for determining resistance to tearing, proposed a modified form of the method of Heidensohn, and determined the tear-resistance of various mixtures by this method. Subsequently, Lefcaditis studied this method further, and determined the effect of fillers and of mastication on resistance to tearing.
Oxygen Pressure Aging. Improved Equipment
Authors: Freeman L. M. 
Published: February 2011

Abstract
Since the introduction of the oxygen pressure-aging test by Bierer and Davis, prevailing standard conditions for the test have been 70° C. (158° F.) and 300 pounds per square inch oxygen pressure. Various types of equipment have been used; usually the equipment has consisted of a pressure vessel immersed in a constant-temperature water bath to which is connected an oxygen supply. In the majority of instances the equipment has been difficult to operate and maintain for several reasons: Immersion of pressure vessels in a water bath made handling difficult. Corrosion was a continuous source of trouble, causing “freezing” of cover bolts and making it difficult to obtain a leakproof oxygen seal between cover and vessel. This caused loss of oxygen. Each time the pressure vessel was removed from the bath it was necessary to disconnect the oxygen supply and make the connection again when the test was started. This also caused loss of oxygen. If more than one pressure vessel was connected to the oxygen supply and a safety released, the entire oxygen supply was exhausted. The original pressure vessels were relatively large. Since the use of age resistors on a large scale, smaller units have been desirable in order to decrease migration of age resistors and eliminate erroneous results. Some of these operation difficulties were outlined by Ingmanson and Kemp, who also emphasized the importance of temperature control to obtain reproducible results. It is the purpose of this paper to describe an improved oxygen pressure installation which avoids some of these difficulties.
Apparatus for Evaluating Puncture Resistance
Authors: Bashore H. H. 
Published: February 2011

Abstract
In the development of improved compounds for products such as tires, inner tubes, conveyer belts, and hose, the need was felt of a quick and accurate test which would approximate the puncturing conditions these goods might receive in service. For such a test an apparatus was developed which provides for a puncturing pin to be pulled through the rubber sample, the pulling force being supplied by a vertical Scott tensile tester. The adaptation to the Scott machine (Fig. 1) eliminates the necessity of additional load-recording and extension-pulling apparatus. Construction The test apparatus, of which three views are shown in Fig. 2, is composed of two sections. The top section is a hollow tube through which the puncturing pin (Fig. 3A) travels downward in puncturing the sample (Fig. 3B), which is gripped firmly at the periphery between an internal shoulder on the tube and a sleeve (Fig. 3C) within a threaded cap (Fig. 3D) which screws on to the tube. Distortion of the test piece, while the screw cap is being tightened, is prevented by the inner sleeve which presses vertically against the specimen while the turning action is taken up by slippage between the sleeve and the cap. A horizontal pin is attached to the vertical puncturing pin to provide means for attaching the bottom tube section which pulls the pin downward. The hollow tube of the top section is slotted to allow vertical movement of this horizontal pin.
Effect of Curing Temperature upon the Properties of a Rubber-Sulfur Mix
Authors: Park C. R. 
Published: February 2011

Abstract
1—Within experimental error, within the range of temperature and in the case of the mix under consideration, the temperature of cure has no effect on the quality of the vulcanized stock. 2—Certain unexplained differences exist in the results obtained by various methods of aging. 3—The temperature coefficient of vulcanization is 2.50 per 10° C.
Standardization of Ozone Testing
Authors: Kearsley E. P. W. 
Published: February 2011

