bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclized Rubber, Particularly Halide Transformations
Authors: Stevens H. P. , Miller C. J. 
Published: February 2011

Abstract
Boron trifluoride or materials which give rise thereto effect a “cyclization” of rubber in solution: that is, the product is less unsaturated than the original rubber. A particular degree of conversion has been shown to give a tough material, which produces strongly adherent films possessing a high degree of alkali-resistance. When used as a paint medium the material acts as an unsaponifiable “breather” and pigment protector, allowing (unlike “sealers”) the passage of aqueous solutions. For this reason it appears suitable for use on plaster and concrete. Analysis of the purified product indicates appreciable oxidation at some stage and it may be further oxidized by aging at raised temperature or by reagents such as hydrogen peroxide. The oxidation products are not identical. The conversion product yields also a hard vulcanized product resembling hard vulcanized rubber, but less thermoplastic and containing less sulfur than hard rubber produced under the same conditions. This work has been carried out on behalf of the Rubber Producers' Research Association, to whom the authors are indebted for permission to publish.
Note on the Extraction of Raw Rubber with Acetone
Authors: Stevens H. P. , Rowe J. W. 
Published: February 2011

Abstract
We have shown that if raw rubbers are exposed to light during acetone extraction, the extract does not reach a steady value but continues to increase slowly with time of extraction. If extraction is carried out in the dark, constant values for the extract are obtained after about 15 to 20 hours' extraction. In the same time the values obtained in the light are about 10% higher than the true values, obtained in the dark. If, however; in an attempt to obtain constant values, the extraction in light is continued for 70 hours, values are obtained about 25% in excess of the true ones. If, therefore, accurate values for acetone extract of raw rubber are required, extraction must be. carried out in the dark until a constant value is reached. If, for convenience, light is not carefully excluded, it would appear that a comparatively short extraction, e.g., 5 to 6 hours, would give the best results, since over 90% extraction is obtainable in 4 hours (Table II), and oxidation is not likely to be considerable in this period. In any case, shielding from direct sunlight is advisable. In view of the general trend of the curves for acetone extract obtained by Endo, it is probable that oxidation of the rubber occurred, and that his results, particularly for the longer periods of extraction, are complicated by the presence of rubber oxidation products. This work has been carried out on behalf of the Rubber Producers' Research Association, to whom the authors are indebted for permission to publish this paper.
An Investigation of the Performance of Flat and V-Type Transmission Belts
Authors: Brazier S. A. , Holland-Bowyer W. , Mellers C. E. 
Published: February 2011

Abstract
A major problem in engineering is and always will be the efficient and effective transmission and distribution of motive power. In spite of the extensive developments which have taken place in individual direct, gear or chain coupled drives, there still remains an extremely large number of drives installed or being installed for the transmission of power in which belting of one kind or another is preferable. Such drives also vary tremendously in character and type, from small machines requiring a fraction of one horse power, to heavy industrial drives, as those used in rolling mills, where the power transmitted often extends to several hundred horse power. The nature of the load may be smooth and uniform or subject to heavy peak loads such as occur in the case of ore crushers or pumping machinery. The use of belting for the transmission of power actually dates almost from the time that mechanical power began to be used, and in fact the name of Leonardo da Vinci has been mentioned as one of the first to devote attention to the fundamental principles of belt drives as well as being the inventor of the tension or jockey pulley. In spite of this, however, very little development in what may be termed the technology of belting appears to have taken place until the latter part of the nineteenth century and, as may be anticipated, most of the earlier writers gave special attention to the question of leather belting.
The Properties of Rubber Prepared from Dialyzed Latex
Authors: Stevens H. P. , Rowe J. W. 
Published: February 2011

Abstract
Rubber articles are prepared from ammonia-preserved latex by two principal processes, viz., evaporation or coagulation, or by a combination of both. The object of this work was to determine what advantages are to be obtained by the use of a latex purified by dialysis. An 8-gallon batch of normal ammoniapreserved latex (from Hevea brasiliensis) was available and all the rubbers were prepared from this batch unless otherwise stated. The latex was kept for several days and decanted from the sludge which settles out. After straining, it was stored in one-gallon cans until required for use. Some of the latex was dialyzed through membranes of regenerated cellulose in the apparatus previously described by the authors. Some aqueous ammonia was added to the latex daily to preserve stability, and three charges of distilled water were used to complete the purification. A pressure was applied to the latex and adjusted to allow slight dilution so that there was no formation of paste on the membranes. The latex was analyzed, before and after dialysis, for total solids and dry rubber content. The former were determined by evaporating a weighed portion of the latex to constant weight at 70°. The dry rubber content was determined by coagulating the latex with about an equal volume of 1% acetic acid, crepeing the coagulum on a washing machine, and drying the crepe at, 70°
An X-Ray Investigation of Crystallinity in Rubber
Authors: Gehman S. D. , Field J. E. 
Published: February 2011

