bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Finite-Element Analysis in the Design of Automotive Elastomeric Components
Authors: Morman Kenneth N. , Pan Tsung Y. 
Published: February 2011

Abstract
FEA provides more detailed information for design than can be possibly measured on an actual component part or computed using classical closed-form solutions. Based on this observation, FEA is an ideal means for developing concept designs. No parts are needed for FEA, while conceptual design evaluation using “cut and try” procedures of the past requires that component parts be molded for testing. Once a rough concept has been developed, FEA can be used more effectively to evaluate design modifications in less than the time required by “cut-and-try” iterations. The major benefit that is realizable from FEA is in time savings. Computer costs can be justified by factors such as efficiency and better component reliability and performance.
The Resolution of Binary Elastomer Blend Properties by Stress-Strain Modelling
Authors: Bauer R. F. , Crossland A. H. 
Published: February 2011

Abstract
For elastomer/elastomer blends in which the dispersed phase has a lower modulus than the matrix, it was shown that the phases are mechanically coupled in a simple parallel manner. Once the stress behavior of each blend component, cured separately, is known as a function of both strain and state of cure, the properties of the blend phases can be resolved unequivocally. This modelling technique, as applied to a 70/30 blend of NR/CIIR, showed that in this blend, curative migration increases the modulus of the NR phase by a factor of three.
Load, Speed, and Pressure Effects on Passenger Car Tire Rolling-Loss Distribution
Authors: Schuring D. J. , Clark J. D. 
Published: February 2011

Abstract
The procedure explained in this paper permits calculation of individual tire region contributions to rolling loss without altering the tire. Many different tire-build configurations can be considered using this technique. Different belt, bead, and subtread materials' contributions to rolling-loss distribution can be studied; different tire shapes and thicknesses can be considered. Only a single tire of each configuration need be built, and it can be retested if necessary. Results obtained here show that the tread region of the tire tested behaves differently than the other regions. Changes in tire pressure, load, and speed lead to changes in the remaining individual tire regions' contributions that are in the same direction as the overall tire loss. A tire design that is altered to accommodate new specifications may lead to an increase in rolling loss that is greater than some designated value. An analysis of the type presented here may show which region of the new tire design should be changed to bring the loss within desired limits. The heat-transfer coefficient of the tire in this model is a linear function of velocity, independent of tire load and pressure. We have confidence in this relation as the model results are derived from both loss measurements and tire surface temperature measurements made in the laboratory. The model output is based on fundamental heat-transfer precepts and treated mathematically by established analysis techniques.
Cure Modification Effected by Cycloalkylthioamines in the Vulcanization of NR Accelerated by Thiocarbamyl Sulfenamides and Dibenzothiazyl Disulfide
Authors: Das Prasanta Kumar , Datta Rabindra Nath , Basu Dipak Kumar 
Published: February 2011

Abstract
The role of the thioamines as retardera in the vulcanization of NR accelerated by the binary system comprising thiocarbamyl sulfenamide and MBTS has been investigated. Several thioamines, namely, cyclohexyl thiomorpholine (CM), cyclohexyl thiopiperidine (CP), cyclohexyl thiodibutylamine (CDBA), cyclohexyl thiodiphenylamine (CDPA), cyclohexyl thiodiisopropyl amine (CDIPA), dicyclohexyl dithiopiperazine (DCDPz), cyclohexyl thiodiethylamine (CDEA), and cyclohexyl thiodibenzopyrrole (CDBP) had been selected for the study. It has been observed that these thioamines provide better cure retardation than CTP and almost in all the cases, cure rates and torque values of the resulting vulcanizates are increased. It is further noticed that the vulcanizates obtained from the stocks containing CDEA, CDBP, and CDPA exhibit notably more heat and age resistance than those obtained from CTP. Some hplc studies were made to understand cure activation. MBT and N-oxydiethylenethiocarbamyl benzothiazole disulfide (OTBD) seem to activate cure, especially in the presence of thioamines. Antioxidants like di-β-napthyl-p-phenylenediamine (DNPD) and N-phenyl-N-sopropyl-p-phenylenediamine (PIPPD), when present in the respective stocks, further enhance both heat and age resistance properties of the resulting vulcanizates.
Prediction of Zero-Shear Viscosity of Linear Polybutadienes from the Crossover Point Using Doi-Edwards Theory
Authors: Rahalkar Ramesh R. , Tang Henry 
Published: February 2011