Abstract
THE progressive deterioration of soft vulcanized rubber, proceeding independently of actual wear, has always been a source of annoyance to the trade. Although evidences of such deterioration are varied in character, the many forms may be conveniently classified as surface deterioration and deterioration throughout the rubber. Surface deterioration, characterized by superficial film formation, is greatly accelerated when vulcanized rubber is exposed to light, particularly rays of short wave length, but that this function of light in the destruction of rubber is indirect in operation was recognized as early as 1883. by Burhardt (Jour. Soc. Chem. hid. 2, 119, 1883). The agency responsible for the changes which rubber undergoes on exposure to the atmosphere is undoubtedly oxygen, and suggested by Spiller (Jour. Chem. Soc. [London] 18, 44, 1865), as far back as 1865. That oxygen is essential for the deterioration of rubber has been shown by Fickenday (Kolloid Ztg. 9, 81, 1911), and many others since. The effect of sunlight on either raw or vulcanized rubber, is believed by Henri (Caout. et Gutta Percha 7, 2848, 1909) to be analogous, although Peachy and Leon (Jour. Soc. Chem. Ind. 37, 56T, 1918) offer the opinion that vulcanized rubber oxidizes less rapidly than raw rubber. Later investigators have proceeded still further in their conclusions, and Tuttle (The Rubber Age, N. Y. 8, 271-2, 1921) states, after studying the acetone solubility curves of vulcanized rubber exposed to light, that the action of the latter is one of oxidation, which when once started proceeds rapidly, due to the catalyzing effect of small amounts of oxidized rubber so formed.
The Influence of Zinc Oxide on the Action of the Principal Accelerators of Vulcanization. The Preparation of Transparent Vulcanized Rubber
Authors: Thiollet R. , Martin G. 
Published: February 2011

Abstract
IT HAS been known for a long time that the action of accelerators of vulcanization proceeds to a conclusion and in a regular way only in the presence of certain metallic oxides, of which zinc oxide is the most widely used. This substance behaves also as a reinforcing pigment, improving the physical properties of vulcanized rubber. We are not at the present time concerned with the second property, we are only concerned with ascertaining under what conditions zinc oxide promotes the action of accelerators. Zinc oxide makes rubber opaque. With certain articles like molded nipples and vulcanized crepe soles, this opacity offers a serious inconvenience and we have studied how it is possible to obtain transparent vulcanizates. To study these questions, we have carried out some vulcanization tests with the principal accelerators on the following three mixtures:
The Influence of the Amount of the Surplus Liquid on the Swelling Maximum of Rubber Jellies
Authors: Blow C. M. , Stamberger P. 
Published: February 2011

Abstract
It has been shown that the so-called “Bodenkörper” effect is caused in the case of rubber by the rubber itself being present in the outside liquid. Rubber swells to a less extent if the solvent contains some dissolved rubber. This effect is reversible if the swollen jelly is placed into solvent containing rubber. An osmotic assumption may be used to explain this process, but it is not possible to draw definite conclusions as to the exact mechanism.
X-Ray Investigations on Rubber
Authors: Ott Emil 
Published: February 2011

Abstract
During some earlier x-ray investigations on cre^pe rubber, it was observed that the originally translucent sample became more and more milky at the spot where the x-rays passed the material. The sample was the same as described in an earlier paper. This rubber gave a distinct x-ray pattern during the first exposure, but, although the lines did not change their position, they became increasingly sharper with each exposure; simultaneously the opaqueness of the milky spot increased. The increase of sharpness of the originally broad lines represents, of course, increase in particle size; but evidently also the increasing cloudiness of the cre^pe rubber shows progressing crystallization.
The Viscosity of Rubber Solutions under Influence of Benzoyl Peroxide. A Contribution to Methods for Determining Inorganic Fillers, Etc., in Rubber Mixtures
Authors: Fromandi G. 
Published: February 2011

Abstract
IN THE determination of mineral and certain organic substances in rubber mixtures by the aid of disintegration with paraffin oil or anisol, difficulties occur during filtration in the presence of golden antimony which require the use of a centrifuge, since the relatively high viscosity of the colloid system does not permit a sufficiently high rate of sedimentation for practical purposes. Some investigations of rubber mixtures containing golden antimony, in which for certain reasons the use of a centrifuge was impracticable, necessitated the development of a method which would obviate the use of a centrifuge. By means of decalin (decahydronaphthalene) and benzoyl peroxide it was possible to so control the ordinary disintegration that the sedimentation of the filler and antimony particles increased to such an extent that filtration was no longer difficult.
Natural and Synthetic Rubber. VI. the Pyrolysis of Natural Rubber in the Presence of Metallic Oxides
Authors: Midgley Thomas , Henne Albert L. 
Published: February 2011

