bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abrasion of Rubber and Its Relation to Tire Wear
Authors: Grosch K. A. 
Published: February 2011

Abstract
Sliding abrasion experiments reveal that the abrasion loss has to be expressed as a power function of the dissipated energy. Both the abrasion loss per unit energy dissipation and the power index depend on the compound and on the type of surface on which the experiment is being carried out. Hence the relative rating of a compound depends on pressure and on surface roughness. This nonlinear dependence on energy dissipation leads also to a rating dependence of slip of the wear of slipping wheels or the wear of tires. If the abrasion energy function for different compounds can be determined, then the wear ranking for different tires should be predictable using the slipping wheel theory. Experiments with tires running under controlled slip conditions show that this is not the case. Predictions differ even in ranking of compounds. Dissipation processes generate heat, so that temperature conditions in the contact area and their influence on the abrasion loss have to be considered in addition to mechanical rupture and fatigue. Laboratory experiments using slipping model wheels are being discussed which use testing conditions designed to generate different temperatures in the contact area. Compound rankings and ranking reversals are obtained which are in agreement with tire wear experiments under controlled slip conditions.
Quantitative Estimation of Filler Distribution in Immiscible Rubber Blends by Mechanical Damping Studies
Authors: Maiti Sudarsan , De S. K. , Bhowmick Anil K. 
Published: February 2011

Abstract
The peak value of tan δ at the glass-transition temperature (Tg) in the plot of tan δ versus temperature is lowered on addition of filler to a rubber. This relative lowering of tan δ at Tg can be used to estimate the filler distribution in an immiscible rubber blend. In the present investigation, distribution of silica filler and carbon black was studied in blends of natural rubber (NR) and epoxidized natural rubber (ENR). It was observed that silica migrated preferentially to the ENR phase. The magnitude of the distribution depends on filler loading and the epoxy content of ENR. The amount of carbon black migrated to the NR phase is higher than that of silica at a similar loading in blends of NR and ENR.
Filler—Elastomer Interactions. Part IV. The Effect of the Surface Energies of Fillers on Elastomer Reinforcement
Authors: Wolff Siegfried , Wang Meng-Jiao 
Published: February 2011

Abstract
Carbon black N110 and a precipitated silica, which have comparable surface area and structure, were selected as model fillers to study the effect of filler surface energies on rubber reinforcement. In comparison with carbon black, the surface energies of silica are characterized by a lower dispersive component, γsd, and higher specific component, γssp. It was found that the high γssp of silica leads to strong interaggregate interaction, resulting in higher viscosity of the compounds, higher αƒ, and higher moduli of the vulcanizates at small strain. The higher γsd of carbon black, in contrast, causes strong filler—polymer interaction, which is reflected in a higher bound-rubber content of the compounds and higher moduli of the vulcanizates at high elongation.
Sulfur Vulcanization of Simple Model Olefins, Part I: Characterization of Vulcanization Products of 2,3-Dimethyl-2-Butene
Authors: Versloot P. , Haasnoot J. G. , Reedijk J. , van Duin M. , Duynstee E. F. J. , Put J. 
Published: February 2011

Abstract
To study the mechanism of the sulfur vulcanization of rubber, 2,3-dimethyl-2-butene (C6H12) was used as a simple, low-molecular-weight model alkene. Only equivalent allylic positions are present in this alkene. Treating C6H12 with a mixture of ZnO, S8, and the accelerator tetramethylthiuramdisulfide at 140°C yields a mixture of addition products (C6H11—Sn—C6H11). RP-HPLC in combination with MS and 1H-NMR shows that the products differ only in the length of the sulfur bridge. Small quantities of isomerized products have been found, in which a 1,3-shift of the double bond has occurred.
The Effect of Pressure on the Ultimate Properties of Elastomers
Authors: Pai P. C-H. , Meier D. J. 
Published: February 2011

