bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective Interactions in Elastomers, a Base for Compatibility and Polymer-Filler Interactions
Authors: Schuster R. H. , Issel H. M. , Peterseim V. 
Published: February 2011

Abstract
This paper describes the determination of accurate solubility parameters for nonpolar rubbers according to a GLC-method developed by Guillet. The data obtained provide a simple but meaningful thermodynamic characterization of the contribution of microstructure units and comonomers (styrene) in polydienes. On this basis quantitative expressions are derived for δ2-parameters of BR and SBR as a function of the vinyl and the styrene content respectively. The consequences on morphology development and miscibility are presented for blends of NR, SBR, BR and EPDM. Furthermore, it is shown for the first time that the method is able to describe the temperature dependence of the δ2-parameter so that temperature induced phase transitions (UCST and LCST) can be predicted. On this basis morphological predictions are made on average domain size and size distribution as well as on the phase inversion region. The contribution of intermolecular interactions to flow-induced phase morphology is discussed in relation to the influence of rheological factors. An extension to polymer—filler systems is made.
Direct Comparison of the Gent and the Arruda-Boyce Constitutive Models of Rubber Elasticity
Authors: Boyce Mary C. 
Published: February 2011

Abstract
The Arruda and Boyce eight-chain network constitutive model for rubber elastic materials is compared to the new Gent constitutive model for rubber elasticity. The salient features of each of the two models are compared. The ability of both models to predict three dimensional large strain deformation is demonstrated showing the near equivalence of these two model constructions as well as their abilities to predict complex three-dimensional deformation with only two material constants.
Fine Scale Characterization of Crosslinking with the Atomic Force Microscope
Authors: Mareanukroh Methporn , Hamed Gary R. , Eby R. K. 
Published: February 2011

Abstract
Fine-scale variations of the crosslink density of elastomers are important scientifically and technologically. We have shown that the atomic force microscope ( AFM), used in the force/distance mode, is sensitive to the crosslink density. In this mode, the sample is pushed against the tip in a manner similar to that for standard hardness testing. However, the end of the tip of the AFM is only 100 to 500 A˚ in radius. Further, it can be moved in a controlled manner in very fine increments both from point to point over the surface and into the surface of a sample. As a result, it can sample much more finely spaced and smaller volumes of material than either the typical hardness tester or the usual methods of measuring crosslink density. Samples of a styrene-butadiene copolymer were compounded with varying amounts of dicumyl peroxide and cured under compression molding at 160°C. Crosslink density was measured by swelling. The results show a significant variation of force/distance penetrated with crosslink density. A plot of experimental value of force/square of distance penetrated vs crosslink density is comparable to a theoretical one calculated with the crosslink density data and the half angle of the conical probe tip. Measurements at a spacing of 170 nm along straight lines are reported as well as measurements which show the technique to be sensitive to oxidation at short times. The effects of variables such as sample roughness, canting of the tip with respect to the sample surface, tilting of the sample surface, penetration depth, sample oxidation, and other variables are considered.
Abrasion of Rubber by a Blade Abrader: Effect of Blade Sharpness and Test Temperature for Selected Compounds
Authors: Gent A. N. , Nah C. 
Published: February 2011

Abstract
Apparatus has been constructed to abrade the flat surface of a rubber disk by rotating it against a stationary knife-blade scraper at constant frictional torque. The ratio of worn surface area to sample volume is relatively large, giving high sensitivity of measurement. Rates of abrasion were measured for several rubber compounds over a range of frictional torque from 0.05 to 1.2 Nm, corresponding to frictional work input from 150 to 3,600 J/m2 per rotation. For some materials, notably SBR compounds, the rate of abrasion decreased markedly as the experiment continued, due to rapid wear and blunting of the blade. Polybutadiene compounds caused much slower wear. Different blades were worn away at different rates, a zirconia blade showing the least wear. Also different elastomers showed different sensitivities to blade sharpness, the rate of abrasion of a high-styrene (48%) SBR compound being reduced the most with a blunted blade whereas the abrasion rate of polybutadiene (BR) was much less affected. Measurements were carried out with blades of known sharpness for several representative rubber compounds at various fnctional torques and at two temperatures, 25°C and 100°C. The high-styrene SBR compound showed the lowest rate of abrasion Unusually rapid abrasion was observed for SBR and BR compounds when the frictional work input exceeded a critical value, close to the tear ( fracture) energy at the same temperature. Also, periodic fluctuations in rate of abrasion were observed for rapidly-aging compounds at high temperatures. This is attributed to repeated formation and removal of a weakened surface layer.
A Study of the Thermal Degradation Products of Styrene-Butadiene Type Rubber by Pyrolysis/GC/MS
Authors: Ghebremeskel Ghebrehiwet N. , Sekinger J. K. , Hoffpauir J. L. , Hendrix C. 
Published: February 2011

