bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theory and Application of the Parallel-Plate Plastimeter. Part 2
Authors: Scott J. R. 
Published: February 2011

Abstract
In Part I (loc. cit.) the behavior of a plastic material in the parallel-plate (Williams) plastimeter was studied, and an expression was deduced showing how the rate of decrease in thickness of the sample during compression depends on the volume of the sample, its plastic properties, the compressive load, and the thickness itself. Subsequently, observations were published which showed that the basic principle adopted in this study was incorrect in certain particulars. Peek (loc. cit.), using these observations as a basis, deduced a new expression for the rate of decrease in thickness, though this is too complex for convenient practical use, except in an approximate simplified form. It has now been shown that the expression deduced in Part I, in spite of the inaccurate basis used, is sufficiently near to the truth to render substantially correct the conclusions there stated concerning the plastic properties of unvulcanized rubber stocks. By adopting the more accurate basis used by Peek, moreover, expressions for the rate of decrease in thickness can be deduced for materials showing more complex types of plastic flow than that considered in Part I or by Peek; this had proved impossible by the method previously used. The expression obtained by Peek for the simple type of plastic flow, as well as those now deduced for the more complex types, can be expressed in a form that furnishes a simple and rapid method of examining and analyzing experimental results. As a result of the work described in this paper, it is thus possible to determine, from results obtained with the parallel-plate plastimeter, whether or not a material such as unvulcanized rubber stock exhibits any of the types of plastic flow represented in the general form by Equation 1, and, if so, to find the values of the plastic constants of the material. The procedure is similar to that described in Part I, and consists simply in comparing, by superposition, a set of standard curves drawn on transparent paper with the curve plotted from experimental data. This further development of the method of studying plastic properties by means of the parallel-plate plastimeter should greatly increase its utility as an instrument of research. It has not yet been possible to apply the new method to a systematic study of rubber stocks, but from an examination of existing data it appears that these stocks, tested at 90° C., agree approximately with various forms of the generalized plastic flow equation already referred to.
The Problem of the Evaluation of Reclaimed Rubber by Analytical Methods
Authors: Kirchhof F. 
Published: February 2011

Abstract
Since the problem of the reclaiming of rubber and the increased use of reclaimed rubber in the rubber and cable industries, even in Germany, has again become of importance, interest in methods for the evaluation of reclaimed rubber has naturally increased. It has been recognized in the past that chemical tests can give only a general idea of the approximate composition of a reclaimed rubber, while they show little or nothing about its mechanical properties. Accordingly in most countries, only the most important chemical determinations have been carried out, such as the acetone extract, ash content and sometimes the combined sulfur, while in the case of black reclaimed rubbers, carbon black and sometimes the cellulose present in the rubber, which are determined by difference, are also included. When carbon black is present in high percentage, as is particularly true of modern tire treads, the results of the determination of the quantity of rubber substance are much too high. Therefore the Rubber Control Bureau in Berlin has justifiably required direct information on the carbon black and cellulose in black live-steam reclaimed rubber. The ash and carbon black contents are evident also in the specific gravity of the reclaimed rubber. The specific gravity is most reliably determined with a vulcanized sample or with very thin, smooth sheets by means of the suspension method in zinc chloride solution of suitable concentration.
Research on Modified Rubbers. Part VII. Expanded Chlorinated Rubber
Authors: Schidrowitz P. , Redfarn C. A. 
Published: February 2011

Abstract
In the course of a research on the properties and applications of chlorinated rubber, some trials in connection with moldings were carried out in an ordinary plunger or positive mold of the type which has been used in molding synthetic resin compositions. It was expected that dense but perhaps comparatively flexible moldings would be obtained, and this indeed is the case under certain conditions, e. g., when the mold is allowed to cool under pressure, and the temperature of molding is relatively low. When, however—as is the practice when molding material of the bakelite type—a comparatively high mold temperature (in the neighborhood of 320–350° F.) was employed, and the pressure released while the mold was still hot, it was observed that a remarkable product was obtained of a light, strong, fibrous, cellular character, many times the size of the mold cavity (British Patent 424,561). Expanded chlorinated rubber is more readily obtained from certain commercial brands of chlorinated rubbers than from others, or alternatively, the degree of fluffiness or porosity, strength, and so on may vary according to the brand used, other conditions being equal. After a certain amount of experimentation, however, it was found practicable so to modify conditions of molding that the majority of the brands on the market yielded reasonably satisfactory results (see below).
Rubber in Lubricants
Authors: Stevens H. P. , Stevens W. H. , Donald M. B. 
Published: February 2011

