bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activators in Accelerated Sulfur Vulcanization
Authors: Heideman Geert , Datta Rabin N. , Noordermeer Jacques W. M. , van Baarle Ben 
Published: February 2011

Abstract
This review provides relevant background information about the vulcanization process, as well as the chemistry of thiuram- and sulfenamide-accelerated sulfur vulcanization with emphasis on the role of activators, to lay a base for further research. It commences with an introduction of sulfur vulcanization and a summary of the reaction mechanisms as described in literature, followed by the role of activators, particularly ZnO. The various possibilities to reduce ZnO levels in rubber compounding, that have been proposed in literature, are reviewed. A totally different approach to reduce ZnO is described in the paragraphs about the various possible roles of multifunctional additives (MFA) in rubber vulcanization. Another paragraph is dedicated to the role of amines in rubber vulcanization, in order to provide some insight in the underlying chemical mechanisms of MFA systems. Furthermore, an overview of Model Compound Vulcanization (MCV) with respect to different models and activator/accelerator systems is given. In the last part of this review, the various functions of ZnO in rubber are summarized. It clearly reveals that the role of ZnO and zinc compounds is very complex and still deserves further clarification.
Naval Applications of Elastomers
Authors: Roland C. M. 
Published: February 2011

Abstract
The fact that rubber can be studied in a state of mechanical equilibrium makes it the most fundamentally interesting polymeric material. Elastomers also find wide application both in industry and the military, due to the unique combination of obtainable properties. This short review describes selected uses of rubber by the U.S. Navy on surface vessels, submarines and aircraft. The emphasis is applications which exploit rubber's capacity for energy transmission, storage and dissipation.
Thermoplastic Elastomers Based on Waste Rubber and Plastics
Authors: Rajeev R. S. , De S. K. 
Published: February 2011

Abstract
This paper reviews the utilization of waste rubber and waste plastics for the preparation of thermoplastic elastomers (TPEs). TPEs based on ground rubber tire (GRT), waste EPDM rubber, waste nitrile rubber, recycled rubber, latex waste, and waste plastics are described with respect to composition and physical properties. It is found that part of the rubber phase or plastics phase or both in the rubber-plastics blend can be replaced with corresponding waste polymer for the preparation of thermoplastic elastomers. In many cases, the materials prepared from waste polymers show properties comparable to those prepared from fresh polymers. However, in some cases, the materials prepared from waste rubber or waste plastics cannot be classified as TPEs, as the blend compositions show very low elongation at break. Modification of the waste polymer or the use of compatibilizers result in stronger composites.
Models for the Component Dynamics in Blends and Mixtures
Authors: Ngai K. L. , Roland C. M. 
Published: February 2011

Abstract
Four models for the component dynamics in polymer blends are briefly reviewed, with an emphasis on their ability to describe anomalous segmental relaxation behavior, secondary relaxations in blends, mixtures which include small molecules, and properties in the concentration limits of probe molecules and neat polymers. While general features of the segmental dynamics of polymer blends can be accounted for by all of these models, only that of the authors addresses all these particular aspects of blend dynamics. Our conclusion is that assessment of blend dynamics models should extend beyond intuitive appeal or general properties, with due attention given to the more subtle and exceptional behaviors.
Cure State Distributions in Rubbers by Dynamic Nano-Indentation
Authors: Tsou Andy H. , Westwood Alistair D. , Schulze Jonathan S. , Herbert Erik G. 
Published: February 2011

Abstract
A depth-sensing and frequency-specific dynamic indentation technique was used to determine the spatial distributions of dynamic moduli, including storage (E′) and loss moduli (E″), in poly-cis-1,4-butadiene (BR) and brominated poly(isobutylene-co-p-methylstyrene) (BIMS) rubbers with varying degrees of cure and with or without carbon black fillers as a function of penetration depth. The BR rubbers were cured with sulfur and a sulfur accelerator and the BIMS rubbers were cured using zinc oxide and stearic acid. The dynamic modulus reached a constant bulk value after the Berkovich indentor penetrated into rubbers far beyond the surface. Spatially averaged bulk dynamic moduli thus determined using the nano-indentation technique were compared with the tensile extensional moduli and the frequency-dependent dynamic tensile moduli both measured from the bulk rubbers. Spatial distributions of cure and its dependence on penetration depth were evaluated as functions of cure level, filler loading, and sample surface preparation. The ultimate goal is to provide quantitative cure distribution maps in rubber blends and compounds through a combination of Atomic Force Microscopy (AFM) and dynamic nano-indentation characterization.
Effect of Network-Chain Length on Strain-Induced Crystallization of NR and IR Vulcanizates
Authors: Tosaka Masatoshi , Kohjiya Shinzo , Murakami Syozo , Poompradub Sirilux , Ikeda Yuko , Toki Shigeyuki , Sics Igors , Hsiao Benjamin S. 
Published: February 2011

