bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gas and Particle Emissions from Automobile Tires in Laboratory and Field Studies
Authors: Cadle S. H. , Williams R. L. 
Published: February 2011

Abstract
The purpose of this work was to determine the contribution which automobile tires make to air pollution. The gaseous hydrocarbon and sulfur compounds emitted in laboratory tests were identified. Although these hydrocarbons can participate in smog reactions, their mass emission rate is less than 0.1% of the current exhaust hydrocarbon emission rate. Hydrocarbons from tires are not measurable near a freeway. The particulate emitted from tires ranges in size from 0.01 to more than 30 µm, with the larger particles dominating the total mass. Measurements along a California freeway showed that most of the tire debris had settled within 5 m of the pavement edge. Airborne rubber concentrations were less than 0.5 µg/m3, or less than 5% of the total tire wear. These field measurements confirm the indoor emission pattern and verify that tire wear products are not a significant air pollution problem.
Influence of Carbon Black on Processability of Rubber Stocks. II. Extrusion Shrinkage
Authors: Cotten G. R. 
Published: February 2011

Abstract
Extrusion shrinkage is caused by molecular relaxation of polymer after exit from the die. The rate of molecular relaxation is extremely rapid and under the present experimental conditions, 80% of limiting extrusion shrinkage, L∞, is reached in less than 10 sec. The dependence of extrusion shrinkage L, on time t may be expressed by an empirical equation: L=L∞(1−kt−n) where k and n are constants. An increase in relaxation temperature increases values of L∞ and decreases n, while increase in shear rate decreases constant k. As found previously, extrusion shrinkage, L∞, is related to shear stress. Maintaining a good uniformity of product in factory extrusion may be accomplished by controlling extrusion pressure as well as by speeding up and controlling the process of molecular relaxation. The latter goal may be attained by maintaining the extrudate at an elevated temperature for about 2 min, and controlling that temperature within narrow limits. The results show the importance of defining extrusion conditions, including extrusion pressure and the temperature at which the extrudate is allowed to relax. The feasibility of rapid measurements (i.e., within ca. 1 min) of extrusion shrinkage using a laser beam detection system was demonstrated, and a good correlation was found with results obtained by conventional (weighing) method. The concept of occluded rubber and its effect on extrusion shrinkage was reexamined and found to provide a very satisfactory prediction of extrusion shrinkage of SBR compounds containing a wide selection of carbon blacks.
Looking at Rubber Adhesion
Authors: Roberts A. D. 
Published: February 2011

Abstract
Rubber has been employed in contact with a variety of surfaces for decades, yet the adhesional mechanisms involved are not fully understood. This article describes fundamental investigations carried out over the last decade. Emphasis is placed upon the use of optical techniques for looking directly at the contact area rubber makes with another surface. The interpretation is based upon a rate-dependent surface energy approach. In this way it is possible to predict the level of peel adhesion between surfaces, for example, when a ball rolls on smooth rubber. Other examples treated in the same way are the time for detachment of a ball from a smooth rubber track under gravity, its resilience when bounced on the track, and its friction when slid over the track. The influence of surface roughness, electrostatic forces, surface bloom, and humidity are considered, together with rubber compound variables such as glass transition temperature, crosslink density, and fillers. The central theme is that the adhesional mechanisms all physically depend upon the product of surface properties and bulk viscoelasticity of the solids in contact.
Nitrile Rubber Functionalized for Silica Reinforcement
Authors: Edwards D. C. , Sato K. 
Published: February 2011

Abstract
1. Conventional silica-reinforced NBR vulcanizates are characterized by stiffness at low elongation and low modulus at high elongations. These properties are associated with reticulate structure formation of silica particles, which occurs rapidly when compounds are heated to curing temperatures. 2. An NBR terpolymer, functionalized with about 0.07 mol of epoxy groups per kg polymer, interacts with silica when mixtures are subjected to combined heat and shear. Vulcanizate stiffness is greatly reduced, modulus at higher extensions is greatly increased, and mechanical properties in general are changed in the directions characteristic of carbon black reinforcement. 3. The interaction is similar in effect, but in principle much more economic, compared to that obtained with a mercaptosilane coupling agent. 4. Early experience indicates that the improvements are attainable to a large degree, although not optimally, in a conventional laboratory Banbury mixing operation.
Optimum Choice for Reference Temperature in Evaluation of Curing Cycles
Authors: Chehebar A. L. , Galli E. J. 
Published: February 2011

