bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Thermal Decomposition of Natural and Artificial Rubber in the Presence of Aluminum Chloride
Authors: Zelinsky N. D. , Koslow N. S. 
Published: February 2011

Abstract
The numerous published works on reactions taking place under the influence of aluminum chloride show more and more what an important part the latter plays in organic chemistry. During recent years experiments by one of the present authors and his collaborators have shown that aluminum chloride acts as a catalyst in the thermal decomposition of complex homogeneous substances, that it lowers the temperature of the decomposition and that it makes this decomposition take place in a well-defined way. This phenomenon consists of a hydrogenation by hydrogen of the unsaturated fragments of the decomposition, where the hydrogen is removed from the condensed mass of organic material. For example, a complete series of hydrocarbons of different composition and constitution are obtained by the decomposition of such substances as cholesterol, oleic acid, and abietic acid, in addition to phytosterols (betulin). These investigations showed that the chemical nature of the hydrocarbons formed differs according to the original substance. Cholesterol, for example, yields, in addition to gaseous and easily volatile paraffins, a preponderance of benzine hydrocarbons in which cyclic forms (cyclohexane and cyclopentane derivatives) predominate. Therefore benzine from cholesterol resembles benzine from crude Caucasian oil. The properties of the hydrocarbons from the higher fractions are likewise different from those of the substances named above.
Fundamentals in the Problem of Resistance to Deterioration
Authors: Taylor Hugh S. 
Published: February 2011

Abstract
The problem of control in processes of deterioration is the problem of control of the speed of chemical reactions. The fundamental reactions in deterioration are oxidation processes involving oxygen, steam or other less universal oxidizing agents as well as reactions of polymerization, decomposition, and depolymerization. Heat and light, ionization, pressure, and the presence of accelerating agents are the important factors which influence the speed of such processes and are thus of major importance in a discussion of the fundamentals of the problem. Control of deterioration is the inverse of the historical occupation of the chemist. Since al-chemical times his prime concern has been the promotion of chemical reactions. A belated attention to the problem of preserving his synthetic achievements is not, however, without its own peculiar scientific interest and practical significance.
The Production of Isoprene from Rubber
Authors: Bassett H. Ll , Williams H. G. 
Published: February 2011

Abstract
For more than a century, researches have been carried out on the distillation of rubber, and the general nature of the products—isoprene, terpenes, and higher terpene compounds—has long been known, but comparatively little work ha been done on the effect of variations in the conditions of distillation, and in particular on the maximum possible yield of isoprene. Williams (Phil. Trans., 150, 241 (1860)), using an iron retort and distilling rubber at a relatively low temperature, obtained some 5% of crude isoprene b. p. 37–44°. Fischer and Harries (Ber., 35, 2156 (1902)) showed that when rubber is distilled at 0.25 mm., less than 1% of isoprene is obtained, and Staudinger and Fritschi (Helv. Chim. Acta, 5, 785 (1922)), working at 0.1–0.3 mm. and 275–320°, obtained 3.1%. These two results are not quite consistent, but they tend to show that a low pressure militates against a high yield of isoprene.
The Surface Affinity of Rubber for a Filler
Authors: Vellinger E. 
Published: February 2011

Abstract
It is known that there is a relation between the mechanical properties of rubber and the nature of the, filler or pigment which is incorporated in it. It has been proved that certain fillers have the property of improving considerably the characteristic mechanical properties of rubber. Thus zinc oxide has proved to be a better reinforcing agent than some substances with a finer particle size. Lithopone, with a fineness which is of the same order of magnitude as that of zinc oxide, has no reinforcing action whatever. Gas black has the most powerful action known. Moreover all reinforcing fillers are very good absorbents. On the contrary inert fillers arc of little account from this point of view. The phenomena of adsorption seem then to play an important part in the reinforcing action of fillers, and consequently substances with strong surface activity are adsorbed by these fillers.
Studies on the Nature of the Action of Organic Accelerators of Vulcanization. The Action of Organic Accelerators on Rubber Sols I–III
Authors: Shimada Keiichi 
Published: February 2011

