bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modification of a Thermogravimetric Balance for Pyrolysis in a Controlled Atmosphere
Authors: Smith Derek A. 
Published: February 2011

Abstract
The quartz spring balance of Madorsky has been criticized by Jellinek. He points out the danger, in any suspended system, of condensation of volatiles on the (cooler) support and spring early in the pyrolysis, resulting in too low a measured weight loss. Later in the pyrolysis, the condensate may volatilize, giving too high a weight loss at long times of heating. To show the absence of such condensation effects, it is clearly not sufficient to weigh the support and spring before and after the pyrolysis, as has been proposed in the literature. A similar difficulty has arisen in the modification of the newer recording thermogravimetric balances for pyrolysis in a controlled atmosphere. For example, the otherwise satisfactory technique of Vassallo employs a downward flow of inert gas which may encourage condensation on the lower part of the weight transfer rod—the rod which transmits the load of the sample in its holder to the balance mechanism. A similar criticism can probably be made of the more elaborate system described by Stonhill. In an attempt to overcome this disadvantage, Soulen and Mockrin have modified the Chevenard balance by passing the weight transfer rod through a sleeve, with most of the outflow gas passing down the outside of the sleeve where condensation may occur without influencing the recorded sample weight. They claim that, in the absence of the sleeve, the thermogravimetric curves may be seriously in error.
Role of Antiozonants in Modern Tire Compounding
Authors: Thornley E. R. 
Published: February 2011

Abstract
The need to provide tire compounds with improved resistance to ozone has been very largely met by the use of N,N′ disubstituted-p-phenylenediamines as protective agents. These chemicals are for this reason commonly thought of as antiozonants but they also possess important antioxidant properties and in considering their role in modern compounding, it is necessary to distinguish between their antiozonant and antioxidant functions. The choice of protective system used in any particular tire component depends a good deal on the nature of the polymer. The relative behavior of natural rubber and SBR with respect to ozone cracking and flexcracking is demonstrated by data given in the paper and it is shown how a typical “antiozonant” such as isopropyl phenyl-p-phenylenediamine (IPPD) will protect SBR tread and sidewall compounds principally from static and dynamic ozone cracking and natural rubber compounds not only from ozone attack but also from various oxidative processes such as flexcracking, cut-growth and heat degradation. The effects of the partial replacement of natural rubber and SBR by polybutadiene on the antiozonant and antioxidant requirements of such tire compounds are also briefly considered.
Accelerated Ozone Test for Predicting Outdoor Effectiveness of Ozone Protective Waxes in SBR
Authors: Mueller W. J. , Palinchak S. , Stickney P. B. 
Published: February 2011

Abstract
Accelerated laboratory and outdoor aging studies were made to establish base lines leading to the development of an accelerated test method which could be used to predict the efficiency of ozone-protective waxes under static conditions. The effect of several variables on the rate of ozone cracking in an ozone chamber was determined, and it was found that exposure temperature was the most critical variable. The type of recipe and time between curing and stretching the samples were also found to be important in arriving at a suitable test procedure. The ozone concentration, although important, was found to be less critical than some of the other variables. An accelerated test method is proposed for determining the effectiveness of ozone-protective waxes. Two outdoor aging studies were made to determine the reliability of the accelerated test in predicting the protective effectiveness of waxes. For a limited number of waxes, it was found that a good correlation exists between the results of the two methods, provided that correct temperatures are used. The best correlation was obtained between dumbbell and bent loop specimens exposed outdoors and the accelerated test if the accelerated test was run at 60° and 120° F. The optimum conditions for correlating between the accelerated test and cable exposed outdoors involved carrying out the accelerated test at 60° and 105° or 110° F.
Diffusion in Elastomers
Authors: van Amerongen G. J. 
Published: February 2011

