bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chromatographic Analysis of Rubber Compounding Ingredients and Their Identification in Vulcanizates
Authors: Bellamy L. J. , Lawrie J. H. , Press E. W. S. 
Published: February 2011

Abstract
The work is still in a preliminary stage, but sufficient has now been done to demonstrate the applicability of chromatographic methods to rubber analysis. The acetone extracts of vulcanizates are complex mixtures not readily amenable to analysis by normal chemical methods. By the use of this elegant technique, however, it has been possible to effect the efficient separation of wax, fat acids, accelerators, and antioxidants, not only from each other but also from naturally occurring coloring matter and from degradation products. The subsequent identification of the main fractions is then a relatively simple matter, as tests such as the cobalt oleate reaction for accelerators and the spot reactions for antioxidants can be applied without interference from any other components. The elegance of the method is further demonstrated by the fact that it can be used in the identification of components present in much smaller quantities than are detectable by other chemical methods. The accelerators and antioxidants studied so far are rather limited in number, but cover the main classes of these materials, and the method should, therefore, be applicable to the analysis of a number of technical vulcanizates, and the authors have, in fact, already made use of it with some success for this purpose. It is noteworthy that the adsorption and elution processes are quantitative, and that the whole of the material put on to a column can, therefore, be recovered from the various fractions. This, therefore, offers the possibility of quantitative work on such problems as the rate of consumption of accelerators during cure or the relationship of antioxidant content to behavior on aging. Such work would necessarily be restricted to experiments using pure accelerators and pure antioxidants which are single chemical entities. In this connection the degradation products obtained from mixes accelerated with T.M.T. or M.B.T.S. or D.P.G. are of interest both in the actual isolation of the components in question and in partial confirmation of the work of others in this field. A much more intensive study of the degradation products of each accelerator in mixes cured to varying degrees may well throw more light on the complex subject of accelerators. Although, therefore, the authors have been able to show the utility of chromatography for their own particular analytical problems, it is likely, ultimately, to be of great value in the exploration of some of the fundamental problems of rubber chemistry.
Vulcanization of Rubber with Sulfur
Authors: Williams Ira 
Published: February 2011

Abstract
Vulcanization is a change in rubber which results in an increased resistance to deformation at ordinary temperature. This definition disregards entirely any chemical agents or chemical actions involved. It requires only that the rubber lose its plastic properties and become more resistant to compression, stretching, or swelling. Freeze resistance may or may not be affected; this depends largely on the extent of any chemical attack which may be involved. The earliest method of vulcanization, discovered by Goodyear over a hundred years ago, still remains the basis for essentially all vulcanization of rubber today. The only refinements which have been introduced consist in the addition of accelerators and accelerating accessories, and in a manipulation of the quantity of sulfur. All of the other methods, such as the use of sulfur chloride, peroxides, quinones, nitro compounds, and selenium, remain quite unimportant from a commercial standpoint. The study of vulcanization, particularly with sulfur, has received the attention of many chemists, most of whom have differed in their final interpretation of the action. The earliest work on the nature of vulcanization was carried out by Henriques, who found that sulfur chloride combines chemically with rubber, and the natural assumption was made that molecules of rubber are joined by means of sulfur. Weber soon found that sulfur combined during hot vulcanization. Stern found that the amount of sulfur combined was directly proportional to the time of heating and depended on the original concentration of sulfur. Whereas Stern conducted his vulcanization in solution, Hübener obtained substantially the same results in a direct manner.
Crude Rubber Preparation. Sheet Production by Continuous Coagulation of Hevea Latex
Authors: Newton E. B. , Stewart W. D. , Willson E. A. 
Published: February 2011

Abstract
Quantitative experiments in controlling the rate of coagulation of fresh Hevea latex are described, and the results have been applied in a process for the continuous preparation of sheet rubber on a laboratory scale. As with most continuous processes, this method is more applicable where large, rather than small, volumes of latex must be worked up. Its apparent advantages reside in a possible improvement in uniformity of product and a reduction in factory floor space for a given output of rubber.
Chemical Changes in Ammoniated Hevea Latex
Authors: Altman R. F. A. 
Published: February 2011