Abstract
While there is a difference of opinion as to the exact mechanism involved, it is generally agreed that the action of organic accelerators in hastening the vulcanization process is usually attributed to the conversion of the sulfur into an active form, probably through the intermediate formation of a compound capable of yielding “nascent” sulfur. But some workers, (Ames, J. Soc. Chem. Ind., 43, 117T (1924); Kirchhof, Kolloid-Z.,, 14, 35 (1914); Twiss, J. Soc. Chem. Ind., 35, 782 (1917); Ditmar, Z. angew. Chem., 34, 465 (1921)) have suggested that the action of organic accelerators might be on the rubber hydrocarbon itself. This theory has not been generally developed, though it has received some small amount of evidence through the works of Le Blanc and Kröger (Z. Elektrochem., 27, 335 (1921)) and Naunton (J. Soc. Chem. Ind., 44, 243T (1925)). These investigators found that the viscosity of rubber solutions decreased with the introduction of an organic accelerator, and referred this phenomenon as a “depolymerization” of rubber. These observations possibly suggest that the influence of accelerators is exerted upon the rubber and constitute the only direct evidence in favor of this view.
Factors Affecting Rate of Vulcanization of Chloroprene Plastic Polymers
Authors: Bridgwater E. R. , Krismann E. H. 
Published: February 2011

Abstract
These tests have clearly shown the desirability of compounding this polymer with zinc oxide, magnesia, and rosin, and have demonstrated that these three ingredients when used together have a desirable effect that cannot be obtained with, or even predicted from, the results obtained with any one of them alone or the combination of any two of them. It has been shown further that, although it is possible to obtain good vulcanized products from this polymer without the addition of sulfur, a great increase in the rate of cure and substantial improvement in physical properties of vulcanized products result from the use of as little as 0.5 per cent of sulfur on the weight of the polymer. it is further shown that pine tar and rosin oil may be substituted for rosin but that they are somewhat less efficacious. The authors postulate that the value of rosin, pine tar, and rosin oil is probably due to the organic acids that they contain. Coumarone resin and brown factice are shown to be desirable compounding ingredients for chloroprene polymers.
Studies in the Interfacial Relationships between Rubber and Fillers. I. The Tear-Resistance of Vulcanized Rubber
Authors: Lefcaditis G. , Cotton F. H. 
Published: February 2011

Abstract
1. The importance of tear-resistance as a criterion of the interfacial relationship between rubber and its fillers has been emphasized. 2. Existing methods of determining resistance to tear in vulcanized rubber have been described, and subjected to a critical examination. 3. The disadvantages peculiar to each of the above methods have been discussed, and experiments whereby it was aimed to overcome these sources of errors are described. 4. A new method of determining resistance to tear has been evolved, whereby the tearability is measured in terms of the mean of the initial and final loads required to tear a 4-mm. length of a butt-ended test-piece prepared by punching with a standard dumb-bell die from the inner disc of a 6-mm. ring test-piece. Figures are given to indicate the consistency of the results.
The Separation and Identification of Sol Rubber Hydrocarbons
Authors: Midgley Thomas , Henne Albert L. 
Published: February 2011

Abstract
(1) Nature produces a definite sol component in any single specimen of natural rubber. (2) The sol component can be separated and purified by refractionation methods. (3) Purified sol rubber retains the it can be vulcanized to yield a product of physical properties of natural rubber; it can be vulcanized to yield a product of superior quality. (4) No experimental evidence exists to justify the opinion that rubber is a two-phase system. (5) Sol rubber and gel rubber are mutually soluble.
The Limiting Degradation of Rubber Solutions
Authors: Bary Paul , Fleurent Émile 
Published: February 2011