Abstract
Many studies have been made on the effect of pressure on the mechanical properties of elastomers, but these studies have invariably been limited to small-strain behavior because of equipment limitations. This small-strain limitation has now been removed with the construction of a novel high-pressure chamber which allows large tensile deformations to be applied to samples at pressure up to 300 MPa and temperatures from 0°C to 200°C. The effect of pressure on the ultimate tensile properties of nitrile, butyl, EPDM, Viton®, silicone, and polyisoprene elastomers has been determined. The tensile strengths and moduli all increase with pressure, but not in a monotonic fashion. In several cases, the tensile strengths increase rapidly with increase in pressure up to about 60 MPa, but then they remain almost constant with further increases in pressure. The ultimate extensions show a more complex behavior. Although the ultimate extensions typically increase with pressure, several samples, e.g., nitrile, EPDM, butyl and Viton, show maxima in ultimate extensions vs. pressure. Other than butyl, these samples also show yielding behavior at large extensions. This is attributed to glass-transition effects for nitrile and Viton, and to pressure-induced crystallization effects for EPDM.
Vulcanization Chemistry. Sulfur, Nt-Butyl-2-Benzothiazole Sulfenamide Formulations Studied by High Performance Liquid Chromatography
Authors: Sullivan A. B. , Hann Cynthia J. , Kuhls George H. 
Published: February 2011

Abstract
The paper reports on the sulfur vulcanization chemistry of cis-polyisoprene formulations accelerated with N-t-butyl-2-benzothiazole sulfenamide. High Performance Liquid Chromatography (HPLC) is utilized to examine the kinetics of accelerator—sulfur disappearance and the formation—disappearance profiles of extra-network cure intermediates across the vulcanization process. Cure profile measurements are reported on three formulations covering a wide range of sulfur—accelerator ratios. Also unique aspects of the analytical methodology are highlighted. The observed cure-intermediate concentration profiles reinforce earlier theories about the chemical details of sulfurization and subsequent crosslinking. On all formulations, benzothiazole polysulfides (S1−S4) reach a maximum concentration at the scorch midpoint coincident with slope changes in reactant and product profiles. Although pendant-accelerator crosslink precursors are not measured directly, their presence is implied from material balance calculations. Also, the formation of a small amount of benzothiazole early in the scorch period is a new observation in sulfenamide acceleration. It suggests that accelerator hydrolysis is a competitive side reaction early in the vulcanization process.
The Elasticity of Rubber
Authors: Rivlin R. S. 
Published: February 2011

Abstract
The experiments of Rivlin and Saunders and Gent and Rivlin are consistent with W having the form (33) in which C is a constant and f is a function of I2−3 only, which decreases monotonically as I2−3 increases. With this interpretation of the experiments, the term f (I2−3) represents the departure from the predictions of the kinetic theory. This conclusion is reinforced by the finding of Gent and Rivlin that W1 exhibits no hysteresis, while all of the hysteresis (i.e., departure from ideal reversibility) exhibited by the rubber resides in W2 (i.e., in the term f (I2−3)). This suggests that the model for a vulcanizate adopted in the kinetic theory must be modified by the introduction in the undeformed rubber network of crosslinks which are broken when the rubber is deformed and are re-formed, nearly reversibly, when the rubber returns to its undeformed configuration. However, so far no satisfactory mathematical development of this idea has been carried out; the construction of a convincing theory which accounts for the departure of W from the neo-Hookean form remains an unresolved problem.
Development of Internal-Mixer Technology for the Rubber Industry
Authors: White James L. 
Published: February 2011

