bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Planar Tension Test of Rubber for Evaluating the Prediction Ability of the Modified Eight-Chain Model under Moderate Finite Deformation
Authors: Xia Yong , Dong Yi , Xia Yuanming , Li Wei 
Published: February 2011

Abstract
In this paper, a novel planar tension test is applied to evaluate the prediction ability of the rubber constitutive models under moderate finite deformation. Based on the automated grid method, it is found that in planar test, deformation in the center region of the specimen is homogeneous but that of the whole specimen is heterogeneous. With three dimensional (3D) finite element (FE) modeling, both the load-stretch relationship and the deformation fields predicted by various constitutive models are obtained under heterogeneous deformation state of the planar tension. By comparing FEA results to the test results, the prediction abilities of these constitutive models are evaluated. According to the results of this heterogeneous planar tension test, the modified eight-chain model is found to be more successful than the eight-chain model and the Van del Waals model in predicting the observed hyperelastic behaviors of rubber material under different deformation states.
Novel Styrenic Thermoplastic Elastomers from Blends with Special Reference to Compatibilization and Dynamic Vulcanization
Authors: Patel J. D. , Maiti M. , Naskar K. , Bhowmick Anil K. 
Published: February 2011

Abstract
A thermoplastic elastomer (TPE) is a rubbery material with final properties and functional performance similar to those of a conventional vulcanized rubber at ambient temperature, yet it can be processed in a molten condition as a thermoplastic polymer at elevated temperature. The main objectives of the present investigation are: to prepare novel styrenic-based thermoplastic elastomers based on blends of a thermoplastic (polystyrene or styrene acrylonitrile) with a rubber (styrene butadiene or ethylene vinylacetate) and to investigate the interaction between various polymers with special reference to compatibilization via oxazoline-modified polystyrene or oxazoline-modified styrene acrylonitrile and dynamic vulcanization. Styrene acrylonitrile/ethylene vinylacetate blends are found to exhibit better overall properties, especially tensile strength, elongation at break and tension set. The solubility or interaction parameter and the morphology of the blends are the key parameters, which basically govern the final properties of blends. Physical properties of these blends have been correlated with the interaction parameter and final morphology.
Phenomenological Hyperelastic Strain-Stiffening Constitutive Models for Rubber
Authors: Horgan Cornelius O. , Saccomandi Giuseppe 
Published: February 2011

Abstract
Many rubber-like materials and soft biological tissues exhibit a significant stiffening or hardening in their stress-strain curves at large strains. The accurate modeling of this phenomenon is a key issue for a better understanding of the thermomechanics of rubber and the biomechanics of soft tissues. In this paper, we provide a review of some phenomenological hyperelastic constitutive models that have been proposed to model this strain stiffening effect and summarize recent advances in the solution of boundary-value problems that illustrate the utility of such models. The emphasis is on constitutive models that reflect limiting chain extensibility at the molecular level. A remarkably simple phenomenological model of this type has been proposed by Gent. The Gent model has a molecular basis related to the inverse Langevin function compact support non-Gaussian statistics for the end-to-end distance function. The mathematical simplicity of the Gent model, which contains just two constitutive parameters, has facilitated the analytic solution of a variety of specific boundary-value problems that are relevant to the rubber industry and we summarize the main results here. These problems include those of torsion, axial, azimuthal and helical shear, anti-plane shear, mode III crack problems, rotation induced deformation of circular cylinders and fracture problems. It is shown that the results are radically different from those obtained in the literature for classical models such as the neo-Hookean and Mooney-Rivlin models for incompressible rubber. Extensions to include thermoelasticity, material compressibility, anisotropy and stress softening are also briefly described.
The Hysteresis Temperature and Strain Dependences in Filled Rubbers
Authors: Scurati Alberto , Lin Chenchy J. 
Published: February 2011