Abstract
In our preceding papers [cf. Compt. rend., 192, 946 (1931); 193, 852 (1931); 195, 655 (1932)] we have pointed out that the degradation of solutions of rubber in xylene at concentrations of one to five per cent and at temperatures of 44° and 92° C. in sealed tubes tends toward a limit which depends upon the concentration and upon the temperature. One of the series of experiments carried out to determine the conditions under which this degradation takes place was continued to the point where the viscosity of the solutions reached a constant value in every case. With five per cent rubber solutions this result was obtained after a time which was practically of the order of 10,000 hours of heating, while the more dilute were the solutions and the higher was the temperature, the shorter was this time. At this limit, the viscosity of the solution reaches a final constant value for the particular temperature. It is therefore of interest to compare the law of viscosity as a function of the concentration of solutions, represented in its final form by the general formula of Arrhenius, for the viscosity as a function of the concentration of lyophylic colloidal solutions:
Rubber Antioxygens. III. The Behavior of Natural and Artificial Protective Agents toward Sunlight and Ultra-violet Light (Preliminary Communication)
Authors: Kirchhof F. 
Published: February 2011

Abstract
It has been shown that the reducing power of the water-soluble substances extracted from raw rubber is destroyed by the action of sunlight and ultra-violet light on raw rubber. This effect of light may be seen in a very striking way by treatment with an ammoniacal solution of silver nitrate of partially irradiated rubber sheets, which in a certain sense represents a “development.” In contrast to raw rubber, the most highly purified Tjipetir-gutta-percha, which contains no protective substances sensitive to light, forms peroxides with natural or artificial irradiation. These peroxides in turn reduce ammoniacal silver nitrate solution, so that irradiated samples of crepe rubber and Tjipetir-gutta-percha when developed with the reagent mentioned give pictures which behave negatively and positively. Finally the behavior toward ultra-violet light of a few artificial protective agents was investigated. Further experiments will be devoted to the problem of vulcanized rubber under the same conditions.
Studies on the Nature of the Action of Organic Accelerators for Rubber Vulcanization. II. Special Properties of Organic Accelerators. Part 1
Authors: Shimada Keiichi 
Published: February 2011

Abstract
In previous communications the author has studied the effect of various organic accelerators on rubber sols, and has been led to the conclusion that organic accelerators can be classified into three main groups according to the characteristic manner in which they affect the viscosity of rubber solutions. The object of the present paper is to invite more quantitative considerations and discussion based on the experimental results obtained in the previous papers. In the first part of this work the author has taken into consideration the special properties of the third group accelerators, which seem to be most important and significant from both a physico-chemical and a technico-chemical point of view.
Studies on the Combined Action of Organic Accelerators for Rubber Vulcanization
Authors: Minatoya Shukusaburo , Kojima Kitaro , Nagai Izumi 
Published: February 2011

Abstract
Keeping pace with recent developments in the rubber industry in general, various organic accelerators of good quality have been invented one after another, nearly one hundred different kinds of them being now put on the market. Though most of these accelerators, even when used singly, are satisfactory for regulating the time of vulcanization and improving the quality of vulcanizates, the combined use of two accelerators has come to be the subject of rubber chemists interested in this field, in order to obtain more. efficient results on vulcanization. Thiollet and Martin (Caout., 26, 14,494 (1929)) and W. Norris (Ind. Rubber World,82, No. 2, 535 (1930)) have already published the results of experiments on the combined effect of organic accelerators, and state that in vulcanization they behave in a different manner from any single accelerators used separately. In these investigations, however, rather impure chemicals on the market were incorporated in rubber stocks, and only in arbitrary proportions, regardless of the proportions corresponding to their chemical constitutions.
The Volumetric Determination of Free Sulfur
Authors: Castiglioni A. 
Published: February 2011

Abstract
In order to determine free sulfur in substances like rubber and antimony sulfide, extraction is carried out with a solvent, preferably acetone. After separation from the solvent, the extracted sulfur is converted into the sulfate and weighed as barium sulfate. With the object of making this determination, easier and simpler, it occurred to the author to determine the sulfur in the acetone extract volumetrically, instead of gravimetrically, by utilizing the observed fact that potassium thiocyanate is formed when the acetone extract is boiled with potassium cyanide. Experimental investigation of this subject showed that in the presence of an excess of potassium cyanide, conversion of the sulfur into potassium thiocyanate is quantitative, so that after evaporation of the solvent a mixture of potassium cyanide and potassium thiocyanate remains behind. To determine the potassium thiocyanate in the aqueous solution of these two salts, the method of Schulek (cf. Z. anal. Chem., 65, 433 (1924–25)) was used, which is based on the decomposition of potassium cyanide by formaldehyde. Instead, however, of adding an excess of titrated silver nitrate solution, as recommended by Schulek, and then determining the excess silver by the Volhard method, the titration was carried out directly with the silver nitrate solution, using iron nitrate as indicator, until the blood-red color of ferric thiocyanate had disappeared. In the following table are given the results of determinations by this procedure.
The Balance-Plastometer: a Simple Instrument for Measuring Plasticity and Recovery of Soft Materials
Authors: Hoekstra J. 
Published: February 2011

