bluuebunny/crossref_metadata_2025_split huggingface dataset:
Processing Rubber Compounds with Polymeric Dispersions of Rubber Chemicals by Automated Pellet Feeding Technology
Authors: Topcik Barry 
Published: February 2011

Abstract
This paper describes the cross-fertilization of plastics technology and the processing of rubber compounds in particulated form, employing an extruder as a mixing device. Stress-strain and rheometer test data established that pelletized compounds based on CR, CSM, EPDM, and SBR are successfully extruder-mixed with their respective curative systems predispersed in polymeric binders and pelletized. Since all ingredients in both types of pellets are in dispersed form, only good blending is required, not intensive, high shear mixing. X-ray radiography confirms that intimate mixing of the pellets was obtained by tracing the progress of incorporation of zinc oxide into a CR compound. The need to modify the extruder screw used in this experimental work by insertion of pins to create an improved mixing action is demonstrated. A screen pack at the breaker plate provides the necessary backpressure to further improve the degree of mixing. With other types of mixing screws, not necessarily made with pins, the screen pack may be eliminated. A process is suggested to manufacture extruded items by metering, blending, and extruder-mixing base and curative pellets. The cost of a second pass Banbury mix can be obviated resulting in the virtual elimination of scorched and bin-aged batches while maintaining the cleanliness of the strained base compound.
Finite Element Analysis of Giant Earthmover Tires
Authors: De Eskinazi J. , Ridha R. A. 
Published: February 2011

Abstract
The stress analysis of an off-the-road earthmover tire subjected to inflation pressure was carried out by the finite element technique by using eight-noded isoparametric toroidal elements. A control design, as well as two variations of this design in which cord angles and end counts were varied, have been examined. Deformations and stresses within the tire were predicted. The results show that variations in the cord angles and end counts may lead to significant changes in the deformation and cord load distribution patterns of the tire. Furthermore, it was observed that, because of the relatively large size of the tire, minor variations in the green cord angles (for example, due to production variations) can lead to magnified differences in the values of the cured angles and thereby cured end counts. These, in turn, can significantly affect the deformation and cord load distributions within the tire. The finite element technique used in this study provides an integrated approach for the structural analysis of tires. Detailed responses to various loading conditions and different changes in the design parameters were computed.
Fluoroelastomer Applications for Pollution Control in the Automotive, Petrochemical, and Electric Power Industries
Authors: Campbell R. R. , Stivers D. A. , Kolb R. E. 
Published: February 2011

Abstract
The effects of percent fluorine, filler, and cure systems on the thermal and acid resistance of fluoroelastomers were evaluated over temperature ranges that would be typical of actual flue duct installations and accelerated conditions such as 275°C for thermal resistance and 149°C for concentrated sulfuric acid resistance. FKM 2176, which contains 65% fluorine by weight, became hard and brittle after two weeks of accelerated air aging at 275°C. The balance of physical properties of FKM 2176 were good when aged at 200°C. FKM 4894, which contains 67% fluorine by weight, retained useful properties after six weeks of accelerated air aging at 275°C. This indicates this material has improved properties for flue duct applications compared to FKM 2176. FKM 4894 filled with MT carbon black had improved retention of tensile strength after aging at 232°C relative to the FKM 4894 filled with SRF/HAF black, Austin Black and litharge. FKM 2176 was totally degraded after aging three days at 149°C in concentrated sulfuric acid. Aging of FKM 4894 in concentrated sulfuric acid at 149°C resulted in a loss of approximately 75 percent of the original tensile and an increase in the elongation, and the appearance of the exposed surface did not indicate chemical attack. Although FKM 4894 was superior to FKM 2176 when aged in sulfuric acid at 149°C, there was little difference between FKM 4894 and FKM 2176 when aged at 121 °C for up to four weeks or after eight weeks at 100°C in concentrated sulfuric acid. Austin Black showed the best retention of tensile of the four filler systems evaluated after aging at 100°C in concentrated sulfuric acid. FKM 4826, which contains 69% fluorine and is vulcanized using organic peroxide and triallyl isocyanurate, has indicated a compatibility with fiberglass that is superior to all fluorocarbon elastomer gums that were tested.
A New Gelled Fluoroelastomer
Authors: Tabb D. L. , Finlay J. B. 
Published: February 2011