Abstract
An exact expression for the optimum reference temperature to be used in evaluating curing cycles is developed. This reference temperature minimizes the dependence of the equivalent cure time on the activation energy. Some examples are analyzed by means of analytical and numerical methods, and the computer program used is listed. The convenience of using the optimum reference temperature criterion is clearly demonstrated.
Compounding Bromobutyl for Heat Resistance
Authors: Timar J. , Edwards W. S. 
Published: February 2011

Abstract
Bromobutyl rubber is a good candidate for heat resistant applications, particularly when cured with zinc oxide in conjunction with sulphur donors or with dithiocarbamates plus active magnesium oxide. Several antioxidants provide added protection. When suitably compounded, bromobutyl compares well with resin-cured regular butyl in heat resistance and is much faster curing.
NBR Vulcanizates Resistant to High Temperature and “Sour” Gasoline
Authors: Dunn J. R. , Pfisterer H. A. , Ridland J. J. 
Published: February 2011

Abstract
NBR compounded in a conventional fuel hose tube formulation is markedly degraded by “sour” gasoline or “sour” ASTM Fuel C within 7 days at 40°C. Furthermore, the conventional NBR compound is not resistant to aging at 125°C. Use of an NBR designed for heat resistant compounding and an appropriate choice of compound greatly improve resistance to fuel which contains hydroperoxides. The preferred system for “sour” gasoline resistance and resistance to long term aging at 125°C is a cadmium oxide activated low sulfur-sulfur donor compound with silica as the principal filler. This vulcanizate is not much more affected after 7 days at 40°C by gasoline of peroxide number 50 than by clean gasoline, and is less affected by gasoline of peroxide number 200 than are other NBR vulcanizates. The balance of high and low temperature properties can be optimized by appropriate choice of plasticizer and acrylonitrile level. Aging resistance is somewhat improved by increase in acrylonitrile content, and fuel permeability is markedly decreased. Permeability to gasoline with 30 aromatic content can be changed appreciably by compounding, but the resistance to Fuel C with 50% aromatic content does not appear to respond to compounding changes. The stability of NBR vulcanizates in “sour” gasoline is reduced by copper salts and, to a lesser extent, by metallic copper. Bound antioxidant NBR does not appear to offer an advantage in “sour” gasoline resistance over heat resistant NBR compounded in a comparable formulation.
Ethylene Propylene Rubber Telephone Drop Wire
Authors: Gabriel A. P. 
Published: February 2011

Abstract
Initially the development of a third distinct variety of telephone drop wire was undertaken to combine the complexities of the reinforced neoprene array with the simplicities of a PVC drop wire construction. In addition, at no time could the excellent properties be sacrificed for manufacturing convenience. In the final analysis, however, the resultant EPDM insulated drop wire, yielded characteristics which placed it above the other constructions in the market. Since its introduction, about 100 million feet have been installed under a myriad of installation and service conditions within the United States.
Fundamental Aspects of Rubber Adhesion to Brass-Plated Steel Tire Cords
Authors: Ooij W. J. Van 
Published: February 2011