Abstract
In this paper the various aspects of diffusion of matter in rubber are reviewed. Besides diffusion itself, attention has been given to the closely related subjects of solubility in and permeation through rubber of foreign matter. First, a survey is given of the fundamental background, including the most important mathematical equations required for an experimental approach to diffusion, the interpretation of measurements, and the application of available data to specific problems. The subjects discussed include furthermore: self-diffusion; diffusion, solubility, and permeation of gases, organic liquids, water, and solids such as sulfur and other compounding ingredients in and through rubber; temperature dependence of diffusion; effect of modification of the rubber by vulcanization, aging, crystallization, and addition of fillers; various technical problems such as diffusion in composite rubber or in porous rubber and separation by diffusion. It is shown that many facts concerning diffusion in rubber can be satisfactorily explained and even predicted from the molecular properties of rubber and the diffusing substance. Knowledge of diffusion moreover offers an opportunity of gaining an insight into the intermolecular forces of rubber and this may help to understand polymer behavior when other properties are concerned.
Fatigue of Rubber
Authors: Beatty J. R. 
Published: February 2011

Abstract
The long-range elastic properties of rubber suit it ideally to dynamic service applications. Vibration isolation, suspension, and force transmittal are examples of such uses of rubber compounds. Common examples illustrating these uses are isolation devices of all types, e.g., motor mounts, torsion, shear and compression springs, and tires—just to name a few. While fatigue failures may occur under static loads, they are generally accelerated by cyclic stresses. In most applications of rubber, a failure is critical in that the device depends for its functioning on the properties of the rubber and ceases to function when fatigue or other types of failure occur. Examples of fatigue failures are groove cracking in tires, tread and ply separations in tires, failures in torsion springs and motor mounts, etc. This review is concerned with fatigue of rubber under conditions of dynamic stress. Two specific areas are treated, the case where frequency of stressing is low enough and the samples are small enough that heat generation is not an important factor in failure and, to a lesser extent, the case where heat generation due to large samples and high frequency load application builds up temperatures which contribute to failure. Both of these cases of fatigue failure are encountered widely in service. For example, the first is found in vibration isolation devices such as motor mounts, and the latter in the shoulder area of heavy duty tires.
Analytical Method for Measuring SBR Tire Debris in the Environment
Authors: Brachaczek Wanda , Pierson W. R. 
Published: February 2011

Abstract
A procedure has been developed for assaying submilligram amounts of debris from synthetic tire tread rubber in aerosol samples collected from the atmosphere. The procedure involves separation from the bulk of the sample by Soxhlet extraction with orthodichlorobenzene in a stream of oxygen, followed by infrared spectroscopic determination of the rubber hydrocarbon SBR (styrene-butadiene copolymer) in the extract. The procedure was developed to overcome serious difficulties having to do with the small amounts of rubber normally encountered and with losses of SBR during extraction from aerosol samples. These matters are discussed in some detail and some applications of the method are illustrated.
A Dynamic Rubber-Cord Composite Adhesion and Fatigue Test
Authors: Langevin P. P. , Payne R. J. , Shephard C. S. 
Published: February 2011

Abstract
Dynamic adhesion and fatigue tests can be conducted on the Firestone Flexometer, where the hysteresis effect of the rubber compound can be brought to bear on the rubber-cord interface. Only minor modifications of equipment need to be made to run this test under a range of different conditions. Although the test is designed for single-station testing, several samples can be run at once, and test conditions can be adjusted to prevent cycle-life from becoming excessive. Rubber-steel cord composites have been studied under dynamic conditions, and indications are that other cord types and dips can also be evaluated with this method. Thus, the study of adhesion can be approached from a different point of view than that which is provided by current static and dynamic tests.
A New Tester for Dynamic Rubber-to-Metal Adhesion
Authors: Beatty J. R. , Dalglish Edward C. 
Published: February 2011

Abstract
A simple test for dynamic fatigue of a rubber to metal bond has been developed which will evaluate cements with reasonable speed and accuracy. It appears more discerning than static results. This is important since most rubber-metal bonds are used under dynamic service conditions. For example, for two cement systems the static conical pull values were 379 lbs vs 325 lbs while the dynamic fatigue lives were 1.5 × 106 vs 0.27 × 106 cycles, respectively. The values of 379 vs 325 lbs are essentially within experimental error while the dynamic test results leave no question as to which is the superior cement.
Fracture Mechanics of Adhesive Bonds
Authors: Gent A. N. 
Published: February 2011