Abstract
FKM 5737 is a highly gelled fluoroelastomer similar in composition to FKM B. It can be added to other fluoroelastomers to improve their performance in the following areas: 1) improved processing in extrusion and calendering with the greatest advantages in extrusion, 2) atmospheric curability in peroxide-curable blends with FKM GF and 3) ultra high modulus, processable compounds for oil and geothermal applications.
Reinforcement of Rubber by Carbon Black
Authors: Rigbi Zvi 
Published: February 2011

Abstract
The mechanism by which carbon black reinforces elastomers is one of the most interesting problems of modern technology and still a subject of much speculation. The effect itself was discovered by S. C. Mote of the India-Rubber, Gutta-Percha and Telegraph Works Co. of Silvertown, near London, as a result of an effort to improve the properties of rubber even more than was possible by zinc oxide. The (American) Goodrich Company purchased certain manufacturing rights from the Silvertown company in 1912, and by 1915, the inclusion of carbon black in rubber compounds of high quality had become general. The most important effect observed upon introduction of carbon black into rubber was the vast improvement in abrasion resistance. As long as natural rubber was the unique elastomer in general use, other effects of carbon black, although by no means insignificant, were not of the same great importance, with the possible exception of tear resistance. With the outbreak of war in 1939 and the consequent shortage of natural rubber in the industrial West, the introduction of the copolymer of butadiene and styrene, then known as Buna or GR-S, as an almost total replacement for natural rubber, would not have been possible without carbon black. It may be stated, with little likelihood of contradiction, that no other product exists which contributes as much strength and abrasion resistance to noncrystallizing rubbers, while maintaining to a large extent their desirable elastic properties, as does carbon black. In spite of the tremendous consumption of carbon black, mainly in tires, and the steady progress made in improving its quality, the reasons for its unique behavior are still largely a matter of speculation and debate. The subject is enormously complex, as may be gathered from a survey of the literature. Many studies have been published describing one aspect or another of the behavior of carbon black (or carbon blacks, since there are many grades available) and these are still appearing. Some excellent papers and books survey and analyze the available information, such as those by Studebaker, Kraus, Donnet and Voet, and Medalia.
Optimization of Silane-Silica OTR Compounds. Part 1: Variations of Mixing Temperature and Time during the Modification of Silica with Bis-(3-Triethoxisilylpropyl)-Tetrasulfide
Authors: Wolff S. 
Published: February 2011

Abstract
This study of the TESPT modification reaction of silicas gives the compounder new and valuable information about rubber filler-silane interactions. It allows TESPT to be used more practically and economically. It also suggests several areas that would be interesting and worthwhile for further investigation. The conclusions based on this study are: (1) The modification reaction of silica with TESPT in situ cannot be considered as an equilibrium reaction. (2) The degree of modification increases with TESPT reaction time and temperature. Temperature has more effect than time. (3) In natural rubber, the highest and most practical modification reaction temperature is about 160°C. By performing the modification reaction between 150 and 160°C, it produces optimum cure rate and 300% modulus. Above 160°C, the thermal reaction of TESPT with natural rubber starts and reduces the sum of filler/rubber and rubber/rubber crosslinks available in the final cured rubber. (4) Up to 160°C, the number of filler/rubber and rubber/rubber crosslinks remains constant. But increasing temperature and reaction time lead to an increasing ratio of filler/rubber to rubber/rubber bonds. This improves the properties that are the most important for an OTR tread. (5) The higher the yield of filler/rubber bonds achieved by using the optimum reaction temperature and time, the less TESPT is necessary to get the desired properties. This produces better cost/performance. (6) To get the highest modification with TESPT, it should be added with the silica, to make best use of the reaction time dependency. (7) Most of the physical properties are dependent on the ratio of filler/rubber to rubber/rubber bonds and can simply be correlated to the 300% modulus of the compound. (8) The previously published standard mixing procedures' do not have to be changed with regard to the mixing sequence. However, by controlling mixing conditions, it may be possible to lower the level of TESPT and still obtain the desired improvements in compound physical and performance properties.
Short Jute Fiber Reinforced Carboxylated Nitrile Rubber
Authors: Chakraborty S. K. , Setua D. K. , De S. K. 
Published: February 2011