Abstract
During the past several years the fundamental knowledge of the processes which lead to rubber-brass bond formation and to bond degradation has increased considerably. As a result of the application of new instrumental techniques to the study of the rubber-brass interface it has been established that the brass surface is chemically attacked under formation of CuxS, ZnS, and ZnO. These products become an integral part of the rubber-to-metal bond. It has unequivocally been demonstrated that excessive or insufficient formation both lead to a low rubber-brass bond strength. The theories put forward by Buchan in the early forties (culminating in the only monograph on the subject thus far) have thus been proven to be largely correct. The rubber-brass bond can be interpreted as an adhesion of sulfur crosslinks to a sulfidized brass surface. These crosslinks are not necessarily bonded to the surface by fully developed “chemical” bonds, but should rather be interpreted as covalent bonds, comparable to those formed by copper oxide or copper sulfide and various organic complexing molecules containing electron-donating nitrogen or sulfur atoms. In spite of the relatively weak bonds between sulfur crosslinks and sulfidized brass surfaces, the adhesion between rubber and brass exceeds the rubber tear strength, since there is a very intimate contact between rubber and sulfide film which actually grows into the polymer. As a result, the contact area of the two phases is significantly enlarged. There is evidence that only certain types of crosslinks, probably the poly-sulfides, give rise to a high bond strength, possibly because of steric reasons. Best results have been obtained if the brass surface consist completely of cuprous sulfide, although there is evidence that a zinc sulfide surface can also be bonded well, provided the growth of the zinc sulfide layer is high enough to provide a sufficient number of points of attachment to the polysulfide crosslinks.
Chemistry and Structure of Natural Rubbers
Authors: Hager T. , MacArthur A. , McIntyre D. , Seeger R. 
Published: February 2011

Abstract
Natural rubbers are synthesized in thousands of species covering most plant families; moreover, rubber has been obtained commercially from over a dozen of them. A later report has suggested that polyisoprene formation is limited to dicotyledonous angiosperms. In recent years there has been renewed interest in developing alternative sources of natural rubber, different from Hevea brasiliensis. In particular there has been considerable development of guayule as a source of natural rubber. As a result there is a considerable body of recent results, using new techniques and extending older work concluded in the 1950's, which give new insight into the production of rubber in plants. This paper will mainly deal with guayule because it can ideally serve as a background for understanding the production of rubbers in other plants, including hevea. First, it is necessary to describe the physical nature of the rubber from guayule and where in the plant it is formed. Figure 1 shows a cross-section of a stem of guayule. The individual cells (parenchyma cells) are the site of rubber manufacture. The rubber can finally be seen as the small latex droplets inside a single cell (Figure 2). Thus the study of the natural rubber in guayule involves the isolation of the latex particles from the cell. It is extremely easy to separate an industrial rubber from other parts of the plant, including resin, by either laboratory or pilot plant methods. However, it is more difficult to get fresh latex in which no additional particle coagulation has occurred. The description of the average latex particle size and the distribution of sizes has been made and is needed to discuss the biosynthesis of rubber. It will not be discussed further. The question addressed in this paper is the chemical structure of the rubber in the plants—the micro-structure of the rubber, the molecular weight distribution, and the branching or gel content. Guayule natural rubber has the remarkable feature of containing no gel when taken directly from a fresh plant and carefully handled in the laboratory. Even the material from the pilot plant extraction process contains only 1–3 per cent gel. This paper describes extensively the chemical structure of natural rubber extracted from fresh guayule plants. Less extensive measurements on chicle, gutta-percha, and castilla elastica are also reported. Finally, all of the data are analyzed to determine if a model of rubber production can be formulated to encompass all of the above plants. Earlier, a model was proposed for guayule only. In this model the polyisoprene chain is polymerized on the polymerase enzyme site by recurring attachment and intermittent polymerization until the rubber droplet (containing a single polymer chain) can no longer be stabilized or further polymerized by the enzyme.
Short Fiber Reinforced Hose—A New Concept in Production and Performance
Authors: Goettler L. A. , Leib R. I. , Lambright A. J. 
Published: February 2011