Abstract
The crystalline structure which rubber exhibits under certain circumstances has come to be regarded as associated with a secondary or micellar structure of long chain molecules. The exact mechanism by which the localized ordered regions appear is a speculative subject in recent developments of the micellar theory of long chain polymeric materials. The views of various workers on this subject have been summarized by other authors. The crystalline structure of rubber displays varying degrees and types of orientation of the crystal units, depending on the conditions under which crystallization occurs. The amorphous x-ray diffraction pattern of unstretched rubber is shown in Figure 1, the unoriented crystalline diagram for frozen rubber in Figure 2. When crystallization is induced by stretching, the crystallites are aligned along the axis of stretching, giving the fiber diagrams of Figures 3 and 4. In this case there is random orientation of the other two axes of the crystallites. “Higher orientation,” in which all three axes of the crystallites are aligned, gives the diagram of Figure 15 and can be secured with suitable dimensions of the stretched piece.
Highly Polymeric Compounds. CLXIV. Unit Cell Diagrams and the Microstructure of “Single Crystals” of Rubber. Determination of the Lattice of Macromolecules of Rubber according to New X-Ray Methods
Authors: Sauter Erwin 
Published: February 2011

Abstract
1. The macromolecular lattice of rubber is rhombic and has the constants: a .......................12.60 ± 0.05 A.U. c ....................... 8.91 ± 0.05 A.U. b ....................... 8.20 ± 0.05 A.U. 2. The number of isoprene residues in the cell is computed to be 7.92, i.e., essentially 8; the density obtained roentgenographically is 0.974, which is in reasonable agreement with the value of 0.965 found experimentally. The discrepancies of earlier measurements are at the same time eliminated. (3) The four chains which pass through the unit cell in the direction of the fiber axis are probably columnar tub-like chains with a cis-arrangement at the double bonds which are assembled after the manner of a lattice face-centered on one side. (4) After being stretched to a considerable extent at ordinary temperature, eucolloidal “fused” rubber crystallizes with formation of microscopic crystalline regions of indefinitely great linear tension.
The Crystal Structures of Cellulose and of Rubber
Authors: Mark H. , Meyer Kurt H. 
Published: February 2011

Abstract
Sauter has made the statement that the interference A2, which was reported by the present authors as a simple point, is the result of the superimposing of two interferences, which he designates as (002) and (300). In addition, he shows photographs of highly oriented rubber. In his diagram on page 725 of this issue of Rubber Chemistry and Technology, it is evident that the strong reflection A2 is quite distinguishable near the inner equatorial point A1 ((200) according to Lotmar and Meyer). However, as can easily be shown, Sauter has fallen into the same error that he did in his work on cellulose, i.e., he has mistaken an incompletely oriented substance for a highly oriented substance. As far back as 1928 Mark and von Susich published diagrams of highly oriented rubber, from which it was quite evident that in no case did the interference (300) show any notable intensity. This experiment was repeated by the present authors. The illustration shows a diagram of highly oriented rubber and also a fiber diagram. The intensity of the interference (200), as well as that of (400), is approximately the same on the two diagrams. Whereas the reflection A2 is very intense on the fiber diagram, only a slight intensity is visible in place of reflection A2 on the photograph of the highly oriented rubber. Even if this intensity originated from the plane (300) it would obviously be much too small to bring about an appreciable displacement of the approximately twenty-times stronger reflection (002) on the fiber diagram. Sauter's displacement of the interference (002) in relation to the position assigned by Mark and von Susich, as well as by Lotmar and Meyer, is therefore without foundation experimentally and consequently his unit cell is invalid.
The Chemistry of Natural Rubber
Authors: Haefele J. W. , McColm E. M. 
Published: February 2011

Abstract
Roberts (J. Chem. Soc., 1938, 215, 219) dissolved air-dried films from fresh latex in acetone-carbon tetrachloride and coagulated the solution by the addition of further acetone; the supernatant liquid contained an ingredient which was soluble in ligroin, contained sulfur, might be elastic, and was termed by Roberts, caoutchol. Roberts stated that removal of this caoutchol ingredient caused marked changes in the properties of the remaining rubber, “characterised by its lack of tensile strength and the remarkably low viscosity of its solutions.” This rubber was dried in air for 24 hours, dissolved in benzene, centrifuged, and emulsified with water and the benzene removed by steam distillation. The rubber remaining was tacky and feebly elastic after drying in a vacuum, and was termed caoutchene. Roberts developed the theory that the elasticity of crude rubber is due to the presence of caoutchol and that, without caoutchol, rubber has very poor elasticity and low viscosity in solution. Insufficient attention has been paid to the role of oxygen in the purifications described. Roberts states: “The process has been carefully examined, particularly with respect to the possibility of oxidative or other changes in the constituents. No evidence of such changes has been obtained.” Yet the coagulated rubber, after removal of the caoutchol but prior to steam distillation, was milled in air, and dried in air for 24 hours, during which time considerable oxidation could have occurred.
On the Crystallization of Crude Rubber. I Experimental Results
Authors: Park Chullchai 
Published: February 2011