Abstract
Silica is not an essential component in the bonding system in XNBR-jute fiber systems. Mechanical anisotropy is observable only at the higher fiber loadings (40 phr and above) in XNBR-jute fiber composites. In composites containing sufficient amounts of bonding agent and fibers for tensile-strength anisotropy to be observed, tensile failure occurs by both fiber breakage and debonding. Fibers increase the aging resistance of XNBR composites. Mill shrinkage and green strength of XNBR improve, while Mooney viscosity increases and scorch time decreases with the addition of jute fiber to XNBR.
Autohesion of Elastomers
Authors: Bothe Lothar , Rehage Guenther 
Published: February 2011

Abstract
Autohesion is a particular form of adhesion. It occurs when two surfaces of the same elastomer are pressed together. The increase of the autohesive strength, with the increase of contact time, is caused by interdiffusion of mobile macro-molecule chain ends across the boundary face. After a certain time of contact, the contact zone disappears and a homogeneous system is obtained. The autohesive strength is then equal to the bulk strength of uncrosslinked elastomers. The autohesion of polybutadiene, butadiene-acrylonitrile copolymers, ethylene-propylene copolymers and polychloroprene was studied. The influences of microstructure, polar side groups, cristallinity, contact time, test rate, and the influence of solvents on autohesion were investigated in detail.
Thermoplastic-Guayule Rubber Blends—Compositions and Mechanical Properties
Authors: Ramos-DeValle L. F. , Ramírez R. R. 
Published: February 2011

Abstract
An experimental study of the mixing and final mechanical properties of blends of guayule rubber with polyolefins was carried out. It was found that (1) variation in total mixing time during blend preparation produced only minor differences in maximum tensile properties; (2) tensile properties of the blends approach those of the plastic at GR concentrations of 50% and lower, those of the rubber at GR concentrations of 70% and higher; (3) tensile properties of partially crosslinked blends improve if the addition of DCP is effected after partial mixing of the pure homopolymers; (4) the partial cross-linking of the blend exerts a strong beneficial influence on the mechanical properties; (5) the addition of carbon black exerts little influence on the mechanical properties of the blend. It can be suggested that, at 60% GR, both polymers (GR and HDPE) show the same tendency to form the continuous or dominant phase. Above 60%, the rubber tends to be the dominant phase, and below 60% the plastic tends to be the dominant phase. The mechanical properties of partially crosslinked GR-HDPE blends are comparable with those of similar commercially available products. This suggests a further alternative in the commercialization of natural guayule rubber, namely, thermoplastic rubbers.
A Comparative Rheological Investigation of Natural and Synthetic Cis-1,4 Polyisoprenes and Their Carbon Black Compounds
Authors: Montes S. , White J. L. 
Published: February 2011

Abstract
A comparative experimental study of the rheological properties of four cis-1,4 polyisoprenes, two naturally occurring and two synthetic, is reported. The two naturally occurring elastomers are from the hevea tree and guayule bush, and the synthetics are produced by alkyl lithium and Ziegler catalysts. Transient and steady state shear viscosity, stress relaxation and elongational stretching experiments were carried out at 100°C. Shear viscosity was measured using creep and constant shear rate modes in a sandwich viscometer as well as with a capillary rheometer. The hevea based elastomer has the highest viscosity and maximum relaxation time. The likeliest reasons for the higher viscosity and memory of the hevea is the presence of large amounts of gel and higher levels of long chain branching than in the other cis-1,4 polyisoprenes. Rheological measurements are also reported for compounds with 0.1 and 0.2 volume loadings of carbon black. Yield values are observed for the 0.2 loading compounds.
Modification of Asphalt by Block Polymers of Butadiene and Styrene
Authors: Kraus Gerard 
Published: February 2011