Abstract
As long ago as 1853 it was found that rubber was a suitable addition to oils to improve their lubricating properties. Thus rosin oil was rendered suitable for lubricating machinery, locomotives, wagons, etc., by adding as much of a 1–2 per cent stock solution of rubber in rosin oil to further amounts of oil as deemed suitable. The rubber was cut in thin strips, masticated, and allowed to dissolve in the rosin oil in a hot water bath. A lower temperature could be used by prolonging the time of immersion. A subsequent patent and formulas in a book by Brunner, propose dissolving the rubber in turpentine and adding it to fish and vegetable oils in proportions of about 5–10 per cent. As will be shown later, these proportions are probably too large to be satisfactory, and moreover at that period the recipes were not economical. In 1855 a patent was taken out by Hyde, which in view of our own observations must be regarded as a very remarkable piece of work. After stating that mineral oils for lubricating machinery at temperatures of 600° F. or over require admixture with castor, sperm, or rape oil, he draws attention to the fact that, on keeping at 212° F., or for several days in sunlight, the mineral oils develop a sludge. The addition of rubber to mineral oils, he states, “exerts a most remarkable action in giving permanence to them … and at the same time improves the lubricating or truly oily character of the oil, and the changes under the influence of high heats or the sun's rays are in like manner retarded or prevented for a longer time so as to give a degree of permanency and lubrication such as no other known oil or mixture possesses when tested by lubrication indicators. When more than 2 per cent rubber is added the valuable qualities are in every case impaired, and even less than 1 per cent is usually all that need be combined; 0.5 per cent will give durability and lubrication much beyond that of sperm oil.” He introduced the rubber by suspending it in a cloth bag in the mineral oil at 80–150° F.
Preparation from Rubber of Plastic Materials Suitable for the Manufacture of Films and Threads
Authors: Waterman H. I. , Max C. G. H. , Leenderste J. J. 
Published: February 2011

Abstract
A technical process is described for the preparation of HCl-rubber. Plasticized rubber was used to obtain highly concentrated rubber solutions in C6H6. The HCl-rubber was proved to have properties useful in technical applications as film material. By the method of dry spinning, threads were also obtained. In so far as they were examined, the films and threads were of good quality.
Koroseal, a New Plastic. Some Properties and Uses
Authors: Brous S. L. , Semon W. L. 
Published: February 2011

Abstract
Rubber has found its widest use in industry because its properties can be altered and improved by compounding and cure to give strong, flexible, resilient products which are resistant to abrasion, impervious to fluids, electrically insulating, and relatively inert chemically. For such other desirable characteristics as resistance to oils and solvents, and freedom from attack by air, sunlight, and oxidizing materials, skillful compounding has brought marked improvements, but even better properties are needed to meet the demands of modern industry. The search for synthetic rubbers has been stimulated not merely by the desire for an economically independent source of supply, but also with the hope that there might be obtained materials having properties superior to the natural product. Whitby and Katz (4) have published a comprehensive historical treatise dealing with the development of numerous synthetic rubbers which have appeared in the last few years. It has been believed that linear polymers obtained from dienes hold most promise for the preparation of rubber-like materials. Carothers (1) has studied the relation between the structure of dienes and the types of polymerization products which may be obtained therefrom. On the basis of these data he inferred that, from the standpoint of their polymerization products, the best dienes will be of the type CH2:CXCH:CH2, in which X is an activating group other than alkyl or aryl. In general it has been found that there may be obtained polymerization products with physical properties equal to, or often superior to those of natural rubber, and with marked resistance to the action of solvents and chemicals. Among the many types of organic materials which will polymerize, the vinyl compounds only recently have been modified suitably to yield commercial rubber-like materials.
The Surface Composition of the Rubber Globules in Hevea Latex
Authors: Kemp I. , Twiss D. F. 
Published: February 2011

Abstract
1. A method for the surface analysis of colloidal particles is outlined. 2. The electrophoretic behavior of the protein, resin, and rubber hydrocarbon of the latex of Hevea brasiliensis is described. 3. The electrophoretic behavior of diluted ammonia-preserved plantation latex has been investigated, and it is shown that the amounts of protein and rubber resin adsorbed at the surface of the rubber globule depend on the degree of dilution of the latex and on the pH of the serum. 4. The fractions of the rubber-globule surface covered with protein and with rubber resin are calculated, and their variation with latex-dilution and the pH of the serum is plotted. 5. The rubber globules at pH 8.0 are completely covered with a protein layer, provided the latex is not diluted below 12 per cent of total solids.
Rubber. XVII. Detection of Methylglyoxal and the Ozone Cleavage of Rubber
Authors: Pummerer Rudolf , Matthäus George , Socias-Viñals L. 
Published: February 2011

