bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Chain Scission during Mixing of Filled Compounds
Authors: Ahagon Asahiro 
Published: February 2011

Abstract
Whether chain scission takes place during mixing of black-filled compounds has been a debatable subject which is yet unsettled. The uncertainty originates from the material system which contains gel. A direct method to evaluate scission is to quantify the change in the number of chain ends, since two chain ends will be newly created on each event of scission. It requires determination of an average molecular weight of the linear components which constitute the gel-containing system. The degree of polymerization denned in the Charlesby-Pinner theory, derived for crosslinking study by means of sol-gel analysis, could be conveniently used for the purpose. The theory, however, cannot be directly applied for black-filled compounds because the composite structure in the compounds does not allow one to satisfy the assumptions made in the theory, i.e., an equal chance of crosslinking for every reactive site. A new technique is developed so that the assumption is satisfied and the sol-gel analysis can be carried out even with black-filled compounds. This technique is applied for numbers of compounds, with the same formulation but mixed under various conditions. A NR and an SBR formulations are used here. The results clearly indicate that chain scission takes place during mixing of both NR and SBR compounds.
Tear Strength of Carbon-Black-Filled Compounds
Authors: De D. , Gent A. N. 
Published: February 2011

Abstract
Measurements are reported of tear strength for several carbon-black-filled compounds over a wide range of temperature. Attention is focussed on “knotty tearing” when the tear deviates from the straight-ahead direction and sometimes splits, and the tear force rises markedly. Knotty tearing occurs only over certain temperature ranges which appear to be related to the glass temperature of the elastomer. It is suppressed when the crosslink concentration is either unusually high or unusually low. It is strongly dependent on the type of carbon black, and sensitive to the particular elastomer used, being virtually absent with one cis-polybutadiene elastomer although evident with others. It appears to be related to the ability of the compound to create a high degree of orientation of carbon black particles at the crack tip and thus induce a marked anisotropy of strength in this region. However, it was often absent in pure shear experiments, when the overall extension of the specimen was much smaller, and absent in conventional tensile tests when the initial crack was small and grew rapidly as a smooth fracture. Even in the absence of knotty tearing, the tear strength of filled compounds was found to be five to ten times higher than for the corresponding unfilled compounds. This is attributed, at least in part, to enhanced hysteresis.
Tire Wet Traction—Explaining Performance Variation Using the ‘Criticality’ Concept
Authors: Veith Alan G. 
Published: February 2011

Abstract
The results of four different wet traction evaluation techniques show that the relative performance for individual candidate tires is a function of the test conditions as well as tire design features. For a given tire, test conditions such as test speed, pavement texture and water depth determine the relative magnitude of two basic footprint lubrication modes (1) boundary layer (BL), with intimate contact and good grip which predominates at low speeds, high texture and minimal water depth, and (2) elastohydrodynamic (EHL), with minimal contact and poor grip which predominates at high speeds, low texture and deeper water. A concept called ‘critically’ is defined as the fraction of the footprint contact area in the EHL mode Knowledge of the test conditions permits an estimate of the relative critically of any testing operation. Definitive wet traction performance interpretation depends on criticallyy information since tests at low critically frequently show minimal differences (among candidate tires) while tests at high critically usually show a wide range of performance.
Sulfur Vulcanization of Simple Model Olefins, Part V: Double Bond Isomerization during Accelerated Sulfur Vulcanization as Studied by Model Olefins
Authors: Versloot P. , Haasnoot J. G. , Nieuwenhuizen P. J. , Reedijk J. , van Duin M. , Put J. 
Published: February 2011

