bluuebunny/crossref_metadata_2025_split huggingface dataset:
Machine for Testing Rubber Products Used to Absorb Vibration
Authors: Abbott Franz D. 
Published: February 2011

Abstract
Data have been presented to show that the commonly used physical tests such as stress at break, stress at 400 per cent elongation (modulus), ultimate elongation, set at break, set after repeated stretch, and static compression-set fail to evaluate properly the resistance of vulcanized rubber to dynamic fatigue of flexure under compression, whereas flexureset as determined in a new machine (the compression flexometer) herein described does evaluate stocks properly as determined by service and dynamometer tests. Accordingly, resistance to flexure under compression (dynamic fatigue) is suggested as a much more important property of rubber products used to absorb vibration under compression than any of the above-mentioned tests.
Dispersoidological Investigations. XXIII. Contributions to the Dispersoidology of Rubber. Part I—The Structure of Jellies and of Other Coagula of Ammonia-Preserved Hevea Latex and Hevea Vultex
Authors: von Weimarn Vultex P. P. 
Published: February 2011

Abstract
In the course of my dispersoidological investigations of natural silk, I succeeded in obtaining it in such a highly elastic state as may truly be called a rubber-like state. However, the highly elastic state of silk is not a lasting one; sometimes it persists only for several minutes, sometimes for several hours, seldom does it last for several days and rarely in the extreme for about a week. Thus the rubber-like state of silk is a temporary state; but the high elasticity of rubber itself is also not everlasting. Evidently in both these cases there exists only a great quantitative difference in the duration of the existence of the highly elastic state under consideration. The ultramicroscopic study of the structure of separate threads of silk in different stages of their swelling, i.e., in different stages of elasticity, has led me to the conclusion that in principle it is possible to obtain in a rubber-like state such disperse systems, the component parts of which are substances quite different in their chemical composition from rubber-hydrocarbons. May the rubber-like state, under certain conditions, be a state universally possible for disperse systems composed of any substances, or not? I answer this question in the negative, because for the imparting to a system of the rubber-like state, the substances composing such a disperse system must possess special properties.
The Vulcanization of Rubber
Authors: Bacon Nicholas 
Published: February 2011

Abstract
Naturally it could not be expected that a work, even as important as that under discussion, would completely satisfy all opinions and objections concerning the complicated problem of vulcanization. The chief point for which there is evidence is that the sulfuration of rubber is a chemical phenomenon, and that in this reaction adsorption plays only a secondary part, or perhaps no part at all if by adsorption is meant a solution of sulfur in rubber. The work of Bacon devotes some attention to unworkable theories based on the existence of two distinct phases in vulcanized rubber, one the sulfurated compound, the other pure rubber. It is only to be regretted that the experiments do not take into account the more modern theories which have been developed and which are based on colloidal properties. It is interesting to note that the observations are not at variance with these more recent theories.
Methods of Determining Abrasion. With Particular Reference to the Relation between Road Performances and Laboratory Tests
Authors: Lambourn L. J. 
Published: February 2011

Abstract
Many previous papers have included descriptions of abrasion machines, but few have dealt particularly with the correlation of road performance and laboratory tests. It must be admitted in the first place that no abrasion machine, however good it may be, has yet been designed to replace road tests. None of the abrasion machines of the small laboratory type takes pattern into account, for example. Of course, there are one or two abrasion testing machines in which a complete tire is used, but they are not in favor, in view of the expense and time involved in obtaining results. Variation in Relative Road Results.—Relative road results on tread wear may be considerably influenced by external factors such as speed, road surface, front or rear wheel service, tire design, etc. In view of this possible variation in relative wear it is obviously necessary to eliminate as many of the causes as possible when comparing two tread compounds on the road. Probably the best way is to make a tire tread in two halves, i.e., one-half of the tread circumference of one mixing and the other half of another mixing; these halves joined together before curing form a perfectly sound tire. If the compounds cure at different rates, and this method cannot be employed, the best plan is to make a pair of tires of the same design and fit them, say, to the rear wheels of a car, and interchange them from near to off wheels every 500 miles. Even so, it is useless to rely on one or two tires to give the relative road results on tread wear; at least four distinct comparisons are necessary. It is not uncommon for the relative abrasion of two mixings to change during the actual course of the road test.
The Effect of Temperature on the Stress-Strain Properties of Vulcanized Rubber
Authors: Somerville A. A. , Cope W. H. 
Published: February 2011