Abstract
The strong hysteresis (tan δ) temperature dependence observed in filled compounds containing functional polymers was investigated by studying the individual effect of filler-filler (F-F) and polymer-filler interactions (P-F). Silica filled compounds were prepared by adding n-octyl-triethoxyl or mercatopropyl-trimethoxyl silane. Both silanes are capable of retarding filler flocculation upon heating and give compounds with less developed filler networks either by reducing F-F interactions or by screening filler networks through P-F attachments. The filler network is shown to mediate the low-temperature hysteresis due to the polymer glass transition (Tg) by changing the temperature dependence of the compound dynamic storage modulus (G′). At temperatures far above the Tg, the compound tan δ is governed by mechanisms that control the degree of filler networking. Compounds with less developed networks show weaker strain dependence on G′ and tan δ. Both reduced F-F and increased P-F interactions will give a compound with a less developed network. However, significant reduced tan δ is only found in a system that shows strong P-F interaction due to less energy loss upon deformation by fewer network breakage and increased P-F crosslinks. This is exemplified by comparing the compound loss moduli (G″) of various stocks with corresponding G′ in G-plot (G″ vs. G′).
Reduced Hysteresis in Truck Tread Compounds by Using Aramid Short Fibers
Authors: Datta R. N. 
Published: February 2011

Abstract
The preparation of an intricate engineering component can be accomplished by using aramid short fibers as the reinforcing medium of an elastomer, especially tread compounds with a target to improve hysteresis without sacrificing other performance properties. For many years short fibers have been used to reinforce all sorts of rubbers. Particularly compounds with relatively low fiber content have been successful in improving hose and belt performance. The use of aramid short fibers, for example, poly-paraphenylene terephthalamide, PPTA (Twaron), poly-(metaphyneleneisophthalamide, MPIA (Conex) and co-poly-(paraphenylene/3,4′-oxydiphenylene terephthalamide, PP/ODPTA (Technora) have been explored in typical truck tread compounds with an objective to improve hysteresis, thereby reducing rolling resistance. This paper presents the results on our latest research in this area focusing on improvement in rolling resistance, heat build up, flex, and dynamic properties. Compounds have been engineered to improve the hysteresis characteristics with a positive effect on wear and tear resistance. Furthermore, the levels of fibers and their sizes have been varied to obtain best performance advantage. This paper will provide a snapshot of all advantages that can be obtained by addition of small amount of fibers, often in a way which is impossible with conventional particulate fillers or with other fibers.
Physical Property Changes in Commercial Natural Rubbers during Long Term Storage
Authors: Yunyongwattanakorn Jintana , Sakdapipanich Jitladda T. 
Published: February 2011

Abstract
The physical properties during long term storage of selected commercial Standard Thai Rubbers (STR), i.e. STR XL, STR 5L and STR CV60 as high-graded natural rubber (NR), were investigated. Sections of commercial NR were subjected to examination after storage-hardening. STR 5L showed clearly an increase in Mooney viscosity (VR), Mooney relaxtion (MR30), gel content and initial plasticity (P0), higher than that of STR XL. This result suggests that STR 5L exhibits the highest inconsistency in physical properties. The increasing viscosity and gel content of STR 5L and STR XL samples suggest the occurrence of a crosslink structure during storage. STR CV60, known as a viscosity-stabilized NR sample, also showed an increase in VR, gel content, P0, and high PRI value during long storage. These findings indicate that storage-hardening occurred in the rubber samples even after carefully controlled production procedures. As for the different sections of samples, there was no clear relation with gel content with respect to storage time, indicating that depth or positions of specimens in a certain rubber bale did not affect the storage-hardening phenomenon.
Mechanistic Study of the Effect of Adhesion-Promoter Resins on the Crystal Structure of the Copper Sulfide Adhesion Layer at the Rubber-Brass Interface
Authors: Patil Pankaj Y. , van Ooij William J. 
Published: February 2011

Abstract
We have previously presented the effect of adhesion-promoter resins, used in the belt compound of tires, on the mechanical properties of the rubber compounds. We have also proposed that the presence of certain adhesion-promoting resins could lead to the formation of a copper sulfide adhesion layer that might protect the residual brass from corrosion during humidity-aging conditions. Highly polished brass coupons were cured against the natural rubber compounds and the cured rubber was later removed using o-DCB (ortho-dichlorobenzene) solvent. To test our proposed theory, we studied the crystal structure of the copper sulfide adhesion layer using synchrotron source Grazing Incidence angle X-ray Diffraction (GIXRD). In this paper, we confirm our previously proposed theory that the presence of adhesion-promoting resins alters the crystal structure of the adhesion layer resulting in a durable rubber-to-brass bonding during aging conditions.
On Multi-Scale Modeling of Elastomeric Laminated Composites for Structural Analysis
Authors: Gurvich Mark R. 
Published: February 2011