Abstract
The sulfur vulcanization of unsaturated rubber has been studied with the use of various olefins as simple, low-molecular models. By treatment of these olefins with a mixture of zinc oxide, sulfur, and tetramethylthiuram disulfide (TMTD) at 140 °C, a mixture of dialkenyl sulfides is obtained mimicking crosslinked rubber. Isomerization of the double bond may take place during this reaction, depending on the olefin used. The position of the double bond is on the one hand determined by crosslink formation mechanisms, and on the other hand by isomerization, which takes place at higher temperatures. The position of the equilibrium between isomeric alkenyl sulfides is determined by the increased stability of the sulfide which in itself results from an increased degree of alkyl substitution at the unsaturation. Due to the isomerization reaction, at higher temperatures no mechanism for crosslink formation can be discerned. At room temperature, however, a radical mechanism appears to be predominant during the vulcanization process.
Vulcanization of Ultrasonically Devulcanized SBR Elastomers
Authors: Levin V. Yu , Kim S. H. , Isayev A. I. 
Published: February 2011

Abstract
Sulfur cured SBR elastomers, devulcanized by high power ultrasonic irradiation, were revulcanized by using the same curing conditions as for virgin SBR. Crosslink density and gel fraction of virgin, devulcanized, and revulcanized elastomers were measured. Curing behavior of some model compounds based on virgin and devulcanized SBR was investigated. Strongly pronounced differences between the curing behavior of virgin and devulcanized elastomers were observed. Torque and DSC studies indicate that two different processes during the crosslinking of devulcanized rubber take place. The existence of these two processes is explained by crosslinking of sulfidized polymer chains followed by crosslinking due to the presence of sulfur and accelerator. Chemical differences between virgin and devulcanized elastomers, explaining the observed phenomena, are discussed.
An Evaluation of Strain Amplification Concepts via Monte Carlo Simulations of an Ideal Composite
Authors: Govindjee Sanjay 
Published: February 2011

Abstract
In the modeling of carbon-black filled elastomers it is important to have a good estimate of the state of the elastomer itself, since many nonlinear effects originate in the matrix material. A common notion in such estimates is the idea of a “strain amplification” factor that relates a macroscopically imposed strain state to the average strain state in the elastomer matrix material. In this paper Mullins and Tobin's interpretation of the Guth—Gold and Smallwood's amplification factor, and a more recent proposal by Govindjee and Simo will be examined. All three theories are compared to the results of a series of Monte Carlo simulations on an ideal composite with a Neo-Hookean matrix and semi-rigid inclusions. It is shown that for the idealized material, one can not interpret the Guth—Gold and Smallwood amplification factors as an estimate of the strain state of the matrix material. The theory of Govindjee and Simo, on the other hand, is shown to accurately predict the strain state of the matrix.
Some Initial Trials and Applications of the DFCS Test for Carbon Black Dispersion
Authors: Murray G. A. W. , Ng B. H. R. , Jahromi M. R. Vaseghi , Southwart D. W. 
Published: February 2011

Abstract
The Dark Field Cut Surface (DFCS) test is a quantitative method for determining the state of dispersion of carbon black in rubber compounds. The method has been described fully in another paper. Here are reported some of the first applications of the test and some trials that were carried out specifically to investigate and develop the DFCS test. The test is demonstrated to follow accurately the progress of dispersion of carbon black in milled or mixed compounds of NR and SBR. Some tests have been carried out using large batches of test results and these have demonstrated a good fit with a normal distribution. By this means, some recommendations have been derived for suitable sampling rates. The relative merits of the standard deviation and the average for characterizing dispersion have been highlighted. A further way of presenting the results as distribution curves has been demonstrated. A check has been performed to demonstrate that mastication of rubber has little or no influence on the DFCS test results. The DFCS test has been used to give an interesting (provisional) insight to the best ways to operate a rubber mixer. To date, the measured patterns of scattered light show a promising correlation with the anticipated dispersion of carbon black in the specimens tested.
Electrical Conductivity of Polystyrene-Rubber Blends Loaded with Carbon Black
Authors: Soares B. G. , Gubbels F. , Jéro^me R. , Vanlathem E. , Deltour R. 
Published: February 2011

Abstract
Polystyrene/rubber blends have been loaded with carbon black (CB) and the filler localization in the two-phase polyblends has been studied in relation to the chemical structure of the rubber. The CB localization and the electrical conductivity are greatly influenced by the substitution of the rubber chains. In polystyrene/polybutadiene blends, the filler is localized within the polybutadiene phase. In contrast, in polystyrene/polyisoprene and polystyrene/ethylene—propylene rubber (EPM) blends, CB is mainly localized at the interface, so that the CB percolation threshold in cocontinuous two-phase polyblends is dramatically decreased.
On the Ogden Strain-Energy Function
Authors: Yeoh O. H. 
Published: February 2011

