bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanostructure in Traditional Composites of Natural Rubber and Reinforcing Silica
Authors: Kato Atsushi , Kohjiya Shinzo , Ikeda Yuko 
Published: February 2011

Abstract
Usual rubber products are a composite from rubber and nano-filler (e.g. silica, carbon black, etc.), and it is believed that the good dispersion of the nano-filler is the most important issue determining the performance of rubber vulcanizates. So far, transmission electron microscopy (TEM) has been the most useful tool for evaluation of the dispersion. However, it affords images of the sample projected on an x, y-plane, and the information along the thickness (z-axis) direction is missing. Three-dimensional (3D) visualization of nanometer structure of nano-filler dispersion in a rubber matrix is what all rubber technologists have been dreaming of. This dream is at last realized, and described in this paper. Use of TEM combined with computerized tomography (abbreviated as 3D-TEM in this paper, which is sometimes called electron tomography) enabled us to reconstruct 3D images of nano-filler (silica or carbon black) aggregates in rubbery matrix. It is said that nano-filler aggregate is a structure of size from 10 nm to 1000 nm, and agglomerate is an even larger structure. The 3D-TEM results on silica aggregates in natural rubber were presented in this paper. Silica aggregates were characterized by combining the 3D images of the vulcanizates. Furthermore, density of silica loaded natural rubber as an example of physical properties, was measured, and explained by the structure elucidated by 3D-TEM.
Generalized Concept of the Reinforcement of Elastomers. Part 1: Carbon Black Reinforcement of Rubbers
Authors: Fukahori Yoshihide 
Published: February 2011

Abstract
The author had a detailed discussion about the new interface model and the concepts proposed by the author concerning the carbon black reinforcement of rubbers, with additional experiments and calculations, and came to the final conclusion. Fundamentally, the changeable and deformable characters of the SH layer in the bound rubber produce the typical phenomena in the carbon black-filled rubbers. The super-networks are constructed through the process of molecular sliding and orientation in the SH layer under large extension, which generate the stress upturn and the great tensile strength in the filled rubber. Both the large scale of molecular slippage and the very large stress increase take place simultaneously in the SH layer. The former occurs for regulating the molecular length between carbon particles and the latter results from the limited extensibility of molecules between carbon particles. Thus, the stress-strain relation of the carbon-filled rubber is governed by the distance between adjacent carbon particles, whose role is similar to the molecular length between crosslinks in the non-Gaussian theory. The very large hysteresis loop observed in the carbon black-filled rubber results from the buckling of the super-network in unloading, whose contribution becomes 40% when the carbon content is 60 phr. Very recently, the above model and the concepts have been verified gradually by other researchers as well.
Correlation of Laboratory Tire Endurance and Rubber Aging
Authors: Bauer David R. , Baldwin John M. , Ellwood Kevin R. 
Published: February 2011

Abstract
Tire endurance as measured by performance on the National Highway Traffic Safety Administration (NHTSA) Stepped Up Load (SUL) test is shown to be a function of both tire construction and the extent of oxidation in the skim and wedge rubber regions of the tire, as measured by peel strength or elongation to break retention. Tire constructions can be distinguished by speed rating. Tires with higher speed ratings (&gt; S) tend to have relatively high times-to-failure (TTF) in the SUL test and are relatively insensitive to rubber oxidation. SUL TTFs for tires with speed rating of S and lower tend to be much more sensitive to rubber oxidation. For these tires, the SUL TTF decreases linearly with aging time in the field. The rate of loss of SUL performance is proportional to the rate of loss of rubber properties. The large variability observed in the SUL results from field aged tires can be explained by the natural variability in oxidation aging rates observed for these tires. For oven aged tires, the correlation between SUL and rubber oxidation is more complex. Initially, the SUL failure time does not change much with rubber oxidation. At a critical oxidation level, however, the SUL failure time begins to drop rapidly with rubber oxidation approaching the behavior of the field tires at high levels of oxidation. The reason for the difference in behavior between the oven aged and field aged tires is the lack of mechanical damage in the belt edge in the oven aged tires relative to the field aged tires.
Pulsed NMR Studies on Long-Term Crystallization Behavior and Melting Process of Natural Rubber under Elongation
Authors: Komura Motonori , Nakajima Ken , Nishi Toshio , Ikehara Takayuki , Zhaobin Qiu 
Published: February 2011