Abstract
Based upon the Doi-Edwards theory, a simple expression has been obtained for zero-shear viscosity in terms of the plateau modulus and the crossover frequency. There are no adjustable parameters in the expression. The model is in very good agreement with the zero-shear viscosity values for linear polybutadienes, the typical discrepancy being ∼5–10%. If the model can be validated for other linear amorphous polymers, it may become possible to estimate the zero-shear viscosity by measuring a single Theological parameter (the crossover frequency).
Resistivity of Rubber as a function of Mold Pressure
Authors: Thompson Corley M. , Besuden T. W. , Beumel L. L. 
Published: February 2011

Abstract
For this N550 carbon black, loaded over a narrow but typically used range, high molding pressure caused a decrease in electrical resistivity of several orders of magnitude. The earlier in the cure cycle the high pressure was applied, the greater was the decrease in resistivity. A suggested mechanism for the effect is the formation of covalent bonds between carbon-black particles that are pushed into closer proximity by the high mold pressure. This postulate is supported by the limited kinetic data available. Clearly, pressure applied to a rubber sample during molding must be given as careful consideration as the loading of carbon black when materials requiring high resistivities are prepared. Although it has not been pursued in this work, the effect of pressure on the electrical resistivity of conductive rubber formulations may be significant. Further work underway is addressing the effect of mold pressure on the electrical resistivity of other rubber compounds as well as loadings of some other types of carbon black.
Dynamic Testing and Reinforcement of Rubber
Authors: Funt J. M. 
Published: February 2011

Abstract
A series of experiments have been run to determine which mechanisms dominate carbon black reinforcement of rubber. A broad range of compounds using oil-extended and non-oil-extended rubbers and carbon blacks covering the spectrum of tread blacks have been tested. The results for measurements made in an all-SBR formulation are reported here. The primary experiment consisted of measurement of the dynamic modulus and hysteresis of the cured and uncured compounds over a broad range of frequencies, temperatures, and strains. Ternperatures ranged from −70°C to +90°C; frequencies varied from 0.01 to 10 Hz; double strain amplitudes varied from 0.5% to 35%. From a discussion of the literature and evaluation of the experimental results, two mechanisms have been found to control the primary effects of carbon black on rubber reinforcement, where reinforcement refers to a general enhancement of properties, such as modulus, as well as the tensile strength of the compound. Hydrodynamic interaction, which is the increase in properties caused by the modification of strain fields in the region of an aggregate, dominates the large-strain dynamic and tensile properties of the compound. The primary carbon black variable in this mechanism is the effective aggregate size, such as measured by tint, which controls the effective volume loading of the carbon black at a given weight loading of carbon black. At low strains, the modulus is even higher than that predicted from the hydrodynamic-interaction/effective-volume model. This additional reinforcement is caused by the entanglement network formed between the tightly absorbed bound rubber on the carbon black surface and the bulk rubber far removed from the surface. The main carbon black variables in this mechanism are surface area and surface chemistry. The strain dependence of modulus is caused by the breaking and reforming of effective crosslinks in the rubber forming a transition zone between the bound rubber and the bulk rubber. To a large extent, this mechanism is dominated by the rubber properties, such as molecular weight and molecular-weight distribution. However, the dynamics of the entanglement network may be modified by altering specific interactions between carbon black and rubber.
Development of Material Constants for Nonlinear Finite-Element Analysis
Authors: Finney Robert H. , Kumar Alok 
Published: February 2011

Abstract
The determination of the material coefficients for Ogden, Mooney-Rivlin, Peng, and Peng-Landel material models using simple ASTM D 412 tensile data is shown to be a manageable task. The application of the various material models are shown to be subject to the type and level of deformation expected, with Ogden showing the best correlation with experimental data over a large strain range for the three types of strain investigated. At low strains, all of the models showed reasonable correlation.
The Mechanism of Phenolic Resin Vulcanization of Unsaturated Elastomers
Authors: Lattimer Robert P. , Kinsey Robert A. , Layer Robert W. , Rhee C. K. 
Published: February 2011