Abstract
Pyrolysis coupled with GC/MS was used to study thermal degradation products of styrene—butadiene rubber (SBR). Introduction of samples, using the pyrolysis carrier gas through the split injection port, followed by sub-ambient focusing of pyrolysis products gave reproducible chromatograms. The styrene content of styrene—butadiene copolymer was determined by plotting the GC areas of styrene and butadiene dimer (4-vinlycyclohexene) vs the percent bound styrene measured by refractive index and infrared spectroscopy. The accuracy and ease of use of the technique in determining the styrene content of styrene—butadiene copolymer is also compared to that of the refractive index and infrared spectroscopy methods. Finally, the effects of carbon black and other fillers on the thermal degradation products of the styrene—butadiene copolymer are also discussed.
Solubility of Antioxidants in Rubber
Authors: Pushpa S. A. , Goonetilleke P. , Billingham N. C. 
Published: February 2011

Abstract
Solubilities of seven phenolic antioxidants in rubber and three antioxidants in low density polyethylene (LDPE) were measured at temperatures ranging trom 40°C–100°C. The antioxidants are more soluble in rubber than in LDPE, which is semicrystalline. The solubility of antioxidants is temperature dependent and both the melting point of the additive and its interactions with the polymer are important in determining solubility. As a general rule, solubility decreases with increasing molecular weight.
Effect of Processing Additives on Carbon Black Dispersion and Grip Property of High-Performance Tire Tread Compound
Authors: Takino H. , Iwama S. , Yamada Y. , Kohjiya S. 
Published: February 2011

Abstract
Rubber and carbon black compounds show complex behaviors in their mixing process due to their complicated microcomposite structure. Therefore, establishing a clear relationship between the mixing state of the rubber compound and the physical properties of its cured rubber has still remained to be solved in spite of formidable efforts by many rubber technologists. This paper investigated the influence of a processing additive on the carbon black incorporation and its dispersion behavior by inspecting Banbury power curves. From this investigation, we considered that good wettability toward the carbon black surface was necessary for processing additives in order to improve carbon black dispersion. The function of the processing additive was thought to enhance the surface lubrication of carbon black for disagglomeration in the early steps of mixing. The dry grip properties of a tire was estimated from the temperature dependence of dynamic viscoelastic properties of rubber compounds, with improved carbon black dispersion due to the processing additive; and it was confirmed by an actual tire running evaluation. Consequently, we found that tread compounds with improved carbon black dispersion had a remarkable effect on tire dry-grip properties at high temperatures.
The Dark Field Cut Surface (DFCS) Test for Estimating the Dispersion of Carbon Black in Rubber Compounds
Authors: Murray G. A. W. , Southwart D. W. , Freakley P. K. 
Published: February 2011

Abstract
A test for estimating the dispersion of carbon black in rubber compounds is described. It works by examining the freshly cut surface of a specimen at low magnification in dark field illumination. Roughness of the surface related to the presence of carbon black causes increased reflection under dark field illumination. The illumination of each field of view is examined as 100 subdivisions and the relative values of these readings give a numerical estimate of the dispersion. Details of how this is done and the corrections applied to the results are described. A second paper reports some initial results obtained with the test. The test works well for certain elastomers, notably NR and SBR. The biggest advantage of the test is its ability to work rapidly and cheaply on small zones at relatively high magnification. This opens up the possibility of detailed studies of macroscopic variations in dispersion, done in reasonable times and at reasonable costs.
Effect of trans-Polyoctenylene on Crosslink Structure of NR and SBR Using Solid State 13C NMR Spectroscopy and RPA 2000
Authors: Chattaraj P. P. , Mukhopadhyay R. , Tripathy D. K. 
Published: February 2011