Abstract
A survey is given of the mechanics of rupture of a simple adhesive joint, comprising two relatively rigid adhering members joined by a layer of a deformable adhesive. Several different modes of failure are treated in terms of a critical energy requirement for growth by unit area of a pre-existing interfacial flaw or debond. They are: (i) Tensile rupture of joints with thick or thin adhesive layers, (ii) Shear rupture, (iii) Separation by stripping apart stiff or flexible adherends, i.e. cleavage. In addition, the stresses set up in joints by shrinkage of the adhesive, for example due to differential thermal contraction, are evaluated. Attention is drawn to probable sites and conditions for failure.
Co-Curing of EPDM and Diene Rubbers by Grafting Accelerators Onto EPDM
Authors: Baranwal K. C. , Son P. N. 
Published: February 2011

Abstract
The object of this work was to find ways to co-cure blends of EPDM and diene rubbers for improved properties. We found that by grafting accelerators onto EPDM we obtain excellent cure compatibility between EPDM and natural rubber. The modified EPDM rubbers were obtained by reacting a benzene solution of EPDM with either 4,4′-dithiobismorpholine or 2-mereaptobenzothiazole (MBT). A method which grafts MBT onto EPDM in the presence of tert-butyl hypochlorite or other halogen donors is more versatile, and can be used for various EPDM rubbers regardless of the nature of the termonomers. We have proposed possible mechanisms by which the modified EPDM rubbers co-cure with natural rubber or other diene rubbers. In these mechanisms we point out the importance of the presence or the in situ formation of reactive sites in modified EPDM rubbers.
Tensile Stress—Strain and Stress Relaxation Behavior of Raw Elastomers Using a High Speed Tester
Authors: Bowerman H. H. , Collins E. A. , Nakajima N. 
Published: February 2011

Abstract
A high-speed, tensile-testing device was used to determine the stress—strain behavior of uncompounded butadiene—acrylonitrile copolymers over a range of temperatures and deformation rates. The strain rates were varied from 267 to 26,700 per cent/sec and the temperature was varied from 25 to 97° C. The high-speed tester was also used for stress—relaxation measurements by applying the strain nearly instantly in conformity with theoretical requirements in order to obtain the short time behavior. The WLF equation was obtained from the stress—relaxation data and then used to reduce the ultimate properties to one temperature over four decades of the strain rates. The ultimate properties could be represented by a failure envelope similar to those obtained for vulcanizates.
Master Curve for Tensile Stress—Strain Behavior of Amorphous Elastomers at Small and Large Deformations
Authors: Nakajima N. , Collins E. A. , Bowerman H. H. 
Published: February 2011

Abstract
A master curve scheme for small and large deformations was developed for tensile stress-strain behavior of butadiene—acrylonitrile uncrosslinked elastomers. Measurements were carried out at strain rates of 267 to 26,700 per cent/sec at temperatures of 25 to 97° C.
Bending Hysteresis Losses in Cord—Rubber Composites
Authors: Skelton John 
Published: February 2011

Abstract
An experimental technique is described which permits the direct measurement of the bending hysteresis loss in cord—rubber composites under carefully controlled conditions of cyclic strain. The equipment can readily detect differences between composites made with different cords. The current version of the equipment is intended only for low-speed cycling, but the extension to high speed capability is contemplated. The robust nature of equipment should make it possible to carry out tests in a wide range of hostile environments.
The Elasticity and Related Properties of Rubbers
Authors: Treloar L. R. G. 
Published: February 2011