Abstract
The Ogden strain-energy function for rubber appears to be gaining popularity among users of finite element analysis. This paper discusses some of the special features of this material model. It explains why nonlinear regression analysis of stress-strain data obtained from just one mode of deformation may yield an Ogden strain-energy function that is unsatisfactory for predicting behavior in other deformation modes. It suggests the regression analysis be constrained such that some of the coefficients are chosen based upon the known behavior of rubbery materials.
Superior Mechanical Properties of Reclaimed SBR with Bimodal Network
Authors: Isayev A. I. , Kim S. H. , Levin V. Yu 
Published: February 2011

Abstract
The correlation between the mechanical properties of revulcanized SBR, total and polysulfidic crosslink density, gel fraction of original vulcanizate, ultrasonically devulcanized, and revulcanized rubber is described. Under some processing conditions the tensile strength of revulcanized SBR is found to be much higher than that of the original vulcanizate with elongation at break being practically intact. A model explaining the increase in mechanical properties of revulcanized rubber is proposed.
Strain-Crystallization of Guayule and Hevea Rubbers
Authors: Choi I. S. , Roland C. M. 
Published: February 2011

Abstract
A comparison was made of the room temperature strain-crystallization of naturally-occurring cis-1,4-polyisoprenes having varying non-rubber content. A variety of measurements were employed to assess crystallization, including stress relaxation, optical birefringence, and the infrared absorption spectrum. All methods yielded the same result: The strain required to induce crystallization is less for polyisoprenes having larger concentrations of impurities. The ability to crystallize at lower orientation presumably underlies the superior failure properties of guayule rubber and the poorer grades of natural rubber (NR) in comparison to deproteinized NR.
Quantitative Determination of the Microstructure and Composition of Crosslinked Rubber Blends
Authors: Thorn-Csányi Emma , Luginsland Hans-Detlef 
Published: February 2011

Abstract
Intermolecular metathetic polymer degradation opens up an analytic method to identify the quality and quantity of the components in blends of different types of rubber even if they are crosslinked and filled with carbon black, mineral oil, etc.. Furthermore the amount of soluble and insoluble additives can be determined. Moreover, metathetic degradation allows for determination of detailed information about the chemical microstructure (e.g. sequence length distribution of 1,2-butadiene and styrene units) of the rubbers used. This method is suitable for analysis of rubber components in tires.
Solid State 13C NMR Analysis of Vulcanized Rubbers XVI. The Competitive Vulcanization of Natural Rubber and Polybutadiene Blends
Authors: Klei B. , Koenig J. L. 
Published: February 2011

Abstract
Solid state 13C NMR was used to study the competitive vulcanization of blends of natural rubber and high cis polybutadiene. A NMR sampling technique utilizing the stacked homopolymers was developed that helps to determine the spectral differences occurring due to competitively vulcanizing an elastomer blend. The small amount of interfacial crosslinking was expected to be undetectable but has been tentatively observed. Concentration of crosslinks at the interface may occur from limited solubility of curative species in both rubbers. The NMR spectra also showed inhibition of cis-trans isomerization in natural rubber with addition of polybutadiene.
Simulation of Non-Newtonian Flow of Rubber Compounds in a Pin Barrel Screw Extruder
Authors: Shin Kyung Chul , White James L. 
Published: February 2011

Abstract
A simulation is presented of flow of a rubber compound, modeled as a power law non-Newtonian fluid, in screw designs including screws with slices and a pin barrel extruder. Calculations were carried out using the flow analysis network (FAN) technique. Pressure fields, flux fields, and screw characteristic curves were determined. Introducing non-Newtonian (shear-thinning viscosity) characteristics reduces screw pumping ability. Slices in screw flights produce backward fluxes in the screw channel and reduce pumping capacity. Introduction of pins into the barrel has only a minor effect on screw pumping characteristics, and the pumping capacity of a pin barrel extruder closely resembles that in a screw extruder with slices in its screw flights.
Crack Analysis of Unfilled Natural Rubber Using Infrared Microspectroscopy
Authors: Neumeister Lori , Koenig J. L. 
Published: February 2011