Abstract
A method has been devised for testing rubber at various temperatures by putting a simple attachment onto a commercial testing machine. Wide variations have been found in the stress-strain curves on the same stock at different temperatures. The stress-strain properties at different temperatures vary for different rubbers. The state of cure causes a wide variation in tests at various temperatures. The amount of sulphur used is a factor in the stress-strain relationship at different temperatures. Successive stresses on the same piece of rubber show large decreases after the first or second stress. Stripping tests on frictions show much lower strength at 100° C. than at 0° C. Overcures are indicated prominently when stocks are tested at 100° C. Artificially aged rubber tested under these conditions shows a very marked deterioration which may be offset by anti-oxidants.
Heat Transfer in the Vulcanization of Rubber
Authors: Sherwood T. K. 
Published: February 2011

Abstract
Temperature lag in the heating of rubber articles is found to cause marked non-uniformity of cure in the product. The theory of “unsteady state” heat flow is discussed, and a method described for analyzing data on temperatures in rubber being heated. From data on the temperatures at different times during the heating process and on the relation between the rate of cure and the temperature, it is shown how the resulting curing effect at different points in a solid rubber object may be calculated. A new water cure process for tires is described which is very effective in reducing the non-uniformity of cure caused by the temperature lag effect, and at the same time appreciably reduces the necessary curing time.
Accurate Method for Comparison of Scorching Qualities of Accelerators
Authors: Thies H. R. 
Published: February 2011

Abstract
The determination of critical point curves for accelerators is of value in ascertaining their scorching tendencies. Also, the index number, defined as that increment of time at which the set-up crosses the 140 mm. “height of column” ordinate, is of value in comparing the scorching qualities of various accelerators. For accurate work the cures on the accelerators compared should be balanced at the temperature of use, and control obscuration readings should be fairly close together in their value. Stocks should be milled in as nearly the same manner as possible. For the complete history of an accelerator's behavior, critical point determinations should be made at at least two and perhaps three, temperatures, one corresponding to the milling temperature, another to the warm storing temperature of stock after it has left the mill or calender, and a third to room temperature, although the experimental results on the last named are not complete at this time. If these determinations are made, the scorching tendencies of an accelerator under actual factory use can be predicted with accuracy.
A Comparison of the Rate of Combination of Sulfur with Rubber and the Rate of Vulcanization
Authors: Bridgwater E. R. 
Published: February 2011

Abstract
The following general conclusions can be drawn from these experiments: 1—The low combined sulfur at correct cure which is, in general, characteristic of fast curing compounds is due both to the stiffening or polymerizing action of the accelerator and to the fact that fast curing compounds suffer less heat degradation during the cure. Some accelerators have a greater physical stiffening or polymerizing effect than others, that being the only way one can account for the difference in the rate of sulfur combination between Vulcanol and mercaptobenzothiazole, since Vulcanol which causes the combination of sulfur at a lower rate causes physical vulcanization or stiffening of the rubber at a higher rate. 2—The differences in the combined sulfur required to produce correct cure between one accelerator and another are not large as compared to the differences which result from changing the percentage of any given accelerator. 3—Accelerators differ among themselves in the benzol absorption which they impart to compounds. Neither the stress-strain curve nor the combined sulfur gives any information as to what the benzol absorption may be. The benzol absorption at any given state of physical cure depends even more upon the rate of cure of the compound than upon the accelerator used. In general, the higher the percentage of accelerator the lower is the benzol absorption. The effect of high sulfur is apparently due to the rate of cure and not to the sulfur itself because the high sulfur compounds which swell relatively little in benzol have low combined sulfur. It is indicated that oil resisting stocks should be highly accelerated but not overcured. In no case has curing beyond the point of maximum stiffness of the stress-strain curve caused a decrease in the benzol absorption. Referring to Table I, there is but little difference between the benzol absorption between 90 and 45 minute cures of either of the first three stocks. To state it another way, benzol absorption depends nearly as much upon the rate of cure as upon the state of cure. These facts should be borne in mind in compounding oil resisting stocks.
A Thermodynamic Theory of Rubber Fillers
Authors: Hock Lothar 
Published: February 2011