Abstract
Elastomeric thermoplastic block polymers of butadiene and styrene are highly effective in converting asphalts into truly rubber-like materials. Additions of 10–14% of these polymers to asphalt result in lower penetration values, greatly reduced flow above room temperature, increases in softening temperature to values in excess of 100°C and superior low temperature flexibility. The blends are characterized by a unique morphology in which the block polymer, swollen with the lower molecular weight constituents of the asphalt, forms a continuous lacework in a bituminous phase enriched with asphaltenes. The polymer-rich phase consists, in turn, of two microphases derived from the block polymer domain structure. At low concentrations, where the swollen polymer forms discrete inclusions in the asphaltic continuum, effects on the physical properties of the asphalt are less pronounced but can still be significant. The multiphase morphology of these composites accounts satisfactorily for the most important features of their mechanical behavior.
Dynamic Mechanical Properties of a Carbon Black-Loaded Butyl Rubber Vulcanizate and a Carbon Black-Loaded Polyisobutylene
Authors: Ferry John D. , Fitzgerald Edwin R. 
Published: February 2011

Abstract
The dynamic mechanical properties of rubbers loaded with carbon black have been the subject of many investigations because of their importance in the performance of products, especially the energy dissipation, skid resistance, and other properties of vehicle tires. However, the important variables of frequency and temperature in oscillating deformations have usually been explored in fragmentary fashion. In particular, the degree to which these variables can be treated with frequency-temperature superposition appears to differ considerably depending on the type of compound investigated. In many cases, data have been insufficient to establish whether the essential criterion for superposition, namely, the same temperature dependence for all relaxation mechanisms, is satisfied. For this purpose, extensive measurements over wide ranges of closely spaced frequencies and temperatures are required. Such data are needed, in any case, to determine the responses of elements of a vehicle tire over the ranges of temperature and time scale to which they are subjected in use and to provide input information for thermo-mechanical modelling of power loss in tires. This paper is intended to be one of a series on dynamic mechanical properties of a variety of carbon black-loaded compounds over wide ranges of frequency and temperature. It describes results for a vulcanized butyl rubber loaded with a medium processing channel black, and the almost chemically identical linear polymer polyisobutylene loaded with a semireinforcing furnace black; these results are compared with previously published data for vulcanized butyl gum and pure polyisobutylene . The shear strain amplitude in these measurements is very small, of the order of 10−5 to 10−7, in a range of linear viscoelasticity as confirmed by sensitive tests, and thus the Mullins effect is avoided. The prominent dependence of viscoelastic properties on strain amplitude, as investigated by Payne and Watson and later workers, appears at considerably higher strains of 10−3 or more. Of course, the behavior in large deformations will be very different from that described here, but it is important to understand first the properties of the structure close to its equilibrium rest state.
The Effect of Petroleum Extender Oil Types on the Properties of a Compounded Radial Styrene Block Thermoplastic
Authors: Recchuite A. D. , Dimeler G. R. 
Published: February 2011

Abstract
This investigation was undertaken to define the relationship between petroleum extender oils and physical characteristics of compounded styrene block elastomer. Styrene block copolymers offer the versatility to be extended with paraffinic, naphthenic, or aromatic type oils. Despite this versatility, highly refined naphthenic oils have found the most use because they offer a better overall balance of YBSR compound properties and color stability. This study verifies the basis for that preference. However, as styrene block copolymers find applications in product areas other than footwear, it is expected that all extender oil types will find wider usage. The compounder can vary oil loading and oil viscosity to achieve the desired properties with the most cost effective formulation.
Flow Criterion for Elastomer Tack
Authors: Hamed G. R. , Shieh C. H. 
Published: February 2011