Abstract
A simple extrusion process has been developed to orient short fibers contained in a rubber stock into a transverse position on the extrudate. The hardware is no more complex or difficult to use in production than conventional hose dies, which always produce a fiber orientation parallel to the flow. This axial orientation is not useful for many products, particularly hose, whereas the system described in this paper provides the proper circumferential orientation to meet the higher hoop stress. The fiber orientation occurs in response to changes in the shape of the channel in the die. In comparison to conventional cord-reinforced hose, the short fiber system offers many advantages. Processing is simplified by the elimination of the braiding or knitting step and the cover extrusion. The short fiber process is well adapted to continuous cure. Manufacturing costs are estimated to be 12% lower than those for the same process route using a conventional hose construction. Moreover, the short fiber hose can meet performance specifications in most low-to-intermediate pressure applications. It is a unique and functional product.
Flammability Properties of Carpets with Polychloroprene Latex Foam Underlayments
Authors: Anolick C. , Cook G. S. , Stewart C. W. 
Published: February 2011

Abstract
The flammability properties of a carpet underlayment system are dependent on all the components of the system. Most important is the choice of carpet fiber and construction. Large differences in results were seen between the various carpets tested. Once the carpet construction is chosen—and this is most often done for reasons of aesthetics, comfort and wear—the fiammability properties are influenced by the the foam pad or underlayment and by the carpet anchor coat. In all cases tested the use of a foam pad decreases the critical radiant flux of the carpet system as measured by the Flooring Radiant Panel Test. The decrease in critical flux is much less severe for foam pads based on polychloroprene latices than for those based on SBR. This is even true where hydrated alumina filler is incorporated in the SBR foam formulation. From this it is concluded that a carpet with a polychloroprene pad is likely to contribute less to the spread of fire than the same carpet with an SBR pad. Other workers have found polyurethane pads to be equivalent to SBR pads. For the optimum flammability properties, foam density and thickness should be held as low as possible. All results are equivalent whether the pad is attached or separate from the carpet. Where a foam pad is to be installed it is important that hydrated alumina filler be incorporated in the latex anchor coat used to lock the pile in place. It is concluded that where a designer requires a certain level of flammability as measured by the Flooring Radiant Panel Test, the broadest range of carpets can be used if hydrated alumina is included in the anchor coat and if the foam pad is based on polychloroprene latex. Foam pads based on this latex also give excellent results in other flammability and smoke tests as well as excellent physical properties.
Studies of Rubber Abrasion
Authors: Southern E. , Thomas A. G. 
Published: February 2011

Abstract
The general model proposed, which assumes that crack growth plays an important part in the abrasion process when abrasion patterns are produced, is supported by evidence from the behavior of noncrystallizing rubbers. In particular, the rate of movement of the pattern across the surface is closely related to the crack growth behavior. Natural rubber behaves under abrasion conditions as if it were prevented from exhibiting its usual crystallization-enhanced strength. An important factor determining the abrasion rate, in addition to the crack growth behavior, is the angle at which the hypothetical cracks at the pattern base grow. What determines this angle is not yet clear, but it appears to be closely related to the geometry of the pattern, and it seems likely, from a study of this geometry, that much of the loss of rubber occurs from the steeply raked face of the pattern. The pattern spacing, as well as depending on the abrading force, also appears to be influenced by the test temperature and the glass transition temperature of the rubber, suggesting that viscoelastic considerations are important.
EDGE Effect Correction for the Mooney Rheometer
Authors: Nakajima N. , Hareell E. R. 
Published: February 2011

Abstract
The Mooney rheometer has been used universally as a tester for quality control of raw elastomers and compounds. White and Tokita showed that the tester modified to operate at a range of speeds could be used to obtain fundamental viscoelastic properties: steady-state shear stress-shear rate relationship, normal stress effect, and elastic recoil. We have also made effective use of this rheometer to obtain steady-state viscosity as a function of shear rate and complex viscosity as a function of deformation rate. In these investigations, the observed torque was converted to shear stress with a theoretical factor derived by taking into account both the parallel plate section and the concentric cylinder section. It was assumed that the edge effect was negligible. The viscosities calculated in this manner were compared to those obtained with other instruments and reasonably good agreement was obtained. Some time ago, Mooney and Treloar expressed the opinion that the viscosity obtained from the Mooney rheometer is somewhat larger than the correct value, attributing the disagreement to neglect of the edge effect. More recently, White and Tokita have restated the problem. In our recent work, the torque measurements were made with both the small and the large rotor. The viscosities calculated without considering the edge effect tended to be somewhat higher for the small rotor than for the large rotor. This observation implies that an edge effect exists, because measurements obtained with the small rotor, which has larger “edge volume”, would tend to be more significantly affected. In this paper a mathematical expression is sought for the edge correction, so that the correction factor may be calculated from the known properties of the material.
Wax Protection
Authors: Dimauro P. J. , Paris H. L. , Fath M. A. 
Published: February 2011

