bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Production of Rubber from Furfural
Authors: Burnette Llewellyn Wilson 
Published: February 2011

Abstract
The preparation of piperylene, or 1,3-pentadiene, from furfural has been undertaken with the view of developing a commercially practical process. Although other paths are possible, the following three steps were considered the most direct and feasible. During the course of this study, a patent was granted which covered essentially the same process, but the claims, particularly of the last two steps, were not substantiated in this laboratory. Vapor-phase catalytic reactions were utilized in the process. For the first two steps, a vapor phase hydrogenation apparatus with a recirculation device, was employed. This effected the saving of considerable quantities of hydrogen and uncondensed materials. The apparatus could also be employed for the dehydration in the last step. More than twenty catalysts were studied for the conversion of furfural to methylfuran (sylvan). Only two types were found to be satisfactory. The copper deposited from the decomposition of copper acetate on a carrier such as activated charcoal was found to give yields of the order of 80–85 per cent consistently with one passage of the furfural over the catalyst. The best catalyst tried, however, was copper chromite dispersed on activated charcoal. This has been observed to give a yield of 95 per cent of sylvan in one passage. The optimum temperature observed for these catalysts was around 200° C. It is interesting to note that copper chromite in the liquid phase produces furfuryl alcohol (or tetrahydrofurfuryl alcohol according to the conditions used) in quantitative amounts.
The Mechanism of Reinforcement
Authors: Goldfinger G. 
Published: February 2011

Abstract
In the fundamental study of the influence of reinforcing pigments, particularly carbon black on rubber, one of the great experimental difficulties is to establish the stress-strain properties of that fraction of the rubber stock which is between the pigment particles, and whose deformation, influenced by the presence of the pigment, is the quantity desired. This paper shows that it is not justifiable to assume that the rubber between pigment particles is equivalent in properties to the original gum stock without pigment, because the addition of pigment induces fractionation of the rubber in such a manner as to concentrate preferentially one molecular configuration around the pigment particle, and hence leave the rubber richer in some other configuration in the spaces between pigment particles.
Stress-Temperature Relations in a Pure-Gum Vulcanizate of Natural Rubber
Authors: Wood Lawrence A. , Roth Frank L. 
Published: February 2011

Abstract
Stress-temperature relations at constant elongation have been investigated for a pure-gum vulcanizate of natural rubber. The rubber was first allowed to relax for about two hours at constant elongation and constant temperature to minimize the effects of short time relaxation of stress. The stress, except under special conditions, was changing very little at the end of this time. The stress-temperature relations for temperatures below the relaxation temperature could be represented by straight lines. The values of the slopes and intercepts of these lines are presented in tabular form. The stresses at the end of the relaxations were used as the basis of stress-strain curves. Crystallization was found to be an easily-recognized factor of considerable importance in the interpretation of the results.
The Stiffness of Rubber on Bending, or Its Dynamic Hardness. The Method of Resonance Vibrations
Authors: Reiss K. H. 
Published: February 2011

Abstract
When used for industrial purposes, vulcanized rubber products must often meet an extraordinarily complex set of requirements. Not only are they subjected to shearing stresses, but they must withstand various compression, tensile and bending stresses, such as are encountered in V-belts, conveyor belts, and diaphragms. In many cases these stresses are very rapid, and consequently a knowledge of the dynamic stiffness of a product may often be of technical interest and value. As will be shown, this dynamic stiffness cannot be estimated directly in terms of static hardness, for it depends also on the character of the fillers or pigments in the rubber.
Dichlorostyrenes and Their Polymers
Authors: Michalek J. C. , Clark C. C. 
Published: February 2011

