bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Thermodynamics of Rubber. II. Temperature Change of Rubber under Adiabatic Stretching
Authors: Ornstein D. S. , Wouda J. , Eymers J. G. 
Published: February 2011

Abstract
In our first communication (Proc. Acad. Sci. Amsterdam, 32, 1235 (1929)) it was shown that the heating effect which takes place in stretched rubber must be due to hysteresis, because from thermodynamic considerations it is obvious that a substance with a positive coefficient of elongation shows a cooling effect. If this is true, rubber without hysteresis must obey the laws of thermodynamics. We have tested this for rubber of the following composition: which we got from Dr. van Rossem of Rijksrubberdienst, whom we heartily thank for his kindness also on this occasion. To determine whether this rubber is free from hysteresis, the following method was used: A piece of rubber was successively loaded more and more, till the elongation was about 250 per cent., and then the load was gradually removed. No hysteresis was shown by the substance. When the rubber is submitted to a force which gives a change of length of this amount, the length of the rubber does not alter with the time. When, however, the elongation is more than 250 per cent., the length changes slightly with the time up to an elongation of 370 per cent.; beyond this elongation no alteration in length takes place again. When, in the case of these large extensions, the force is gradually decreased, the elongations come to much larger values than before, when the same force was applied to the rubber from its zero state. However, this is not an effect of hysteresis, for, however great the force and however long the time might have been during which the force acted (even more than 24 hours), the rubber always momentarily assumed its original length when the weight was removed at once. In Fig. 1 the areas from O to E and from B to C must be ascribed to different phases, and the difference between the graph for increasing and decreasing force can be explained by a retardation of phase. Moreover, the slope of the curve AB can be much steeper as in this case, with a longer time between the application of different forces. Further, the rubber in the region DE is not in a stable state, for a slight impulse affecting the rubber causes the elongation to decrease at once. Since the second phase already shows itself above an elongation of 200 per cent., we have taken all our readings for thermodynamic relation below that elongation. It is known that from thermodynamical considerations one can get the formula for the change in temperature:
Some Properties of Carbon Black
Authors: Parkinson D. 
Published: February 2011

Abstract
The term “carbon black” will be used in this paper to include all the varieties of moderately pure carbon existing in the form of soot. So far as the rubber industry is concerned, four distinct types of carbon black are in general use, as follows: (1) Gas Black.—Sometimes itself called carbon black, made by the incomplete combustion of natural gas, the principal component of which is methane. The flames of burning gas impinge on metal surfaces, on which the black is deposited. (Cf. Neal and Perrott, Bull. No. 192, United States Bureau of Mines, 1922.) (2) Acetylene Black.—Produced by the explosive combustion of purified acetylene in closed chambers. (3) Lamp Black.—Obtained by incomplete combustion of fats, oils, tars, etc. Unlike the gas black particles, which are removed from the interior of the flame, those of lamp black pass through the outer layer before deposition. (Twiss, India Rubber J., 65, 607, 651, 393 (1923)). (4) Thermatomic Black.—Made by thermal decomposition of natural gas out of contact with air. The difference in physical properties of these blacks depends largely on differences in heat treatment during manufacture. They are arranged above in order of the size of the individual particles, those of gas black easily averaging the smallest.
The Testing of Automotive Rubber Parts Assembled under Compression Part I—Deflection under Compression
Authors: Abbott Franz D. 
Published: February 2011

Abstract
Present-day test specifications on automotive rubber parts are not only incomplete and misleading, but entirely lacking in uniformity. This is particularly true of compression and permanent-set tests on automotive mechanical rubber parts assembled under compression. Consequently, an effort has been made to show the urgent need for unification of such methods. Data are presented in Part I to show that high tensile is no criterion of relative resistance to compression set and that hardness is not a measure of deflectability. In addition, deflection and permanent set under compression are greatly influenced by the size and shape of the test piece, the method of cutting the sample, the gage and methods of measuring it, and condition and kinds of surfaces in contact with the test piece. Compression and compression-set testing equipment are discussed, and some newly designed laboratory equipment is described. One piece of apparatus, the compressetometer, has been found extremely useful in making deflection, hysteresis, and set tests. These tests may be performed under constant load or constant distortion. The constant-load (spring) compression-set clamp is suggested as a suitable laboratory standard for permanent-set testing under compressive loads.
Cryoscopic Measurements of Rubber Solutions and the Separation of Mixed Phases from Benzene Solutions of Rubber. [9th Communication]
Authors: Pummerer Rudolf , Andriessen Albrecht , Gündel Wolfgang 
Published: February 2011