Abstract
Purely thermal measurements indicate that the physical reënforcement of rubber, i. e., the increase in the work expended in rupturing, brought about by the admixture of active fillers, depends upon the free surface energy between rubber and filler, besides a work of friction, and can be measured in absolute units. Experience has shown that the addition of so-called active fillers to rubber improves the physical properties of the latter, the work expended in breaking the rubber mixture being considerably greater than that expended in breaking the pure rubber. Furthermore, it has been found that the finer the active filler, e. g., carbon black or zinc oxide, the greater is the reenforcing effect. Obviously then the wetting of rubber and filler is the cause of the reenforcing action. In developing from these basic principles a theory of the action of fillers, the free surface energy between rubber and filler must be considered responsible for the increased work of breaking the loaded rubber. It is desirable, therefore, to find a way to determine this free surface energy. Now if a rubber-zinc oxide mixture is swollen in benzine, the rubber component swells and the zinc oxide is wet. This process is accompanied by a heat tone which can be measured calorimetrically, and which is not the sum of the heat of swelling of the same quantity of rubber and the heat of wetting of the zinc oxide when these are measured separately, but shows a distinctly different value. This difference represents the heat of adhesion of the filler and rubber. It also represents the total surface energy, and therefore is not a measure of the free surface energy to which is attributed the increase in the work of rupture.
Practical Method for Obtaining Dry Air for Humidity Control in a Rubber Laboratory
Authors: Conover F. S. 
Published: February 2011

Abstract
THE effect of relative humidity on rubber-testing has been the subject of much recent investigation. String-field and Conover and Depew have published papers on this subject. The last-named authors recommended that the rubber be stored in dry cabinets before milling, between milling and vulcanization, and between vulcanization and testing, at a temperature of 75° ±5° F. A short time later the Physical Testing Committee of the Rubber Division of the American Chemical Society recommended that all laboratory testing be carried out at 45 per cent relative humidity and 82° ±5°F. While both methods have undoubted merit, it was believed that for physical testing laboratories, particularly such as this one, zero humidity was both more conducive to reliable results and easier to maintain. Accordingly, equipment was installed for maintaining zero humidity and its performance has been consistently good. Since several of the larger rubber laboratories have shown interest in the equipment, it has been decided to present this description of the installation and its operation.
An Attempt at a Rational Classification of the Principal Accelerators of Vulcanization
Authors: Martin G. , Thiollet R. 
Published: February 2011

Abstract
AT the present time there are many accelerators on the market for the vulcanization of rubber, but it is often difficult to choose among them those best suited for a required purpose. Accelerators are often classed as slow medium, rapid and ultra rapid. These brief terms are entirely unsatisfactory for characterizing clearly the properties of these properties, and it frequently happens that two accelerators which have been placed together in one class behave in reality in very different ways and are not entirely replaceable one by the other. The object of this study is to establish a rational classification of the principal accelerators of vulcanization, which is based not only on their activity but also on their other important characteristics. The following points will be considered in their order: (1) The time required for the fixation of mixtures at different temperatures. (2) The time required to bring about vulcanization giving the maxima mechanical properties at different temperatures. (3) Aging. (4) These three points of view will be completed by a study of the plasticizing power and of the influence of different charges on the action of the accelerators.
Determination of the Iodine Number of Raw Rubber
Authors: Gorgas Adolf 
Published: February 2011

Abstract
In the course of an investigation dealing with the nature of the state of unsaturation of raw rubber, it became necessary to have available a precise and convenient method for determining the iodine number of raw rubber. Though iodine reacts only slowly with unsaturated compounds, chlorine and bromine form both addition and substitution products. In the substitution reactions, the hydrogen halide is evolved, and by addition of potassium iodate, e.g., in the method of MacIlhiney, it is possible to determine the hydroden halide formed and thus the quantity of halogen substituted. In all methods, however, where extensive substitution as well as addition take place, the results are variable and uncertain. Accordingly in the chemistry of fats where the iodine number is of the greatest importance, iodine halides have been used for determining the iodine number, for under certain conditions there is very little substitution. Thus Hübl, Waller and Wijs solutions contain iodine chloride and Hanus solution contains iodine bromine. The Hanus method has in fact to a great extent replaced all other methods For determining the iodine number of rubber, the Wijs method in the form in which it was modified by Kemp is probably used more than any other. In the Kemp method about 0.1 gram of rubber is swollen in 75 cc. of carbon disulfide, and is then allowed to react for 2 hours at 0° C. with 25 cc. of Wijs solution, i.e., 0.5 N iodine chloride in acetic acid.
The “Freezing” of Raw Rubber
Authors: Rossem Avan , Lotichius J. 
Published: February 2011

Abstract
The experiments lead to certain general conclusions. 1. Measurements of the changes in density, hardness, and light absorption show that all three properties suddenly decrease at the same temperature, doubtless as a result of the fusion of a crystalline component. 2. Measurements by means of a Bunsen ice calorimeter show that hard frozen samples of rubber have a definite heat of fusion. 3. The “melting point” of frozen rubber changes as time goes on, a phenomenon which may be explained by the growth of crystals. 4. A study of the freezing of raw rubber at ™10° C. and at 4° C. shows that freezing occurs in a few days, and that such rubber melts at a lower temperature than rubber which has been kept frozen for several years, phenomena which are explainable by the ordinary known laws of crystallization.
The Absorption of Oxygen by Rubber
Authors: Kohman G. T. 
Published: February 2011

Abstract
In order to determine the relation between natural aging and oxygen absorption at 80° C., the effects upon oxygen absorption of a number of factors which are known to affect natural aging have been studied. An apparatus is described with which it is possible to follow the absorption of oxygen at constant pressure, temperature, etc., over long periods of time. It has been found that the absorption of oxygen is autocatalytic in nature and appears to consist of at least two separate reactions—a decomposition and an addition reaction. The rate of absorption of oxygen at 80° C. is dependent upon surface area when the area is small, but when it is increased to as large as 40 square centimeters per gram, small variations in surface area are without great effect, probably because under these conditions rates of diffusion are high enough to keep the rubber particles practically saturated with oxygen. As rubber absorbs oxygen it appears to undergo changes similar to those occurring during vulcanization with sulfur. Surface checking is regarded as a preferential surface oxidation. The mechanism of oxygen absorption appears to be different for raw rubber from that for cured rubber. Curing rubber increases both the rate and amount of oxygen absorption over that for raw rubber, and changes the character of the absorption curve. The rate of absorption increases with the degree of cure. The action of anti-agers is one of negative catalysis rather than one of preferential absorption. The rate of oxygen absorption may be greatly retarded by their presence and their effectiveness varies with their concentration and constitution. The type of absorption of ozonized oxygen differs markedly from that for pure oxygen. The former is taken up very much more rapidly at first, but the rate rapidly decreases and less oxygen is finally taken up than in the case of pure oxygen. The action of ozonized oxygen upon rubber appears to protect it from the action of pure oxygen. The reaction between rubber and ozonized oxygen is not autocatalytic.
A Temperature-Recording Micropress for Studying the Course of Vulcanization
Authors: Walton James C. 
Published: February 2011

Abstract
A microscopic study of the course of vulcanization offers many possibilities, especially since, by its aid, the progressive changes which take place during vulcanization can be followed. Using the micropress described above, it is possible to observe these changes and to record the temperature at which they take place. A rubber-sulfur-litharge mixture after cure exhibits no recrystallization of sulfur even when cured for a very short time. A further microscopical study of the vulcanization of this type of rubber mixture may yield an explanation of the bloom-preventing properties of litharge. m-Dinitrobenzene and benzoyl peroxide both vulcanize rubber in the absence of sulfur. The former requires an activator such as litharge and does not recrystallize from the mixture when a cure is effected, whereas the latter does not require an activator and recrystallizes after cure in a manner very similar to sulfur.
Vulcanization without the Use of Sulphur
Authors: Ostromislensky Iwan 
Published: February 2011

Abstract
AS far back as 1915 I described the various methods of vulcanizing rubber without the use of sulphur which I was the first to discover. At the same time these researches gave rise to an international controversy in scientific circles. For reasons beyond my control I have not until now been able either to publish the results of my physical or strictly technical tests of rubbers vulcanized by my new methods, or to place numerical valuations on their physical properties. Many chemists who have repeated my experiments, of course under somewhat different conditions, often obtained results that did not coincide with mine. In consequence a number of discrepancies have gradually crept into the literature and in places even generalizations that are contrary to fact (C. Harries). Among others, B. D. Porritt claims that 1.3.5. trinitrobenzene, although a vulcanizing agent for rubber, is inactive in the absence of oxides. This statement, as will be shown subsequently, is incorrect. Moreover, some of the experimenters have come to the conclusion that the vulcanization of rubber without sulphur cannot be applied practically in the rubber industry.
Essentials for Accurate Gauging for Compressible Material
Authors: Brown Roy W. 
Published: February 2011

Abstract
Variables affecting the accurate thickness measurement of compressible sheet materials such as fabric and rubber stock are indicated as: 1. Linear accuracy of the micrometer. 2. Pressure exerted by the micrometer foot. 3. Size of the micrometer foot. 4. Friction in the micrometer mechanism. A unit area foot pressure of (70.3 gram. per sq. cm.) 1 lb. per sq. in. has been found satisfactory. Friction in the micrometer mechanism is shown to limit the minimum foot pressure to approximately (199.5 grams) .44 lbs., hence a (1.906 cms.) 3/4″ diameter circular foot, or equivalent, is required on present available mechanical gauges. Methods of meeting the above fundamental requirements are indicated for optical and magnetic gauges. Limiting factors in the accuracy sccurable by the use of dielectric gauges arc discussed. The necessity for standardised practices is so apparent as to command consideration of all concerned.
The Consumption of Accelerator during Vulcanization
Authors: Wistinghausen L. v. 
Published: February 2011

Abstract
THE so-called chemical theories of acceleration are based on the transformation of the accelerator during the process of vulcanization, but the quantitative study of such reactions is confronted by tremendous difficulties. From the increase in the amount of combined sulfur with time of cure, Hardman and White have drawn conclusions as to the relative stability of various accelerators. In these experiments they chose conditions which were specific for each accelerator, affording optimum effects. In the following work an attempt has been made to obtain some insight into the fate of the accelerator in the course of heating by a quantitative estimation according to the methods described below of the amount of accelerator found in the acetone extract of vulcanizates with increasing time of cure. In order to study the effect on the accelerator of various ingredients, the type of raw rubber, the quantity of sulfur, and the addition of fillers were considerably varied, while the ratio of accelerator to rubber remained constant.