Abstract
Long-term crystallization and melting process of natural rubber under elongation was investigated by measuring spin-spin relaxation time T2 by pulsed nuclear magnetic resonance (NMR). We examined the dependence of the both processes on extension ratio, crystallization temperature and crosslink density. It was found that the crystallization of natural rubber continued over three months even at 10 °C. According to the two-step melting process found for the first time under elongation, we proposed a model that crystalline part of natural rubber under large elongation is composed of two kinds of crystallites from highly extended and loose chains. The situation is caused by the microscopic distribution of extension ratio of the chains between crosslink points.
Continuous Ultrasonic Devulcanization: Comparison of Carbon Black Filled Synthetic Isoprene and Natural Rubbers
Authors: Sun Ximei , Isayev A. I. 
Published: February 2011

Abstract
Continuous ultrasonic devulcanization of carbon black (CB) filled isoprene rubber (IR) was carried out. Similar to unfilled IR, power consumption during the devulcanization of the filled IR increased with the increase of ultrasonic amplitude indicating a greater extent of devulcanization. This was in contrast with the devulcanization of CB filled natural rubber (NR) where power consumption showed a maximum at an intermediate amplitude suggesting a lesser extent of devulcanization at higher amplitude. Such a behavior evidently resulted from the difference in the amount of stereoregular structures in the IR and NR rubbers. Gel fraction and crosslink density of the virgin vulcanizates, devulcanizates and revulcanizates were characterized. Kinetics of revulcanization, rheological properties of the devulcanizates and mechanical properties of revulcanizates were compared with those of virgin uncured IR and their vulcanizates. The effect of processing oil on the IR vulcanization, devulcanization and revulcanization was examined indicating a slight delay of the vulcanization and lower torque without affecting the degree of reversion. The addition of oil caused more devulcanization as indicated by an increase in the ultrasonic power consumption and a reduction of the gel fraction and crosslink density of devulcanized rubbers. The revulcanization of the IR occurred without the induction period, regardless of the presence of CB and processing oil. The retarder introduced in the recipe was effective in improving the scorch safety and minimizing the reversion in revulcanization. The experimental data on normalized gel fraction versus crosslink density of filled IR and NR at low CB loadings was found to fall into the master curve, which is probably determined by the main chain structure of both rubbers consisting of cis-1,4 isoprene. At high CB loadings, some differences were observed. The simulation results predicted such a behavior.
High Strength - Low Hardness Thermoplastic Elastomers from Ethylene-Butene Copolymers and Low Density Polyethylene
Authors: Tembhekar Sandeep , Maiti Madhuchhanda , George Jinu Jacob , Biswas Anjan , Bhowmick Anil K. , Saroop Madhumita , Biswas Amit 
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 as a thermoplastic at elevated temperature. The main objective of the present investigation was to prepare novel olefinic thermoplastic elastomers based on blends of a thermoplastic i.e. low density polyethylene (PE) and new ethylene-butene copolymers (PEB), which would have higher strength and lower hardness compared to the existing TPEs. The 70:30 PEB: PE blend exhibited the best properties. Ethylene vinyl acetate was found to work as compatibilizer at lower loadings in these blends. The resultant blends were of low hardness (60–80 Shore A) and high strength (26–33 MPa). The interaction parameter and the morphology of the blends were the key parameters, which governed the final properties of blends.
Thermoreversible Crosslinking of Maleated Ethylene/Propylene Rubber Using Ionic Interactions, Hydrogen Bonding and a Combination Thereof
Authors: van der Mee M. A. J. , Goossens J. G. P. , van Duin M. 
Published: February 2011