Abstract
Strain-induced crystallization of natural rubber (NR) and synthetic isoprene rubber (IR) with various crosslinking densities was investigated by wide angle X-ray diffraction using a synchrotron radiation and simultaneous tensile measurements. The elongation ratio at the onset of crystallization (αc) was almost independent of crosslinking density. IR samples showed larger αc values than NR because of the lower stereoregularity of IR. These results suggest that the onset of crystallization is determined by increased melting temperature by strain due to an entropic reason. The amount of oriented amorphous component changed approximately linearly with strain, and was a little larger in IR than in NR when compared at the same elongation ratio. At small strain (and stress), crystallinity in IR was lower than in NR. These results indicate that, at small strain region, the more stress is assigned to oriented amorphous in IR than in NR.
Modeling of Stress-Softening for Elastomeric Materials
Authors: Gentot Laetitia , Brieu Mathias , Mesmacque Gérard 
Published: February 2011

Abstract
An experimental study of deformed reinforced elastomeric materials in uni-axial tension test has been carried out and brings to the fore a significant stress-softening during the first cycles. A new predicted stress-softening model is proposed and well adapted to many rubber-like materials.
Online Electrical Conductivity as a Measure to Characterize the Carbon Black Dispersion in Oil Containing Rubber Compounds with a Different Polarity of Rubber
Authors: Le H. H. , Prodanova I. , Ilisch S. , Radusch H.-J. 
Published: February 2011

Abstract
The influence of viscosity, polarity of the rubber matrix and the types and contents of extender oil on the carbon black dispersion has been characterized using the online electrical conductivity measurement. A corresponding change of the online conductivity with the rubber infiltration and extent of carbon black dispersion has been observed. The infiltration rate increases with increasing polarity and decreasing viscosity of the rubber matrix, whereby the matrix polarity shows a stronger effect than the viscosity. The oil addition accelerates the infiltration process. This is caused by the reduction of the matrix viscosity and the intensification of the filler-matrix interaction. Oil addition affects the carbon black dispersion in non-polar rubber much more than in polar rubber. Furthermore, in non-polar rubber, polar oil shows a stronger effect than non-polar oil.
Mechanistic Study of the Role of One-Component Resins in Rubber-to-Brass Bonding in Tires
Authors: Patil Pankaj Y. , van Ooij William J. 
Published: February 2011

Abstract
Adhesion between rubber and brass-coated steel cords is enhanced by using resins as adhesion promoters. Experiments were carried out using a squalene liquid rubber modeling approach to study the effect of resins on the chemistry of the vulcanization reaction. The formation of new intermediates during vulcanization and changes in chemical concentrations with reaction time was studied using Gel Permeation Chromatography (GPC) analysis of the reacted squalene mixtures. Also, the effect of presence of resins on the surface of sulfidized brass cords was studied by analyzing the adhesion layer's elemental composition using the Electron Dispersive X-ray Spectroscopy (EDX) and Secondary Ion Mass Spectrometry (SIMS) characterization techniques. The changes in surface morphology of the adhesion layer with reaction time was noted by taking micrographs using the Scanning Electron Microscopy (SEM) technique. In this paper, a new mechanism is proposed for the role of resins in the improvement of initial and aged adhesion performance between rubber and brass-coated steel tire cords.
Pre-Vulcanization Inhibition of a N-t-Butyl-2-Benzothiazole Sulfenamide Cure by N-(Cyclohexylthio)Phthalimide
Authors: Gradwell M. H. S. , Stephenson N. R. 
Published: February 2011