Abstract
The early rubber industry was largely based on mixing with two-roll mills. The coming of the pneumatic-tire industry associated with the rise in popularity of the automobile brought increasing production and large quantities of fine particles and poisonous vulcanization accelerators. This made necessary the introduction of internal mixers into the rubber industry by the second decade of the 20th century. This paper treats the development of internal mixer technology from its origins in the 19th century to the late 1980's, largely through critically following the patent literature. There seems to be no other critical review of the development of internal mixer technology, and this manuscript is unique. Briefly, the technology development we will describe is as follows: There were two conflicting design approaches, one based upon a single-rotor masticator devised by Thomas Hancock in the early 19th century and a second based upon two nonintermeshing counterrotating rotors which were championed by Paul Pfleiderer later in that century and manufactured by his firm, Werner and Pfleiderer. As late as the mid 1920's, machines based on both the single rotor and two nonintermeshing rotor designs competed with each other for the internal-mixer market. The insight, perseverance, intensity, and dedication of Fernley H. Banbury and the Birmingham Iron Foundry (later merged into Farrel-Birmingham) brought about the design which proved to be the paradigm of the industry. Innovation, however, continued in internal-mixer technology. The most striking new development of the post-Banbury period was the invention and application of intermeshing counter-rotating rotor mixers in 1934 by Rupert Cooke of Francis Shaw and Company. Werner and Pfleiderer developed and worked with many internal-mixer designs and in time began to manufacture both nonintermeshing- and intermeshing-rotor machines. In the 1950's and 1960's, Kobe Steel and Pomini began to manufacture internal mixers as Farrel-Birmingham licensees. This period also saw developments of nonintermeshing-rotor internal mixers. The basic Banbury design maintained its position and its manufacturer, Farrel-Birmingham (later Farrel), devised improvements of it. Innovations in the design were also made from the late 1970's by Kobe Steel, now operating independently. Pomini also began operating independently, manufacturing not only nonintermeshing machines but a unique intermeshing-rotor machine with variable clearance between the rotors. In recent years, we have seen the development of increasingly improved control systems for the internal mixer.
Structural Analysis of Conveyor Belts. Part I. Analytical Approach
Authors: Harandi J. N. , Kavousian A. , Parvini M. , Soufian M. 
Published: February 2011

Abstract
Closed form equations for calculating forces in plies and shear stresses in interplies of conveyor belts are derived. Eigenvalues for 2 to 6 ply belts are calculated. A three-ply conveyor belt is completely analyzed and it is found that at a rubber interply thickness equal to that of the fabric, the interply shear stress would be minimum.
Foaming of Vulcanized PP/EPDM Blends Using Chemical Blowing Agents
Authors: Dutta A. , Cakmak M. 
Published: February 2011

Abstract
Using two different chemical blowing agents, foaming behavior of partially vulcanized PP/EPDM blends with high EPDM ratio has been studied. The objective was to induce foaming within the EPDM phase prior to complete curing. The results suggest that with proper choice of blowing agent and by optimum balance of curative loading, foams with densities as low as 0.55 g/cm3 could be obtained. This corresponds to nearly 90 percent density reduction which is significantly greater than the 15 to 20% afforded by similar fully-vulcanized dynamically cured blends reported previously. The degree of cure in the rubber phase was determined to play a key role in determining the overall foamability. In particular, the foamability of the blend was found to decrease linearly with increase in the gel content. In addition, the compounding technique also plays a major role in controlling foamability of these blends. Attempts at extrusion foaming of these blends, however, were successful only for blends with a rather low degree of cure.
Different Curing Systems for Ethylene-Propylene Elastomers
Authors: Hernández Luis González , Díaz Andrés Rodríguez , de Benito González Juan Luis 
Published: February 2011

Abstract
The scope of this paper is to review peroxide curing of ethylene-propylene elastomers, where apart from crosslinking, other reactions occur, such as chain scission, which account for the drop in physical properties. The results are compared with an alternative crosslinking system which is being assessed in our laboratory. With the new curing agent the chain-scission reaction is not present and the physical properties of the vulcanizates are improved. The effects of the different crosslinking systems on the reaction transitions are studied with the aid of dynamic mechanical analysis.
The Role of Functional Polymers in Ground Rubber Tire-Polyethylene Composite
Authors: Rajalingam P. , Baker W. E. 
Published: February 2011

Abstract
The impact energies of different polyethylene-ground rubber tire (GRT) composites were investigated. All the thermoplastic composites were prepared on a Haake Buchler batch mixer and injection molded test specimens were tested on Rheometrics drop weight instrumented impact tester. Addition of small amounts of functional polymers increases the impact energy of the polyethylene-GRT composite as much as 60%. The percent improvement in the impact energy for linear low density polyethylene (LLDPE) and the composites prepared from them is greater than for the corresponding high density polyethylene (HDPE) composites. Precoating of GRT particles with ethylene-acrylic acid (EAA) copolymers improves the impact energy of the composite, whereas precoating with the other functional polymers does not. An attempt has been made to identify the role of the functional polymers as to whether they act as toughening agents for the polyethylene matrix or coupling agent at the polyethylene-GRT interface. The results show the increase in impact energy resulting from the addition of styrene block copolymers is due to toughening of the polyethylene matrix while the reactive ethylene copolymers increase the impact energy by a coupling action with GRT.
Influence of Composition and Processing History on the Cellular Morphology of the Foamed Olefinic Thermoplastic Elastomers
Authors: Dutta A. , Cakmak M. 
Published: February 2011

Abstract
Foam extrusion of a series of dynamically vulcanized polypropylene (PP)/ethylene-propylene-diene terpolymer (EPDM) blends (commercially available Santoprene) by using chemical blowing agents have been studied. Results suggest that foaming occurs only within the thermoplastic phase and for each composition there exists a limiting density which controls the maximum volume expansion. This limiting density is controlled only by the composition and is independent of the blowing agent concentration, extrusion conditions, and the geometry. For the softest and the hardest blends, maximum volume expansion was found to be about 20 and 100%, respectively. Considerable differences in cell structure were also observed with change in the blend composition. As the rubber content increases, bubbles change their shapes from spherical to highly elongated channels where long axes are primarily along the extrusion direction. When the shapes of the bubbles are viewed by cutting the specimen, the bubbles were found to become highly irregular as the rubber content was increased. The fractal dimension of the perimeter profiles revealed that increases in rubber content give increases in the characteristic fractal dimension. Additionally, wide angle x-ray pole figure analysis, which gives an average orientation behavior of the material, indicates that low levels of preferential crystalline chain orientation develop in the extradates. This preferential orientation was found to vary from skin to core.
Chain Ends and the Mullins Effect in Rubber
Authors: Santangelo P. G. , Roland C. M. 
Published: February 2011

Abstract
It has been suggested that “Mullins softening”, which is the anomalously low stress found in crosslinked rubbers that have been subjected to a reversing deformation history, might be caused by retraction of the chain ends along their primitive paths. Using natural rubber networks made from precursors of varying molecular weight, and an end-linked polytetrahydrofuran rubber, the fraction of chain ends was varied. From stress-strain relationships measured on these rubbers, it is concluded that Mullins softening is unrelated to the presence of chain ends, or to polydispersity in the lengths of network strands.
The Dispersion of Carbon Black in Rubber Part I. Rapid Method for Assessing Quality of Dispersion
Authors: Coran A. Y. , Donnet J-B. 
Published: February 2011

Abstract
Carbon black is the most important reinforcing filler for rubbers. The incorporation of carbon black into rubber vulcanizates generally gives improved strength, extensibility, fatigue resistance, abrasion resistance, etc. In order to exert its beneficial influence on the properties of rubber vulcanizates, the carbon black must be sufficiently dispersed therein. Indeed, poor dispersion can, in itself, give rise to detrimental effects (e.g. reduced product life, poor performance in service, poor product appearance, poor processing characteristics, poor product uniformity, raw-material waste, high finished-product rejection rates, and excessive energy usage). These inadequacies are generally the result of the presence of rather large, undispersed agglomerates. The present work was initiated in order to develop an improved understanding of the carbon-black dispersion process including the understanding of factors which affect the kinetics of dispersion. The work described here is focused on methodology for reproducibly mixing carbon black with rubber in the laboratory, and reproducibility, but rapidly and easily estimating the degree of dispersion of the carbon black into the rubber as a function of mixing time. Procedures were developed for introducing rubber, filler, and other ingredients into a small, laboratory internal mixer and for mixing the batches for various periods of time. Also, an improved, simple-to-use, reproducible method for determining the degree of carbon black dispersion in rubber has been adapted. The extent of dispersion was correlated with various measures of tensile strength and with other performance-related properties.
Studies of in-situ Compatibilized Blend of Silicone and EPDM Rubbers
Authors: Kole Swapan , Santra Rabin , Bhowmick Anil K. 
Published: February 2011

Abstract
The effect of three different compatibilizers — ethylene methylacrylate copolymer (EMA), ethylene vinyl acetate copolymer (EVA), and silane grafted polyethylene (VMX) — on the physical properties, ageing behavior, thermal stability, morphology, and dynamic mechanical properties of a 50/50 blend of silicone/EPDM has been studied. Improvement in physical properties is in line with the level of technological compatibilization. Strength of adhesion for silicone-EPDM joints is significantly enhanced by the compatibilizers due to the increase in surface energy of silicone and reaction of the rubbers with the compatibilizers. Morphology study shows smaller domain size for the compatibilized blend. Dynamic mechanical analysis also reflects strong interaction of the compatibilizer with the blend components. Ageing properties are improved with the addition of the compatibilizers. Thermogravimetric analysis indicates an increase in activation energy of degradation and hence marked improvement in the thermal stability of the blends containing compatibilizer.
Morphological Investigations on Carbon-Black Particles by Atomic Force Microscopy
Authors: Niedermeier W. , Stierstorfer J. , Kreitmeier S. , Metz O. , Göritz D. 
Published: February 2011

Abstract
The atomic force microscope (AFM) can profile surfaces similar to the scanning tunneling microscope (STM) at resolutions down to the atomic level. To investigate carbon-black particles and subsequently styrene-butadiene-rubber, filled with carbon black, a STM was modified to run as an AFM. An optical detection system is used to measure the deflection of the cantilever. Atomic resolution was achieved by forces in the order of 5·10−8 N on mica with the AFM. Structural investigations of carbon-black particles of different dimensions with the AFM agree with the data of the manufacturer. The model of the microstructure of such particles, built up of 1–3 nm large, tilted domains of graphite structures, could be confirmed. This surface roughness is probably an important parameter for the strengthening mechanism of carbon black in elastomers.
Mechanical Seal with Elastomeric Rotating Element. Part 1: Theory of Operation
Authors: Kholodenko Arnold , Rivkin Michael 
Published: February 2011

Abstract
This paper presents the results of fundamental research on flexible faced mechanical shaft seals. The effect of stretch and preload on the contact stress were investigated using a nonlinear finite element modeling package. The characteristics of the rubber materials including the stress-strain curves to elongation at break were required to complete the analysis. Pressure forces resulting from the static pressure in the pump stuffing box as well as the friction effects on all contacting surfaces were considered in the model. Stress distribution across the contact surface established the basis for the formation of multiple distinct lips: at least one on the outside or fluid side of the seal and the other on the inside or air side of the seal. This phenomenon is explained by the step change in magnitude of axial stress while traversing the contact in the radial direction allowing the formation of exterior lips and the development of an annular region trapping debris products and process fluid. Photomicrographic images of the wear track taken with a Scanning Probe Microscope show distinct wear tracks and the topology of each. Although the chemical composition of the debris in the annular spaces has not been determined quantitatively, increased levels of fluorine were present, suggesting fragments of the monomers in the elastomeric rotary or migration of Teflon fillers. Axial variations in the stretched rotary dimensions (waviness) affects seal performance. Statistics for a typical batch of rotary elements are presented and a method of factoring these variations into the seal design is presented. The formation of axial waves on the contact vertex affects the seal performance and is considered in the final design of the seal pair configuration. The results of this work were incorporated into a suite of mechanical face seals covering shaft sizes from 1.125 to 5.000 inches using seven pairs of seals, each pair consisting of a stretched rotary sliding against an unlapped silicon carbide annular ring. Each of these seal pairs were tested on an experimental test device to determine the heat generation and friction coefficients for a wide range of temperature, pressure, speed, and sealing fluid. Results of the experimental work are reported in a companion paper.