Abstract
The characterization and analysis of the crack tip region of unfilled natural rubber is crucial in developing a fatigue resistant material. Therefore, the molecular structure and orientation of the material in the crack tip region has been compared to the bulk. Cracks formed by different methods were evaluated using both transmission and reflection techniques of infrared microspectroscopy. The material around the crack tip and crack edges shows much higher absorbances than the bulk material for stressed rubber. This is due to a higher concentration of material and residual orientation effects. For unstressed material the crack tip region exhibits identical characteristics to the bulk material.
Preparation and Characterization of Solution SIBR via Anionic Polymerization
Authors: Halasa Adel F. 
Published: February 2011

Abstract
Harnessing anionic terpolymerization of styrene, isoprene and butadiene to a degree where one can achieve simultaneous control of composition, microstructure and sequence distribution results in a unique family of elastomeric materials. We now can tailor-make elastomers having diverse viscoelastic responses to suit specific tire applications, in particular, those required for high performance tires. Furthermore, we have demonstrated unique morphologies attainable for SIBR ranging from lamellar to spherical. Such morphologies were reported previously for soft/hard block copolymers, i.e. SBS and SIS, but not for soft/soft systems. It is our contention that this will further contribute to our understanding of the relationship between morphology and cured physical properties.
Scanning Probe Microscopy of Polymer Surfaces
Authors: Tsukruk Vladimir V. 
Published: February 2011

Abstract
Basic principles and recent results of scanning probe microscopy (SPM) studies of polymer surfaces are reviewed. Applicability of various SPM techniques—including contact, dynamic, force modulation, friction force, chemical force, electrostatic, adhesion, and thermal modes—to probing of polymer surfaces is illustrated. Examples of recent studies of surface morphology and properties of various polymers are presented and briefly discussed. An extensive bibliography of more than 200 references is included. Classes of polymers considered here are: crystalline and amorphous, composites and blends, fibers and deformed polymers, block polymers and latexes, rubbers and liquid crystalline polymers, thin films and ionomers. Current focuses and future trends are summarized including quantitative SPM measurements, probing of nano- and microscale mechanical properties, studying dynamical surface properties, and exploring local chemical interactions.
NMR Imaging of Elastomers: A Review
Authors: Blümler P. , Blümich B. 
Published: February 2011

Abstract
From curiosity driven investigations about 10 years ago NMR imaging of materials has developed into a useful tool for characterization of polymers, in particular of elastomer products. A clear indicator of this development is the increasing number of imaging spectrometers in use at industrial research and quality-control laboratories. Typical applications of NMR imaging to elastomers are investigations of the homogeneity of a compound or product components like gaskets or tire profiles, studies of the aging behavior under different loading conditions, the mapping of stress, strain and temperature distributions, and the analysis of material change after application of an overload. Elastomers constitute a class of materials particularly suitable to NMR imaging, because they are rich in protons, the most sensitive, stable NMR nucleus, and the material is soft, giving rise to small dipole-dipole couplings and thus to comparatively narrow lines and favorable imaging conditions. Yet the residual dipole-dipole interaction which remains unaveraged from the thermal motion of intercrosslink chains is a most valuable source of information. It determines the relaxation times so that measurement of various relaxation parameters provides information on cross-link density, stress, strain, and temperature in rubber materials. Spectroscopic investigations on the other hand are not very informative, because they are sensitive to chemical change, which is often too small to be detectable under reasonable conditions even for chain scission or additional cross-linking during aging. The measurement of relaxation times does not require homogeneous magnetic fields, so that new NMR devices based on inexpensive, permanent magnets can be developed, which are applied to the surface of arbitrarily large elastomer products. The NMR MOUSE is such a mobile NMR scanner, which has been shown to be sensitive within limits to changes in cross-link density, strain and temperature. Thus NMR imaging is progressing from the acquisition of entire images which show distributions of material properties to the monitoring of volume-selective NMR information, which can be expected to be used not only for quality control and failure analysis but also for process control and on-line monitoring in the future.
Effect of Various Bonding Agents on the Sulfidation of Brass-Plated Steel Cords Immersed in Squalene Mixtures
Authors: Hamed G. R. , Paul R. 
Published: February 2011