Abstract
Wax migrates from the bulk of a rubber article to its surface to form a physical barrier to ozone attack. The extent of migration depends upon the solubility/mobility characteristics of the specific wax under a given set of environmental conditions. Factors which influence migration include time and temperature of storage after cure, wax concentration, wax composition, and amount and type of filler and extender oil present. This makes it difficult to select a wax which performs effectively over a broad temperature range. Paraffinic waxes generally protect better at low exposure temperatures, while microcrystalline waxes are more effective at elevated temperatures. Wax blends offer a wider temperature range of protection. An optimum migration temperature exists for each wax, and DTA can predict this optimum. Best ozone resistance is also attained at the temperature corresponding to optimum wax migration. Under dynamic ozone conditions, waxes alone can be harmful. Addition of a chemical antidegradant is required to obtain protection under these conditions.
Structure-Property Relationships in One-Step Urea-Urethan Elastomers
Authors: Rausch K. W. , Martel R. F. , Sayigh A. A. R. 
Published: February 2011

Abstract
A series of one-step urea-urethan cast elastomers has been prepared employing various diisocyanates with 3,3′-dichloro-4,4′-diaminodiphenylmethane and 3,3′-dichlorobenzidine. The effects of diisocyanate structure are not as pronounced as those previously reported for prepolymer systems. Significant variation in stress-strain properties may be obtained, however, depending on the molecular weight and the backbone structure of the polyglycol. A complex catalyst situation, arising from differences in reactivity of the diisocyanates, may also affect these properties considerably as a result of improper balance of reactions during chain buildup. The use of a newly available diisocyanate, “mixed isomer” MDI, which affords high strength elastomers while eliminating safety hazards and cumbersome handling techniques, is also described.
Effect of Intracarcass Pressure Buildup on Tubeless Tire Performance
Authors: Banks S. A. , Brzenk F. , Rae J. A. , Hwa C. S. 
Published: February 2011

Abstract
Intracarcass pressure buildup is generally considered to contribute significantly to separation failures in tubeless tires. This study demonstrates the effect of internal pressure in the cord area on the durability of two-ply rayon tubeless tires. A practical mathematical model has been developed to describe the mechanism of intracarcass pressure build-up and to indicate the effect of liner properties (i.e., permeability and thickness) on this pressure. Liner permeability, thickness and heat resistance have all been shown to be dominant factors in the minimization of pressure buildup in the carcass plies of tubeless tires. In addition, the buildup of air pressure in tire cords has been shown by wheel durability tests to exert a significant influence on the service life and nature of failure of these tires.
Determination of the Surface Tension of Latex
Authors: Aupetit André 
Published: February 2011

Abstract
After describing the Dognon-Abribat tensiometer exclusively used for measurements, the authors compare the two methods—plate and ring—used as a rule to determine the surface tension of latex. The plate method is simple and accurate, gives consistent results and allows both dynamic and static measurements. Differences between the two procedures are slight.
Infrared Studies of the Rubber-Filler System. I. Infrared Absorption Spectra of Inorganic Fillers
Authors: Suito E. , Arakawa M. 
Published: February 2011

Abstract
Infrared spectra of 33 kinds of commercial reinforcing fillers were measured by use of the KBr pellet method in connection with studies of the filler effect in rubber-filler systems. Characteristic absorptions of individual fillers are discussed in relation to their method of preparation.