Abstract
Analysis of complex structures is often based on multi-scale modeling, where effective properties of certain substructures are used instead of actual properties of smaller components. Laminated composites are usually considered as such sub-structures in components with laminated design. In case of elastomeric composites, well-known classical laminate theories could hardly be used due to significant non-linearity and incompressibility of material deformation. A convenient engineering variant of laminated model is proposed in this study for composites where neither physical nor geometrical non-linearity may be ignored. Possible material incompressibility is also taken into account. The model is primarily based on a previously developed constitutive approach to describe effective properties of anisotropic hyperelastic materials. Analytical and computational implementation of the model is considered in detail. Numerical examples illustrate accuracy and convenience of the model for representative cord/rubber composites.
Dispersion of Layered Organosilicates in Isobutylene-Based Elastomers
Authors: Tsou Andy H. , Measmer Matthew B. 
Published: February 2011

Abstract
Dispersion morphologies of polymer-layered silicate nanocomposites based on either brominated poly(isobutylene-co-para-methylstyrene), BIMSM, or brominated poly(isobutylene-co-isoprene), BIIR, and an organosilicate, dimethylditallow ammonium-exchanged montmorillonite, Cloisite™ 6A, with and without N660 carbon black fillers were examined using SAXS, WAXS, AFM, and TEM. These compounds were prepared using an internal mixer and cured for property measurements. Due to the observed partial orientation of organosilicates and their possible heterogeneous intercalation, degrees of exfoliation and dispersion of organosilicates in BIMSM and BIIR were unable to be characterized and quantified simply by TEM, AFM, or SAXS alone. Instead, using the projected aspect ratio of organosilicates in BIMSM or BIIR, extracted from Gusev-Lusti equation based on measured permeability ratios, was found to provide a relative measure of their dispersion state. Since better dispersion, higher planar orientation, and/or increasing extent of exfoliation lead to higher aspect ratio, this calculated aspect ratio was used as a measure of organosilicate dispersion in BIMSM and BIIR compounds. According to experimentally extracted projected aspect ratios, it was found that BIMSM disperses organosilicates better than BIIR and that carbon black filler does not affect the organosilicate dispersion in BIMSM. Addition of tertiary amines in BIMSM enhances the dispersion of organosilicates, possibly through favorable interactions between organosilicates and quaternary ammonium functionalized BIMSM, resulting in further reduction in permeability.
Electron Beam Curing of Elastomers
Authors: Bhowmick Anil K. , Vijayabaskar V. 
Published: February 2011

Abstract
Modification of thermoplastic and rubbery materials by electron beam (EB) radiation is a potential method for development of new polymers and composites. Irradiation of polymeric materials results in grafting and subsequently formation of a three dimensional network through the union of generated macro radicals. In the Green drive, i.e. to make the world pollution free, this technology takes an important position. Curing of a number of both non-polar and polar elastomers using an electron beam was carried out in our laboratory. The effects of irradiation dose in presence and absence of radiation sensitizer on the crosslinking and structure of ethylene propylene rubber, ethylene octene copolymer, nitrile, acrylic and fluorocarbon rubbers were investigated. An analysis of crosslink to scission ratio on the basis of Charlesby-Pinner Equation was done. Mechanical and dynamic mechanical properties showed that these improved with radiation dose and sensitizer level up to certain values, beyond which the properties deteriorated due to chain scission reactions. The properties of the vulcanizates were correlated with the structure. EB cured samples were compared with the samples having conventional crosslinks. Some applications of the electron beam curing are highlighted.
Mechanical Behavior of Rubber at High Strain Rates
Authors: Roland C. M. 
Published: February 2011

