bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultimate Tensile Properties of Elastomers. I. Characterization by a Time and Temperature Independent Failure Envelope
Authors: Smith Thor L. 
Published: February 2011

Abstract
The tensile stress at break (σb) and the associated ultimate strain (εb) of an elastomer depend on (1) the chemical and topological characteristics of the polymeric network, and (2) the test conditions under which rupture is observed. To separate these effects, the ultimate tensile properties can often be characterized by a “failure envelope” defined by values of σb and εb determined at various strain rates over a wide temperature range. Provided time—temperature superposition is applicable, such data superpose on a plot of log σbT0/T versus log εb, where T is the test temperature (absolute) and T0 is an arbitrarily selected reference temperature. The resulting failure envelope is independent of time (strain rate) and temperature and thus it depends only on basic characteristics of the polymeric network. To illustrate the characterization method, data on two styrene-butadiene gum vulcanizates, SBR-I and SBR-II, were analyzed. For SBR-I, values of σb and εb obtained over extensive ranges of strain rate and temperature superposed to give a failure envelope. Data at elevated temperatures also gave a reliable value for the equilibrium modulus. For SBR-II, data obtained at various temperatures under conditions of constant strain and constant strain rate yielded identical failure envelopes; this strongly suggests that the failure envelope is independent of the test method. A theoretical consideration of the time-to-rupture associated with different test methods showed that for given values of σb and εb the time-to-rupture from the following types of tests should increase in the order: constant strain &lt; constant stress &lt; constant strain rate &lt; constant stress rate.
Tensile Strength of Gum and Reinforced EPR and SBR Vulcanizates
Authors: Dudek T. J. , Bueche F. 
Published: February 2011

Abstract
The tensile strength and elongation at break of EPR and SBR gum vulcanizates were determined as a function of network chain density. A large viscous contribution to the tensile force was found at low crosslink density, and the maximum in the tensile strength versus chain density curve decreased as more nearly equilibrium conditions were approached. The rate dependence of tensile strength of black-filled EPR was studied by creep rupture experiments. The temperature dependence of the tensile strength of filled EPR and SBR was studied and compared. The same limiting degree of cure was obtained for both filled and gum vulcanizates of EPR.
Level and Variation of Tensile Strength in Relation to Dispersion of Compounding Ingredients
Authors: May W. 
Published: February 2011

Abstract
Tensile strength—being a distinctive property—is sensitive to flaws in the rubber vulcanizate. A procedure is described by which the occurrence of flaws can be detected. These are interpreted in terms of dispersion of certain ingredients and the various possibilities are illustrated by examples of work carried out on styrenebutadiene rubber and polyisoprene rubber. It is shown how this procedure teads to better processing and thus to better product properties.
Vulcanization of Elastomers. 36. Vulcanization of Natural Rubber and Synthetic Rubbers with Sulfur in Absence of Accelerators. II
Authors: Scheele W. , Müller H. , Schulze W. 
Published: February 2011

Abstract
In continuation of earlier work with natural rubber, the kinetics of sulfur decrease were studied in certain synthetic rubbers for different temperatures and sulfur concentrations. At the same time the formation of polysulfide bound sulfur was studied, using as example the reaction of sulfur with natural rubber and synthetic rubbers. It was found that: 1) When the decrease in sulfur concentration is portrayed by curves which are convex to the time axis (Perbunan), the 0.6th order time-law is fulfilled, (as in the case of natural rubber independent of temperature and concentration. 2) In contrast, the concentration dependence of the rate at which sulfur decreases, both in Perbunan and cis 1,4-polybutadiene, denotes a first-order reaction in agreement with experience with natural rubber. 3) The activation energy of sulfur decrease has the same magnitude for all the elastomers investigated (34 to 36 kcal/mole). 4) The disagreement between the time law and the concentration dependence of the rate of sulfur disappearance encountered in all the experiments with 1,5-polyenes, is interpreted as indicating autocatalysis, which likewise explains the shape of the curves for sulfur disappearance. 5) Sulfur reacts considerably faster in natural rubber and Perbunan than in cis 1,4-polybutadiene; consequently a homolytic dissociation of the S8-ring cannot be rate-determining. 6) Polysulfide sulfur shows, in each case, a maximum with reaction time, and in completely reacted vulcanizates it tends toward a limiting value. An equation was found, which provides a good description of change with time of polysulfide concentration (natural rubber and cis 1,4-polybutadiene). 7) An explanation is given for the appearance of the polysulfide maximum; and how the reaction of sulfur with 1,5-polyenes can be represented, making use of all available results, is discussed.
Characterization of Polymer Decomposition in an Inert Atmosphere by Thermogravimetry
Authors: Smith D. A. 
Published: February 2011