Abstract
Since the work of Harries, the question whether methylglyoxal is found in the ozone cleavage of rubber has played an important part in explaining the constitution of this hydrocarbon. Since Harries found no methylglyoxal, he assumed a cyclic formation of isopentene, —CH2.C(CH 3):CH.CH2—, residue sand the absence of a corresponding —CH:C(CH3).CH:CH2 end group, which would necessarily yield methylglyoxal. Nevertheless, in view of the probability that a very long open chain is present in the rubber molecule, the necessity again arose of trying to identify methylglyoxal as n product of the ozone cleavage. This involved the problem of detecting extremely small quantities, since the length of the chain might be very great. Provided that no secondary reaction takes place, the yield of methylglyoxal, if formed, should give information about the length of the chains. If, for example, in the cleavage 0.1 per cent of the carbon skeleton were to appear as methylglyoxal, it might be concluded from the three carbon atoms that the chain length is 1000 times greater, viz., 3000 carbon atoms, or 600 isoprene units. These investigations have been undertaken as a conclusion of our earlier work on the ozone cleavage of rubber, in which approximately 90 per cent of the cleavage products were obtained as compounds of the levulinic aldehyde (acid) series.
Isoprene and Rubber. Part 45. Viscosity Measurements of Solutions of Rubber and Hydrorubber in Various Solvents
Authors: Staudinger H. , Mojen H. P. 
Published: February 2011

Abstract
It has been observed many times that solutions of the same concentration of rubber in various solvents show marked differences in viscosity. For example, solutions of rubber in chlorinated solvents such as carbon tetrachloride have higher viscosities than do solutions of the same concentration in benzene or benzine. These differences in viscosity are attributable to the fact that the rubber molecules are solvated in different ways in the various solvents. It may be further assumed that in a particular homologous series of polymers, all members, i. e., substances of both high and low molecular weights, are solvated in the same solvent in the same way, for only in this way is it possible to believe that the specific viscosity of solutions of like concentration increases with increase in the chain length, as has been found to be true of cellulose derivatives. In the previous experiments with squalene and hydrosqualene (cf. preceding article), the constants necessary for calculating molecular weights and chain member indices n were determined. The constants for carbon tetrachloride are higher than those for benzene. In the case of squalene, therefore, as in the case of rubber, carbon tetrachloride gives more viscous solutions than does benzene. If, now, rubbers and hydrorubbers are solvated in the same way as squalene and hydrosqualene, then the same chain lengths of an homologous series of rubber polymers would be obtained by calculations using constants derived from the simple compounds of the chain member index, and from this the degrees of polymerization, are calculated by means of these constants in the formula:
The beta-Modification of Gutta-percha Hydrocarbon
Authors: Pankow Georg W. 
Published: February 2011

Abstract
Clark and later Hopff and von Susich have shown that there are two modifications of gutta-percha hydrocarbon. Hauser and von Susich have studied very carefully the transformation of one modification into the other, and have obtained good x-ray fibre diagrams of both. The identity periods in the direction of elongation were 8.8 A. U. for the α-modification and 4.8 A. U. for the β-modification. The following surprising observation was made: In the fibre diagram of elongated well oriented β-gutta there was found, in addition to the already well known interferences, an interference at a very small angle of deflection in a direction parallel to the fibre axis, corresponding to a lattice plane distance of approximately 115 A. U., i. e., about twenty-four times the identity period. β- Gutta.—Filtered copper radiation, 30 kv., 16 milliamperes. Distance of film 202 millimeters. Screen 0.3 millimeter in diameter. The deep central blackening in Fig. 1 is due to direct radiation which in the photograph in Fig. 2 is intercepted by a lead plate.
The Use of Factice in Rubber Manufacture
Authors: Hurlston E. H. 
Published: February 2011

Abstract
The two main classes of vulcanized oil substitute or factice are heat-cured brown factice and cold-cured white factice. They were both introduced into the rubber industry at about the same time (1846–1847), the former variety by Anderson and the latter by Parkes. It has been stated (Twiss, Trans. Inst. Rubber Ind., 7, 234 (1931)) that Parkes first opened a proofing factory at Birmingham but that the business was shortly afterwards absorbed by Chas. Macintosh & Co. and transferred to Manchester. This probably dates the commencement of the use of white factice in proofings. The early history of the development of the use of brown factice on a works scale is more obscure. As the name implies, these vulcanized oils were used in the first place as ingredients which could economically substitute part of the crude rubber content of mixings, but as time went on it became apparent to compounders that these materials possessed intrinsic properties which made them almost indispensable in certain mixings, both for ease of manufacture and for high quality of the resultant article. The utility of factices in the general rubber trade is therefore in many respects analogous to that of reclaimed rubbers.
The Pendulum as a Source of Energy for Plasticity Measurements
Authors: Williams Ira 
Published: February 2011