Abstract
Methods to obtain the mechanical response of rubber at high rates of strain are reviewed. These techniques include the extrapolation of low strain, low strain rate data, the limitations of which are discussed, extrapolations to elevated hydrostatic pressure, and direct determinations using split Hopkinson bar and drop weight testers, as well as miscellaneous methods. Some applications involving rubber at strain rates sufficient to induce a transition to the glassy state are described.
Staining Polymers for Microscopical Examination
Authors: Smith Ronald W. , Bryg Victoria 
Published: February 2011

Abstract
Polymers find widespread use in blends, graft copolymers, polymer alloys, and composites. Staining is an important tool for microscopically visualizing polymer phases and morphologies in these multi-component systems. Three stains have been used in most investigations. These stains (and the functional groups they are aimed at) are: osmium tetroxide for chemical unsaturation; ruthenium tetroxide for styrenics; and phosphotungstic acid for polyamides. Beyond these three basic stains there are a significant number of additional ones that have been developed for special cases. Aside from reacting chemically with functional groups, stains have been used as: negative (outline) stains; stains to delineate amorphous-crystalline regions; stains for microvoids, and stains for phase boundaries. Stains are most commonly transported to the target functional groups in tow ways — dissolved in liquid media or by direct contact with stain vapors. Improvisations have been developed to meet special staining problems. These improvisations most often involve: 1) chemical alteration of a polymer backbone to introduce a stainable functionality; 2) tailoring of staining media to provide adequate diffusion into the matrix; 3) preferential swelling of a blend component in order to accept a stainable moiety; 4) tactical use of a staining temperature to take advantage of differences in glass transition temperatures of blend components; and 5) optimization of chemical equilibria to expedite staining time or extent. Examples of these modifications are presented along with some cautionary notes regarding some artifact that may arise. A plea is made for more adequate descriptions of staining protocols in published articles. In too many cases there is inadequate description of staining methods and experimental duplication is put in jeopardy.
HXNBR Coating for Improving Aging Resistance of Natural Rubber Products
Authors: Joseph Rani 
Published: February 2011

Abstract
HXNBR (Hydrogenated Carboxylated Nitrile Rubber) has very good heat ageing resistance and oil resistance. A novel accelerator system is designed to bring about the vulcanization of HXNBR at room temperature. The room temperature cured samples showed good mechanical properties equivalent to those of high (150 °C) temperature cured samples. Natural rubber vulcanizates are highly prone to oxidative and ozone degradation. The oil resistance of natural rubber vulcanizates is also very low. The oil resistance, ozone and oxidative degradation resistance of natural rubber vulcanizates are considerably improved by placing a thin coating of HXNBR over it.
Multifunctional Additives as Zinc-Free Curatives for Sulfur Vulcanization
Authors: Heideman Geert , Noordermeer Jacques W. M. , Datta Rabin N. , van Baarle Ben 
Published: February 2011

Abstract
Concern about the release of eco-toxic zinc species from rubbers into the environment leads to an increasing interest in potential substitutes. This investigation reports on the application of Multifunctional Additives, amines complexed with fatty acids, for sulfur vulcanization of rubbers. Good physical properties can be obtained in s-SBR compounds using the MFA/S cure system, albeit at the cost of a shortened scorch time as compared to a ZnO/stearic acid system. Inclusion of ZnO lengthens the scorch time, though it reduces the state of cure and ultimate properties. The amount of ZnO used in the MFA-formulations is considerably lower than in the conventional systems. The introduction of CaO and MgO leads to an improvement in the state of cure and physical properties. Amines play a vital role in the vulcanization process, hence various amine-complexes have been synthesized and investigated as zinc-free curatives in s-SBR compounds. It is observed that the scorch time is related to the basicity of the amines. The results of Model Compound Vulcanization studies with MFAs reveal a fast decomposition of the accelerator and some differences in the distribution of the crosslinked products. The conclusion must be drawn, that the chemistry involved in the MFA-systems is fundamentally different from the conventional vulcanization systems.
Online Method for Characterization of the Homogeneity of Rubber Compounds Filled with Non-Conductive Carbon Black
Authors: Le H. H. , Tiwari M. , Ilisch S. , Radusch H-J. 
Published: February 2011