Abstract
Maleated ethylene/propylene copolymer (MAn-g-EPM) was thermoreversibly crosslinked using different routes, i.e. ionic interactions (ionomers), hydrogen bonding and a combination thereof. Microphase separation into polar MAn-rich aggregates occurs for MAn-g-EPM and all crosslinked materials, which act as physical crosslinks. The crosslink density does not change upon modification, but the strength of the aggregates is significantly increased, resulting in improved mechanical properties. All materials except the potassium ionomer with high degree of neutralization (DN) could be remolded into homogeneous and smooth films without chemical changes, indicating that the crosslinks are truly thermoreversible. A comparison of the mechanical properties, i.e. tensile properties and compression set at room temperature, for the different crosslinking routes showed that the poorest properties are obtained for hydrogen-bonded materials. The potassium ionomer with high DN has the best properties by far, but is difficult to process. Comparable mechanical properties are obtained for zinc ionomers, potassium ionomers with low DN and amide-salts, which combine ionic interactions and hydrogen bonding. The amide-salts have a distinct advantage in processing over the ionomers, since they can be compression molded at much lower temperatures, although high temperatures should be avoided because of irreversible imide formation.
Goodyear Medalist Lecture: Rubber Research in the Service of Mankind
Authors: Kennedy Joseph P. 
Published: February 2011

Abstract
It all started at the EXXON Research and Engineering Co. during the 1960-ies where I became an apprentice/coworker of Robert M. Thomas (by the way, Thomas (Figure 1) was another Goodyear Medalist honored for the invention and early development of butyl rubber).1
Mesoscopic Mechanical Analysis of Filled Elastomer with 3D-Finite Element Analysis and Transmission Electron Microtomography
Authors: Akutagawa Keizo , Yamaguchi Ken , Yamamoto Atsushi , Heguri Hisashi , Jinnai Hiroshi , Shinbori Yuki 
Published: February 2011

Abstract
Analysis of deformation of the filled elastomer in mesoscopic scale was investigated with 3-D FEM (Finite Element Analysis). Combination of 3-D TEMT (Transmission Electron Micro Tomography) and Voxel-FEM enables us to reconstruct mesoscopic scale 3-D image and calculate 3-D strain distribution. To the first approximation, the calculated stress-strain behavior shows a good agreement with the experimental results. The strain concentration over 200% can be seen between carbon black aggregates, even if the overall strain is only 15%. The rubber occluded by carbon black aggregates can also be observed. The virtual rubber model constructed with perfectly dispersed fillers was also calculated. This shows less overall stress than that of the actual filled model reconstructed with 3-D TEMT image. It is found that the occluded rubber can behave as a hard domain and is an important factor of the filler reinforcement effect on rubber.
A Mechanistic Approach to EPDM Devulcanization
Authors: Dijkhuis K. A. J. , Babu I. , Lopulissa J. S. , Noordermeer J. W. M. , Dierkes W. K. 
Published: February 2011

Abstract
The extensive utilization of rubber in a wide variety of products causes a problem in terms of waste. Reclaiming of end-of-life products or production scrap is a potential solution. A high quality reclaim would preferably be obtained by devulcanization, to leave the polymer chains intact. Reclaiming of natural rubber is common practice, although the fundamental knowledge about de- and re-crosslinking is rather limited. EPDM-based rubber is even more unexplored in terms of reclaiming and re-utilization. This paper gives a mechanistic insight into the thermal reclaiming of two differently vulcanized EPDM compounds, using hexadecylamine (HDA) as devulcanization agent. Reclaim from conventionally vulcanized EPDM, mainly polysulfidic of nature, shows the largest decrease in remaining crosslink density with increasing HDA concentration and at lower reclaim temperatures. After reclaiming at the lower limit of the experimental temperature window applied: 225 °C, the concentration of remaining di- and polysulfidic crosslinks is higher than the concentration of monosulfidic bonds, while at the upper temperature level: 275 °C, the concentration of monosulfidic bonds is highest. For efficiently vulcanized EPDM with primarily monosulfidic crosslinks, HDA again has a positive effect on the reclaim efficiency at low applied reclaiming temperatures of max. 225 °C. At higher temperatures, the crosslink density increases with increasing concentrations of HDA. Application of a treatment proposed by Horikx shows, that conventionally vulcanized EPDM devulcanizes to a larger extent by crosslink scission compared to the efficiently vulcanized material, which primarily shows main-chain scission. Both reclaimed materials can be added up to 50 wt% to a virgin masterbatch, with limited decrease in properties. This is a high amount compared to max. 15 wt% of ground powder rubber, commonly known to be the practical limit.
Improvements in the Hydrogenation of Nitrile Rubber Using Wilkinson's Catalyst
Authors: McManus N. T. , Rempel G. L. 
Published: February 2011