Abstract
Styrene, which was first synthesized by Berthelot in 1866, has done much to foster the rapid growth of those two prodigious youngsters of chemical industry—synthetic rubber and plastics. Polymerized to polystyrene, it has made available a thermoplastic with good dimensional stability and unique insulating properties. Copolymerized with butadiene, it has made possible the widely used GR-S (or Buna-S). Both polystyrene and GR-S have suffered from a common difficulty. They are adversely affected by heat. The strength of GR-S is greatly decreased at the high temperatures developed by heavy-duty tires. Polystyrene wilts below the temperature of boiling water, and, as a result, its uses have been restricted. Attempts have been made to modify polystyrene and GR-S by the addition of other compounds to the plastic or rubber-compounding formula. These have been successful in raising the heat resistance of such materials at the expense of other valuable characteristics, such as the insulating property of polystyrene.
Large Deformation Analysis for a Cylindrical Hyperelastic Membrane of Rubber-Like Material under Internal Pressure
Authors: Guo Xiaoping 
Published: February 2011

Abstract
This work studies the large deformation of a cylindrical hyperelastic membrane circumferentially bonded and sealed at each end to a rigid tube. The membrane is subjected to the delivery of an inflating fluid through the tubular channel, causing it to undergo the large, quasi-static axisymmetric deformation. The membrane is made from a rubberlike material and assumed to be isotropic and incompressible. The Lagrangian formalism is employed to develop geometric relations of the deformation field and the system of governing equations in terms of principal stretches and Cauchy stresses. With the material's constitutive laws and proper boundary conditions, the incorporation of the geometric relations and governing equations is made to derive the numerical solution system of the deformation field in the form of two-point boundary-value problem as composed of four first-order ordinary differential equations. Special attention is given to relevant numerical formulation. The Newton-Raphson iterative algorithm, together with the fourth-order Runge—Kutta algorithm, is utilized. A geometric approximation on an inflated bulge is presented to give an initial guess to a deformed membrane profile. In an attempt to obtain convergent behavior of numerical solution along the equilibrium path of deformation, a displacement control strategy is suggested to mimic the quasi-static volume-controlled inflation process. Numerical results are presented. The occurrence of deformation instability is discussed. The effects of various strain energy density functions on inflation kinematics are analyzed.
Relationships Between Mixing Method, Microstructure and Strength of Nr:Br Blends
Authors: Clarke J. , Clarke B. , Freakley P. K. 
Published: February 2011

Abstract
Much published literature on the way in which phase morphology and filler distribution affect blend properties is contradictory or confusing. Experiments were carried out to elucidate the relationships and to determine whether the use of compatibilizers or special mixing techniques might have a beneficial effect on natural rubber:butadiene rubber (NR:BR) blend properties. NR:BR blends were prepared using both a masterbatch method and a single-stage mixing method. A cure system which gave an even distribution of crosslinks between the phases was used. The morphology, tensile strength and tear strength properties of the blends were measured. Results indicated a high degree of compatibility with fine textured blends (domain sizes &lt; 1µm) being quickly and easily produced, even from masterbatches of very different viscosities. Strength properties of these fine textured masterbatch blends could be predicted by applying the simple rule of mixtures to properties of individual compounds mixed under the same conditions. Although in particular situations a coarse morphology could result in high tear resistance values, for most applications a fine textured morphology gives the most satisfactory overall tensile and tear strength properties. For blends mixed in a single-stage process, development of a fine textured morphology was much quicker than that of filler dispersion. For NR:BR blends containing an optimum cure system it was concluded that the mixing cycle should be chosen to optimize filler dispersion and that use of a compatibilizer will not significantly shorten the mixing cycle or improve the properties of the blend.
Reversion Stable Networks with Polysulfide Polymers as Vulcanization Agents
Authors: Hahn J. , Palloch P. , Thelen N. , Weidenhaupt H-J. 
Published: February 2011