Abstract
In the present work, the effect of carbon black (CB) type on the electrical conductance of CB filled rubber compounds measured online in the internal mixer and the corresponding CB dispersion were investigated. The CB dispersion is strongly affected by the specific surface area and structure of CB which can be directly monitored by use of the online electrical conductance method. The effect of CB mixture ratio of a high conductive CB and a non-conductive one on the online electrical conductance was investigated for CB filled rubber compounds. By addition of a small amount of a high-conductive CB type into a non-conductive CB filled rubber compound, a characteristic online conductance - time characteristic is observed that is a result of the formation of a joint network of the two CB types. It could be shown, that such a characteristic is suitable to monitor the dispersion process of the non-conductive CB in the rubber compound.
Aging of Black Filled Rubber under Deformation
Authors: Ahagon Asahiro , Kirino Yoshiaki 
Published: February 2011

Abstract
Prolonged dynamic deformation of a rubber is found to significantly accelerate oxidative crosslinking due to mechanochemical oxidative crosslinking. The extent of acceleration is larger at lower temperatures and increases with increasing strain. The activation energy of the rate of oxidative crosslinking decreases with increasing strain toward the highest value among the unit reactions of oxidative chain reaction cycle or the value of diffusion of oxygen, which is much smaller than that of static aging. On the other hand, static deformation is also found to accelerate oxidative crosslinking but to considerably lesser extents. Mechanochemical acceleration can be noticed only in the early stage of prolonged deformation. The degree of acceleration in prolonged deformation increased with increasing strain without change in the activation energy. The acceleration observed in prolonged static deformation is considered to arise from the increased area of exposure to the oxidizing atmosphere. It appears that mechanochemical acceleration is merely spent to compensate the loss in crosslink density upon deformation in this case.
Preparation and Properties of New in-situ Acrylic Copolymer/Terpolymer- Clay Hybrid Nanocomposites
Authors: Patel S. , Bandyopadhyay A. , Vijaybaskar V. , Bhowmick Anil K. 
Published: February 2011

Abstract
Acrylic copolymer- and 5% acrylic acid (AA) modified terpolymer-hybrids with unmodified montomorilonite clay (Cloisite Na) and organo-modified clay (Cloisite 10A) were synthesized by in-situ free radical bulk polymerization. Hybrid nanocomposites were investigated by Atomic Force Microscopy (AFM), X-ray diffraction (XRD) technique, thermogravimetric analysis (TGA), dynamic mechanical and mechanical properties. XRD results suggested polymer intercalation in both unmodified and organo-modified clay in the copolymer and terpolymer hybrids. AFM analysis further confirmed these results. Cloisite 10A hybrids and the terpolymeric nanocomposites demonstrated superior mechanical and dynamic mechanical properties. Terpolymer-clay hybrids with 9 wt% Cloisite 10A also showed higher thermal stability. The possible reasons for improvement of mechanical properties and thermal stability were discussed with reference to the structure and interaction.
Modeling the Equilibrium Compressed Void Volume of Carbon Black
Authors: Joyce George A. , Henry William M. 
Published: February 2011

Abstract
In this study, a broad range of furnace carbon blacks from very low to very high structure and fineness were evaluated for compressed void volume, colloidal and in-rubber properties. Compressed void volume measurements were investigated over applied pressures of approximately 18–159 MPa using a commercially available instrument. The void volume data was statistically modeled using logarithmic pressure curves, exponential energy curves and an inverse variable root curve. Parameters generated from the void volume models were analyzed using advanced non-linear multiple regression resulting in strong relationships to crushed oil absorption numbers and in-rubber properties. A comparison of void volume and oil absorption numbers indicates the void volume method offers a significant improvement in describing carbon black structure. The relationship between void volume and parameters related to rubber reinforcement found in this work is a confirmation that compressed void volume is more specific to primary structure than oil absorption numbers. Compressed void volume should provide the carbon black industry a faster, more meaningful and lower cost structure characterization than oil absorption methods.