Abstract
In order to form a tack bond, the first step is to establish molecular contact between the two sample surfaces. This requires viscous flow of material near the surfaces under the contacting pressure. The tack of specimens with model surface roughness has been performed using a T-peel geometry. A simple flow parameter has been found that uniquely correlates with the relative tack of NR samples of varying molecular weights. For various contacting pressures and molecular weights, a single mastercurve was found in which relative tack is a linearly increasing function of the cumulative creep compression strain of the material. For instance, consider two samples of NR, one with a high molecular weight (I) and the other with a lower molecular weight (II). For a given contacting pressure, Sample II will exhibit a greater value of relative tack. However, if a different contacting pressure is selected for each sample such that both exhibit the same extent of flow, (i.e., possess equal cumulative creep compression strains) during tack bond formation, then relative tack is identical for both samples. That is, difference in the tack strength of NR samples of various molecular weights can be completely explained on the basis of differences in viscous flow behavior without consideration of molecular interdiffusion rates.
Processing Parameters of Continuous Microwave Heating of Ethylene-Propylene Terpolymer
Authors: Wang C. S. 
Published: February 2011

Abstract
In continuous microwave heating, the temperature rise of rubber extrudates and the level of unabsorbed or reflected microwave power are strongly dependent upon the microwave power level, residence time, and extrudate configuration. It is therefore essential to control these processing parameters, together with the energy absorption characteristics of rubber materials, to improve the efficiency of microwave heating process.
Effect of Interfacial Bonding on the Self-Adhesion of SBR and Neoprene
Authors: Bhowmick A. K. , Gent A. N. 
Published: February 2011

Abstract
When two elastomer layers are partially crosslinked in contact with each other, the strength of adhesion increases. This effect has now been studied for simple vulcanizates of SBR and for CR vulcanizates crosslinked with sulfur and/or oxide linkages. Under threshold conditions, e.g., at high temperatures and in the swollen state, when both viscous effects and strain-induced crystallization are virtually eliminated, the work of detachment is small and approximately proportional to the inferred degree of interlinking, rising from a few J/m2 when only Van der Waals' attractions are present, up to 40–70 J/m2 in the fully-interlinked state. No significant differences were observed between SBR and CR vulcanizates, or with different types of crosslinking of CR. The principal structural factors governing the adhesive strength under threshold conditions appear to be the number and length of the molecular strands comprising the network and crossing the interface. The threshold fracture energy is directly proportional to the density of such strands and is smaller for shorter strands, in accord with the theory of Lake and Thomas. Under normal conditions, e.g., at room temperature and in the unswollen state, CR vulcanizates were found to adhere much more strongly for a given degree of interlinking, presumably due to strain-induced crystallization. Indeed, some enhancement of strength persisted even at temperatures of 100–150°C, in the unswollen state.
Scale-Up of Internal Mixers
Authors: Manas-Zloczower I. , Tadmor Z. 
Published: February 2011

Abstract
In this paper, a new criterion for scaling Banbury type internal mixers is proposed. The new criterion is a dimensionless number Xt*, representing the product of the fraction of broken agglomerates during one pass through the high shear zone of the internal mixer and the average number of passes through this zone, for a given mixing time. It can be calculated for a given system of polymer-additive from a knowledge of machine geometry and operating conditions. The dimensionless number Xt* is uniquely related to the fraction of undispersed agglomerates, ψ, which is a frequently encountered mixing quality criterion. Experimental results reported in literature, for a broad range of mixer sizes, fit, within practical acceptable error, the theoretical curve ψ versus Xt*, lending support to its validity. Moreover, the dimensionless number Xt* correlates almost linearly with the presently used scaling-up criteria, the unit work input and the total shear strain, which in turn proved to be interrelated to other properties of the compound, such as Mooney viscosity and die-swell. However, while the unit work input and the total shear strain can be used in scaling only as long as proper operating conditions are met, the dimensionless number Xt* provides a reliable scale-up criterion for a broad range of mixer sizes and geometries as well as different operational parameters. Derived from a theoretical model of dispersive mixing in internal mixers based exclusively on fundamental considerations, this new criterion can be used also for mixing cycle optimization and basic machine design.