bluuebunny/crossref_metadata_2025_split huggingface dataset:
Method of Making Micro-Sections of Rubber Stocks
Authors: Allen Raymond P. 
Published: February 2011

Abstract
THE possibility of seeing pigment particles in a rubber stock has always been a desire of rubber chemists. There has been a natural belief that if the particles in rubber could actually be observed with a microscope more could be learned about their action and properties. The main difficulty in attaining this end lies in the preparation of sufficiently thin sections. For clear observation of highly loaded gas-black stocks the sections must be less than 1 micron thick. For bright-field work with light-colored or colorless pigments, such as litharge and zinc oxide, the sections may be somewhat thicker. However, if the examination is to be made with dark-field illumination the sections for even the colorless pigments must again be very thin. Several methods have been proposed and utilized for making thin sections, and the names of Dannenberg (2), Depew (3), Green (4), Grenquist (5), Hauser (7), Moore (11), Pohle (9), Ruby (3), Spear (11), and Walton (12) are identified with the skilful manipulation which is necessary for achieving the desired result. There have been many other workers in this field, including Weber (13), Breuil (1), Loewen (8), Regnaud (10), and Hardman (6). The method to be described was developed in this laboratory in 1926. It has been used continually since that time and has proved valuable in the study of rubber compounds and pigments. While it bears a slight similarity to some of the other methods, it has certain unique and distinct advantages of its own.
The Infrared Absorption of Rubber and Related Hydrodcarbons
Authors: Williams Dudley 
Published: February 2011

Abstract
The infrared absorption spectra of rubber and certain related hydrocarbons have been studied by using extremely thin films of the samples as absorbing layers. In the spectra of styrene, isoprene, and cymene intense absorption bands appear at 3.4µ, 6.2µ, and 7.0µ and also weaker bands between 7µ and 9µ. These bands were common to most of the hydrocarbons studied. The principal variations in the spectra of the compounds mentioned above are found in bands whose positions vary between 5.5µ and 5.7µ in the different compounds. In the case of “pure gum” rubber a band was found at 5.8µ and in a vulcanized rubber of low sulfur content corresponding absorption occurs at 6.0µ. At all other wave-lengths between 2.5µ and 9.0µ the absorption spectrum of rubber has a striking resemblance to that of isoprene, a result which is in agreement with the chemist's model of the rubber molecule as a long chain of isoprene units. The absorption in the 5.8µ region probably arises from a mechanism which is intimately connected with the process of polymerization. The spectrum of polymerized butadiene contains strong bands at 5.5µ and 6.0µ and also less intense bands beyond 7.0µ, whose positions are not the same as those in the spectrum of natural rubber. Rubber hydrochloride has a very intense band at 8.4µ which is not characteristic of the other hydrocarbons studied.
Studies of Hard Rubber Reactions III. Changes in the Acetone Extract during Vulcanization
Authors: Numaziri Seiiti 
Published: February 2011

Abstract
In the former communications (Part I and Part II) the author dealt with the characteristic changes in some physical properties with time of cure of hard rubber compounds. The work has now been extended by chemical observations. In the first place, the author studied the acetone extract of the same compounds of the previous reports with a view to ascertaining the nature of the hard rubber reactions. Preliminary Examination of the Acetone Extract Samples were prepared for acetone extraction in two ways. In the case of soft rubber products, the material was sheeted out to thin crepe by passing between the tightly closed rolls of a laboratory mill and was then cut with scissors into fine strips. Hard rubber samples were prepared by buffing with an alundum grinder and sifting through a 100-mesh screen. In each case the sample taken for the extraction was 0.5–1.0 gram. The extraction apparatus was a new design, as illustrated in Fig. 1, which has the advantage of extracting the sample in the vapor of boiling acetone, and in many other respects is more efficient and convenient than the Cottle type of extractor. There has been considerable discussion as to a standard time of extraction for hard rubber. According to the specification of the Society of Rubber Industry of Japan, for example, extraction of at least 48 hours is recommended, while it is specified in the British Standard Specification No. 234 (1933) that only 8 hours of continuous extraction are necessary for ebonite for electrical purposes. Besides these, extraction periods of 72 hours, 20 hours, etc., have been advocated by various authors.
Studies on the Artificial Aging of Vulcanized Rubber. I. Depolymerization during the Heat-Aging
Authors: Nagai Hiroshi 
Published: February 2011

