bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Plastic Material—AXF
Authors: Shinkle S. D. , Brooks A. E. , Cady G. H. 
Published: February 2011

Abstract
RUBBER technologists are familiar with the increasing number of uses to which rubber has been put in recent years through modifications and adaptations effected by skilful compounding. At the same time, however, active research has been carried out, stimulated by the desire for new materials to meet still more exacting requirements—for example, greater resistance to oils and solvents and to oxidation. In general these investigations have taken one of two directions; they have been directed to a search for new synthetic rubber-like materials or to a study of new derivatives of rubber. In both of these fields of research, achievements of outstanding importance have been disclosed. Whitby and Katz (9) reviewed and summarized the development work on synthetic rubber from its early beginnings. The announcement of poly-chloroprene or DuPrene by Carothers (2) and his associates was soon followed by recognition that this product is a synthetic rubber-like material with physical properties not only rivaling those of rubber but superior in many particulars in which rubber is most deficient. Various olefinpolysulfide reaction products have been described by Patrick (6) and, under the trade name of Thiokols, have been presented to the industry. Other synthetic products which have attracted the attention of rubber compounders include the glyptal resins (10), flexible phenol resinoids, and the recently announced Koroseal (1). A paper by Thies and Clifford (8) has summarized the reactions of the rubber hydrocarbon, apart from oxidation and vulcanization reactions.
The State of Rubber in Solutions. Part II. The Effect of the Temperature on the Viscosity of Solutions of Various Concentrations
Authors: Dogadkin B. , Lawrenenko M. 
Published: February 2011

Abstract
1. The relative viscosity of a rubber solution, the concentration of which does not exceed 0.3 per cent, does not change with change in temperature. 2. The viscosity of rubber solutions at concentrations from 0.3 to 10 per cent diminishes in direct proportion to an increase in the temperature. 3. Based on the results mentioned above and on the measurements of Abernethy the state of rubber in solutions is characterized by the fact that at concentrations up to 0.3 per cent the solutions are molecular. At concentrations from 0.3 to 10 per cent the solutions contain micelles. In solutions of still higher concentrations the rubber forms a continuous phase of the system.
Diphase Rubber. The Diphase-forming Tendency of Rubber as Shown by the Action of Pigments
Authors: Menadue F. B. 
Published: February 2011

Abstract
In recent years increasing attention has been paid to a fact emphasized by Weber, viz., that when rubber is carefully treated with solvent two layers separate out, the one drying out to a rubber considerably tougher than the other. The former is the well-known “insoluble” portion, though with exclusion of the protein component it is merely insoluble to a greater degree than the other portion. Its toughness is also to an extent due to the protein it contains. It has been suggested that rubber is a diphase substance, and also that the harder portion occupies the shell or the skin of the particle. Other very interesting suggestions have been that elasticity is due to the association of the two phases, while recently Whitby has stressed the striking theory that rubber is composed of an unbroken series of polymers. By the following series of experiments the author has sought to investigate further the suggested diphase property of rubber by an investigation into the separation into “phases” exhibited by the action of pigments. The investigations also produce matter of interest in relation to vulcanization and the behavior of rubber in general.
The Stress-Strain Relationships of Vulcanized India-Rubber. Part I. The Inflection Point
Authors: Shacklock Cecil Wilson 
Published: February 2011

Abstract
Definition.—The relation between applied load and the resulting extension of vulcanized or unvulcanized rubber may be represented graphically as a curve which is “s” shaped, and there is a point of inflection in the curve. If a load W grams be applied to the rubber, and the resulting length be L, the point of inflection is defined as the point on the curve where the second differential becomes zero and changes sign. More simply, the point of inflection is where the tangent to the curve crosses the curve. It is well known that the point of inflection exists, but there appears to be no reference in the literature to any attempts to determine precisely its position. It is also apparent from the many stress-strain curves of rubber which have been published that the point of inflection varies with both the period of cure and the compounding of the rubber. What follows is an account of some experiments made to investigate the position of the point of inflection in the stress-strain curve of vulcanized rubber.
Studies on the Nature of the Action of Organic Accelerators for Vulcanization. VI. Detection and Analysis of Organic Accelerators. 3. The Analysis of Water-Soluble Ultra-Accelerators and a New Colorimetric Method for the Micro-Analysis of Copper and Manganese
Authors: Shimada Keiichi 
Published: February 2011