Abstract
Pale crepe rubber pyrolyzed in the presence of zinc oxide or magnesium oxide gives the same decomposition products as in the absence of the oxides, but in different proportions. This modification is attributed to an action of the oxides upon the double bonds of the rubber molecule.
The World's Rubber Supplies
Authors: Rae George 
Published: February 2011

Abstract
Until the beginning of the present century, the world's supplies of crude rubber were obtained from trees and shrubs growing naturally in the equatorial regions of the earth, mainly in South and Central America and Central Africa; this rubber is generally known as wild rubber. Today, owing to the rapid increase in the production of cultivated rubber, the output of wild rubber is sufficient to supply only about 3 per cent of the world's requirements. In 1900 the total output of wild rubber amounted to about 54,000 tons, but this included considerable quantities of moisture and other impurities, and the dry rubber equivalent probably did not exceed 40,000 tons, while plantation output was nil. In 1929, the latest year for which complete statistics are available, the output of wild rubber was only 26,000 tons, while the output of cultivated rubber amounted to 821,000 tons. Cultivated or plantation rubber, as it is more generally called, is subdivided into estate and native rubber. Estate rubber is produced on estates owned and managed by Europeans, and on estates over 100 acres owned by Asiatics. Native rubber is produced on holdings under 100 acres. (Some of the larger native holdings in Sumatra and Dutch Bornea may be greater than 100 acres.)
Observations on the Effect on Vulcanization of the Lipin of Hevea Latex
Authors: Eaton B. J. , Rhodes E. , Bishop R. O. 
Published: February 2011

Abstract
Some preliminary vulcanization tests which have been made with the Hevea lipin (vide Quarterly Journal of the Rubber Research Institute of Malaya, 2, 125 (1930)) are described.
Isoprene and Rubber. Part 32.The Constitution of Rubber
Authors: Staudinger H. 
Published: February 2011

Abstract
1. The establishment of the molecular size of high molecular compounds which are composed of fiber molecules by the end-group method of determination is only possible if homologous polymeric series of similar type are concerned. 2. The end-group method assures reliable values with molecules up to a molecular weight of 1000 at the highest. With higher molecular products, like cellulose and rubber, the method is inexact. 3. The molecular weight of rubber and balata may be determined by viscosity determinations in the following two ways: (a) M=ηsp/cKm (b) M=Kc.Kcm. The constants Km and Kcm are determined with low molecular decomposition products. 4. Rubber and balata are composed of fiber molecules, which in one dimension have the magnitude of colloidal particles and in both the others, the dimensions of low molecular substances. 5. In highly viscous rubber solutions, there is the characteristic state of solution. As a result, the sphere of action of the dissolved molecule is greater than the volume at the disposal of the solution. This solution is midway between a true solution and a gel, and is therefore designated as a gel solution. It occurs only with high molecular substances, and is characteristic of them. 6. The readiness with which rubber solutions vary is explained by the fact that the rubber molecules are very sensitive to chemical influences and to changes in temperature as a result of the position of the double bonds. This sensitivity varies with the length of the molecules.
Rubber. Part XII. Levulinic Acid Peroxide from Rubber
Authors: Pummerer Rudolf , Ebermayer George , Gerlach Karl 
Published: February 2011

Abstract
The so-called levulinic aldehyde diperoxide, which has already been described by Harries and which we call more correctly “levulinic acid peroxide,” is formed not only by “over-ozonization” of the rubber ozonide, but always when rubber ozonide solutions are kept sealed up for a long time, for example, in an ice box. While frequently at first there is only a very slight precipitation after the ozonization, in the course of eight to fourteen days it increases greatly. After filtering and after washing with ether, the yield may reach from 15–20% of the carbon skeleton of the rubber, and it is therefore a decomposition product of the rubber ozonide, which is formed in the neutral medium, perhaps by traces of moisture. Since it is also especially easy to isolate beforehand and is a suitable weighing substance for levulinic acid, we have attempted to confirm for ourselves that the substance still contains the unchanged carbon skeleton of levulinic acid.