Abstract
It is well known that during the sulfur curing of unsaturated rubbers, two competing reactions occur: (a) crosslinking or vulcanization, and (b) reversion or devulcanization. In the case of butyl rubber, these two competing reactions have been summarized in earlier reports. Tire curing bag (bladder) compounds are usually made of butyl rubber (IIR), a copolymer of isobutene and isoprene, with typically 1–5% of the diene monomer. Curing bags were originally manufactured using sulfur cures. The high temperatures (140–180°C) employed in tire curing caused reversion, however, and these bladders had very short service lives. The deterioration of the IIR bladders was evidenced by a gradual softening of the surface. A major technical advancement for increasing the service life of curing bladders was the development of phenol/formaldehyde (resole) resins for vulcanizing IIR. These resins can give IIR cures with very thermally stable crosslinks. The vulcanizates are essentially immune to reversion, even at the high use temperatures of tire curing operations. The basic curing resins used are generally 2,6-dihydroxymethyl-4-alkylphenols 1 or their condensation polymers 2 (Scheme 1). These materials are produced via the base-catalyzed reaction of the p-substituted phenol with formaldehyde. R is typically methyl, t-butyl, or t-octyl in commercial resins. The use of a blocking substituent in the para position maximizes the formation of o-hydroxymethyl groups. R′ is either methylene (—CH2—) or dibenzylether (—CH2—O—CH2—), depending on the conditions of the resin synthesis or the cure.
Diels-Alder Reaction Curing of Chlorobutyl Rubber by bis-Maleimides
Authors: Ho K. , Steevensz R. 
Published: February 2011

Abstract
Different bis-maleimides are found to have different efficiencies and reactivities in the crosslinking of CIIR in the presence of zinc oxide. Although the degrees of crosslinking of CIIR by bis-maleimides cannot be defined absolutely, some trends concerning the efficiencies of the crosslinking are evident. In general, the aromatic bis-maleimides gave higher degrees of crosslinking than the aliphatic analogs. The reactivity and crosslinking efficiency of an individual bis-maleimide is very much affected by its end-to-end chain length and its electronic distribution, resulting from the interaction between the maleimide groups, and from the interaction between the maleimide groups and other functional groups present in the same molecule. The longer the bis-maleimide molecule and the more electron deficient the maleimido double bond, the greater its effectiveness as a crosslinking agent. Other curing mechanisms, possibly including polymerization of the maleimido groups, appear to be operative when using aromatic bis-maleimides as curing agents for CIIR.
Nonseparable Behavior in Rubber Viscoelasticity
Authors: Sullivan J. L. , Mazich K. A. 
Published: February 2011

Abstract
New large-strain rubber viscoelasticity results for a filled and an unfilled IIR vulcanizate and previously published results for two NR gum vulcanizates have been discussed. The data show that the “mixed” response functions of large-strain stress relaxation, and the incremental storage and relaxation moduli do not demonstrate factorizability of time and strain effects. This is a consequence of the elastic and relaxation contributions in each of the mixed functions being different. The incremental dynamic data also show that the loss modulus for the filled IIR and unfilled NR vulcanizates (unavailable for the unfilled IIR) are separable functions of time and strain. This directly shows that the relaxation spectra for the filled IIR and unfilled NR vulcanizates are independent of strain for the deformations studied. In fact, it is argued that a necessary and sufficient condition for the relaxation spectrum to be independent of strain is that the loss modulus is a factorizable function of time and strain effects. The quantitative success of the Generalized Solid-Liquid (GSL) model in representing the viscoelastic behavior of the gum NR vulcanizate has been reviewed. Although the GSL model applies only to unfilled vulcanizates, it has also been successfully used to qualitatively interpret the results for the filled IIR compounds. Both successes are attributed to the physical assumptions intrinsic to the GSL model; more specifically, 1) the relaxation spectrum is independent of the state of strain, and 2) the deformational dependences of elastic and relaxation contributions to the overall response of the system need not be the same. Physical arguments justifying these assumptions have been covered. It has also been shown with the aid of the GSL model, that a material might exist which demonstrates factorizability in stress relaxation and incremental loss modulus behaviors but nonfactorizability in the incremental storage and relaxation moduli.
Solid-State Carbon-13 NMR Studies of Vulcanized Elastomers. VI. Relaxation in Sulfur-Vulcanized Natural Rubber
Authors: Andreis Mladen , Liu Juwhan , Koenig Jack L. 
Published: February 2011