Abstract
(1) A reliable method has been described for the quantitative analysis of the so-called water-soluble dithiocarbamate accelerators, such as piperidine pentamethylenedithiocarbamate, diethylamine diethyldithiocarbamate, dimethylamine dimethyldithiocarbamate, sodium diethyldithiocarbamate and sodium dimethyldithiocarbamate. It depends upon the fact that these ultra-accelerators readily react with soluble nickel salts in solution, forming very sparingly soluble precipitates which can be estimated quantitatively by gravimetric analysis, the weight of the insoluble nickel derivatives obtained being a direct measure of the dithiocarbamate present. Copper, cobalt and zinc react similarly with the accelerators and form sparingly soluble precipitates, respectively, but the solubilities of these metallic derivatives, determined from the results of the conductivity measurements, are about three times as large as that of the nickel derivatives; hence the precipitation of the accelerators with these metals does not give a means of evaluation by practically quantitative yields with the accelerators met with commercially.
The Volumetric Determination of Free Sulfur in Rubber
Authors: Robertson J. A. , Young J. 
Published: February 2011

Abstract
The determination of free sulfur is probably the analytical process most frequently carried out in the chemical laboratory of a rubber factory, and it would be even more often used, could it be more quickly performed. For the oxidation of the sulfur contained in the acetone extract from rubber, Mackay (J. Soc. Chem. Ind., 49, 401-3T (1930)) has described a rapid method which has been used in these laboratories for several years with complete success, but the sulfate produced has to be determined gravimetrically and the process is still too slow for use in factory control work. The acetone extraction of the rubber samples can usually be carried out at night on a bath with automatic time control, and if a rapid method for the determination of sulfur in the extract were available, the results of the analysis could be ready early next day. From a review of the literature the volumetric determination of sulfate by rhodizonate (Strebinger and von Zombory, Z. anal. Chem., 79, 1 (1929)) appeared to be promising, and on trial has given satisfactory results.
The Influence of Time on the Elongation of Soft Rubber under Constant Load
Authors: Everts W. W. C. 
Published: February 2011

Abstract
According to specifications for the testing of rubber prepared by Committee Thirteen of the Deutscher Verband für die Materialprüfung der Technik, there are at the present day two common and at the same time distinct methods for studying the mechanical properties of soft rubber, viz., tensile tests, and, secondly, determinations of elasticity. As carried out in practice, the tensile test is based fundamentally on the tensile testing of metals. With its great elastic properties, however, soft rubber exhibits to a very high degree changes in its elongation with time, and earlier testing methods give relatively unsatisfactory information about the effect of time during the stretching of rubber. Of course the determination of elasticity in the specifications mentioned above, where the so-called permanent elongation is measured, gives a certain insight into this influence of time. Nevertheless this earlier method is not suitable for obtaining comparable results in all cases.
Studies of the Conditions Affecting the Vulcanization of Rubber. V. The Effect of Accelerators on the Heat of Vulcanization
Authors: Toyabe Y. 
Published: February 2011