Abstract
1. Aging in nitrogen results in very little deterioration below about 80° C., whereas deterioration is rapid above this temperature. 2. There is no metamorphic point in the curve representing aging in nitrogen. 3. During aging in air below 80° C., disaggregation is brought about by oxygen, aside from an independent effect of sulfur; above this temperature depolymerization takes place through the agency of heat. Depolymerization and disaggregation are most rapid at the metamorphic point.
The Errors in Tensile Strength Testing
Authors: Davies O. L. , Horrobin S. 
Published: February 2011

Abstract
The conclusions drawn from the data of Wiegand and Braendle and of Fric that the breaking of rubber during tensile strength testing is essentially an event governed by the laws of chance, and that therefore some form of average is the only appropriate method of estimating the “correct” result from a number of tests is supported by the nature of the data obtained in routine testing in the rubber service laboratories. The presence of an excess of abnormally low values and of a few high values is also confirmed. After calculating the standard error of a test, a rule has been devised for eliminating abnormal results before averaging the remainder. This rule is to be preferred to any of the various arbitrary rules hitherto in use. The authors wish to acknowledge the help given by the staff of the rubber service laboratories in collecting data for this investigation, and to Imperial Chemical Industries, Ltd., for permission to publish the results.
Hot vs. Cold Breakdown of Rubber
Authors: Comes D. A. 
Published: February 2011

Abstract
The value of, and methods for, breaking down crude rubber have been the subjects of much opinionated discussion among rubber men of many generations. The questions normally center about such points as the kind of equipment and its best adjustment; time, temperature, and sequence of conducting operations; methods of measuring the degree of softness obtained; and the quality of the crude rubber and finished product, both unaged and aged. Time has brought a reasonable unanimity of opinion on some points, for example, the efficacy of a series of short breakdown periods on an open mill, with intermittent intervals of cooling, compared with a single long period of continuous mastication. Among other points not in common agreement, hot vs. cold breakdown takes a prominent position. Here differing viewpoints not only exist between various plants, but between different persons of the same plant and even of the same laboratory. If an attempt is made to compare results in different plants, one will find it difficult to draw any definite conclusions, owing to differing conditions of physical manipulation and measurements, not the least of which are the various types of plastometers used. Because of this set of conditions the present author was prompted to conduct a series of experiments with the object of obtaining data with which the relative plasticizing effects of different methods of breaking down rubber over the, greatest practicable temperature range on both open mills and in internal mixers could be evaluated.
The Components of Hevea Latex. Part I. The Isolation and Quantitative Determination of the Components
Authors: Roberts K. C. 
Published: February 2011

Abstract
(i) A method is described for the quantitative isolation of the chief components of Hevea latex in the form in which they occur in nature. (ii) Several hitherto unknown components have been observed, and receive a preliminary description. They include a sulfur-containing plastic material which is of major importance. (iii) The known major components—sugar, quebrachitol, phosphates, protein, fat acids—are shown to exist in fresh latex, chiefly as components of stable chemical complexes. (iv) It is hoped in the near future to report the results (a) of more detailed investigations, and (b) of applications of the method in the study of some fundamental problems.
Properties of Hard Rubber. I. Plastic Deformation
Authors: Church H. F. , Daynes H. A. 
Published: February 2011