Abstract
As generally accepted, the preservative action of ammonia on latex is due to the neutralization of the acids formed from certain latex components by bacteria or enzymes and to its inhibiting action on bacterial growth. The chemical composition of latex undoubtedly changes on ammoniation as different components, probably including the rubber itself, are chemically affected by the alkaline action of ammonia. So far, only little insight has been obtained into the chemistry of these changes. In this connection reference should be made to the work of Rhodes, who systematically followed the changes in various characteristics of the latex over a period of fourteen months. The averages of the figures obtained by Rhodes are recorded in Table 1. The reader is referred to the original paper for the interesting comments made on these figures. In the present publication the changes in the nonrubber ether-soluble part of the latex have been followed analytically over a fifteen months' period. The experiments were conducted in such a way that, at certain time intervals, samples of 100 cc. were taken from the vigorously shaken bulk of latex which had been ammoniated immediately on arrival in the laboratory. Exclusively latex of clone Tjirandji 1 from the Experimental Garden Tjiomas near Buitenzorg, Java, was gathered for this purpose.
The Thermoplasticity of Thermoprene. A Study of the Adhesion of Rubber to Metal
Authors: Jarrijon André , Louïa Pierre 
Published: February 2011

Abstract
Among chemical derivatives of rubber, there is a type to which has been given the name of isorubbers or cyclorubbers in the technical literature. Kirchhof has described at length these products, which can be prepared by various methods, e.g., by the action of heat, as described by Harries, who isolated a white amorphous powder, having a density of 0.992, by heating rubber for several hours in ether at 250–300°, under pressure, or by the action of chemical reagents, particularly sulfuric acid and inorganic and organic halogenated compounds, with which a range of products suitable for molding powders, paints, sheets, wire, etc., can be prepared. The present work is concerned, not with a further study of these products, but rather with an investigation of a particular one of these products, viz., that which is obtained by treating rubber with phenolsulfonic acid. The B. F. Goodrich Company, and Fisher in particular, have successfully developed the manufacture and use of this product, and have given it the generic and commercial name of Thermoprene. At the beginning, a large number of applications of Thermoprene were foreseen, but only one application has survived and undergone any extensive development, viz., the use of Thermoprene as an adhesive for bonding rubber to metal, a process known as the Vulcalock process. As a result of newly observed facts, it seemed of interest to take up this problem again in an attempt to improve the process in certain ways.
Determination of Resistance to Abrasive Wear. V. Influence of Calender Grain
Authors: Parris R. W. , Scott J. R. 
Published: February 2011

Abstract
The standard form of test-piece used on the type of abrasion testing machine of the Akron Standard Mold Company is a disc of about 63.5 mm. diameter and 12.5 mm. thick. This can be made either (1) by vulcanizing in a mold of appropriate shape, which is filled with a blank cut from a sheet of stock about 13 mm. thick, or (2) by cutting out from a mold-vulcanized slab 12.5 mm. thick. In either case the abrasive wear takes place on a surface corresponding to the edge of a disc cut from the sheet of stock. The same is true if tests are made on discs cut from rubber articles such as soles, flooring, or other material in sheet form. In the actual use of such articles as tires, soles and heels flooring, conveyor belting, and tough rubber cable sheaths, the abrasive wear occurs on a surface representing substantially the flat surface of the sheet of stock. If the stock contains fillers that produce a calender grain effect, e.g., magnesium carbonate and clay, it cannot be assumed that the wear on the flat surface of the sheet is the same as that on the edge of a disc cut from it, which lies in a plane perpendicular to the former surface. If there is a difference between the rates of wear on these two surfaces, the type of test-piece described above must give an incorrect indication of the abrasion resistance of the rubber in actual use.
Determination of Resistance to Abrasive Wear. VII. Uniformity of Results Obtained with the Du Pont Machine
Authors: Morley J. F. , Scott J. R. 
Published: February 2011

Abstract
(1) Tests have been made to investigate the variability of the abrasive papers used on the du Pont abrasion machine; the data obtained have also been examined to detect any variation in rate of abrasion during one test, and differences between the right- and left-hand specimens. (2) Differences in abrasiveness of 13 per cent were found between the different sheets of emery paper, even when compared with the differences between the rubber specimens, and it is considered that a solid disc of bonded abrasive, as used on the Akron machine, would be preferable to emery papers. (3) As there is no evidence of variation in rate of abrasion during a 20-minute run, there seems to be no objection to using different test-periods for different rubbers if circumstances render this desirable. (4) There are small, but not consistent, differences between the abrasion losses on the right- and left-hand specimens, which may arise from the 8-lb. load not being equally distributed between them. It is considered that the machine could be improved by making the arm that carries the specimens free to oscillate in a plane perpendicular to the abrasive, so that the loads on the specimens would be automatically equalized. The practice of rigidly fixing the arm parallel to the plane of the abrasive seems unsound because, if the parallelism were really rigid, the rates of wear on the two specimens would of necessity be equal, even if the rubbers had different abrasion resistances. Moreover, any suggestion to test the sample under examination and a standard rubber simultaneously is clearly unsound unless a freely oscillating arm is provided.
The Effect of Air Circulation by Convection in the Test-Tube Method of High-Temperature Aging of Synthetic Rubbers
Authors: Juve A. E. , Boxser H. , Reahard D. H. , Doner S. R. , McWhorter J. F. , Cashion C. G. , McCarthy G. D. , Howlett R. M. 
Published: February 2011