Abstract
The heat of vulcanization of rubber compounds containing various quantities of sulfur and several organic vulcanization accelerators were traced by means of a differential thermocouple during the vulcanization. The profiles of the heating curves were similar to those obtained in the case of unaccelerated compounds, but the temperature maxima appeared sooner with accelerated than with unaccelerated compounds. The vulcanizates corresponding to the temperature-maxima were analyzed chemically by ordinary methods and the ratios of the free to total sulfur were calculated. They vary a little from 50 per cent, and show that the extent of sulfur combination is not much different from that with unaccelerated compounds. The accelerators tested were hexamethylenetetramine, aldehyde-ammonia diphenylguanidine, di-o-tolylguanidine, p-nitrosodimethylaniline, thiocarbanilide, “Vulkacit P”, “Vulkacit PX”, “Vulkacit M”, and tetramethylthiuramdisulfide The results of the experiments show that these accelerators promote the disaggregation of the micellar structure of rubber (as shown in reports II and III 0. this work) before chemical combination of rubber and sulfur occurs. By thus making the single micelle of rubber smaller, they increase the number of chemical units of rubber coming into reaction with sulfur; i. e., the probability of combination of rubber and sulfur becomes greater. The times for the temperature maxima to appear in the experiments above, which are shortened by accelerators, show that this theory holds good, when it is considered that the temperature maxima correspond to the disaggregation maxima of the rubber hydrocarbon under consideration.
Isoprene and Rubber. Part 22. Isorubber Nitrone
Authors: Staudinger H. , Joseph H. 
Published: February 2011

Abstract
Rubber Micelles or Macromolecules The idea of Pummerer that the parent molecule of rubber is [C5C8]8 is based upon molecular weight determinations carried out by him and his colleagues upon rubber in menthol and above all upon isorubber nitrone. This latter product, which has been prepared by Alessandri and again by Bruni and Geiger by the action of nitrosobenzene on rubber has, according to Pummerer and Gündel, the constitution [C5H6,C6H5NO]8. On this subject the authors say that: We made cryoscopic molecular weight determinations of isorubber nitrone iii benzene and nitrobenzene. Even in these generally used solvents the nitrone gives depressions which indicate a molecular weight lying between 1200 and 1400. For a parent rubber molecule of 8 isoprenes which reacts with 8 molecules of nitrosobenzene with a splitting off of 16 atoms of water, a weight of 1384 is calculated, agreeing very well with the above. As is the case with determinations of rubber in menthol, here the final measurements can be undertaken only when the constant is obtained (in this case after 1-2 hours) and not immediately after the solid substance disappears, for otherwise the value will be about 1000 or 2000 higher, which probably results from a still incomplete solution of the micelles. The study of isorubber nitrone, therefore, supports our opinion on the size of the parent rubber molecule which was expressed earlier. These opinions apparently do not conform to the view expressed by one of us some time ago, according to which rubber has a very high molecular weight, and the primary colloid particles, therefore, the particles in dilute solution, form macromolecules. These have a molecular weight of about 68,000, so that approximately 1000 isoprene residues are united in a chain . This concept was based on a study of models, especially on experiments on polysterol and further by conversion of rubber into colloid-soluble rubber-phosphonium salts, by the preparation of homologous polymeric series of polyprenes, by the decomposition of rubber, and finally by relations between viscosity and molecular weight in this series.
The Fusion Curve of Natural Rubber
Authors: Susich G. v. 
Published: February 2011

Abstract
Katz has shown that the melting point of frozen raw rubber is 35°–38° C. when determined by the disappearance of the crystal interferences upon warming. The discontinuous changes in the specific gravity, in the hardness, and in the light absorption, as well as the γ-anomaly of the specific heat, lie within this temperature range.
Micromanipulations of Latex in the Dark Field
Authors: Hauser E. A. 
Published: February 2011