Abstract
The paper reports weight loss vs temperature data for the pyrolytic decomposition of polyethylene, Polyvinylchloride; natural, styrene-butadiene and isopreneisobutene rubbers. A nonisothermal kinetic treatment is developed, based on proposals by Doyle and by Newkirk, resulting in characterization of the pyrolysis by two principal parameters, the “integral procedural decomposition temperature” (Tp) and the “procedural activation energy” (Ep). The effects of environmental variables are discussed and it is concluded that Ep is insensitive to detailed procedural variation but appears to reflect differences in stability between polymers. For a number of polymers, the values obtained agree well with values from isothermal measurements reported in the literature. An indication is given of how the method may be used to assess rapidly the effects of compounding on the pyrolytic stability of polymers.
Transmissibility through and Wave Effects in Rubber
Authors: Payne A. R. 
Published: February 2011

Abstract
Instruments and precision machine tools are now being used in increasing quantities, and often in places which are subjected to severe vibration environments. Precise and costly electronic equipment in aircraft and missiles are currently subjected to severe vibration hazards. Increasing use is now being made of intentionally produced vibrations for such purposes as a drive for a mixing sieve, for conveying, for mold shaking and for vibration and shock testing. All these environmental situations demand the development of suitable and effective vibration isolation devices. Unhappily, adequate vibration isolation is not merely a matter of interposing any kind of rubber or metal springing, because the incorrect use of such elastic materials may actually make matters worse. Our understanding of the requirements for the best type of rubber, or rubber compounding is limited and only of recent origin, but it is the purpose of this review to discuss the problems of vibration isolation and insulation, not from the point of view of mechanical vibration theory alone, but to discuss how these theories can help to decide what properties are required of the rubbers to obtain maximum protection. It is not intended to discuss the actual design of antivibration shock mountings and couplings as these have been surveyed in recent publications.
Carbon Black-Rubber Interactions and Bound Rubber
Authors: Stickney P. B. , Falb R. D. 
Published: February 2011

Abstract
The interaction of elastomers with fine particles has been a subject of great interest and much controversy for many years. This is easy to understand when it is remembered that reinforcement is one of the three great developments that underlie the extensive use of elastomers in our modern world. The other two are, of course the discovery of the principle of vulcanization, and the development of synthetic elastomers, including many having special properties superior to those of natural rubber. A large part of the controversy currently includes specifically the question of the special position—or lack of it—of carbon black as a particulate filler for elastomers. The resolution of this question is beyond the scope of our present knowledge, although strong opinions are held on both sides of the question. However, for two reasons, the present review will be restricted almost entirely to a consideration of the nature of the interaction of carbon black with hydrocarbon elastomers. The first reason for this is the undeniable technological importance of these systems. The second is the relatively small amount of work that has been reported on other types of fillers. In addition, the inclusion of other fillers would certainly add to the complexity of any attempt to analyze polymer-filler interactions at this time. However, it must be admitted that the possibility exists of explaining all polymer-filler interactions ultimately in similar and relatively nonspecific terms. In the past few years, an enormous amount of work has been reported that has a bearing on this problem. From the results of these investigations, a coherent explanation appears to be emerging. This paper attempts to review some of the more important work in this field in order to present an over-all picture of our present knowledge. The problem can be summarized in three questions:
A Review of Cord-Rubber Elastic Characteristics
Authors: Clark Samuel K. 
Published: February 2011