Abstract
We consider the separation of mixed phases in cryoscopic investigations of colloidal systems and of rubber mixtures in particular as a dangerous source of error. Therefore we place no importance on the great variations in the depressions which occur with sol-rubber in benzene. The menthol values vary less, but nevertheless more than usual. The depressions of camphor fusions proceeded strictly stoichiometrically and led to almost the same value (about 1200) as the cryoscopic menthol measurements. In both the latter instances the composition (rubber content) of the crystallized phase has not yet been studied, since the experimental difficulties involved in the separation of the crystals from the viscous fusion liquid have not yet been overcome.
Isoprene and Rubber. XIX. The Molecular Size of Rubber and Balata
Authors: Staudinger H. , Bondy H. F. 
Published: February 2011

Abstract
It was shown in the preceding work that a very dilute solution of balata in an organic solvent contains macromolecules in solution and not micelles. The same is true of rubber. On the basis of these findings it is possible to calculate the molecular weight of rubber and balata from viscosity measurements by means of the formula developed in a previous work: M=η8p/c. Km. The supposition is made that the molecules of rubber and balata have the form of threads and double threads, respectively. Also it is necessary to determine the constant KKm, and this may be calculated in the case of low molecular products, where the average molecular weight can be determined as well as the viscosity of the solutions. Such semi-colloidal decomposition products were obtained by heating rubber or gutta-percha in either tetralin or xylene. As shown by the following table the four samples thus obtained gave the constant: 0.3×10−3,5
The Constitution of Rubber According to Its Swelling in Liquids
Authors: Bary Paul 
Published: February 2011

Abstract
In various publications we have previously shown that in many cases it is advantageous to consider jellies as formed of a polymerized colloidal substance, the length of the molecular chains being easily changed according to the conditions of the system and unlike one another at all times in a single sample. These chains retain free affinities at their extremities to which can be linked so-called solvating groups arising from the solvent or from soluble substances contained in the jelly. The present work refutes the interpretation given to recent experiments on the vapor pressure of jellies and confirms in certain new ways this constitution. (1) The experiments of Stamberger on the vapor pressure of rubber jellies and their consistency before and after a prolonged mastication do not support the Harries hypothesis on the stability of the rubber molecule, but merely show that the theory of true liquid solutions is not applicable to jellies. (2) Based on the idea that polymerization changes with solvation, it is easily shown that the relative swelling in a solvent and in its saturated vapor are not contradictory with the principles of thermodynamics, as it would seem, but on the contrary proceed normally and could have been predicted. (3) In the study by Scott on the slow but unlimited swelling of rubber beyond the saturation point, this author has come to assume that swelling is a double phenomenon, which confirms our point of view. (4) The experimental study of the contraction of rubber during swelling shows that this effect does not change its sign at any moment and that consequently the change of sign of the heat evolved in this same process has a cause distinct from that of the initial swelling; perhaps it is to be attributed to the chemical phenomenon of solvation.
Isoprene and Rubber. Part 20. The Colloidal Nature of Rubber, Gutta-Percha, and Balata
Authors: Staudinger H. 
Published: February 2011