Abstract
To study the network structure generated by the polysulfide polymer [[(CH2)2S4]p as a crosslinking agent, model compound vulcanization with 2,3-dimethyl-2-butene as the model alkene was carried out. It was found that the polysulfide polymer generates hybrid bridges of the general constitution Sn−(CH2CH2−Sm)k(n=1−4,m=1−4,k=1−6). To a lesser extent the polysulfide polymer behaves as a sulfur donor generating conventional sulfur bridges Sx(x=1−5). Polysulfidic bridges (x=4, 5) were only detected in the very early stage of network formation. The process of network formation and the development of the bridges during prolonged heating was monitored by 1H NMR spectroscopy and compared with that of a sulfur cure. In the case of the polysulfide polymer cure the early network contained a relatively high amount of mono-and disulfidic bridges and a stable network was formed after at least 60 min of heating (150 °C). This effect results from the higher thermal stability of hybrid bridges in comparison to conventional sulfur bridges. The higher stability of the hybrid bridges also leads to a suppression of the formation of 3,4-dimethylthiophene which has been identified in the sulfur cure as a product of reversion processes. Thus, the increased reversion stability of polysulfide polymer cures, which has been claimed earlier, can be related to the formation and the increased stability of the hybrid bridges.
Ozonation of Unstretched Natural Rubber: Part I. Effect of Film Thickness
Authors: Rodrigues F. H. A. , Santos E. F. , Feitosa J. P. A. , Ricardo N. M. P. S. , de Paula R. C. M. 
Published: February 2011

Abstract
Unstretched films of natural rubber from Hevea brasiliensis were exposed to ozone flow of 5 and 15 mL/min for 4 to 60 min. The effect of reaction time and the film thickness was studied by viscometry and gel permeation chromatography (GPC). For film thicknesses, in the range of 40 to 350 µm, an initial increase in the intrinsic viscosity, [η], was observed within 8 min of reaction, followed by a decrease for longer times. For thin films, only a decrease in the [η] was observed. The viscosity increase, followed by its decrease, suggests the formation of crosslinking and chain cleavage, respectively, both expected by Criegge mechanism. The plot of [η] versus film thickness and the Chromatographic analysis, related either to 8 or to 60 min of reaction, show that the ozone penetration and the ozone reaction progresses into deeper layers than those previously described in the literature (∼0.5 µm), in this case, 170 and 250 µm, respectively. One model was proposed to explain the viscosity, GPC and attenuated total reflection (ATR) results.
Aging of Natural Rubber in Air and Seawater
Authors: Mott P. H. , Roland C. M. 
Published: February 2011

Abstract
Accelerated aging experiments were carried out on a natural rubber vulcanizate exposed to air and to seawater. Failure strain, shown to correlate well with the fatigue lifetime, was used to monitor the extent of degradation. The effect of temperature on the rate of aging followed an Arrhenius law, with activation energies equal to 90 ± 4 and 63 ± 3 kJ/mol for air and seawater aging, respectively. The difference can be accounted for by the difference in oxygen concentration for the two environments.
Structural Characterization of Natural Polyisoprenes: Solve the Mystery of Natural Rubber Based on Structural Study
Authors: Tanaka Yasuyuki 
Published: February 2011

Abstract
Structural characterization of naturally occurring polyisoprenes was carried out to solve the mystery of natural rubber (NR), such as the biosynthesis mechanism of rubber formation, the origin of outstanding properties of NR and the role of rubber in rubber trees. The NMR analysis, based on terpenes and polyprenols as models, disclosed the structure of both terminal groups of rubber chain. Structural evidence indicated that the biosynthesis of rubbers from Lactarius mushroom and leaves of high plants starts from trans, trans-farnesyl diphosphate or trans, trans, trans-geranylgeranyl diphosphate and terminates by dephosphorylation to form a hydroxyl terminal group. The biosynthesis of NR was presumed to start from unidentified initiating species containing two trans-isoprene units and peptide group and to terminate forming a phospholipid terminal group. The initiating group of NR associated with proteins formed branch points, which can be decomposed by enzymatic deproteinization. The branch points formed by phospholipid group were decomposed by transesterification with sodium methoxide. Rapid crystallization of NR was explained by the presence of mixed fatty acids synergistically with linked fatty acids, which were included in phospholipid. Saturated fatty acids linked to rubber chain induced crystallization, while mixed unsaturated fatty acids acted as plasticizer and accelerated the crystallization rate. This was confirmed by the preparation of model cis-polyisoprene grafted with stearic acid. The green strength of NR decreased to the same level as synthetic cis-polyisoprene after transesterification, indicating the effect of branching formed by the phospholipid terminal group and fatty acids in NR. The role of NR in Hevea trees was analyzed using NR from Hevea trees never tapped before. The formation of hard gel and oxidative degradation during the storage of NR in Hevea trees suggested that NR acted as a radical scavenger to remove hydroperoxide.
The History of Rubber—A Survey of Sources about the History of Rubber
Authors: Long Joan C. 
Published: February 2011