Abstract
RhCl(PPh3)3 is an efficient catalyst precursor for the selective hydrogenation of C=C in acrylonitrile butadiene rubber(“nitrile rubber”, NBR). The established technology for the process using RhCl(PPh3)3 is to carry out reaction in the presence of a large excess of triphenylphosphine (PPh3), with monochlorobenzene (MCB) as solvent. In parallel with the hydrogenation of unsaturation in the rubber there is a side reaction involving the MCB, which produces benzene. This likely occurs via oxidative addition of the C-Cl bond in the monochlorobenzene to a Rh intermediate in the catalytic cycle for hydrogenation, followed by reductive elimination of benzene in conjunction with H2 addition to the Rh centre. This leads to formation of less active Rh intermediates which lead to rapid deterioration of catalytic activity in the absence of excess PPh3. It was postulated that some of the PPh3 in solution acts as a base that “mops up” excess HCl formed as a by product of the catalytic cycle. Supporting evidence comes from a novel improvement of the hydrogenation process, where the deactivation of catalyst, can be offset by the presence of bases, such as amines and metal oxides (as an alternative to adding a large excess of PPh3). This modification can improve catalyst activity with respect to levels of Rh used, or could be used to minimize the level of added co-catalysts needed to maintain useful rates of hydrogenation.
Heat Aging Behavior of Novel Poly (Phenylene-Ether) Based Thermoplastic Elastomers
Authors: Gupta Samik , Kamalakaran Radha , Maldikar Avdhut , Menon Ashok , Bhowmick Anil K. 
Published: February 2011

Abstract
The heat aging performance of a series of novel poly (phenylene ether) (PPE) based thermoplastic elastomers (TPEs) from styrene-ethylene-butylene-styrene (SEBS), ethylene vinyl acetate (EVA) and PPE-polystyrene (PS), was studied. This quaternary blend showed superior heat aging performance due to the high Tg thermoplastic component (PPE). At 80 °C, different compositions of the quaternary blends were exposed for 500 hours. Effects of compositions, vinyl acetate (VA) content of EVA and different molecular weights (MW) of SEBS, on the mechanical properties upon heat aging were analyzed in detail. A representative composition (based on the mechanical properties) of the quaternary blend (SEBS/EVA/PPE-PS: 45/30/25) was exposed at different temperatures, i.e. 80 °C, 120 °C, 140 °C and 170 °C, for 2000 hours. Thermal degradation profiles of change in tensile strength and percent elongation at break due to thermal degradation of the blends were monitored and “half-life” temperature was estimated. Using the Arrhenius equation, the “lifetime” of the quaternary blend was predicted (100,000 hours at ∼131 °C). Change in functionalities due to chemical degradation was also monitored using Fourier Transform Infrared Spectroscopy (FTIR). As a consequence of degradation, the shift in Tg was observed by temperature modulated DSC (Differential Scanning Calorimeter). Detailed microstructural studies were done to establish the structure-property correlation, for degraded as well as pristine materials. The degradation mechanism was elucidated on the basis of morphology and structure studies of the blends.
Effect of Plasma Polymerization on the Performance of Silica in NBR, EPDM and NBR/EPDM Blends
Authors: Tiwari M. , Noordermeer J. W. M. , Dierkes W. K. , van Ooij Wim J. 
Published: February 2011