Abstract
Tests have been made at temperatures from about 15° to 100° C. on (a) subpermanent set due to torsion; and (b) rate of plastic flow under torsion, of a number of commercial and specially made hard rubbers, the latter consisting of rubber and sulfur with or without high grade hard rubber dust. Temperature-set curves showed marked maxima at temperatures, depending mainly on the vulcanization of the sample and comparatively little on arbitrary conditions of test. The peak temperature rose with advancing vulcanization, but reached a limit when combination of sulfur had practically ceased. Hard rubber dust depressed the peak temperature and introduced a second peak at a higher temperature, both peak temperatures rising with advancing vulcanization. Vulcanization-set curves also showed sharp maxima except at the highest temperatures, but became flat when combination of sulfur had practically ceased. Rate of flow under a torsional stress sufficient to give a fixed initial twist showed substantially the same characteristics as the set after torsion. It is concluded that at an early stage in vulcanization hard rubber acquires an elastic structure which becomes the dominant control at high temperatures, the plastic structure being dominant at low temperatures. Some practical consequences of these results are discussed, relating to testing of materials for plastic deformation, methods of manufacture to avoid after-shrinkage, detection of hard rubber dust, and investigation of changes of structure during vulcanization.
Softening and Freezing of Crepe
Authors: Messenger T. H. , Scott J. R. 
Published: February 2011

Abstract
The outstanding results may be summarized as follows: (i) Heating gristly crepe to 60° C. or above causes softening, a change characterized by a large fall in tensile strength and rigidity and by increase in breaking elongation and permanent set. With some crepes there is a transient initial rise in tensile strength. Subsequent storage at 0° C. produces changes in the reverse direction, which, however, are rapidly eliminated by heating at 34° C. or above. It appears, therefore, that heating above 60° C. produces: (a) a permanent change not reversible by freezing; and (b) a temporary change reversible by freezing. (ii) Heating gristly crepe below 50° C. only moderately increases the extensibility and flexibility, true softening being absent. These changes are reversible by freezing, the recovery being quicker than with softened crepe. (iii) Prolonged storage at 0° C. (beyond 20–30 days) causes a gradual decrease in strength and stiffness in both gristly and softened crepes. With gristly crepe these effects are more than counteracted by thawing at 25° C., giving a tougher, stronger product than the original. (iv) The statement that golden crepe does not harden is incorrect; as, however, this is a softened crepe the hardening is only temporary and does not restore the original gristly qualities. (v) Uniform temperature and rate of elongation are essential in tensile tests on raw rubber. The permanent set of broken rings becomes sensibly constant in 2 hours.
Chemical Aspects of Vulcanization
Authors: Rossem Avan 
Published: February 2011

Abstract
C. O. Weber was the first to give an elaborate theory of vulcanization. It is well known that he considered the hot vulcanization process as an addition of sulfur to polyprene (C10H16)n on account of the fact that no large amounts of hydrogen sulfide were evolved during the process. Wo. Ostwald, starting from quite the opposite point of view to Weber, put forward in 1910 the adsorption theory of vulcanization, considering it from an entirely colloidal standpoint, the sulfur being adsorbed by the rubber. It soon became clear that vulcanization was much more complex, and that neither of the two theories was able to explain the facts. Since then many investigations have been carried out, and many views, hypotheses, and theories on vulcanization put forward. If one tries to classify these, it becomes apparent that at the present time there is still a chemical theory and a colloidal theory of vulcanization. The chemical theory of vulcanization may be divided in two opposing hypotheses, viz.: (a) Polymerization of the rubber molecule, combination with sulfur being incidental. (b) Chemical combination of sulfur with rubber as the principal factor. To support this statement a few references and quotations from various investigators are given below.
Concerning the Alleged Absorption of Gaseous Nitrogen by Benzene Solutions of Rubber and Gutta-Percha Hydrocarbons
Authors: Howard Louis B. , Hilbert Guido E. 
Published: February 2011

Abstract
Experiments described by de Jong have been interpreted as indicating that dilute benzene solutions of rubber or gutta-percha hydrocarbon from sheet balata, when exposed to sunlight for a few days in either quartz or ordinary glass vessels, absorb gaseous nitrogen in appreciable amounts. If such a photochemical combination of rubber and nitrogen actually occurs, one might reasonably expect other unsaturated hydrocarbons containing isoprene units such as carotene and xanthophyll to behave similarly. These substances which always are found closely associated with chlorophyll in green plants possess physiological functions which, as yet, remain quite obscure. It therefore seemed of very great importance from both a theoretical and a practical standpoint to attempt to confirm these results of de Jong. In the present study the experimental procedure of the original investigation was followed as closely as the description of the work allowed. Several variable factors, such as temperature, barometric pressure, vapor pressure of the benzene solutions, and the heating effect of sealing the tubes, were controlled. In one experiment Pyrex tubes of 150-cc, capacity were filled with 100 cc. of nitrogen gas and 50 cc. of benzene solutions containing about 0.5% of either pale crepe rubber or balata. After sealing, these tubes and a benzene control were exposed to direct sunlight during the summer for various lengths of time up to five weeks. At the end of the tests the changes in volume of the nitrogen in the tubes containing the rubber solutions differed from that of the benzene control by a maximum of 0.5 cc. which was found to be about the limit of experimental error.
The Stability of Abiarana Gutta-Percha Latex
Authors: Daniel F. K. , Freundlich H. , Söllner K. 
Published: February 2011