Abstract
It has already been ascertained that crystallization of rubber can be induced in various ways, such as stretching, freezing, milling and compressing. if a narrow strip of smoked sheet rubber is stretched extensively, the x-ray diffraction pattern shows a fibrous arrangement of the microcrystals. At an elongation of about 150 per cent, a faint fibre diagram is obtained and at 500 per cent elongation, the diffraction spots become sharp and intense. The amorphous halo peculiar to unstretched rubber remains unchanged in width and position, but its intensity decreases with increase in elongation, in contrast to the increase in intensity of the fibrous spots. It was found by Katz and Bing that crepe rubber is crystalline. This point was confirmed by Tanaka and the writer; the Debye-Scherrer rings obtained by them with crepe rubber is shown in Fig. 1 of Plate I. In preparing a sheet of crepe rubber, coagulated strips are passed between rolls 8 to 12 times, and the coagulated strips are strongly crystalized by such severe milling. In preparing smoked sheet, milling of the coagulated sheets is not so severe as in the case of crepe rubber, and some of the rubber crystals formed during milling melt when heated in the process of smoking.
Specific Heat of Strained Rubber
Authors: Boissonnas Charles G. 
Published: February 2011

Abstract
The specific heat of unstrained rubber as a function of temperature has been the subject of many investigations; but only one set of data has been published on the specific heat of strained rubber. (Ornstein, Wouda and Eymers, Proc. Acad. Sci. Amsterdam, 33, 273 1930). Ornstein and his coworkers heated samples of strained vulcanized rubber to 80° C and dropped them into a calorimeter at room temperature. The results they obtained are presented in Figure 1, where the specific heat of one gram of rubber is plotted against extension: As Figure 1 shows, the specific heat diminishes to about two-thirds of its original value when the extension is increased from 0 to 100 per cent (Δl=1); it increases again on further extension. According to Ornstein et al., “the form of the curve for the specific heat is most interesting, as the strong variation of this quantity with the elongation must be of utmost importance for the understanding of the molecular state of rubber.” In order to check these results by another method, the writer measured the specific heat of rubber at room temperature (19° to 21° C) by a process involving temperature changes of less than 0.1° C. Two samples of rubber were chosen. Sample I was highly vulcanized for 30 minutes under 3 atmospheres' pressure. Its composition was as follows:
Oil-Resisting Rubber. Part XII. Vulcanized Rubbers Containing Organic Accelerators
Authors: Scott J. R. 
Published: February 2011

Abstract
In spite of the vast amount of work which has been devoted to organic accelerators and their influence on the physical properties of the vulcanizate, very little information can be found in the literature concerning their influence on the swelling of the vulcanizate in organic liquids. The present experiments were not intended to form a systematic investigation of the influence of organic accelerators on the swelling properties of the vulcanizate, but rather to obtain a general idea of the swelling of rubbers containing the commoner types of commercial accelerators and to find out to what extent swelling could be correlated with the mechanical properties and combined sulfur content of the vulcanizate.
Fatigue in Rubber. Part III. Fatigue and Reinforcement
Authors: Naunton W. J. S. , Waring J. R. S. 
Published: February 2011

Abstract
Rubber, unvulcanized and vulcanized, is both elastic and plastic and it is generally accepted that the function of vulcanization is to decrease the plasticity rather than to develop elasticity. It is, of course, essential that unvulcanized rubber after mastication should be predominantly plastic to allow all of the usual factory processing of the unvulcanized material. Incidentally it should be mentioned that this is one of the most difficult problems connected with the synthesis of artificial rubbers, namely, to produce a rubber which is essentially plastic before vulcanization and yet predominantly elastic after vulcanization. From the point of view of theoretical conceptions, various theories have been put forward to explain the elasticity of rubber. The old mechanical analogies of elastic bags containing fluid are of historical interest only. The first theory, which was attractive in many respects, was the spiral molecule theory of Meyer and Mark, but it has since been generally recognized that it is not in agreement with many of the known facts, and the theory has been dropped.
Multipore—A Thin Perforate Latex Sheet
Authors: Shriver G. E. , Jordan H. F. 
Published: February 2011