Abstract
The theory of parallel-plate plastometry has recently been studied extensively by Scott and by Peek. Though the time-flow relations for substances following Bingham's or de Waele's laws are more or less mathematically solved by these authors, this is not the case for substances like rubber, which have no true yield value. Peek says that, in the case of rubber, there occurs an “overlapping of the elastic and the plastic stage,” so that the results are ambiguous. This remark seems to us very much to the point. By reason of this “overlapping” the question of the “recovery” of masticated rubber and related substances is as yet rather unsolved. Karrer's method of expressing plasticity (“softness”) and recovery in one figure is not to be regarded as a solution of the problem. Moreover, his instrument for measuring the recovery has the great disadvantage of a fixed time and rate of compression. There is no possibility of varying the time and the percentage of compression to any great extent; therefore, with his instrument it is not possible to study the way in which the “yield value” or the degree of plasticity varies with the time and the percentage of compression.
Low Sulfur Compounding
Authors: Somerville A. A. , Russell W. F. 
Published: February 2011

Abstract
Since the beginning of the rubber industry, sulfur dosages used for soft rubber have declined from 20 to 2 or 3 per cent customary today. The decline is still under way, and present sulfur ratios are high in comparison with what is actually required to produce satisfactory commercial vulcanization—fractions of 1 per cent. Vulcanization with extremely low sulfur ratios, the use of selenium and tellurium as auxiliary vulcanizing materials, and the proper type of acceleration required to “cure in” all the sulfur and produce satisfactory commercial results, are discussed. Comparative data, covering many physical attributes, are shown for pure gum and gas black stocks compounded with 3 per cent sulfur on the one hand, and 0.3 and 1 per cent (gas black stock) on the other. Advantages of very low sulfur compounds are less tendency to scorch, better physical properties, better aging, higher resilience and lower power losses, less discoloration, greater resistance to hot solvents, greater abrasion resistance, and less flex-cracking on aging; disadvantages are higher set at low temperatures and reduced capacity to adhere to metals. It seems probable that, in the future, compounding will be based largely on the use of very low sulfur ratios.
The Proöxygenic Role of Iron in the Oxidizability of Rubber
Authors: Dufraisse Charles , Vieillefosse Roger 
Published: February 2011

Abstract
The influence of iron on the oxidizability of rubber, though not as a matter of fact neglected in the past, has perhaps not received sufficient attention. However, the various ways in which this metal and its derivatives have caused contamination are certainly too obvious to imagine that they have passed unobserved. As is known, traces of iron can be detected in latex at the time it is tapped, and regardless of the method of treatment which it undergoes later, the rubber has an opportunity at every step in its preparation to become further contaminated with iron. Milling, calendering, and molding are carried out with iron equipment, and the ingredients used in rubber compounding may contain more or lees iron, at least as impurities, even when they are not primarily iron compounds, as is the case of certain pigments. In short, manufacturing processes, contamination by iron from ingredients, adventious causes such as iron containers for latex, dust and various other causes which need not be enumerated, all contribute to the presence of iron in rubber. Certainly then iron cannot be a very dangerous element under ordinary conditions, for otherwise its harmful effects would have been recognized long ago, and would have led to the avoidance of iron in practice, as has happened in the case of copper. Nevertheless experiments of the authors to determine why vulcanization increases the oxidizability of rubber have led to the suspicion that iron may be harmful, and a desire to ascertain the role it plays in deterioration prompted the authors to carry out the experiments which are described in the present paper. The object of the work was thus limited, and it aimed not to settle the problem of the influence of iron on rubber, but rather to investigate in a simple manner in what way iron gets into a rubber mixture, in what form it exists, and what are its harmful effects. Incidental to this, some of the observations may perhaps be of some value in current practice.
Investigation of the Aging Processes in Rubber. I. The Effect of Irradiation with Ultra-violet Light or the Surface Tension of Rubber Solutions
Authors: Dogadkin B. , Pantschenkow G. 
Published: February 2011