Abstract
1. The latex of Abiarana gutta-percha is more stable than that of Hevea. In the absence of preservatives Abiarana latex is stable for many months, while Hevea coagulates readily in a few hours. On addition of electrolytes, Abiarana only creams up and is readily and reversibly redispersed; Hevea is coagulated jrreversibly. Under the influence of the electric current Abiarana does not form a coherent skin on the anode; Hevea does so easily. 2. The stability of Abiarana latex is due to a protecting substance reversibly adsorbed on the particles. This substance may be removed by allowing the particles to cream-up repeatedly and by separating the serum from the particles. The serum of Abiarana (or the whole latex) added to Hevea latex strongly protects the latter and causes it to behave like Abiarana latex. 3. A similar protecting action in small concentrations cannot be produced by substances such as gelatin, peptones, lysalbinic acid, starch, etc. The chemical nature of the protecting substance could not be identified. It must have a large molecular weight, since it does not diffuse through membranes. 4. The reversible creaming-up of Abiarana latex is influenced by the cations of the electrolytes added according to their valency, in agreement with the fact that the particles are negatively charged. H+-ion and ter- and tetravalent cations are able to reverse the electrical charge of the particles. 5. The difference in creaming velocity due to different electrolyte concentrations (i. e., to different degree of discharge) seems to depend on time average size and number of aggregates of particles which are formed.
A Study of Deproteinized Rubber
Authors: Okita Tadao 
Published: February 2011

Abstract
In Part I we assumed that deproteinized rubber would deteriorate more rapidly than washed smoked sheet. But the present experiments indicate that our supposition was not correct, because the former was more resistant than the latter to mechanical deterioration. The same result was true of the specially treated rubber. It can be assumed that this depends on differences in the aging of the rubber hydrocarbon itself. But for several reasons, it is more likely that the major causes are differences in impurities and uniformity of cure. From several reports concerning protein in crude rubber by Stevens and others (Stevens, Kolloid Z., 14, 91 (1914); Park and Sebrell, India-Rubber J., 73, 265 (1927); Pickles, Trans. Inst. Rubber Ind., 3, 60 (1927)), water-soluble protein would have an immense effect on deterioration. Depolymerization and disaggregation would be the cause of deterioration by the aging of vulcanized rubber. This depolymerization, especially in artificial aging, cannot be explained merely by oxidation of the unsaturated part of the molecules, but must be attributed also to oxidation of combined sulfur, the formation of hydrogen sulfide, oxidation or other change in the free sulfur, metallic salts, proteins, and abietic acid. It has already been shown that oxidizability increases with increase in the time of cure, and that there is no relation between oxidizability and optimum cure. It has also been found that addition of acid to rubber decreases the heat deterioration (unreported experiments). Moreover, it has been found that resistivity to deterioration is increased by smoking and that the most easily oxidizable mixes contain in the neighborhood of 7 per cent of combined sulfur (cf. Kohman, J. Phys. Chem., 31, 23 (1927)), lower percentages of combined sulfur resulting in greater resistance to deterioration (cf. Boggs, Ind. Eng. Chem., 22, 748 (1930)).
Deproteinized Rubber
Authors: Boggs C. R. , Blake J. T. 
Published: February 2011