Abstract
By modifying the present test-tube method of high-temperature aging to permit air circulation by convection, the test is made appreciably more severe, but at the same time more reproducible. The velocity of air circulation under the conditions used here, which varied over a three-fold range from 1.1 to 3.4 changes of air per hour, did not affect the results obtained. The loss in weight during aging was somewhat greater in the circulating-air tests than in the stoppered-tube tests. The poorer reproducibility of the stoppered test-tube method over the circulating-air method is thought to be due to variations in the permeability of the stoppers used. The more impermeable the stopper, the less severe is the test. It is recommended that the present test-tube aging method D-865 be amended to require the use of a pair of glass tubes extending through the stopper using the dimensions and arrangement illustrated in Figure 1.
Effect of Fungicides on Natural and Synthetic Rubber
Authors: Stief J. L. , Boyle J. J. 
Published: February 2011

Abstract
During the recent war a great part of the military operations were conducted in warm, humid, tropical regions, ideal for the growth of fungi. The protection of the cotton cloth used in rubber-coated fabrics thus became a major problem of the armed forces. Because the area was of minor importance in the world consumer market, comparatively little work had been done on this problem by the research laboratories of private industry. A tropical testing chamber which simulated tropical conditions was built at Fort Belvoir to study the problems of fungus growth and effective countermeasures. The problem was complicated by the possibility that the fungicide which had a protective effect on the cloth might have had a destructive effect on the rubber coating. Tests on pentachlorophenol and 2,2′-methylene-bis (4-chlorophenol) by two industrial concerns had indicated that these two fungicides had no adverse effect on either natural rubber or GR-S when used in small concentrations. Tests by another industrial concern had indicated that salicylanilide was satisfactory for use with natural rubber and Neoprene. However, because of the meager amount of information available, a study was conducted to determine what fungicides, and in what concentrations, might abnormally deteriorate rubber coatings.
Certain Fundamental Concepts Relating to Nonpolar Mechanisms in Olefinic Systems
Authors: Farmer E. H. 
Published: February 2011

Abstract
The application of polar concepts to the interpretation and systematization of experimental observations in the field of organic chemistry has had such striking success and usefulness during the past twenty-five years that the concepts have become an integral part of organized chemical knowledge. Recent years, however, have seen the steady accumulation of experimental results which do not fit in the polar scheme, and these may be rationally and consistently interpreted as resulting from the occurrence of apolar types of reaction in which the participants are short-lived neutral entities (molecules or atoms) displaying free-radical characteristics. On the apolar basis, the author outlines a hypothetic correlation of a considerable array of experimental results with which he has been concerned—both as an immediate aid to making sense of what would otherwise seem to be unusually complicated and unintelligible, and with the hope that the views tentatively advanced will furnish suggestive starting points for future kinetic experimentation. The foregoing account relates to subjects forming part of a program of fundamental research undertaken by the British Rubber Producers' Research Association.
The Addition of Thiocompounds to Olefins. I. Reactions of Thioglycolic Acid, Thiophenol, and Isopentanethiol
Authors: Cunneen J. I. 
Published: February 2011

Abstract
The interaction of thiols with unsaturated hydrocarbons was first reported by Posner, who treated thiophenol and benzylthiol with a variety of olefins at room temperature in the presence of acetic and sulfuric acids. With simple olefins, conjugated and nonconjugated, addition of fragments of the thiol produced by scission of the S-H link proceeded readily and, at asymmetrically substituted double bonds, in opposition to Markovnikov's rule: CR′R″:CHR‴+SHPh→CHR′R″⋅CH(SPh)R‴. More complex nonconjugated olefins (terpinolene and sylvestrene) showed depressed reactivity in that addition occurred at only one double bond, and the highly conjugated systems, stilbene and diphenylbutadiene, failed to react at all. Ashworth and Burkhardt confirmed Posner's formulation of the styrene-thiophenol reaction, and pointed out the catalytic activity of sunlight and the inhibition induced by small amounts of piperidine. Ipatieff and others investigated the reaction of thiophenol and ethanethiol and propylene, isobutylene, trimethylethylene, and isopropylethylene at 100–150°, and found that, although addition products abnormal with respect to Markovnikov's rule were formed in the absence of catalysts, yet the presence of sulfuric acid, contrary to Posner's findings, reversed the orientation of the addition and led to normal products. Contemporaneously, Jones and Reid and Kharasch, Reid, and Mayo showed that traces of peroxides, either as present normally in unsaturated hydrocarbons or as added ascaridole, strongly catalyze the abnormal addition, and that quinol effectively impedes the reaction. Mayo and Walling have proposed a free-radical chain-reaction mechanism, but kinetic evidence on which to found a detailed reaction scheme is so far lacking.
Structural Changes in Rubbers Brought about by Molecular Oxygen
Authors: Dogadkin B. 
Published: February 2011