Abstract
Molecular motions in sulfur-vulcanized NR are investigated by solid state 13C NMR relaxation techniques. Since the high-resolution spectra of crosslinked samples exhibit overlapping in the aliphatic region, a combined application of variable temperature spin-lattice relaxation measurements and the computer simulation of the overlapped spectral region is used in order to detect resonance signals. Motional restrictions introduced by crosslinks are investigated from the temperature dependence of nT1 relaxation times for individual carbons. The V-curves for all polyisoprene signals and for the detectable signals arising from the network units exhibit a similar general trend with increased curing time: curve broadening, shift of the minima to higher temperatures, and increase of the T1 min values. All the backbone carbons show quantitatively similar effects of vulcanization on the spin-lattice relaxation. At shorter curing times, motional restrictions for the methyl side group are more pronounced compared to the main-chain carbons. The experimental data suggest that the isotropic motion is strongly affected by the crosslinking. Librational motion is less affected, while the change in rotational motion has no significant influence on the relaxation curve. Although experimental data cover a relatively narrow temperature range, not sufficiently wide for a more accurate quantitative analysis, the results indicate that concepts of plural correlation times and a distribution of correlation times are applicable.
Fracture Morphologies of Carbon-Black-Loaded SBR Subjected to Low-Cycle, High-Stress Fatigue
Authors: Goldberg Alfred , Lesuer Donald R. , Patt Jacob 
Published: February 2011

Abstract
In the absence of a mechanical defect at the surface, failure is almost always initiated in the bulk of a sample at a material flaw. A variety of flaw morphologies are observed; however, the extent of cyclic damage could not be related to either flaw size or flaw type. Energy dispersive spectographic analysis did not reveal any differences in chemistry between a flaw site and regions remote from a flaw. The size and definition of a flaw increase with an increase in carbon-black loading. Initiation flaw sites are enveloped by fan-shaped or penny-shaped regions which develop during cycling. With the highly loaded carbon-black samples, these regions consist of concentric bands which increase in number and become more prominent with an increase in test temperature. This is attributed to the presence of knotty tearing. With low carbon-black loadings, the absence of any significant disorientations in the tearing paths during either a cycle or a series of cyclic events results in the absence of individual resolvable bands within the fatigue-tear regions. The size and morphology of a fatigue-tear region appears to be independent of the fatigue load or the extent of the damage (strength loss). By contrast, either an increase in cycling load or an increase in damage at constant load increases the definition of the fatigue-region morphology for all formulations of carbon black. The morphologies in regions leading to failure during the final cycle are identical to the morphologies of fractured surfaces obtained in conventional tensile tests—tear steps or ridges at low magnifications and slow crack-growth with coarse tear paths and fast crack-growth with fine tear paths at high magnifications. Morphologies typical of slow crack-growth are also seen within the banded (fatigue) regions. On the finest scale, the morphology can be described in terms of tearing of individual groups of rubber strands, collapsing to form a cell-like structure.
Network Formation by Association of Polar Groups in Elastomers
Authors: Nakajima N. , Huang C. D. , Scobbo J. J. , Shieh W. J. , Harrell E. R. 
Published: February 2011