Abstract
The reactions of N-(cyclohexylthio)phthalimide (CTP), in the absence of zinc oxide, leading to the inhibition of vulcanization in a N-t-butyl-2-benzothiazole sulfenamide (TBBS) accelerated sulfur cure were studied in the presence and absence of rubber. Mixtures of CTP, TBBS and sulfur were heated in a DSC and the reaction products and residual curatives analyzed by HPLC. Cyclohexanethiol, a decomposition product of CTP, reacted with TBBS producing 2-mercaptobenzothiazole (MBT) and t-butylamine, both of which reacted with CTP. In a polyisoprene compound, the addition of CTP did not delay the formation of the initial crosslinks, however the crosslink density did not increase substantially until the CTP had been consumed. MBT, a product of the crosslinking reaction, reacted preferentially with the CTP and not the TBBS. In the absence of CTP, the MBT was shown to accelerate the rate of TBBS polysulfide formation leading to a rapid rise in crosslink density.
Dynamical Mechanical Analysis of Conductive BR/EPDM/CB Blends
Authors: Ibarra-Gómez Rigoberto , Márquez Alfredo , Mendoza-Duarte Mónica 
Published: February 2011

Abstract
In the present work, Dynamical Mechanical Analysis (DMA) was employed in order to evaluate viscoelastic properties of polybutadiene (BR)/EPDM/Carbon black (CB) blends as a function of the strain amplitude. As expected, storage modulus, G', of conductive samples presented a strong dependence on strain amplitude as described by the Payne effect. This effect appears in compounds at the electrical percolation threshold and is stronger as CB content is rinsed. However, linear viscoelastic region (LVR), a characteristic section of the curve which has had little attention in this type of studies, presented also a great dependence on CB concentration, i.e. LVR is shorter as carbon black content and, hence, the conductivity of samples, increases. Respect to the influence of the elastomeric ratio BR/EPDM, EPDM alone (ratio 0/100), which had the highest viscosity, was the only formulation without a significant G' dependence on strain at 15 % w/w of CB. Also, conductivity was measured before and after the deformation cycle, in such a way that these data were useful as an indication of the structure recovery. As electrical end mechanical hysteresis is related to the state of (CB) distribution these results are envisaged to balance mechanical and electrical stability.
Dynamically Vulcanized PP/EPDM Blends: Multifunctional Peroxides as Crosslinking Agents — Part I
Authors: Naskar Kinsuk , Noordermeer Jacques W. M. 
Published: February 2011

Abstract
Thermoplastic vulcanizates (TPVs) or dynamic vulcanizates are a special class of thermoplastic elastomers, produced by mixing and crosslinking of a rubber and a thermoplastic polymer simultaneously. In a previous study, it was demonstrated that the use of dicumyl peroxide in combination with triallyl cyanurate as crosslinking agents provides a good overall balance of physical properties of PP/EPDM TPVs. Commonly used peroxides like dicumyl peroxide generally produce volatile decomposition products, which sometimes provide a typical smell or show a blooming effect. In this paper multifunctional peroxides are described, which reduce the above-mentioned problems. They consist of a peroxide and co-agent-functionality combined in a single molecule. The multifunctional peroxides provide properties of TPVs, which are comparable with commonly employed co-agent assisted peroxides. The solubility and kinetic aspects of the various peroxides are highlighted, as well as the decomposition products of the multifunctional peroxides with respect to the avoidance of smelly by-products. Particularly, 2,4-diallyoxy-6-tert-butylperoxy-1,3,5-triazine turns out to be a very good alternative to the dicumyl peroxide/triallyl cyanurate combination.
Simultaneous Control of 1,4-cis Selectivity and Molecular Weight of Polymer in Polymerization of Butadiene with Co(acac)3/MAO Catalyst
Authors: Endo Kiyoshi , Hatakeyama Naoyoshi 
Published: February 2011