Abstract
I. The Molecular Weight of Rubber, Gutta-Percha, and Balata In the preceding work the molecular weight of rubber and balata was calculated on the basis of relations between specific viscosity ηsp and molecular weight which are shown by semi-colloidal decomposition products, on the assumption that this relation is also true for eucolloids. The value ηr−1 was taken as the specific viscosity, i. e., the characteristic viscosity increase of a substance of definite concentration and known solvent. The expression “specific viscosity” has already been used by J. Duclaux. In viscosity investigations of nitrocellulose solutions he represents this by a constant K which is calculated from the relations of the change of viscosity at various concentrations derived by Arrhenius: Based on these constants, nitrocelluloses show different average molecular weights for the increase in viscosity, that is, this constant K is greater with high molecular products than with low. In the following, this constant represents not the specific viscosity, but the viscosity-concentration constant Kc; the earlier constant Km which, on the basis of the formula: expressed the relation between the specific viscosity and the molecular weight, is called the viscosity-molecular weight constant.
An Investigation of the Viscosity of Rubber Solutions
Authors: Blow C. M. 
Published: February 2011

Abstract
Viscosity measurements have frequently been made with rubber, and very many suggestions have been put forward to explain the cause of the changes of viscosity in rubber solutions. According to Staudinger (Kautschuk, 5, 128 (1929)), if measured under certain conditions, e. g., in dilute solutions where no irregularities are found, the viscosity can be used as a measure of the molecular weight of the dissolved substance. Fickentscher and Mark (Kolloid-Z., 49, 140 (1929)) even calculate from viscosity measurements the length of the molecule and hence relative molecular weights. It is well known that the viscosities of rubber solutions differ greatly and that mechanical treatment of the rubber decreases the viscosity of its solutions to a very large extent. The latter effect has been explained by Staudinger as well as by Fickentscher and Mark (loc. cit.) as a depolymerization. The latter authors calculate that the molecular weight of rubber decreases to one-third of the original if it is masticated for 225 minutes. It has further been pointed out recently by Herschel and Bulkley (Kolloid-Z., 39, 291 (1926)) that rubber solutions show irregularities in their viscosity, e. g., the viscosity is not linearly proportional to the pressure. (According to Poiseuille's formula for the rate of flow of a liquid through a capillary, the viscosity coefficient:
The Measurement of the ph Value of Rubber Latex
Authors: Mackay J. G. 
Published: February 2011

Abstract
E. A. Hauser has stated in his Gow Lectures on “The Colloid Chemistry of Rubber” that the most satisfactory method of determining the ph value of latex is by means of the Wulff ph tester. This instrument, which is manufactured by Messrs. F. and M. Lautenschlager, Münich 2, S.W. 6, determines ph value by a colorimetric method. Strips of gelatin which have been impregnated with various indicators to render them suitable for different portions of the ph range are supplied; the range of ph values has thus been subdivided into five zones, and a scale of comparison colors is supplied for each of these zones. The principle of the instrument is that gelatin is permeable only to the serum of a turbid dispersion such as latex; when an impregnated strip, or, as it is usually termed, an indicator foil, is dipped into the turbid liquid some serum liquid passes within and produces a change in the color of the indicator; at the same time the gelatin, by swelling, prevents any considerable diffusion of this colored portion of the serum into the bulk of the turbid dispersion. The foil is left in the turbid liquid for one minute and then dried in blotting paper. Its color is then compared with the series of colors on the comparison scale supplied.
Experiments on the Causes of the Deterioration of Ebonite when Exposed to Light and Air
Authors: Webster D. M. , Porritt B. D. 
Published: February 2011

Abstract
(1) The surface film of a sample of ebonite—containing no “free” sulfur—has been shown to develop distinct traces of sulfurous and sulfuric acid after exposure to light in a moist atmosphere for a period of four weeks. (2) The above acids appear to result from the oxidation of hydrogen sulfide formed through the decomposition of the hydrocarbon-sulfur nucleus of the ebonite. (3) The rate of evolution of hydrogen sulfide from ebonite when heated in an atmosphere of hydrogen has been investigated for temperatures ranging from 180° to 250° C., and for three different samples of ebonite. (4) For a given temperature the rate of evolution is rapid at first, but falls off quickly and finally remains uniform over a long period, the latter portion of the time-H2S curve being linear within the limits of experimental error. (5) The rate of evolution increases with increasing temperature. (6) Under the heat treatment the ebonite changes in color, becoming reddish in appearance. At the same time it becomes unsaturated and more and more soluble in acetone and carbon disulfide. (7) The decomposition which takes place on heating ebonite to temperatures not exceeding 250° C. does not appear to give rise to appreciable amounts of either free sulfur or volatile organic compounds. (8) The bearing of the above results on the problem of the electrical deterioration of ebonite has been discussed.
Studies in the Vulcanization of Rubber. I—Thermochemistry of Vulcanization of Rubber
Authors: Blake John T. 
Published: February 2011