Abstract
The increased use of cord- and filament-reinforced materials in structural applications during the last few years has resulted in a greater interest in their elastic properties. In part the reason for this may be found by considering the basic nature of redundant structures, in which the loads carried by individual cords are determined to some extent by the elastic characteristics of the entire system. In such situations, a knowledge of elastic characteristics becomes important to structural design practice. As a second reason for increased attention to the elastic properties of such materials, one might cite the body of work which is now developing in the general area of filamentary reinforcement of materials. A knowledge of elastic characteristics is important in obtaining optimum reinforcement properties, and such studies inevitably lead to a clearer understanding of the internal stress-states of all reinforced materials. One result of all this activity is that much of the work done in the areas of fiberglass and whisker reinforcement increases the general understanding, in a broad way, of the action of cord-reinforced rubber since in many respects the problems are similar, although major differences do exist in the structure of the reinforcement itself. The elastic properties of cord-rubber materials are understood today much better than they were even ten or fifteen years ago. A great deal of this development has paralleled, and is well represented by, internal stress analysis techniques developed for what is perhaps the primary utilization of cord-reinforced rubber, namely, the pneumatic tire. In the case of the pneumatic tire, these stress analysis techniques have essentially followed three distinct phases. In the first, the anisotropic nature of such materials was completely ignored and loads and stresses were determined on the basis of assuming the materials to be isotropic or unreinforced. In the case of shell structures, this is the equivalent of calculating the statically determinate membrane stresses. In some cases such information was valuable and in a few instances it comprised a major portion of the effects being studied so that some reliance could be placed on such an analysis. However, in general, due to the complex nature of such reinforced materials, little faith can be given to analyses based on isotropic conditions.
Observations on the Crosslinking of Natural Rubber with Nitrosophenols and Diisocyanates
Authors: Lautenschlaeger F. K. , Myhre M. 
Published: February 2011

Abstract
1. The vulcanization system based on nitrosophenols (quinone monoximes) is not primarily based on the formation of a urethane group. Evidence is presented that the crosslink consists of carbon—carbon, carbon—sulfur, and urea groups. Urea groups can be identified in reaction products which also contain the free phenol group of the nitrosophenol (oxime); urethane groups are identified in products which also contain quinone groups. 2. The presence of zinc dithiocarbamate is conducive to the formation of the amino group which is the functional group on which the crosslinking reaction with diisocyanate is based. The dithiocarbamate also acts as a sulfur donor. The dialkyl amino group of the dithiocarbamate is bound into the network. 3. Nitroso compounds which have no tautomeric oxime structures show no vulcanization in combination with free diisocyanate. 4. The level of vulcanization of various substituted phenols, when used in combination with a diisocyanate precursor, is dependent on their thermal decomposition termperatures, but such a dependence is not apparent when these compounds are used in combination with free diisocyanate. 5. A reaction mechanism is suggested for the vulcanization with oximes and diisocyanates which does not require the splitting of their adducts into their components but instead into ionic fragments. This mechanism explains why monoximes lead to vulcanization whereas nitroso compounds do not. 6. Attempts to effect premature vulcanization should be directed towards delaying the formation of the diisocyanate/oxime adduct since it provides the vulcanization-active intermediates. Towards this goal it has been shown that a diisocyanate precursor can be applied but then a thermally stable nitroso compound (oxime) is required. 7. Tautomerism between O-derivatives of oximes, nitrones, and oxaziridines can be assumed to provide a working hypothesis for the discovery of new N-O-containing crosslinking agents for unsaturated polymers.
Variations in Tire Hysteretic Losses Due to Tire Design
Authors: Willett P. R. 
Published: February 2011