Abstract
Simultaneous control of 1,4-cis selective polymerization and molecular weight of polymer in the polymerization of butadiene (BD) with Co(acac)3/MAO catalyst was investigated. The polymerization of BD with the Co(acac)3/MAO catalyst strongly depended on catalyst preparation, and the polymerization rate of BD with Co(acac)3 activated by MAO in the presence of BD was faster than that with previous reported results that the Co(acac)3 activated by MAO in the absence of BD. From a kinetic study, linear relation between ln[BD]0/[BD]t and polymerization time and no induction period for the polymerization were observed in the polymerization of BD with Co(acac)3 activated by MAO in the presence of BD. This indicates that the active site for the polymerization kept constant throughout polymerization. The molecular weights of the polymers increased linearly with polymer yields, and the line passed through the original point. The Mw/Mn of the polymers kept constant during reaction time. The polymerization of BD performed at 0 °C in the Co(acac)3/MAO catalyst gave high molecular weight 1,4-cis poly(BD) (1,4-cis content &gt; 95) and narrow polydispersity (Mw/Mn=1.36). On the basis of these results, it is clear that simultaneous 1,4-cis selective and molecular weight control is possible in the polymerization of BD with the Co(acac)3/MAO catalyst.
Utilization of Maleic Anhydride Modified Ground EVA Waste in NBR Vulcanizates
Authors: Soares Bluma G. , Gomes Ana C. O. , Moreira Viviane X. , Oliveira Marcia G. 
Published: February 2011

Abstract
The influence of poly(ethylene-co-vinyl acetate) (EVA) waste (EVAW) on the rheological and mechanical properties of NBR vulcanizates compounds was studied. The optimum concentration of EVAW, which has presented higher ultimate tensile strength, was found to be 70 phr. In addition, the influence of EVAW modified with maleic anhydride as adhesion promoter was studied. Two distinct routes of modification with maleic anhydride were selected, originating a carboxylated EVA waste (EVAWCOOH) and an anhydride EVA waste (EVAWMA). An improvement of tensile strength and aging resistance was observed with the substitution of EVAW by EVAWCOOH or EVAWMA. A very good resistance to compression set has been achieved with the addition of EVAWCOOH. The improvement of mechanical performance was attributed to a better dispersion of EVAW along NBR matrix, promoted by the enhanced modified-waste polarity, which allowed a good interaction with polar NBR. The presence of anhydride group in functionalized EVAW resulted in the highest values of tensile strength but lower elongation at break and also lower values of tan delta obtained from dynamic testing. These behaviors have been attributed to an increase of crosslink density due to the reaction between zinc oxide and succinic pendant groups of EVAWMA.
Structure-Property Relationship of a Thermoplastic Vulcanizate (Tpv)/Layered Silicate Nanocomposites Prepared Using Maleic Anhydride Modified Polypropylene as a Compatibilizer
Authors: Mishra Joy K. , Kim Il , Ha Chang-Sik , Ryou Jin-Ho , Kim Gue-Hyun 
Published: February 2011

Abstract
Thermoplastic vulcanizate(TPV)/organoclay nanocomposites have been successfully prepared by melt intercalation method. Maleic anhydride modified polypropylene has been used as a compatibilizer. The TPV/organoclay nanocomposites have been characterized by Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and Transmission Electron Microscope (TEM). The nanocomposite as evidenced by X-ray diffraction is an intercalated one. The nanocomposites exhibited remarkable improvement in tensile and storage modulus over their pristine counterpart. The dynamic mechanical analysis reveals that the glass transition temperature of the polypropylene phase of the nanocomposite is increased (compared to its pristine counterpart), whereas the EPDM phase remains same. The nanocomposites showed improved solvent resistance over its pristine counterpart. The structure-property correlation of the nanocomposites is attempted.
Investigating the Non-Linear Viscoelastic Behavior of Filled Rubber Compounds Through Fourier Transform Rheometry
Authors: Leblanc Jean L. 
Published: February 2011

Abstract
Fourier transform (FT) rheometry was used to investigate the non-linear viscoelastic behavior of a series of carbon black filled rubber compounds with various filler levels. Using a purposely modified commercial dynamic rheometer, i.e. the Rubber Process Analyzer RPA 2000® (Alpha Technologies), special strain sweep tests protocols were designed and performed in order to capture the actual strain and torque signals up to 500% deformation at constant frequency and temperature. FT yielded the main component and harmonics of strain and torque signals. Results show that the quality of the applied strain signal somewhat deteriorates with increasing stiffness of filled compounds, but remains excellent in the high strain region, where the non-linear viscoelastic response of the materials is investigated. Above a filler volume fraction of around 12–13%, tested materials no longer exhibit a linear viscoelastic response, at least in the strain window investigated, and the FT rheometry results are more complex than what was observed with pure gum samples. This means that most practical rubber compounds are intrinsically non-linear. By essence, FT rheometry is a valid technique for both the linear and the non-linear domains and, as shown, provides original information about complex polymer systems such as filled rubber compounds.
Effect of Compound Ingredients on Adhesion between Rubber and Brass-Plated Steel Cord
Authors: Hotaka Takeshi , Ishikawa Yasuhiro , Mori Kunio 
Published: February 2011