Abstract
In Section I the relation of rubbers to other classes of polymers and the molecular basis of rubber elasticity are briefly examined. In Section II the methods used in the quantitative development of the statistical-thermodynamic theory of a molecular network are outlined, and the main conclusions, in the form of stress—strain relations, etc., are presented and compared with experimental data. Section III examines the photoelastic properties of rubbers from both theoretical and experimental standpoints and discusses in detail the evidence derived from photoelastic studies on the statistical segment length in the molecular chain and its relation to intramolecular energy barriers. Section IV is concerned with the thermodynamic analysis of stress—temperature data for rubber and other polymers, with particular reference to the internal energy and entropy changes during extension under constant pressure or constant volume conditions. Methods of deriving these quantities are compared and the results related to the modified molecular network theory due to Flory. Section V deals with the phenomena of swelling in liquids and considers both the effect of swelling on the mechanical properties and the effect of different types of stress or strain on the swelling equilibrium. Sections I–V are concerned mainly with the statistical theory and its applications. The final section examines in considerable detail the formulation of more general theories of large elastic deformations on a purely empirical or phenomenological basis, so as to overcome some of the limitations of the statistical theory. The logical basis of these formulations is presented and the conclusions are discussed in relation to the available experimental evidence. Some common pitfalls to be avoided are emphasized.
Heat Generation and Rubber—Filler Coupling Bonds
Authors: Wagner M. P. 
Published: February 2011

Abstract
It is well known that heat generation is dependent upon the type of polymer, filler, and other components of the compound. In addition, the state of cure has a large effect on heat buildup. With any given vulcanizate system, network constraints can reduce heat generation to a minimum. These network constraints include crosslinks, as well as coupling bonds between filler particles and the polymer chains. Using peroxide crosslinking of natural rubber and organofunctional silanes with a silica filler, network crosslinks, and filler coupling bonds can be independently varied. From equilibrium swelling, it was possible to determine the quantity of each type of constraint. Network crosslinks and coupling bonds respond to equilibrium swelling in approximately the same way, although the peroxide and silane functionality interact chemically to influence the number of each type of constraint. The rate of heat buildup and the maximum temperature generated were obtained from the Goodrich Flexometer (ASTM—D623). Increasing either network bonds or coupling bonds reduced the rate of heat generation and the heat buildup monotonically to a minimum value dependent upon the elastomer system. Both types of network constraint affected these responses about equally. Comparison of silica and carbon black fillers in SBR demonstrated that the insertion of coupling bonds was an efficient method of reducing heat buildup. Other rubber properties (particularly modulus and abrasion resistance) optimized more readily since their response to the coupling bonds and network crosslinks were quite different.
The Effects of Carbon Black on Rubber Hysteresis
Authors: Ulmer J. D. , Hess W. M. , Chirico V. E. 
Published: February 2011

Abstract
The viscous modulus of oil-extended SBR loaded with carbon black relative to the gum stock increases with volume fraction of carbon black. This increase is much larger than predicted by the Guth-Gold equation and also greater than the increase in the elastic modulus. This behavior reflects the sum of at least three effects: geometrical (strain amplification), changes in the viscoelastic properties of the rubber, and formation of a three-dimensional network of carbon black and rubber. The geometrical effect increases with volume fraction of carbon black. Its per cent contribution to the viscous modulus decreases as the carbon black loading increases because of increased contribution of the viscoelastic effect at low loadings and of the network effect at high loading. The geometrical effect can be described reasonably well by the Guth equation with a shape factor and with the volume fraction increased by the additional immobilized rubber (bonded elastomer). The viscoelastic effect due to 60 phr black contributes at least 20 per cent to the viscous modulus and is related to structure, surface area, and volume fraction of the carbon black. It can be at least partially accounted for by rubber breakdown during mixing. At high volume fractions of carbon black (60 phr), network formation contributes about 25 to 45 per cent to the viscous modulus. It increases with decreasing interunit spacing which depends on the average volume of the carbon-black units and the amount of bonded elastomer. For a thermal black, N—990, the interpretation of the results is complicated by the distinct possibility that slippage contributes to hysteresis. We conclude, however, that at low loadings the increase of the viscous modulus is much greater than that of the elastic modulus and that network effects contribute to the viscous modulus at high loadings.
Dynamic Viscoelastic Properties of Raw Butadiene—Acrylonitrile Elastomers
Authors: Nakajima N. , Collins E. A. , Kumler P. R. 
Published: February 2011