Abstract
This paper is a bibliographic survey of the major sources of information about historical aspects of rubber and rubber products that appeared in the 20th century. These sources, primarily those in the English language, on various aspects of rubber history have been categorized according to whether the emphasis is on natural or synthetic rubber, general rubber history and processing, rubber organizations, and people and companies that have played an important role. A section on the history of tires is included.
Fundamentals of Rolling Resistance
Authors: Hall David E. , Moreland J. Cal 
Published: February 2011

Abstract
Increasing pressure over the last three decades to improve vehicle fuel economy and decrease emissions along with a strong sense of environmental stewardship has driven the tire and rubber industries to reduce tire rolling resistance. This has been accomplished while simultaneously improving other aspects of tire performance dramatically. Reductions in rolling resistance of 50% relative to 1980 levels have been realized, and efforts continue to decrease rolling resistance further. Laboratory measurement and empirical modeling of rolling resistance behavior have evolved substantially, and the tire industry can characterize a tire's rolling resistance with great precision and accuracy. Rolling resistance behavior is quite complex, and nearly all conceivable operating conditions have a measurable effect. The effect of each parameter has received considerable attention in the archival literature, and this review highlights the conclusions of these studies. One of the most powerful tools available to the tire industry is numerical modeling. Combined with accurate dynamic material property measurements, finite element models have provided designers with a tool to understand the behavior of each rubber product and optimize tire construction and material properties to minimize rolling resistance. However, with the current level of understanding and optimization of rolling resistance, substantial breakthroughs in the areas of material development and tire construction are needed to achieve further rolling resistance reductions.
Basic Studies on Development of Structure Hierarchy in Tubular Film Blown Dynamically Vulcanized PP/EPDM Blend
Authors: Wang M. D. , Cakmak M. 
Published: February 2011

Abstract
The processing characteristics and structural hierarchy development in a tubular blown, dynamically vulcanized polypropylene/ethylene—propylene—diene monomer rubber (PP/EPDM) blends were investigated. The semi-crystalline PP phase exhibited a* and c-axis orientations with the a* oriented populations dominating low draw-down ratio (DDR) conditions. At high DDR, both a* and c-axis oriented populations were observed. Little or no preferential orientation was detected in the discrete EPDM phase using dichroism studies. The blown films were found to exhibit an unusual asymmetric structure: The PP phase was found to fibrillate at the outside surface while the inner surface remained relatively featureless. This was attributed to disproportionately rapid cooling of the outside surface by the air stream blown externally onto the film being extruded. This, in turn, resulted in solidification of very thin PP surface layers that caused their fibrillation under the heavy stresses they had to endure. Increasing the blow-up ratio was found to expand this web-like surface texture. As a result of this fibrillation mechanism, the increase of both the blow-up ratio and draw-down ratio was found to reduce the mechanical properties.
Carbasulfanes as Crosslinker for Dienerubber — A Model Compound Study
Authors: Hahn J. , Palloch P. , Walter E. , Thelen N. 
Published: February 2011