Abstract
FOR some years deproteinized rubber has been used by this company in the manufacture of rubber insulation, and the rate of consumption is increasing rapidly. This new and unique raw material is now also being manufactured for the Simplex Wire and Cable Company by The Goodyear Tire and Rubber Company on plantations in the Far East. The special virtue of deproteinized rubber is its low water absorption and the electrical stability which it imparts to vulcanized rubber compounds immersed in water. Electrical engineers are specifying such compounds for submarine, underground, and duct cables and all other insulation that may be exposed to water. The electrical properties of ordinary rubber insulation are impaired by increasing water absorption; the dielectric strength decreases, and the capacitance and leakance (or dielectric loss) increase. Power cables become useless when decreasing dielectric strength is insufficient to withstand operating voltage. Communication cables deteriorate rapidly by water absorption because their increasing capacitance and leakance prevent the practical transmission of signals long before dielectric strength is low enough to cause failure at the extremely low operating voltage of such cables.
Transparency of Rubber Compounds Containing Magnesium Carbonate
Authors: Bixby W. F. , Hauser E. A. 
Published: February 2011

Abstract
1. Basic magnesium carbonates of the type 5MgO·4CO2·xH2O will produce transparent vulcanized rubber. 2. Neutral carbonates of the magnesite type result in stocks of poor light transmission, even at low loading. 3. The basic carbonates, although of extremely fine particle size, are definitely crystalline in structure, as revealed by x-ray analysis. 4. The sample of magnesium carbonate producing the best transparency was a Japanese variety. When 25 per cent by weight was compounded in rubber, an over-all transmission of 45 per cent was produced. None of the domestic varieties gave higher than 36 per cent, and only two samples out of the eighteen examined produced this value. 5. The best Japanese carbonate (sample 3) and the best domestic carbonate (sample 9) possessed the same structure— that of a basic magnesium carbonate of the general form type 5MgO·4CO2·xH2O. 6. The Japanese carbonate, corresponding to the formula type 5MgO·4CO2·6H2O, gave higher total light transmissions at low filler concentrations than the best domestic carbonate, corresponding to the formula 5MgO·4CO2·9H2O. 7. Mixes containing between 25 and 40 per cent by weight of basic magnesium carbonate passed the greatest amount of undeviated light. 8. The amount of undeviated light passed by samples compounded with good Japanese magnesium carbonate and good domestic carbonate was essentially the same between 25 and 40 per cent filler—about 22 per cent. 9. The tensile strength of compounds containing domestic carbonate was higher in the 25 per cent filler range than that of mixtures containing Japanese carbonate.
The Oil Resistance of Rubber. IV. Mechanism of the Oil Resistance of Neoprene
Authors: Kambara Shĭ 
Published: February 2011

Abstract
To study the mechanism of the oil resistance of Neoprene, the following points were investigated. 1. The dielectric properties of Neoprene and its comparison with the crude and purified natural rubber. 2. The viscosity of benzene solutions of Neoprene and natural rubber of various concentrations. From data on the relation between polarization, the chain-length of solute and the concentration, the state of solutes in solution was discussed, and the oil resistance of Neoprene is explained on the basis of its high polarization and its complex structure. In conclusion, the author wishes to express his thanks to Professor Yoshio Tanaka for valuable suggestions and criticisms.
Impact Machine for Rubber Testing. Determining the Stress-Strain Diagram at High Speed
Authors: Albertoni Geo J. 
Published: February 2011

Abstract
IN CONTRAST to the ordinary standard procedure at low speed, various methods have been devised to carry out tensile tests of rubber under rapid application of load, with the purpose of securing more definite indications, at a speed in agreement with actual performance. The application of those methods to the study of the tensile properties of rubber stocks goes as far back as 1910, when Beadle and Stevens (1) made use of the pendulum to investigate these properties. Their work applied to rubber compounds of different compositions and different loadings. More recently, Van Rossem and Beverdam (2) presented a set of results tending to prove an optimum in the tensile properties, coinciding with the best cure as determined by practical observation. However, all experiments, previous to those here reported, are limited to the determination of the tensile strength of rubber, and no attempt was made to extend the investigations to the determination of the resistance of rubber at different elongations. The machine here illustrated is designed to measure not only the energy absorbed at break, under conditions of high speed, by impact, but also the stress-strain relation.