Abstract
The dynamic viscoelastic properties of four samples of butadiene—acrylonitrile raw elastomers, were obtained with a Rheovibron at 110 Hz and temperature range of −80 to 160°C. The complex properties were in agreement with the master curves obtained previously from stress-strain measurements. A master curve encompassing 13 decades of time was constructed using data from Mooney rheometer shear stress-strain, MTS high speed tensile stress-strain, and the Rheovibron. The master curve represents the rubbery region of viscoelastic behavior in terms of time, temperature, and the magnitude of deformation up to the breaking point. This study demonstrates that corresponding states can be found between small (ca. 1 per cent) and large deformation up to break (e.g., 1400 per cent).
Effects of Compounding on Dynamic Mechanical Properties of Rubber
Authors: Studebaker M. L. , Beatty J. R. 
Published: February 2011

Abstract
Stiffness—hysteresis charts show differences in dynamic mechanical properties resulting from compounding changes, such as elastomer, crosslink density (and, under certain test conditions, crosslink type), filler type(s) and loading (s), and softeners and their level. Processing, including vulcanization, aging, and any network changes during testing or service can be depicted by these charts.
Petroleum Pitch as a Plasticizer for SBR and SBR Blends
Authors: Deviney M. L. , Weaver E. J. , Wade W. H. , Gardner J. E. 
Published: February 2011

Abstract
Two petroleum pitch products have been shown to impart greater stiffness and hardness, and lower rebound properties to SBR and SBR/BR vulcanizate systems, through unusual molecular interaction effects. These solid pitch materials can be used alone as plasticizers or in combination with conventional aromatic extender oils. Vulcanizates containing these materials at 10–25 per cent concentrations maintain enhanced stiffness and hardness at temperatures to 150° C. Plasticizer evaporative loss and migration from higher to lower concentration areas is much less in pitch-containing vulcanizates than in stocks containing usual aromatic extender oils. Vulcanizate physical properties are presented. An immersional microcalorimetry study was conducted to investigate the energetics of interaction of carbon black with pitch in comparison with other major components of the elastomeric matrix. The thermodynamic measurements, which indicate specific pitch—carbon black interactions, provide much insight into the mechanisms responsible for the unusual properties which pitch imparts to rubber systems.
Thermal Diffusivity Measurements on Elastomers
Authors: Frensdorff H. K. 
Published: February 2011

Abstract
Thermal diffusivity, rather than thermal conductivity, is the property which governs rates of heating up and cooling down of a rubber article in the mold. It is preferable to measure it directly, rather than to derive it from separate measurements of thermal conductivity and volumetric heat capacity. A straightforward measurement method is described together with procedures for deriving the required results from the raw data. The sources of error are discussed, and ways for minimizing them are suggested. Thermal diffusivities for gum and black EPDM and fluoroelastomer are reported for temperatures from 0° to 100° C.
New Studies of Carbon—Rubber Gel
Authors: Ban L. L. , Hess W. M. , Papazian L. A. 
Published: February 2011

Abstract
High resolution electron micrographs of undistorted carbon—rubber gel were obtained by ultramicrotomy of frozen unvulcanized SBR compounds which were subsequently extracted with benzene to remove any soluble rubber. The remaining black and rubber form a 3-dimensional, meshlike network which is larger than the size of primary units of the black itself. The networks for different blacks indicate considerable compaction which increases in the direction of lower structure and surface activity (e.g., normal vs. graphitized carbon black). Removal of the soluble rubber from the carbon—rubber gel network produces visible gaps between the black units which diminish in size as the black loading increases. Soluble rubber is also removed from many regions of the black surface indicating that there is no uniform layer of surface-bonded rubber. The swollen carbon—rubber gel networks are readily dispersible in good solvents using ultrasonic energy. In the process, a high percentage of the rubber is solubilized and removed from the black surface. GPC analyses of this soluble rubber from the gel indicate higher molecular weight in comparison to the soluble portion removed by benzene extraction.