Abstract
Effect of several ingredients in the rubber on adhesion characteristics between brass-plated steel cord and rubber was thoroughly investigated. Amine component is generated by N,N'-dicyclohexylbenzothiazole-sulphenamide- (DCBS) accelerated sulfur vulcanization, and it is known to promote stress-induced corrosion crack in the brass layer at the brass plated steel cord. Hexamethoxymethylmelamine (HMMM), which is formulated for the condensation reaction of RF resin, has a function to trap amines, which was found to effectively improve the adhesive strength in water-aged degradation. It was clarified that the physical properties of the vulcanized rubber such as crosslink density and strain modulus are also improved by trapping the residual amine accompanying improved adhesive strength for the formulation with HMMM. Influence of carbon black on concentration of the residual amine and adhesive strength was also studied. Amount of the amine was inversely proportional to the carbon gel content, while adhesive strength linearly increased with the level of carbon gel. It was assumed that the carbon black dose enhances the adhesive strength due to a preferential entrapment of the amine at the stage of carbon gel formation.
Rubber/Fiber Interactions During the Tearing of Rubber Coated Polyester Fabrics
Authors: Tao Z. , Chen J. , Stacer R. G. , Mead J. L. 
Published: February 2011

Abstract
Results on the characterization of the tearing behavior of a series of uncoated and butyl rubber coated polyester plain weave fabrics are reported. Polyester fabrics were obtained from commercial source to cover a broad range of fill yarn properties. Dip coating was used to obtain coated fabrics. Data indicates that the tear behavior of this composite system can be analyzed in terms of initiation and arrest loads, stiffness, and number of yarns per peak. Results show that yarn mobility and subsequent del zone structure play a critical role in each of these characteristics.
A Contribution to the Understanding of Elementary Wear Mechanisms of Rubber Filled Compounds
Authors: Petitet G. , Loubet J-L. , Zahouani H. , Mazuyer D. 
Published: February 2011

Abstract
Tire rubber treads wear patterns that are described as craters can appear in mild conditions. This article demonstrates that craters can be recreated on a laboratory tribometer, which has been developed especially for rubber filled compounds testing. A local analysis of the worn surfaces has shown that the dimension, density and location of craters are closely related to carbon black agglomerates found within compounds. The viscoelastic properties of the agglomerates have been found by carrying out nanoindentation tests: these give a Young's modulus of around 300 MPa and a elasto-plastic limit between 7% and 14%. Finally, an original system is proposed to explain the crater formation on the release of internal stresses due to an agglomerate mechanical plasticizing of the rubber surface. Electronic microscope observations and a finite element analysis show that the agglomerates are flattened by the indentor contact and tilted, to create craters on the worn surface.
Modeling the Stress-Strain Behavior of Rubber
Authors: Muhr A. H. 
Published: February 2011

Abstract
This review focuses on models for rubber that have been used to solve practical problems, either analytically or through the use of finite element analysis (FEA). The emphasis is on the mathematical structure of fully three dimensional models and the scope of behavior that they describe. The mechanisms that are responsible for the behavior are referred to in passing, and prominence is given to models with firm mechanistic foundations. The review starts with definitions of stress and of measures of deformation, and shows how even the simplest model, classical elasticity theory with appropriate values of shear and bulk moduli, gives useful analytical expressions for many products. Viscoelasticity and hyperelasticity are briefly discussed, as well as the more recently introduced models for inelastic effects, notably the Mullins and Payne (or Fletcher-Gent) effects. Some phenomena not yet addressed by models implemented in commercial FEA packages, such as set, cyclic creep and cyclic stress relaxation, are mentioned, and indications of emerging approaches to modeling them are given.