Abstract
The use of petroleum oil as a processing aid is well established in the rubber industry. However, it has certain demerits when used in a critical rubber compound. To overcome this and to get certain other advantages, new non-conventional processing aids (solid in nature) are preferred. trans-Polyoctenylene (TOR) is one of them which is crosslinkable with sulfur and accelerator. The effect of TOR on natural rubber (NR) and styrene—butadiene rubber (SBR) vulcanizates has shown that the retention (%) of network properties at high temperatures, after aerobic and anaerobic aging, is better with incorporation of TOR in conventional vulcanization (CV) curing systems. This has been attributed to the change of network to a more efficient-like system. The purpose of the present work is to establish the change of network structure/crosslinks and their kind and distribution in NR and SBR, with incorporation of TOR followed by a spectroscopic study of the vulcanizate. The study is extended to different crosslinking systems (CV, efficient vulcanization (EV), and semi-EV (SEV) with respect to NR and SBR) considering the effect of anaerobic aging on the vulcanizates. Crosslink distribution (in CV and EV) and network structural change after aging has been explained by a suitable mechanism. Elucidation of crosslink structure of SBR vulcanizates by NMR and estimation of chemical crosslink density by the Rubber Process Analyzer (RPA 2000) are key points of this study.
Ultrasound Devulcanization of SBR: Molecular Mobility of Gel and Sol
Authors: Johnston S. T. , Massey J. , von Meerwall E. , Kim S. H. , Levin V. Yu , Isayev A. I. 
Published: February 2011

Abstract
In an effort to support the recycling of rubbery polymers and composites, 1H NMR relaxation and pulsedgradient spin echo diffusion measurements have been performed on virgin and unfilled vulcanized strene-butadiene rubber (SBR), and networks after various extents of devulcanization using an ultrasound technique. The NMR methods recognize unentangled light molecules (e.g. sol), but do not distinguish between unattached entangled large molecules and chemical network segments. Devulcanization generates additional sol with a wide mass distribution, thus increasing both sol and gel mobility, but decreasing sol mean diffusivity. The latter effect is accounted for by the increasing mean sol molecular mass but also by the increasing glass transition temperature, which is related to main-chain stiffening seen in our earlier 13C NMR experiments. In addition to improving the molecular-level understanding of devulcanization, this study provides guidance for the optimization of the devulcanization parameters.
Structure and Properties of Reinforcing Fractal Filler Networks in Elastomers
Authors: Klüppel Manfred , Schuster Robert H. , Heinrich Gert 
Published: February 2011

Abstract
The effect of filler networking on mechanical and electrical properties of elastomers is discussed on the basis of percolation theory and a recently developed kinetical cluster-cluster aggregation (CCA) model, respectively. In percolation theory pure geometrical arguments are considered and the physical properties of the filler network are related to the infinite cluster that is formed at percolation threshold. In the CCA-model the particles are allowed to fluctuate around their mean position on length scales that are comparable to the polymer fluctuation length. Upon contact of neighboring particles or clusters they stick together and form larger clusters. At sufficiently large filler concentrations (above the gel point of the filler network), a fractal filler network results that corresponds to a space-filling configuration of CCA-clusters. Structure and properties of the filler network in this model are compared to the fractal characteristics of percolation networks. In particular, the influence of anomalous diffusion of charge carriers on the scaling behavior of the conductivity is demonstrated for both types of fractal networks. For the elastic modulus an universal power law behavior results that is independent of the size of the filler particles and the applied rubber in both cases.
Hydrogenation of Diene Elastomers, Their Properties and Applications: A Critical Review
Authors: Singha N. K. , Bhattacharjee S. , Sivaram S. 
Published: February 2011