Abstract
The technique of analyzing energy losses of tires that have reached a state of thermal equilibrium has been applied to cross-ply and radial-ply passenger car tires and cross-ply truck tires. The derived formulations relating the tire energy losses to the viscoelastic properties of the tire components show the dependence of these losses on tire size and construction. The analysis was carried out by systematically varying tire tread compounds and operating parameters. This investigation of the energy losses experienced by tires operating in a state of thermal equilibrium, has enabled the losses due to the various stress-strain deformations to be characterized. In particular, the losses due to the strain deformation have been correlated with two mechanisms, which are outlined. The results described enable a better understanding of the mechanisms responsible for tire energy losses and allow the tire losses to be predicted at the design stage.
The Effects of Oil on Adhesion of Rubber
Authors: Beatty J. R. 
Published: February 2011

Abstract
It has been shown for poly(isoprene) rubber, both natural and synthetic, that the usual processing oils have essentially no effect on adhesion. The materials to which this statement apply are brass-plated wire, brass metal, steel, and R.F.L. dipped rayon, nylon, and polyester. The modulus of the rubber compound must be maintained constant by addition of carbon black to obtain these results. This work opens a new approach to the compounding of rubber compounds where good adhesion is necessary. It provides improved processing and reduced cost with no detrimental effect on adhesion properties.
Viscoelastic Properties of Polyurethane Block Polymers
Authors: Seymour R. W. , Cooper S. L. 
Published: February 2011

Abstract
Orientation measurements using differential infrared dichroism experiments have been applied to the study of the viscoelastic properties of polyurethane block polymers. The time dependence of the orientation function reflects the influence of both the viscoelastic nature of the blocks and of the two-phase microstructure. A study of the effect of hard block length on the orientation response suggests the presence of an interlocked hard phase structure for most compositions. Such a structure severely restricts relaxation of orientation under strain. At very short hard segment lengths, this morphology is not present and extensive relaxation does occur.
Dependence of Laboratory Tire Cord Adhesion on Rubber Properties
Authors: Erickson D. E. 
Published: February 2011

Abstract
H- and strip adhesion results on nylon and glass tire cords were found to depend on various physical properties of the adhering rubber compounds. The strip adhesion test was most affected by changes in tensile strength and elongation, with higher values of adhesion being measured with high elongation-high strength compounds. Tensile strength was especially influential in the case of hot strip adhesion. H-adhcsion results were more affected by the characteristics of the rubber during curing than by the tensile properties of the cured rubbers. Compounds having higher Mooney viscosities developed higher pressures in the curing mold. Because of this tendency, the rubber was postulated to penetrate more thoroughly into the tire cord, giving better mechanical and physical bonding because of the better contact. Rubbers which were slower curing, as indicated by long optimum cure times, tended to increase H-adhesion, presumably because they allowed better interfacial bonding by their capability for increased curative or polymer diffusion before complete self-curing of the rubber. High Mooney viscosities and long optimum cure time were particularly effective in increasing H-adhesion of glass cord because of the normally low level of mechanical bonding of the rubber to glass cord (because of its low twist). Nylon cord, normally higher in mechanical bonding which results in overall higher levels of H-adhesion, was high in room temperature H-adhesion to high Mooney compounds. However, the tensile strength was controlling in the case of hot H-measurements of nylon cord because of the greater level of mechanical bonding already present. Room temperature and hot “tear ratings” representing the rubber coverages on delaminated strip adhesion samples varied with the optimum cure times of the rubber compounds rather than with tear strength. As in the H-adhesion samples, the lower-cure-rate rubbers are thought to increase the bonding between dip and rubber by increasing the diffusion of curatives or polymer segments at the rubber-to-dip interface. Hot “tear ratings” also showed an inverse correlation with tensile strengths, indicating that the hot strength of the rubber layer is low enough in some cases to make that intermediate layer the weakest point in the laminate, and strong enough in other cases to force the delamination to occur between the cord and rubber, giving low tear ratings. The delamination force measured in hot strip adhesion tests varied as the square of the tensile strength of the ply rubber, in agreement with Kaelble's theoretical expression. However, the peel force did not vary inversely with the 100 per cent rubber modulus, as predicted if that parameter is related to Young's modulus.
The Effect of Carbon Black Parameters on the Fatigue Life of Filled Rubber Compounds
Authors: Dizon E. S. , Hicks A. E. , Chirico V. E. 
Published: February 2011