Abstract
The surface modification of precipitated silica powders by plasma-polymerization with acetylene monomer in order to improve their performance in NBR, EPDM and NBR/EPDM rubber blends, by matching the surface energies of the silica fillers of the rubbers, is the subject of this study. Silica, used as reinforcing filler for elastomers, is coated with a polyacetylene (PA) film and characterized by water penetration measurements, Cetyltrimethyl Ammonium Bromide (CTAB) area, Thermo Gravimetric Analysis (TGA), Time of Flight-Secondary Ion Mass Spectroscopy (ToF-SIMS) and Scanning Electron Microscopy with elemental analysis by Energy Dispersive X-ray spectroscopy (SEM/EDX). All techniques show the evidence of a PA-film deposition on the surface of silica. The properties of NBR, EPDM and blends based on NBR and EPDM, filled with untreated, PA- and silane-treated silica, are investigated by measurement of the Payne effect, the bound rubber content and weight loss related to bound rubber, the reinforcement parameter and mechanical properties. The PA-silica filled samples show a lower Payne effect for EPDM and NBR/EPDM compared to the rubbers filled with unmodified silica. However, PA-silica filled NBR shows a higher Payne effect. This indicates an improved filler dispersion in the EPDM and NBR/EPDM, and a poorer dispersion in the NBR. The reduction of the reinforcement parameter as found for NBR, EPDM and NBR/EPDM indicates a lower degree of agglomeration in comparison with untreated and silane-treated silica. The PA-silica filled samples show the highest bound rubber contents and “in-rubber structure” for both rubbers as well as for the blend, compared to both other silica samples. The mechanical properties of untreated silica filled blend of NBR/EPDM are worse compared to the pure rubbers, but acetylene polymerization onto silica results in a significant improvement relative to the unmodified silica. The combined effects all point in the direction of improved compatibility of the PA-silica with the apolar EPDM. This results in better dispersion and stronger interaction with the EPDM, particularly in the blend with NBR, so as to significantly improve the mechanical properties of the blend relative to the use of untreated or silane-treated silica.
Correlation between Physico-Mechanical Properties of NR-BR Blends in Tire Tread Formulation with their Thermal Behaviors
Authors: Taghvaei-Ganjali Saeed , Motiee Fereshteh , Fotoohi Farsa 
Published: February 2011

Abstract
Thermal analysis provides a successful technique for the characterization and identification of rubber compounds. In this study, TGA (thermogravimetric analysis) and DTG (TGA derivative) profiles are used to predict and define the physico-mechanical properties of natural rubber — butadiene rubber (NR / BR) blends, using their thermal behaviors. DTG curves of vulcanizate showed that the initial degradation temperature of NR is lower than BR. According to TGA-DTG profiles we have demonstrated two useful factors, ΔTmax (Tmax BR100−Tmax BRX) and peak height ratio of NR-BR blends which are correlated with physico-mechanical properties of blends.
Glass Transition and Interfacial Segmental Dynamics in Polymer-Particle Composites
Authors: Robertson C. G. , Roland C. M. 
Published: February 2011

Abstract
We review the literature concerned with the effect of proximity to a filler surface on the local segmental mobility of polymer chains. This mobility is commonly assessed from either the glass transition temperature, Tg, or the segmental relaxation times measured by mechanical, dielectric, or NMR spectroscopy. Published studies report increases, decreases, or no change in Tg upon the addition of carbon black, silica, and other reinforcing fillers. Similarly, the segmental relaxation times have been found to increase or be invariant to the presence of nanometer-sized particles. Some of these discrepancies can be ascribed to ambiguous methods of data analysis; others likely reflect the variation in filler-polymer interaction among different systems. There are unequivocal examples of polymers that have segmental dynamics and glass transitions unaffected by nano-particle reinforcement. However, the general principles governing the behavior remain to be clarified, with further work, focusing on the micromechanics at the particle interface, required for resolution of this important aspect of rubber science and technology.
Fiber Adhesion to Rubber Compounds
Authors: Wennekes W. B. , Datta R. N. , Noordermeer J. W. M. , Elkink F. 
Published: February 2011

Abstract
The present paper provides an overview of literature published on fiber-rubber composites. A brief history of Fibers used in rubber applications is given. The emphasis is on the adhesion between fiber materials and rubber compounds. Special attention is given to the standard RFL-treatment and the double-dip treatment used for aramid and polyester Fibers to enhance the adhesion with rubber compounds. Some alternatives to the RFL-treatment are described: fiber surface roughening, adhesion promoter additives to the rubber compound, impregnated Fibers and plasma treatment.