Abstract
Brass-plated steel cords have been immersed at elevated temperatures in various squalene mixtures containing sulfur curatives and commercially available bonding agents. Copper sulfide growth was characterized by scanning electron microscopy and energy dispersive x-ray analysis. The bonding agents cause early sulfide growth, even prior to “scorch,” but mitigate sulfide overgrowth upon humid aging. Both effects are expected to improve joint durability.
Chemical Interaction between Surface Oxidized Carbon Black and Epoxidized Natural Rubber
Authors: Manna Ajoy K. , De P. P. , Tripathy D. K. , De S. K. , Chatterjee M. K. 
Published: February 2011

Abstract
This study—based on Monsanto Rheometer measurements, determination of bound rubber, enthalpy of reaction, solvent swelling studies, and measurement of physical properties— revealed that the functional groups of intermediate super abrasion furnace (ISAF) carbon black chemically interact with the epoxidized natural rubber. The extent of interaction is greater in the case of an oxidized grade of ISAF black than the nonoxidized grade. Infrared spectral studies show that the interaction between the rubber and carbon black leads to chemical bond formation. It is believed that the oxidized grade of carbon black forms ester-type as well as phenolic ether-type bonds, while the nonoxidized grade forms primarily the phenolic ether-type of linkages.
Viscoelastic Behavior of NBR/EVA Polymer Blends: Application of Models
Authors: Bandyopadhyay G. G. , Bhagawan S. S. , Ninan K. N. , Thomas S. 
Published: February 2011

Abstract
The viscoelastic properties of blends based on nitrile rubber (NBR) and ethylene-vinyl acetate copolymer (EVA), a thermoplastic elastomer, are investigated in terms of storage modulus and loss tangent for different compositions. These small-strain dynamic mechanical properties have been evaluated using a Rheovibron Viscoelastometer covering a wide temperature range. Attempts have been made to fit the experimental results with computations based on mean field theories developed by Kerner. Predictions based on the discrete particle model (which assumes one of the components of the blend to be the matrix and the other dispersed as inclusions) are found to be satisfactory in the case of 30/70 NBR/EVA blend but not 70/30 and 50/50 blends. The packed grain model (which assumes neither of the components to be the matrix but approximates a co-continuous structure of the two) predictions do not agree with the experimental data on 50/50 blend for which a co-continuous morphology was revealed by SEM observations.
Solid-State C-13 NMR Studies of Vulcanized Elastomers XVII. Effect of Carbon Black Grade on the Network Structure in Natural Rubber Vulcanizates
Authors: Mori Makio , Koenig Jack L. 
Published: February 2011

Abstract
The vulcanization chemistry and network formation of carbon black filled natural rubber vulcanized with sulfur and TBBS were studied using solid-state C-13 NMR and equilibrium swelling measurements. A reduction in the sulfur rank of the A1 type sulfide and increased production of B1 type polysulfide are observed when the carbon black concentration increases in natural rubber. At the same loading level, the structural property or grade of carbon black does not affect qualitatively the type of sulfide formation. The efficiency of the intermolecular crosslinking over the whole range of sulfurizations is 45.7% for the unfilled vulcanizate. The extent of the chemical sulfurization reactions (NMR result) is constant with black incorporation, while the total network (swelling result) increases with increases in the black loading. The amount of physical entanglements, estimated from the comparison of the NMR and swelling results, is found to increase linearly with the carbon black concentration. The entanglements increase as a function of the 300% modulus, which suggests that the effective level of reinforcement depends on the nature of the individual carbon black. It is assumed that physical adsorption plays a major role in the polymer-filler interactions in the natural rubber/carbon black system.