Abstract
This chemistry and technology of hydrogenation of diene elastomers have substantially grown during the past decade. New applications of hydrogenated elastomers have emerged. Homogeneous hydrogenation has several advantages over heterogeneous hydrogenation because of its higher selectivity, faster rate and cleaner end products. However, separation of catalysts and recycle/reuse of expensive metals still poses problems. The preferred alternative for the hydrogenation of elastomers in solution is the use of Zeigler type catalyst which are less expensive than the noble metal catalysts like Rh, Pd etc. However, such catalysts are not effective when strongly coordinating groups are present in the elastomer. One approach would be to use transition metals, which have less tendency to coordinate with polar monomers in the elastomer. Research is also warranted in the use of less expensive metals for elastomer hydrogenation (Ni, Co, Ru). Use of large quantities of solvent (to keep the solution viscosity low) is another significant cost center in elastomer hydrogenation. Novel agitator systems/reactor configuration to handle higher concentration of rubber in solution, yet provide adequate heat and mass transfer in gas-liquid hydrogenation reaction, needs to be explored. Hydrogenation of diene elastomers in the latex form using water soluble catalyst appear to be hold great promise at the present time since many diene elastomers (like SBR, CR and NBR etc.) are commercially produced directly in the form of latex. Creative exploitation of biphasic catalysts for hydrogenation is expected to gain momentum since early results look promising. This would require greater fundamental understanding of the aqueous-organic interphase in a latex process and the mechanism of transport of catalytic reagent across this interphase. More studies are needed to achieve homogeneous chemical reaction inside of each individual latex particles.
Thiuram- and Dithiocarbamate-Accelerated Sulfur Vulcanization from the Chemist's Perspective; Methods, Materials and Mechanisms Reviewed
Authors: Nieuwenhuizen P. J. , Reedijk J. , van Duin M. , McGill W. J. 
Published: February 2011

Abstract
This paper describes research methodologies for the investigation of the mechanism of vulcanization and discusses the reactivity of thiuram and dithiocarbamate chemicals. The combined knowledge is subsequently applied to thoroughly review the mechanism and chemistry of both thiuram- and dithiocarbamate-accelerated sulfur vulcanization. Integration of the original mechanistic ideas from the 1960s and the results obtained in the past three decades now have led to a more balanced appraisal of events during vulcanization. Questions have been answered, solutions for old problems are proposed, and remaining fields of endeavor are identified.
Business Information Support for the Rubber Industry
Authors: Long Joan C. 
Published: February 2011

Abstract
This paper is a survey of the organizations which regularly provide business and economic information that concern the rubber and rubber products industry. The publications issued by various organizations are examined with detailed information on availability given in the references. The objective of this review is to provide an awareness of what sources are available rather than the retrieval of the information through the various database services. Among the organizations whose publications are mentioned are the International Rubber Study Group (IRSG), the International Institute of Synthetic Rubber Producers (IISRP) and the Rubber Manufacturers Association (RMA). Publications of commercial organizations such as Crain Communications, Lippincott and Peto, and Rapra Technology Ltd. are also included, as are sources of information from the U.S. Government. Internet sources are briefly reviewed.
The Microstructure of Natural Rubber Latex Films
Authors: Cook S. , Cudby P. E. F. , Davies R. T. , Morris M. D. 
Published: February 2011

Abstract
An electron microscopy technique which has been used to visualize the crosslinked regions in vulcanized blends of dry rubber has now been applied to films made from natural rubber (NR) latex. The method involves swelling the latex film with styrene, polymerizing the styrene, sectioning the sample and then staining with osmium tetroxide to reveal the rubber network when observed by transmission electron microscopy (TEM). The micrographs show the higher ratio of interparticle to intraparticle crosslinks in a sulphur post-vulcanized film as compared with a sulphur prevulcanized film. They also show that, as in dry rubber films, the mesh size of the visible rubber network correlates with the crosslink density of the rubber. The technique also reveals that the crosslink distribution in peroxide prevulcanized latex (PPVL) is significantly different from that in latices prevulcanized using sulphur or radiation.
Effect of Leaching and Humidity on Prevulcanized NR Latex Films
Authors: Amir-Hashim M. Y. , Morris M. D. , O'Brien M. G. , Farid A. S. 
Published: February 2011