Abstract
WHEN a chemical reaction takes place, it is usually accompanied by an absorption or evolution of heat. The amount of the heat interchange is not a direct measure of the chemical affinity involved in the reaction, nor is it a measure of the free energy of the reaction. The heat of reaction, however, is a measure of the total change in internal energy and is of importance, therefore, in calculating the effect of temperature on a reaction and in elucidating the mechanism of it.
Studies in the Vulcanization of Rubber. IV—A Theory of Vulcanization of Rubber
Authors: Boggs G. R. , Blake J. T. 
Published: February 2011

Abstract
A new theory has been advanced which, it is believed, explains completely the various phenomena connected with the vulcanization of rubber. It is entirely a chemical theory based on the existence of two separate and distinct rubber compounds, soft vulcanized rubber and ebonite. The theory explains satisfactorily the aging of rubber, the variation in combined sulfur at optimum cure caused by acceleration, the kinetics of vulcanization, the characteristics of various vulcanizing agents, the thermochemistry of vulcanization, the electrical properties of rubber, the reclaiming of rubber, and the Joule effect. A brief review and discussion of the phenomena and past theories of vulcanization have also been given.
Autographic Stress-Strain Curves of Rubber at Low Elongations
Authors: Somerville A. A. , Ball J. M. , Edland L. A. 
Published: February 2011

Abstract
(1) Ring or loop test pieces permit autographic records to be drawn at constant speed. (2) A longer, larger test piece permits more accurate results to be obtained. (3) The effect of temperature of the test room is most important; speed of testing machine and direction of mill or calendar grain in sample less so; effect of relative humidity is nil. (4) The 10-inch (2.5-cm.) loop test piece described gives fairly accurate stress-strain data at low elongations, which probably is within the field approaching the action of rubber goods in service.
Carbon Black in Rubber Insulating Compounds
Authors: Wiegand W. B. , Boggs C. R. 
Published: February 2011

Abstract
1—It has been shown that, in conformity with published behavior of other conducting substances (metallic sols, etc.), carbon black may be incorporated in a dielectric such as rubber without detracting from its insulating or dielectric properties. Published results to the contrary were in error, probably because the material was added in excessive amounts. 2—In addition to this effect, it has been shown that the well-known ability of carbon black to adsorb water and dissolved electrolytes endows carbon black???rubber insulating compounds of various types with improved dielectric strength, resistivity, and power factor, the specific inductive capacity remaining substantially unchanged. In some cases this improvement may exceed 50 per cent. 3—The prevailing opinion that carbon black is injurious to rubber insulating compounds which are to be used next to the wire, or which in general are expected to serve as electrical insulation, has been shown to be erroneous, provided the proper proportions are employed. 4—These results would seem to render advisable the rewriting of many specifications dealing with rubber insulating compounds, and thus make it possible to apply the well-known beneficial effects of carbon black compounding—improved toughness, density, wearing resistance, imperviousness to light, tear resistance, etc.—to the electrical insulation field, from which it has hitherto been barred. 5—Although it is strongly recommended that the proper dosage of carbon black (which must be of suitable quality and thoroughly dry) be redetermined in each case, the writers' results would indicate that up to 10 per cent of carbon black on the crude rubber (plus the rubber content of any reclaimed rubber present) will effect the desired improvement in electrical properties.
The Structure of Synthetic Types of Rubber. Polychloroprenes
Authors: Klebanskii A. L. , Vasil'eva V. G. 
Published: February 2011