Abstract
If an elastomer containing polar groups forms interchain associations, can we observe them independently from the effect of chain entanglement? Polyethylacrylate and polyepichlorohydrin are polar elastomers. Our previous deformational study indicated that these elastomers contain interchain associations, which are stronger than the physical entanglements. The conclusion was based on the results of large, unidirectional extension and small simple shear measurements. On the other hand, butadiene—acrylonitrile copolymer (NBR) containing 33% acrylonitrile did not indicate a presence of such a strong interchain association. In this work, we examined NBRs containing 40% acrylonitrile. The polar association, though weak, was detected with these elastomers. This indicates that the effective association involves a number of polar groups closely placed along the polymer chain. Also, in this work, nonpolar elastomers, SBRs, were chemically crosslinked and used as models. The polar association turned out to be not as strong as the chemical crosslinks. This indicates that the polar association disengage and reengage during the deformation.
Analysis of Components in Rubber Compounds Using Mass Spectrometry
Authors: Lattimer Robert P. , Harris Robert E. 
Published: February 2011

Abstract
A large number of very successful mass-spectrometric methods have been developed for rubber-compound analysis. The high sensitivity, high specificity, and superb mixture analysis capabilities of modern mass spectrometry make it an invaluable tool in the polymer industry, particularly for qualitative identification of organic additives. In many cases, mass spectrometry can provide unique information that is not available by use of any other technique.
The Radial Tire, a Peaceful Revolution
Authors: Massoubre Jean-Marie 
Published: February 2011

Abstract
Now, summing up in terms of everyday life, the consequences of the turning the tire industry took 40 years ago, we can refer to a peaceful revolution. It resulted in: 1. Precise steering and cornering. 2. Higher speeds, together with safer and more stable conditions. 3. Less wear and longer use (at least twice as many kilometers, high re-treadability for heavy trucks). 4. Materials and energy savings. 5. Much lower cost per mile. 6. Much safer and quieter drive. 7. Transportation of persons and goods never a problem. Can we imagine today our industry turning out 2 or 3 times more tires than it does, manufacturing 3 or 4 times more rubber, our vehicles burning 15–20% more fuel, to say nothing of the extra energy needed for production. What about the mountains of scrap tires, 2 or 3 times higher? Just like any radical change, we cannot imagine bypassing it. The only dark side can be found in the forgetfulness or contempt of a valiant and inexpensive servant, which ends in bad maintenance and dangerous neglect.
Pulsed NMR for Molecular Structure Analysis of EPDM
Authors: Tomlinson Richard W. , Sheridan Daniel F. 
Published: February 2011

Abstract
The use of pulsed NMR analysis under proper operating conditions has proven to be useful for controlling various polymer compositions in the manufacture of EPDM. It can be used in determining the amount of oil incorporated into oil-extended EPDMs. At higher oil contents, the differences in EPDM properties will affect this test method, which will require a separate calibration curve for each type of polymer. It can be used to measure the propylene content of EPDM. Comparison data have shown that this technique is more accurate in predicting crystallinity or propylene content than the standard IR method within the propylene range of 22 to 41%. Pulsed NMR can also be used to predict uncured EPDM compound tensile strength and EPDM/PP compression-molded tensile strength. Since these properties are affected by the crystallinity of EPDM, of which percent ethylene is the major contributor, then tensile strength can be determined indirectly. Based on the tensile and SER correlation, it seems obvious that this technique is measuring the spin-spin relaxation times of the crystalline phase, whereas the ir method is only measuring propylene content.
Crack Initiation and Propagation in Model Cord-Rubber Composites
Authors: Huang Y. S. , Yeoh O. H. 
Published: February 2011

Abstract
The present study suggests that the development of penny-shaped cracks at cord ends is the first stage of fatigue failure of cord-rubber composites. An approximate theory for calculating the strain-energy release rate (tearing energy) for the propagation of penny-shaped cracks and predicting the life of model composites has been outlined. The basic premise of this theory is that the rate of propagation of these penny-shaped cracks is governed by the usual crack-growth characteristics of rubber vulcanizates customarily determined using simple test pieces such as the pure-shear test piece. Fatigue studies on two model composites show experiment and theory to be in semiquantitative agreement. Breidenbach and Lake have already established the relationship between the crack-growth characteristics of the rubber material to interply crack propagation, a later stage in the fatigue failure of cord-rubber composites. Therefore, it is clear that the crack-growth characteristics are an important screening criterion for compound development aimed at improving the life of cord-rubber composites.