Abstract
ADVANCEMENT in methods for studying the consistency of rubber during the last 10 years has been confined largely to various modifications of previous tests and to better interpretation of the data obtained. The extrusion plastometer introduced by Marzetti (11) has been modified by Behre (1) to provide a battery of instruments, by Dillon and Johnston (5) to provide more simple apparatus capable of operating at increased rates of shear, and by Dillon (4) to provide an instrument for rapid control work. The parallel-plate plastometer (16) has received numerous modifications of form. DeVries (2) modified the plates to provide a constant area of contact with the rubber. This modification was used by van Rossem and van der Meyden (14) who stressed the necessity of following the elastic recovery as well as the rate of compression. Karrer (8) pointed out the need for controlling the time factor during compression and recovery and has described an instrument (9) with which each measurement requires about 30 seconds. The balance plastometer, which employs parallel plates, was described by Hoekstra (7) and is well adapted to following the elastic recovery after the rubber has been compressed under any conditions of thickness and time. A parallel-plate instrument with interchangeable parts to provide various methods of applying pressure and following recovery was described by Lefeaditis (10). The relation between compression and the extent of recovery has been considered by Dillon (3), who concluded that the measurement of either the compression or the elastic recovery as obtained with the usual parallel-plate plastometer was sufficient if the comparison was confined to a number of batches of a given stock or type of rubber. He also pointed out that elastic recovery depends on the speed of the previous deformation. Hoekstra (6), after considering some of the factors involved in plastic flow, concluded that elastic recovery should be measured only after compression of a rubber to the fixed thickness. The general usefulness of the parallel-plate plastometer has been greatly increased by the mathematical treatment of Peek (13) and Scott (15). A third type of plastometer, consisting of a disk which rotates in compressed rubber while the resistance to shear is measured, has been described by Mooney (12).
Determination of Sulfur in Rubber Compounds. I. Precipitation of Barium Sulfate in the Presence of Picric Acid
Authors: Lindsly C. Herbert 
Published: February 2011

Abstract
THERE is probably no single operation in analytical chemistry that has received more attention from investigators than that of precipitation of barium sulfate by means of a soluble barium salt for the determination of sulfate or of barium. The literature on this subject is voluminous and the conclusions reached by different investigators as to the proper procedure to employ in order to obtain a precipitate which will be filterable and reasonably pure are highly contradictory. The procedure which seems to be in most general use at present for the determination of sulfate is that of adding the barium chloride solution to the hot sulfate solution very slowly, stirring vigorously meanwhile, then allowing the whole to digest at an elevated temperature for several hours before filtering. The diversity of opinion as to the proper procedure arises, the author believes, from the fact that the barium sulfate precipitate is exceedingly sensitive to its environment and that a very slight change in the amount or kind of impurities present in the solutions during precipitation has a profound effect upon the crystal size and shape of the precipitated particles as well as upon their purity. Kolthoff and Vogelenzang (2) have stated that it is impossible to prescribe a general procedure for the accurate precipitation of sulfate in arbitrary mixtures. In other words, a precipitation procedure which gives satisfactory results in the determination of sulfur in copper ores, for instance, may not yield a satisfactory precipitate when applied to the determination of total sulfur in hard rubber dust, and a study of each type of determination, with due consideration for the amount and kind of impurities present, must be made in order to find the conditions necessary to obtain a precipitate which is pure and easily filterable.
The Coating and Impregnation of Textiles with Latex
Authors: Stevens H. P. , Stevens W. H. 
Published: February 2011

Abstract
Of the various uses to which rubber latex might be expected to be applied, the textile industry is one of the more obvious, yet so far latex has been little used by the manufacturers of textiles, and relatively little work appears to have been done in this field of application. No doubt this arises from the fact that knowledge of the properties and handling of latex is not usually found among textile manufacturers. Where textiles impinge on rubber manufacture the conditions are otherwise, and the earliest application of latex to fibers is to be found in the manufacture of rubber goods. Perhaps the first example of this application consists of the impregnation of tire cords with latex in the place of rubber sols, initiated and developed by the United States Rubber Company (British patent 178,811 (1921); 210,397 (1923)). No information is available as to the extent to which the latex treatment is carried on today, but it does not appear that such has become universal practice in spite of the advantages claimed by the inventors. There are no published data which enable a comparison of the advantages and disadvantages of latex impregnation to be made in comparison with the older process, but it is certain that the impregnation of textile fibers with latex is not as simple an operation as would appear at first sight.