Abstract
Ozonization is one of the most successful and most exact methods for determining the structure of rubber. It was this method which was first used by Harries and his numerous collaborators for determining the structures of various types of natural and synthetic rubbers. By ozonizing solutions of natural rubber, Harries obtained ozonides, the decomposition of which yielded levulinic acid and levulinic aldehyde. This was proof that the combination of isoprene residues in the rubber molecule is in the 1,4-1,4 position, and it also showed the nature of the base molecules of rubber and the manner in which they are united in chain formation. On the other hand, these investigations did not give any decisive evidence as to whether the rubber molecule is an open chain or has a ring structure. At the beginning of his investigations in this field, Harries assigned to the hydrocarbon which is the fundamental constituent of the rubber molecule the following formula:
The Amphorous and Crystalline Forms of Rubber Hydrocarbon
Authors: Parks George S. 
Published: February 2011

Abstract
The coefficients of thermal expansion and the heat capacities of rubber hydrocarbon, both in an amorphous and in a so-called crystalline form, have been recently reported in two papers by Bekkedahl and Matheson. According to these investigators, the amorphous form undergoes a transition of the second order in the neighborhood of 199° K. Above this temperature they found a rather abrupt increase of approximately 205 per cent in the volume coefficient of thermal expansion, and one of about 38 per cent in the heat capacity. These phenomena are strikingly similar to those found in numerous studies on glasses in this laboratory, and especially in the recent investigation on polyisobutylene by Ferry and Parks. Thus, with the particular sample of polymerized isobutene employed, the transition region centered around 197° K. and the subsequent increases in volume coefficient and heat capacity were 200 and 32 per cent, respectively. Bekkedahl and Matheson found that, by cooling the amorphous rubber hydrocarbon to about 230° K. and then permitting it to warm up slowly over a period of days, their material could be obtained in a “crystalline” form. These “crystals” melted at 284° K. with a heat of fusion of 4.0 calories per gram. They also exhibited the previously mentioned second-order transition at about 199° K., but with somewhat smaller subsequent increases with rising temperature, i. e., about 165 per cent increase in the volume coefficient of thermal expansion and 28 per cent in the heat capacity. Two facts appear surprising and highly significant with these “crystals”: (1) the value of the heat of fusion which is extremely low compared with the figures of 20 to 54 calories per gram hitherto reported for various aliphatic hydrocarbons melting near room temperature, and (2) the duplication of the second-order transition found previously for amorphous rubber hydrocarbon.
Gutta-Percha. Effect of Vulcanization on Its X-Ray Diagram
Authors: Fuller C. S. 
Published: February 2011

Abstract
EARLY x-ray investigations by Clark (2) and Ott (13) on gutta-percha and balata established the fact that these materials were crystalline in nature even in the unstretched condition. In 1927 Hauser and his co-workers (5) pointed out the similarity of the diagrams obtained on gutta-percha and balata, but it remained for Hopff and Susich (7) to establish definitely the identity of the x-ray diagrams of the two substances. In addition they brought out the interesting fact that, on heating above 60° C., a characteristic change took place in the gutta-percha diagram. Hauser and Susich (6) made a detailed study of this change. They showed that gutta-percha (and hence also balata) underwent a change in crystalline structure at about 68° C. The beta modification, obtained above this temperature, did not transform back into the low-temperature or alpha form, but remained unchanged unless the cooling took place very slowly through the transition point. The last-named authors gave much attention to the securing of well-oriented fiber patterns of both crystalline forms in order to calculate their respective identity periods along the fiber axis. Their results, which are probably the most reliable published to date, give the. alpha form of the hydrocarbon an identity period of 8.78 ± 0.12 A˚. and the beta form an identity period of 4.87 ± 0.07 A˚. More recently Bruni and Natta (1) have examined gutta-percha by means of electron rays and have given a solution for the alpha form in which they find the unit cells to be orthorhombic and to have the axes: a=6.53 A., b=7.68 A˚., and c=9.60 or 4.80 A˚. (fiber period). They find the number of isoprene units (C5H8) per cell to be four.