Abstract
Charles Goodyear, who perhaps anticipated more fully the versatility of rubber than anyone since his time, suggested in his treatise on rubber that perforated rubber might be used for “sieves, colanders and strainers” and that it might “also be substituted in a great many cases, if not generally, for woven wire cloth.” With the need for products of this type intensifying in recent years, much research has been done toward improving the processes and products related to this field. Two recently developed porous sheet rubber products are Multipore and microporous hard rubber. Both have extensive application as aids to filtration, and each has other potential uses peculiar to itself. The present article will be devoted to a discussion of Multipore, and microporous hard rubber will be treated in a succeeding article. Multipore is a porous rubber sheet made from latex rubber, and derives its porous characteristics from many minute and uniformly spaced holes that extend perpendicularly through the sheet. The types now produced commercially have 1,100 to 6,400 holes per square inch and poor diameters of 0.012 to 0.004-inch, depending on the type. At present Multipore can be obtained in soft rubber, hard rubber, flexible hard rubber and soft Neoprene.
Nomenclature of Synthetic Rubbers
Authors: Fisher Harry L. 
Published: February 2011

Abstract
Sixty years ago, synthetic indigo, a dream of organic chemists, became a reality. Thirty years ago the increase in the knowledge of the chemistry of rubber made organic chemists dream also of synthesizing that important natural product. However, rubber or more specifically the rubber hydrocarbon has not yet been synthesized, in spite of the tremendous amount of time and effort already expended on this intriguing problem. But in scientific journals, books, newspapers and advertisements there is much that is published about “synthetic rubbers”. Indigo was synthesized, and there is no question about speaking of synthetic indigo. Since rubber has not been synthesized, why do we hear so much about synthetic rubbers? Are there any other names which could be used to describe the various “synthetic rubbers” and other rubberlike products? These are the questions which will be discussed in this paper. Indigo is crystalline and can be purified easily; rubber hydrocarbon can be crystallized only under very special conditions, cannot be distilled, and therefore is not easy to purify. Indigo has a comparatively low molecular weight which can easily be determined; rubber hydrocarbon is an elastic polymer, the molecular weight of which is very high and cannot be determined with precision. A determination of the identity of natural and synthetic samples of indigo can readily be made, but with rubber it is almost impossible with our present methods to show the absolute identity of two specimens, although it is possible for all practical purposes to do so.
The Specific Gravity of Rubber in Hevea Latex
Authors: de Vries O. 
Published: February 2011

Abstract
Since my former communication on this subject several papers have appeared which form valuable contributions to the interesting problem of the actual specific gravity of the rubber particles in (original or preserved) Hevea latex. Rhodes recalculated his data, and came to an average figure of 0.9064 for the specific gravity of rubber in ammoniated latex, preserved during several weeks in the East; the rubber content being determined after coagulation by acetic acid in the usual way. Using the term proposed in my former paper, this may be called the specific gravity of “crepe rubber in preserved latex”, which may differ from that of “crepe rubber in original latex” by the effect of possible changes by the prolonged action of ammonia, by the settling out of the sludge (ammonium magnesium phosphate, mixed with protein-like substances), and other changes that occur in preserved latex. Leaving these unknown factors out of consideration, we have to take into account the fact that the rubber content was determined by acid coagulation, which means that a certain amount of serum substances, principally proteins, was precipitated with the rubber, and may have influenced its specific gravity. In my former communication I have shown that the specific gravity of “crepe rubber in latex” is found lower, the higher the rubber content of the original latex, i.e., the smaller the ratio of serum to rubber, and the smaller, therefore, the amount of acid-precipitated serum proteins in per cent of the rubber. Plotting, in this line of thought, Rhodes' figure in the graph (Figure 1), it will be seen that it corresponds to 45 grams rubber per 100 cc, or about 46.6 in percentage of weight, not abnormal for a preserved latex. Protein, precipitated with the rubber, has a still smaller effect in another figure given by Rhodes, namely, the specific gravity of rubber from a centrifuged cream of 56.7 per cent rubber content (acid coagulation). The corrected figure for the specific gravity of this rubber is given by Rhodes as 0.9011, which in Figure 1 corresponds to 55.5 grams of rubber per 100 cc, or about 58.5 per cent by weight; this is in reasonable agreement with the real figure of 56.7, taking into account the unavoidable errors of an extrapolation, such as in Figure 1.
The Action of Pyridine on Chlorinated Rubber
Authors: Lichtenberger J. , Naftali M. 
Published: February 2011

Abstract
In the various publications on the properties of chlorinated rubber which have appeared, the solubility in pyridine has been mentioned frequently. In 1935 and 1936 the present authors had occasion to occupy themselves with this problem, and the present paper deals with some of the results which were obtained. Chlorinated rubber is extremely soluble in pyridine, even in the cold; in fact from a practical point of view the solubility is unlimited, and chlorinated rubber and pyridine may almost be regarded as miscible in all proportions. Two definite phenomena were observed during the dissolution of chlorinated rubber on pyridine: (1) a gelation of the system, and (2) the formation of a quaternary pyridinium salt. By the correct choice of conditions, the reaction can be made go, at least partially, to either of these two directions.