Abstract
It can be conclusively proved that the individual particle in latex of Hevea brasiliensis after the evaporation of the dispersing agent is surrounded by an adsorbed layer, probably of protein and resin. In the dispersed condition, the particle shows a difficulty penetrable and not deformable surface. After puncture a highly viscous mass flows out from the interior, and at the moment it comes in contact with the dispersing agent it stiffens to a plastic jelly, while the remaining shell exhibits remarkably elastic properties. After the evaporation of the dispersing agent, there occurs a progressive gelation and transformation into an elastic substance. The same result is obtained when the rubber phase is coagulated by acids or electrolytes. The establishment of this fact is important in connection with the usual preparation of raw rubber. It was proved that the consistency of the particles and the thickness of the elastic shell are dependent on the age of the trees. We are dealing not with a definite membrane, but with a variable enveloping shell whose strength seems dependent on the degree of polymerization of the hydrocarbon. In general the results of the present work prove the latest concepts of the structure of rubber, i. e., the existence of various degrees of polymerization, which can be traced back to the structure of the latex particles.
Hard Spots in Vulcanized Rubber Compounds
Authors: Howey J. H. 
Published: February 2011

Abstract
Although positive evidence is lacking, it is believed that the correlation between localized internal flow and the accompanying hardness of the “flowed” regions must be due either to the production of a local grain effect by the flow or to an alteration of the dispersion in that region, or possibly to both. The correlation cannot be attributed to non-uniformity in the mixture, elastic strains, or orientation of the original grain. This explanation is a matter of theoretical interest in connection with the divergent views now held as to the mechanism of reënforcement by pigmentation. However, the results of this investigation may be applied to increase the precision of testing the hardness of carbon-black stocks whether we understand the underlying phenomena or not.
The Vulcanization of Rubber with m-Dinitrobenzene
Authors: Wright J. M. 
Published: February 2011

Abstract
The literature referring to the vulcanization of rubber with m-dinitrobenzene indicates the present undeveloped state of knowledge of the reaction and of the most favorable conditions for its employment. Much is vague and even contradictory. Ostromislensky (J. Russ. Phys.-Chem. Soc., 47, 1462 (1915)) stated that certain nitro compounds are capable of vulcanizing rubber in the absence of auxiliary substances, and that the products of vulcanization are superior in some respects to sulfur vulcanizates; tensile strengths obtained were comparable with those of sulfur vulcanizates; aging properties were found to be good; color and finish were better than those of sulfur vulcanizates. On the other hand, Porritt (J. Soc. Chem. Ind., 35, 986 (1916)), and Stevens (J. Soc. Chem. Ind., 36, 107 (1917)) failed to confirm these statements, but agreed that the presence of litharge is beneficial. Again in 1929, Ostromislensky (India Rubber World, 80, 55 (1929)) confirmed his original report, stating that he believed that this form of vulcanization is due to an action between rubber and the oxygen of the nitro compound. Blake (Ind. Eng. Chem., 22, 7 (1930)) stated that vulcanization of rubber with dinitrobenzene involves a monomolecular chemical reaction between rubber and dinitrobenzene, in which, of the 6 per cent dinitrobenzene, practically all of the nitrogen combined with the rubber. The end-product of the reaction appears to be a soft vulcanized rubber; no one has claimed to be able to produce an ebonite by the use of this reagent.
The Properties of Rubber Cements
Authors: Ford T. Foster 
Published: February 2011

Abstract
Rubber cements used in factories manufacturing rubber goods consist of rubber-solvent dispersed systems. They usually contain, in addition to rubber, various pigments, softeners, curing agents, etc. The smoothness and thickness of the films deposited, the readiness with which the films break over small apertures in dipped objects, the viscosity, and the stability of the cements as liquid systems are characteristics which affect their utility. The purpose of this paper is to present a summary of empirical data relating such working properties and important variables in composition. Whereas there is in the literature much data on the properties of extremely dilute rubber solutions, obtained in the course of theoretical researches, little information is available concerning the much more concentrated cements used commercially. Of the classical properties of liquids only viscosity will be discussed in this paper.
pH Properties of Colloidal Carbon
Authors: Wiegand William B. 
Published: February 2011