Abstract
In an attempt to improve the understanding of the mechanism by which aqueous leaching of prevulcanized natural rubber latex films improves their physical properties, experiments have been carried out on such films after storage under controlled humidity conditions. Under conditions of ambient and high humidity, unleached films were found to absorb much more moisture than their leached counterparts. Results obtained from the equilibrium volume swelling measurements and from the C1 constant of the Mooney-Rivlin plots indicated that crosslink density was not affected by leaching. The effect of leaching on the tensile strength and modulus however was generally significant. Under high humidity conditions an increase in modulus on leaching was observed. These results are explained in terms of the hydrophilic nonrubbers having a stiffening effect under dry conditions and a softening effect when wet. Conditioning humidity also had a direct effect on the tensile strength. As humidity increases, the peak in tensile strength against modulus shifts to lower strength and modulus values. Some of the findings were supported by data from experiments in which a hydrophilic nonrubber component, namely sucrose, was deliberately added to prevulcanized natural rubber latex.
Tire Wear Caused by Mild Tread Slip
Authors: Fujikawa Tatsuo , Yamazaki Shunichi , Uchiyama Yoshitaka 
Published: February 2011

Abstract
The purpose of this study is to examine the relationship between the tread wear of rolling tires and the wear of a sliding rubber pad. In the experiments, frictional parameters, i.e. sliding distances, sliding velocities, and contact pressures, are evaluated at points on the tire-tread surface. Using these experimental results, tread wear rates are estimated from the rubber pad wear tests. The estimated values were found to agree with the actual tread wear rates.
Viscoelastic Properties of Elastomers and Tire Wet Skid Resistance
Authors: Takino H. , Nakayama R. , Yamada Y. , Kohjiya S. , Matsuo T. 
Published: February 2011

Abstract
Many studies concerning tire wet skid resistance have been published in the past, but they have in general involved the use of only a few grades of SBR and BR. We have evaluated the British Portable Skid Tester (BPST) wet skid resistance of eighteen sulfur curable polymers which might be used for automobile tires. These results have been analyzed in relation to the viscoelastic properties of the polymer systems. Analysis of wet skid resistance in terms of the peak value of tan δ over a prescribed temperature range, designated as Tα, and abrasion loss—derived from the theory of rubber friction—was concluded to give a better general relationship for a wide range of polymers.
Frictional Heating of Vulcanized Rubber Surfaces and the Behavior of Race-Tire Treads on Dry Pavement
Authors: Maláč Jiří 
Published: February 2011

Abstract
Frictional heating and rubber “melting” processes have been studied on the basis of laboratory experiments and simple models. A new two-temperature mechanism of rubber “melting” is proposed. Race-tire tread behavior at conditions of competition on dry pavement is discussed. Significance of frictional heating and rubber “melting” processes for behavior of common passenger and truck tires is mentioned.
Tetraisobutylthiuram Monosulfide: How Can It Be Both a Cure Retarder and Accelerator with Benzothiazole Sulfenamides?
Authors: Chasar Dwight W. 
Published: February 2011

Abstract
N, N, N′, N′-Tetraisobutylthiuram monosulfide (TiBTM) performs both as a retarder and kicker when used with 2-benzothiazole sulfenamide accelerators. Model reactions were run and followed by HPLC to identify the intermediates that form between TiBTM (and its various analogs) and the primary accelerators. Some of these intermediates were independently synthesized and evaluated as retarders/kickers. The isobutyl groups are responsible for imparting the scorch delay characteristics to one of these intermediates. One other intermediate is most likely responsible for the kicker effect.
Effect of Crosslink Type on the Ultrasound Devulcanization of SBR Vulcanizates
Authors: Levin V. Yu , Kim S. H. , Isayev A. I. 
Published: February 2011

Abstract
Sulfur-cured non-reinforced SBR with different amounts of poly-, di- and monosulfidic crosslinks is devulcanized by high power ultrasound irradiation in a continuous process under various processing conditions. Total crosslink density, the proportion of polysulfidic crosslinks, gel fraction, and glass transition temperature are measured. The effect of the initial fraction of polysulfidic bonds on the devulcanization process is discussed.