Abstract
Fatigue is defined as decay caused by cyclic deformations at an amplitude less than necessary for fracture in one cycle. Such failures are initiated by flaws which act as stress concentrators. These flaws occur in the material either through mechanical or chemical action during service or through agglomeration of certain ingredients during mixing and fabrication. This paper deals with the latter process, where the nature and size of the flaws as well as the properties of the matrix are contingent on carbon black variables. Using the tearing energy concept of fatigue developed by Lake and Lindley, it was shown that the size of the flaw is primarily determined by carbon black particle size. On the other hand, the cut growth constant depends on carbon black structure. When translated to actual fatigue life using the Monsanto Fatigue-to-Failure Tester, these relationships mean that under constant strain conditions, compounds containing coarse carbons will have a significantly higher fatigue life than those with fine carbons. Under conditions of constant strain, higher structure carbons will impart a slight positive effect. However, under conditions of constant stress, the beneficial effects of structure become magnified. Other factors known to affect fatigue life were also considered. These are : set, stress relaxation, hysteretic energy dissipation, and flaw size distribution.
Effect of Heterogeneous Carbon Black Distribution on the Properties of Polymer Blends
Authors: Sircar A. K. , Lamond T. G. , Pinter P. E. 
Published: February 2011

Abstract
The results of this work support earlier findings regarding the transfer of carbon black in blends of BR with SBR, NR, and CIIR. Compared to conventionally-mixed compounds, in most cases vulcanizates with a heterogeneous carbon black distribution have superior hysteresis properties, presumably due to the presence of the unloaded layer mitigating the generally observed deleterious effects of carbon black upon these properties. The effect of unloaded SBR or BR layers on stress-strain values is quite small in SBR/BR blends where the zone size of the elastomer phases is small, but significant in SBR/NR and BR/NR where the zone size of the elastomer phases is larger. Superior cut growth resistance is seen for NR/BR and SBR/BR blends containing unloaded BR. The properties of SBR/BR and NR/BR blends in which most of the black is in the BR phase suggest that they may find utility in applications where superior hysteresis properties are required; e.g., in radial-tire sidewalls. Compounds with a heterogeneous carbon black distribution may also find utility in wire and cable applications, due to their superior insulating properties.
Preliminary Investigation of the Feasibility of Radiation Vulcanization of Silicone Rubber
Authors: Przybyla R. L. 
Published: February 2011

Abstract
Radiation vulcanization of silicone rubber is commercially feasible from the standpoint of obtaining useful physical properties at relatively low dosage rates. These physical properties are approximately equivalent to those obtained by peroxide vulcanization. We found that, for the limited number of samples tested; the electrical properties, the confined heat resistance, the compression set resistance, and the heat aging were all equivalent to their peroxide counterparts.
The Synthesis and Spectral Characteristics of Some Nitrosoanilines and Their Possible Mode of Action as Curing Agents for Various Types of Rubbers
Authors: Potts K. T. , Kane J. , McKeough D. , D'Amico J. J. 
Published: February 2011

Abstract
Spectral characteristics of several known and new N-substituted-p-nitrosoanilines, e.g., Nitrol, of established utility in promoting the bonding between rubber and carbon black are described. A possible mode of action in their enhancement of the bonding process involving a classical free radical process is discussed.