Abstract
IF ONE part of colloidal carbon pigment is boiled for 15 minutes or more with three to ten parts of distilled water and cooled, the supernatant liquid decanted, and the sludge placed in contact with the glass electrode of a pH electrometer, a reading is obtained which is characteristic of the material. A representative list of the pH values thus obtained is shown in Table I. In this preliminary account some of the factors will be given which influence pH values of particulate carbon, some of the relations between pH and other properties of colloidal carbon, and something of the significance of these pH properties.
Some Applications of the Microscope to Rubber Technique
Authors: Tidmus J. S. , Parkinson D. 
Published: February 2011

Abstract
This paper is not intended to be a review of work done in the rubber industry with the aid of the microscope, but rather a record of some investigations by the authors in this field. The examination of rubber products usually consists of a chemical examination of the ingredients used, and physical and actual service tests of the finished products. In the course of manufacture one often meets with phenomena which cannot be explained by the results of these examinations. In many of these instances an explanation can be found with the aid of a microscope. Microscopical methods do not seem to hold the place in rubber testing which they merit. This is due partly to the technique required in preparing specimens, and also to the experience required for the proper interpretation of the facts observed. One must, however, recall the valuable work of Depew and Ruby (Ind. Eng. Chem., 12, 1156 (1920)), Green (Ind. Eng. Chem., 13, 1130 (1921)), Greenquist (Ind. Eng. Chem., 20, 1071 (1928); 21, 665 (1929)), Steele (Ind..Eng. Chem., Anal. Ed., 2, 421 (1930)), and Arnes (J. Roy. Microscop. Soc., 1923, 265).
The Goodrich Flexometer
Authors: Lessig E. T. 
Published: February 2011

Abstract
The Goodrich flexometer is of simple design and is easily operated at ordinary or elevated temperatures. Test pieces procured from laboratory specimens or from finished rubber or rubber-fabric products may be tested, using moderate loads that produce equilibrium temperatures during flexure or larger loads that rupture the test piece. This machine may be used to study the effects on heat generation of the time of cure, the magnitude of the applied load, changes in pigmentation, and variations caused by anisotropy in rubber compounds. It is so designed that the structural changes such as softening or stiffening may be followed during the period of flexure.
Enhanced Polymerization and Depolymerization of Natural Rubber by Quinones and Related Compounds
Authors: Spence D. , Ferry John D. 
Published: February 2011

Abstract
1. The enhanced polymerization or the depolymerization of natural rubber may be effected thermally or photochemically by one and the same reagent. 2. The action of quinones, carbonyl compounds, and other quinonoid compounds in this connection has been studied. 3. Depolymerization is favored by (a) dilution of the rubber by a solvent or swelling agent, (b) increase of temperature, (c) presence of molecular oxygen. 4. The results are interpreted in terms of concurrent reactions.
Rubber. XVIII. Various Ozonides of Rubber and the Problem of the Existence of the Primary Ozonides of Harries
Authors: Pummerer Rudolf , Richtzenhain Hermann 
Published: February 2011

Abstract
A permanently valuable service was rendered by Harries when he introduced the ozone cleavage of unsaturated compounds as a general method of investigation in organic chemistry. By analogy with other addition reactions of double bonded carbon atoms he derived the formula (a) for the ozonides which are first formed, but to support the existence of which he was able to obtain only scant experimental data. Harries relied above all on two observations, first, that mesityl oxide ozonide reverts to mesityl oxide when heated by itself, and, secondly, that fumaric acid is supposed to combine loosely with ozone and then readily split off again. Both of these suppositions have remained undisputed up to the present time. Harries reported that it was not possible, with any of a wide variety of reducing agents, to reduce the ozonides to the original compounds or to 1,2-glycols, as would be expected from their structure. Staudinger has laid great stress on this fundamental objection, and he considers that most ozonides have an isoözinide formula, as shown by formula (b) above, in which the carbon chain is already ruptured, so that by reduction only the usual types of cleavage products rather than glycols with intact carbon chains can be formed, as has been found experimentally. Staudinger assumed that the primary reaction products of treatment with ozone are molozonides containing the group: