bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Fillers on Wet Skid Resistance of Tires. Part I: Water Lubrication Vs. Filler-Elastomer Interactions
Authors: Wang Meng-Jiao , Kutsovsky Yakov 
Published: February 2011

Abstract
From results of testing materials using a new filler, it was recognized that the wet skid resistance of tires is determined not only by dynamic properties of the tread compounds, but also by elastohydrodynamic lubrication, especially on the micro scale. By reviewing the basic concepts of friction under dry and wet conditions, and friction coefficients of possible model materials that are at the worn surface of tire tread compounds and road surface, it is inferred that after skid testing under wet conditions, the top skin of the worn surface contains some bare silica for silica-filled compounds, but the carbon black aggregates remain covered by rubber film. This inference is supported by measuring the surface energies of the fillers, analyzing the properties of filled vulcanizates, and direct investigation of worn surface of the compounds after skid test by AFM. The different surface compositions between silica- and carbon black-filled vulcanizates would lead to different effects on micro-elastohydrodynamic lubrication, hence wet skid resistance, which will be the topic of next report of this study.
Chemically Modified Emulsion SBR in Tire Treads
Authors: Thielen Georges 
Published: February 2011

Abstract
A series of Emulsion SBRs (E-SBR) with polar and nonpolar third co-monomers are studied in silica filled compounds. The applied third co-monomers include polar types such as acrylonitrile (ACN), hydroxypropyl methacrylate (HPMA) and 1-vinylpyridine (VP) and nonpolar types such as isoprene and 1,3-pentadiene. The impact of the third co-monomers on compound reinforcement, hysteresis, abradability and viscoelastic properties is studied for single polymer compounds as well as polymer blends with 1,4-cis-polybutadiene (cis-BR) and Natural Rubber (NR). Changes in miscibility of the polymer blends are studied via viscoelastic temperature sweeps and via Atomic Force Microscopy (AFM). All blends show a miscibility behavior in agreement with Hildebrand solubility parameter predictions. The nonpolar co-monomers lead to an increased miscibility while the polar co-monomers reduce the miscibility with cis-BR and NR. These changes only show up in blend Tg's and viscoelastic response and stay associated with a heterogeneous AFM blend structure with different degrees of mixed phase compositions. The impact of the third co-monomers is more pronounced in the case of cis-BR than in the case of NR blends in this study. The preferred chemically modified ESBR is the one with 3% HPMA showing improved performance relative to unmodified ESBR and unmodified Solution SBR (SSBR).
Population Balance Kinetic Model for Interaction of 2-Bisbenzothiazole-2-2'Disulfide (MBTS) with Sulfur
Authors: Goyal Ayush , Patkar Priyan , Medvedev Grisha , Venkatasubramanian Venkat , Caruthers James M. , Cao Jun , Midkiff Samuel P. 
Published: February 2011

Abstract
The first step in accelerated vulcanization is the formation of the active sulfurating species via the incorporation of sulfur by an accelerator like benzothiazole. Several mechanisms for the pick-up of sulfur by the accelerator have been proposed, including lumped pick-up of the full S8 species, sequential pick-up of individual sulfur atoms in S8 and numerous proposals where the stoichiometry is not clearly specified. For the reaction of MBTS with S8 Gradwell, et al. observed that benzothiazole terminated sulfurating species with lower sulfur rank form in greater concentrations than the sulfurating species with higher sulfur rank, where a sequential sulfur pick-up mechanism was then postulated. A detailed kinetic model will be developed to describe the Gradwell, et al. data. Density functional theory (DFT) simulations were used to provide information on the thermochemistry of the various reaction intermediates. The DFT simulations indicated that both sequential and lumped S8 pick-up are thermodynamically feasible. Population balance models have been developed that explicitly account for all polysulfidic species that are present in the MBTS+S8 reaction system. The chemically consistent population balance model includes the following reactions: (i) dissociation of polysulfides, including the opening of S8 rings, to form radical pairs, (ii) combination of a pair of persulfenyl radicals, (iii) reaction of a persulfenyl radical with a polysulfide. The effect of chain length on the kinetic constants for these reactions was determined from the DFT simulations, where the bonds that are close to the benzothiazole groups have significantly different rates of reaction. It is shown that (i) lumped sulfur pick-up alone is not thermodynamically consistent, and (ii) sequential sulfur pickup alone can not adequately describe the experimental data of Gradwell, et al.; however, a chemically consistent model with both sequential and lumped sulfur pick-up can explain the data. The identification of the above mechanism and the associated distribution of sulfurating species of different sulfur rank provide the starting point for a quantitative kinetic description of the accelerated vulcanization.
Production and Properties of Yulex® - The Natural Solution to Latex Allergy
Authors: Cornish Katrina , Williams Jali , Hall Julie L. , McCoy Raymond G. 
Published: February 2011

Abstract
Natural rubber is an irreplaceable raw material vital to industry, transportation, medicine and defense, largely produced from clonal plantations of Hevea brasiliensis in Southeast Asia. Additional rubber-producing crops are greatly desired to increase biodiversity, protect supplies, and provide a safe alternative for people suffering from Type I latex protein allergy. Basic and applied research approaches were used to make the production of latex (Yulex® latex) from Parthenium argentatum (guayule) a commercial reality. In contrast to Hevea brasiliensis, from which rubber latex is tapped by hand from laticifers, guayule latex rubber is contained within individual bark parenchyma cells. Processing involves disrupting these cells to release the rubber particles, and then purifying the latex. As in the Hevea industry, latex concentration can be achieved by centrifugation and/or by creaming agents. An artificially produced guayule natural rubber latex is then produced, under the material name of “Yulex® latex”. The Yulex Pilot Plant has been constructed, optimized and automated, and extracts then purifies latex from guayule shrub without detectable losses. The natural rubber polymers in guayule latex are high molecular weight and products made from this material have the desired high performance properties. Because guayule latex contains very little protein, all of which is hydrophobic and bound to the rubber phase, and because none of the protein cross-reacts with Type I latex allergy to Hevea latex products, its use is initially aimed towards the high-value medical products marketplace. Clinical and performance trials continue to ensure that guayule processing provides a safe, high performance, non-allergenic natural rubber latex that is safe for human use.
Temperature Controlled Dispersion of Poly(N-Isopropyl Acrylamide) Treated Silica Clusters
Authors: Bava Luciana , Feke Donald L. , Manas-Zloczower Ica , Rowan Stuart J. 
Published: February 2011

Abstract
The dispersion of particle agglomerates is affected by the presence of any chemical additives incorporated within the agglomerate structure. Traditional additives change the particle-particle and particle-matrix interactions to a degree that depends primarily on the chemical nature of the additive and its concentration within the agglomerate. A new generation of additives, based on polymeric systems that respond to external stimuli, allows the adjustment of interparticle interactions by manipulating the variable to which the additive is responsive. In this study, dispersion tests in simple shear flow are used to examine the effect of a thermally responsive additive, poly(N-isopropyl acrylamide) (PNIPAM), on the dispersion behavior of silica agglomerates. The temperature sensitivity of the dispersion mechanisms and kinetics for silica clusters treated with either linear or crosslinked PNIPAM has been examined.
Synthesis and Characterization of Styrene-Butadiene Rubber-Clay Nanocomposites with Enhanced Mechanical and Gas Barrier Properties
Authors: Meneghetti P. , Shaikh S. , Qutubuddin S. , Nazarenko S. 
Published: February 2011

Abstract
Five styrene-butadiene rubber (SBR)/clay nanocomposite or hybrid systems were synthesized via mechanical mixing of SBR using a Brabender mixer and a 2-roll mill in the presence of unmodified sodium montmorillonite (Na-MMT) clay, MMT modified with octadecylamine (C18amine), MMT modified with a zwitterionic surfactant, octadecyldimethyl betaine (C18DMB), and MMT modified with a polymerizable cationic surfactant, vinylbenzyl octadecyldimethyl ammonium chloride (VODAC) or vinylbenzyl dodecyldimethyl ammonium chloride (VDAC). The surfactant chain length and functional groups affected the dispersion of clay nanolayers in the matrix and the overall properties of the nanocomposites. X-ray diffraction (XRD) revealed peaks corresponding to intercalated structures; transmission electron microscopy (TEM) observations agreed well with XRD assessment of the composites. SBR/VODAC-MMT system exhibited the best dispersion among the nanocomposites studied. VODAC-MMT was partially exfoliated in SBR matrix and the average aspect ratio of the nanolayer stacks or aggregates was high (20). Depending on the amount of clay, considerable mechanical reinforcement and gas barrier enhancement were achieved in nanocomposites over pure rubber. Tensile strength in excess of 18MPa was observed in SBR nanocomposites with 30 phr C18 organoclays. The storage modulus at 25C increased by a factor of four by incorporating 10 phr VODAC-MMT in SBR. The most pronounced oxygen barrier enhancement was again observed in SBR/VODAC-MMT nanocomposite with the reduction of permeability by 60% at silicate volume fraction of 0.06. The superior performance of nanocomposites containing VODAC-MMT is attributed to the presence of the vinyl-benzyl group and 18 carbon-atom tail in the surfactant leading to high compatibility with SBR and nano-scale dispersion in the SBR matrix.
Synthesis and Characterization of Chemically Crosslinked Styrene-Butadiene Rubber Nanogels and their Effect on Various Properties of the Rubber
Authors: Mitra Suman , Chattopadhyay Santanu , Bhowmick Anil K. 
Published: February 2011

Abstract
Nano-sized styrene-butadiene rubber (SBR) latex gels were prepared by pre-vulcanizing SBR latex with different sulfur to accelerator ratios. These gels were characterized by swelling studies, dynamic light scattering, atomic force microscopy, mechanical and dynamic mechanical properties. With the increase in sulfur to accelerator ratio, the gels had higher amount of crosslink density and gel content. Particle size distribution did not alter much in the crosslinked gels. Incorporation of these nanogels into raw SBR led to the considerable drop in viscosity of the gel filled systems under capillary melt flow conditions. However, the reduction in viscosity was found to be dependent on the loading and crosslink density of the nanogels. Energy dispersive X-ray mapping of sulfur was used to check the dispersion of these gels into raw SBR matrix. The die swell values of gel filled SBR were much lower than that of the raw SBR. The reduction in principal normal stress difference values combined with the reinforcement effect of the gels was found to be responsible for the lowering of die swell values. Scanning electron photomicrographs of extrudates of gel filled systems showed much-improved surface smoothness compared to the unfilled SBR. The mechanical and dynamic mechanical properties also showed excellent improvement in modulus with the addition of gels in the raw rubber. A new empirical relationship was proposed to explain the reinforcement properties of nanogels as viscoelastic fillers.
Modeling of an Elastomeric Friction Damper
Authors: Li C. G. , Wang S. W. , Lu H. Y. 
Published: February 2011

Abstract
Frictional resistance of a hollow rubber cylinder steadily sliding inside a rigid sleeve has been studied theoretically and reported here. This is inspired by a new class of elastomeric friction damper consisting of an unbonded rubber cylinder, axially compressed and radially expanding to contact an outer rigid sleeve and generate friction. By considering the force equilibrium of each thin section of the rubber cylinder and adapting the principle of superposition, the tri-bological problem was decomposed into three fundamental sub-problems, which were solved consecutively. The results shed lights on the functional effects of various design parameters such as part dimensions, friction coefficient, and Young's modulus on the total friction force. Finite element analyses were also performed, and the results were compared with the closed-form solutions.
On the ABAQUS FEA Model of Finite Viscoelasticity
Authors: Ciambella J. , Destrade M. , Ogden R. W. 
Published: February 2011

Abstract
Predictions of the QLV (Quasi-Linear Viscoelastic) constitutive law are compared with those of the ABAQUS viscoelastic model for two simple motions in order to highlight, in particular, their very different dissipation rates and certain shortcomings of the ABAQUS model.
Dynamic Nanofishing of Single Polymer Chains
Authors: Nakajima Ken , Nishi Toshio 
Published: February 2011

Abstract
Single molecule force spectroscopy (SMFS) realized by atomic force microscope (AFM) on a single polymer chain (static nanofishing), where a polymer chain is picked up and pulled at its chemically modified terminals, only gives structural information such as persistence length and contour length. Beyond this technique, dynamic nanofishing, where an AFM cantilever is imposed on the forced oscillation at its resonant frequency (∼10 kHz), enables us to investigate more fruitful information. The method gave extension-dependent changes of entropic elasticity and frictional coefficient with solvent molecules for mono-disperse living-polymerized polystyrene (PS). The solvent temperature dependence revealed that the frictional coefficient could be correlated with macroscopic “intrinsic viscosity.” Another novel technique, nanofishing at fast pulling rate (fast nanofishing), exhibited internal entanglement of a single PS chain and its subsequent relaxation.
Adhesion of Steel Tire Cord to Rubber
Authors: Vanooij William J. , Harakuni Prasan B. , Buytaert Guy 
Published: February 2011

Abstract
This paper reviews the literature on rubber-brass bonding that has been published in approximately the last decade. Previous reviews of this topic by Van Ooij were published in 1979, 1984, 1991 and 2001. The scientific and technical literature is reviewed exhaustively; the patent literature is reviewed in a more selective way. Only U.S. patents are covered, and then only those that clearly propose new processes or materials. Emphasis in this review is on those papers that have contributed to an increased understanding of the mechanisms of rubber-brass bonding as it is of importance to the performance of brass-plated tire cords. Another major component of this review is the literature on compounding for brass adhesion. Literature on tire failure, tire design, or steel cord construction, is not included. This paper is concluded by an updated adhesion model that can be distilled from the recent literature.
Effects of Bio-Fuels on Common Static Sealing Elastomers
Authors: Walker F. J. 
Published: February 2011

Abstract
The purpose of this investigation was to explore the effects of bio-fuels on several common static sealing elastomers. This study explored ethanol-enriched gasoline and soy-based diesel. Exposed to these fuels were fifteen common static sealing elastomer compounds. These were comprised of eight FKM compounds, and two NBR compounds. In addition, other compositions were also included in the study. These comprised VMQ, FVMQ, AEM di-polymer, HNBR and a high temperature ACM. The percentage of ethanol enrichment was varied from zero to 100 percent. The bio-diesel section of this study examined comparative effects of conventional low-sulfur diesel, twenty percent soy diesel, and 100 percent soy diesel. Effects on conventional mechanical properties of hardness, tensile strength, elongation and volume change were measured.
A Numerical Model for Edge Effect Correction of the Mooney Rheometer
Authors: Montes Sergio A. 
Published: February 2011

Abstract
The flow of a power law fluid within the cavity of a multi-speed Mooney rheometer is studied by means of finite difference techniques with the aim of quantifying the edge effects that occur in the vicinity of the rotor corner. As expected, a significant concentration of shear stress occurs near the rotor edge. As the power law index varies, significant stagnation zones are found within the cavity, which combined with thin-shearing behavior near the moving surfaces, yield complex shear rate distributions. However, when torque is calculated, the edge effect can be described by a factor which is numerically very similar to a factor obtained from one-dimensional models described in the literature. Comparison of theoretical predictions and experimental data was found to be satisfactory.
Characterization of the Steel Tire Cord - Rubber Interface
Authors: Buytaert Guy , Coornaert Frederik , Dekeyser Willem 
Published: February 2011

Abstract
Brass-coated steel cords are extensively used as reinforcement material in radial tires, high-pressure hydraulic hoses and heavy duty conveyor belts. Bonding between rubber and steel cord is obtained via the formation of an adhesion interface layer during the curing process. The adhesion build-up mechanism involves the chemical reaction of sulfurating species contained in the rubber skim compound and copper of the brass coating, forming a CuxS layer at the rubber-brass interface. Advances in mechanistic investigations are presented, using analytical techniques such as X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), atomic force microscopy (AFM) and optical microscopy (OM). XPS and AES provide chemical in-depth information, whereas OM and AFM highlight the morphology of the resulting interfacial layers. These investigations improve the understanding of the adhesion mechanism, both for adhesion buildup and for bond degradation.
Cyclic Stress Relaxation (Csr) of Filled Rubber and Rubber Components
Authors: Asare S. , Thomas A. G. , Busfield J. J. C. 
Published: February 2011

Abstract
Under repeated stressing it is well known that rubber materials exhibit cyclic stress relaxation (CSR). Previous work has shown that the amount of relaxation observed from cycle to cycle is significantly greater than that expected from static relaxation measurements. The reduction in the stress attained on the second and successive loading cycles as compared to the stress attained on the first cycle in a stress strain cyclic test of fixed amplitude has been measured for elastomer test pieces and engineering components. It is seen that the peak force, under cyclic testing to a specific maximum displacement, plotted against the number of cycles on logarithmic scales produces a straight line graph, whose slope correlates to the rate of cyclic stress relaxation per decade. The rate of cyclic stress relaxation was found to increase with displacement amplitude in all modes of deformation. Plotting the rate of stress relaxation per decade against the maximum average strain energy attained in the cycle reduces the data measured in different deformation modes for both simple test pieces and components to a single curve. This approach allows the cyclic stress relaxation in a real component to be predicted from simple laboratory tests.
Assessing Effect of the Migration of A Paraffin Wax on the Surface Free Energy of Natural Rubber
Authors: Ansarifar A. , Critchlow G. W. , Guo R. , Ellis R. J. , Haile-Meskel Y. , Doyle B. 
Published: February 2011

Abstract
The effect of the migration of paraffin wax on the surface free energy of natural rubber (NR) was investigated. The rubber was mixed with the wax and then stored at ambient temperature for up to 168 hrs before its surface free energy was measured using contact angle measurement. Static secondary ion mass spectrometry was also used to provide a chemical fingerprint of the rubber surfaces. The surface free energy decreased as a function of storage time because of the migration of the wax to the rubber surface. The highest rate of reduction was recorded up to 3 hrs and thereafter, the surface free energy decreased at a much slower rate, reaching a plateau after 48 hrs in storage. In total, the surface free energy reduced by approximately 46% as a result of the migration of the wax to the rubber surface. The reduction in surface free energy could adversely affect ability of the rubber to stick to itself and to other dissimilar elastomers.
Compression of Rubber Disks Between Frictional Surfaces
Authors: Gent A. N. , Discenzo F. M. , Suh J. B. 
Published: February 2011

Abstract
An approximate analysis is given of the axial compression and retraction of a rubber disk sandwiched between two rigid frictional surfaces. The rubber is assumed to be linearly-elastic and incompressible, and Coulomb's law of sliding friction is assumed to apply. The amount of interfacial slipping during compression is calculated and the distributions of normal and shear stress are determined. The overall compressive stiffness is then evaluated for disks with a wide range of aspect ratio a/h, where a is the radius and h is the thickness, and for several values of friction coefficient. Force-displacement relations during retraction are obtained and the energy expended in frictional sliding is calculated in some representative cases. It is found to be a large fraction (about one-half) of the input energy for disks of large aspect ratio, compressed between low-friction surfaces. Finite element analysis (FEA) was carried out for disks with various aspect ratios and friction coefficients. Stress distributions and force-displacement relations are compared with the analytical results. Agreement is generally good, even though the stress singularity at the edge of the disk is ignored in the analysis. It appears to have little influence away from the edge.
The Effect of Thermal Boundary Condition on the Crosslink Density Distribution and the Curing Time of the Thick Cylindrical Dampers
Authors: Saeb Mohammad R. , Mostafaiyan Mehdi 
Published: February 2011

Abstract
Optimization of curing process conditions of elastomers so as to achieve a part with homogeneous network is of crucial importance. One of the indicative parameters in the curing process is state of cure (SOC) that is investigated in this study in order to verify the influence of thermal boundary conditions on the curing of a cylindrical damper based on NR.. Furthermore, the newly introduced parameter of state of reversion (SOR) is defined, and this parameter will be set as a controlling parameter in the curing time; in order to avoid the unfavorable phenomenon of thermal decomposition. In this work, the curing process is numerically modeled using a finite element code which is developed by authors and results are compared with experimental results, as a verification step for validity of the code. Employing this code, the curing process is subjected to various molding temperatures, and it is demonstrated that a constant temperature of mold for elastomeric parts of high thickness will not result in a homogeneous crosslink network, unless the curing time is very long. Therefore, a varying with time temperature profile for mold is proposed that leads to a decreased curing cycle time, while giving complete SOC at a lower SOR value, simultaneously.