Abstract
Model compound vulcanization in combination with reversed-phase high-performance liquid chromatography (RP-HPLC), NMR spectroscopy, and mass spectrometry was used to study the properties of the polysulfide polymers [Sx(CH2)y]p  (x=2,3,4, y=1,2,3,6) as crosslinking agent in the vulcanization process. It was found that the tetrasulfidic polymers [S4(CH2)y]p are capable of forming hybrid bridges of general constitution Sn-[(CH2)y-Sm]k. Besides, they react as sulfur donors producing ordinary sulfur bridges. The yield of hybrid bridges strongly increased when the alkanediyl unit ((CH2)y) of the polymer was changed from methanediyl (y =1) to ethanediyl (y =2) and remained nearly constant for longer alkanediyl segments (y =3, 6). In general, the repeating unit k also increased with increasing length of the alkanediyl segment. The only exception was observed for poly(tetrathiopropanediyl) [S4(CH2)3]p. Compared to [S4(CH2)2]p it gave a slightly lower portion of hybrid bridges and also the maximum value of k appeared to be somewhat reduced. When the number of sulfur atoms in the poly(polythioethanediyl) polymers [Sx(CH2)2]p(x=2–4  was reduced from 4 to 3 the yield of bridged molecules diminished slightly. But in the case of the disulfidic polymer nearly no crosslinked products were observed. The disulfidic polymer could be activated by the addition of sulfur into the vulcanization mixture. Hybrid bridges Sn-[(CH2)6-Sm]k of low k-values were obtained when 1,6-bis-(N,N-dibenzyl-thiocarbamoyldisulfido) hexane was used as curing agent. In addition to RP-HPLC, we also used gel permeation chromatography (GPC) in the characterization of the vulcanizates. In contrast to RP-HPLC, where the number of sulfur atoms has the strongest influence on the retention time, GPC separates the vulcanization products according to the number k of alkanediyl units present in the hybrid bridge.
Pyrolysis-GC/MS and TGA as Tools for Characterizing Blends of SBR and NBR
Authors: Shield Stephanie R. , Ghebremeskel Ghebrehiwet N. , Hendrix Cebron 
Published: February 2011

Abstract
There is increased technological interest to use blends of various dissimilar elastomers in applications for which service, material availability, or cost of a single elastomer do not provide the necessary processing, vulcanizate, or economic properties. Properties of polyblends are sensitive to variations in the amounts of the individual polymers used. Therefore, there is a need for developing a variety of analytical tools that will enable the compounder to monitor the consistency of blend compositions. In this study, the feasibility of using pyrolysis-GC/MS and thermogravimetric analysis (TGA) to estimate the blend composition of SBR/NBR blends was investigated. Pyrolysis-GC/MS degradation products that are characteristic of each polymer were identified. The GC/MS peak areas were used to determine the blend composition. The blend compositions were estimated by TGA from the linear correlation between the polymer composition and the temperature required to pyrolyze a sample to a specific “% weight loss.” The results obtained by pyrolysis-GC/MS and TGA were compared to calculated blend ratios of SBR/NBR in order to estimate the accuracy of the test methods presented in this study.
Synthesis, Characterization and Properties of Montmorillonite Clay-Polyacrylate Hybrid Material and its Effect on the Properties of Engage-Clay Hybrid Composite
Authors: Ray Sudip , Bhowmick Anil K. 
Published: February 2011

Abstract
Clay-Polyacrylate hybrid material was prepared from Montmorillonite (M) clay and polytrimethylol propane triacrylate (PA) using intercalation polymerization process. Characterization of the composite was done by x-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) techniques. The results show the successful intercalation of PA in the M moiety. The MPA hybrid material was then blended with a polyolefin elastomer, Engage. Tensile and dynamic mechanical properties were measured on the polymer-filler composite and the results showed interaction between the treated clay and the base polymer. There was a significant improvement in modulus, tensile strength and elongation at break of the base polymer as compared to the composite prepared with the untreated clay.