Abstract
The nature of the changes of physical properties of rubber resulting from oxidation processes is determined by its initial structure and also by the conditions of the process (temperature, concentration of reagents, extent of their interaction, type of reaction, etc.). In the interaction of molecular oxygen with linear polymers containing double bonds in the main chains, e.g., with natural rubber, a disintegration of the chains takes place in the initial stages, as a result of which an increase of solubility, a decrease of strength, an increase of plasticity and a decrease in the viscosity of solutions of the rubber are observed. The decrease in solubility and the increase of strength and elasticity set in at that stage of oxidation at which local links of ether type are formed between individual chains, or at which the accumulation of polar groups containing oxygen increases to a noticeable extent the intensity of intermolecular attractive forces. In the interaction of molecular oxygen with spatial (network) polymers, e.g., with the insoluble fraction of butadiene and butadiene-styrene polymers, with a solvent medium, there occurs a disintegration of structure and passage (dispersion) into the solvent medium. The solutions obtained contain massive particles of spherical form and display over a wide range of concentrations a Rayleigh type of light scattering and obedience to the law of Einstein and Poiseuille. The chemical nature of the dissolution of spatial polymers is confirmed by the magnitude of the activation energy of the process (27,000 calories per mole). A similar breakdown of spatial structures occurs in the milling of rubbers of this type, in which, in contrast to cases of mastication of linear polymers, the viscosity of solutions of spatial polymers does not change during the time of mastication. In the interaction of molecular oxygen with linear polymers containing double bonds in side chains, e.g., with sodium-butadiene rubber, the principal effect which takes place is the secondary process of combination of chains to spatial structures, resulting in the observation of a decrease of solubility, and an increase of strength and elastic properties of the polymer. This formation of spatial structures in the second stage of oxidation is facilitated by the polyfunctionality of the products of the initial stage of oxidation of the original polymer. The structural changes described, proceeding under the action of oxygen, constitute one of the causes of the appearance of the vulcanization optimum.
The Action ox Benzoyl Peroxide on Natural Rubber in Solution
Authors: Compagnon Patrice , Delalande André 
Published: February 2011

Abstract
An earlier publication described experiments on the combination of active ethylene compounds, such as maleic anhydride and acrylonitrile, with rubber in solution under the influence of benzoyl peroxide. Control experiments on the action of benzoyl peroxide alone under the same conditions were carried out also, and from the results it was possible to come to certain conclusions. Since then, the reactions of unsaturated compounds with rubber have been investigated more extensively, and further experiments have been carried out on the action of benzoyl peroxide alone. The authors believe that it is of interest to discuss these observations at the present time, for it is not intended to continue with any systematic study of this problem, which actually is only of secondary importance as far as the main purpose of the investigation under way is concerned. Furthermore, it is felt that some of the experimental results may be of importance to other investigators who have studied, in the past few years, the photogelation and oxidation of rubber from the theoretical viewpoint. Finally, in the work already cited, no mention was made of the important part played by oxygen, even when in very low percentages, and this led to an incorrect interpretation of the phenomena, for which it is well to make amends at this time.
Influence of Structure on Polymer Liquid Interaction. I. Relative and Absolute Values of Swelling Equilibria
Authors: Salomon G. , Van Amerongen G. J. 
Published: February 2011

Abstract
To reach a better understanding of the correlation between molecular structure and intermolecular attraction, a comparison was made of swelling equilibria. With this aim we studied the absolute value of the swelling equilibrium under the influence of polar and polarizable groups, which were introduced in solvents and polymers with different molecular structures. The influence of temperature, cross-linking, external pressure, and mechanical strain on the position of the equilibrium was also studied. Any general treatment of swelling is obviously limited by our present knowledge of the properties of liquid mixtures. Experimentally, however, the study of high polymeric solutions and gels offers several advantages over that of ordinary liquids. Our experiments, designed to elucidate the structure of polymers, also reveal properties of some organic liquids which could not be observed easily by other means. Results obtained with commercial rubbers will be given in this paper, while analogous measurements on a series of copolymers with increasing numbers of nitrile groups will be dealt with in a second paper.