Abstract
1. Irradiation of rubber solutions in the presence of air with ultra-violet light brings about a pronounced lowering of their surface tensions at the boundary of solution and water. This lowering is connected with the formation of oxidation products of rubber, which are surface-active. 2. The kinetics of the changes in the surface tension are similar to those of the changes in viscosity brought about by irradiation of the solutions. 3. Irradiation of solutions of purified rubber in an atmosphere of nitrogen does not bring about any change in their surface tensions, as judged by the values of the minima of their isotherms. 4. These facts show that, in the absence of oxygen, light may exert an independent effect on rubber by causing depolarization of the rubber molecules and disaggregation of the micelles, which is closely related to this depolarization. In a general way, the nature of the action of light on rubber and the conditions necessary for the light to be effective are explained by the present work. In conclusion, the authors wish to express their appreciation to Professor A. A. Seide for his kindness in furnishing the samples necessary for the work.
The Russell Effect with Rubber
Authors: Rossem Avan , Hessels J. H. E. 
Published: February 2011

Abstract
(1) The Russell effect from raw rubber, after exposure to light and air, depends on three factors: (a) smoke components: smoked sheet shows a strong Russell effect owing to the presence of these components; Para does not because it is prepared with a different kind of smoke; (b) tackiness: most crepes show little Russell effect, but prolonged exposure after acetone extraction causes concurrent increases in both the Russell effect and tackiness; (c) acetone extract: the extract shows a strong Russell effect, but this is scarcely apparent when it is present in the rubber. (2) The gaseous products that cause the Russell effect are decomposed or driven off at 80° C. (3) These gaseous products are not the same as those formed by treatment with ozone. (4) Antioxidants for raw rubber do not affect the Russell effect, but sodium bisulfite weakens it. (5) Mastication or mixing with sulfur alone has little effect, but mixing with diphenylguanidine, triphenylguanidine or hexamethylenetetramine plus sulfur, or with mercaptobenzothiazole alone, considerably weakens the Russell effect. (6) Vulcanized rubber (normally or overcured, or oxidized by aging) shows a very weak Russell effect; this effect therefore will not detect incipient oxidation or a tendency to oxidation. (7) Quartz mercury vapor lamps are not suitable for experiments on the Russell effect, because the results are complicated by the ozone formed around them. (8) Ozone, even in very low concentrations (0.01 per cent or less), causes a strong Russell effect in both raw and vulcanized rubber.
The Electro-Deposition of Rubber on a Zinc Anode
Authors: Dogadkin B. , Sandomirsky D. 
Published: February 2011

Abstract
1. During the electrophoresis of rubber on a zinc anode in a weakly alkaline latex (concentration of ammonia less than 2 per cent), there is a sudden drop in the current, and as a result a diminution in the rate of deposition of the rubber. In a strongly alkaline bath, the rate of deposition remains practically constant. 2. The addition to the latex of salts the anions of which give soluble compounds with zinc diminishes to a marked degree the drop in the current strength. 3. The action of salts and alkalies is explained by the nature of the phenomenon at the anode and the structure of the film of rubber deposited. 4. The electrolytic deposition of rubber on zinc electrodes surrounded by a diaphragm of plaster or of glass takes place at a practically constant rate, irrespective of the concentration of the alkalinity in the latex. A diminution in the rapidity of the deposition of rubber still takes place upon the addition to the bath of salts the anions of which form insoluble compounds with zinc. In conclusion the authors wish to express their very deep gratitude to the Director of the Institute, Dr. L. G. Landau, for the interest which he has taken in their work.