bluuebunny/crossref_metadata_2025_split huggingface dataset:
Viscoelastic Behavior of High Polymers at Large Deformations
Authors: Becker G. W. , Rademacher H.-J. 
Published: February 2011

Abstract
Stress relaxation at different strains, and retarded deformation at different stresses were measured for rod-shaped test specimens of plasticized PVC in tension. Temperature was varied in such a way that changes in properties of the material, within the entire range from the glassy-amorphous to the quasi rubber-elastic states, could be comprehended. From results of the two types of experiment it was concluded that outside of the linear stress region, and at all temperatures, the time and deformation dependence of stress could be separated, but this was not possible for the time and stress dependence of strain.
EV Systems for NR. I. The Purpose of Efficient Vulcanization and Development of Curing System
Authors: Skinner T. D. , Watson A. A. 
Published: February 2011

Abstract
By means of a simple relaxed modulus test, a comparison has been made of the efficiency of sulfur utilization of various vulcanizing systems based on commercially available accelerators, or accelerator combinations, plus elemental sulfur or a sulfur donor. These initial experiments indicate three ways of increasing efficient use of sulfur for crosslinking: (1) the employment of synergistic combinations of accelerators; (2) the use of a high accelerator/sulfur ratio; (3) the substitution of elemental sulfur by a sulfur donor. Characterization of the networks formed using the EV systems developed shows that it is possible to obtain systems which are as efficient as the “sulfurless” TMTD-zinc oxide system in terms of the number of sulfur atoms combined in the network per chemical crosslink present. Independent evidence, gained by the use of chemical probes, has established that the network formed by an EV system contained only monosulfidic crosslinks and that little modification of the main chains by sulfur had occurred.
An Internally-Consistent Thermodynamics for Elastomers
Authors: Livingston H. K. , Reghi G. P. 
Published: February 2011

Abstract
Thermodynamic relations for solids in the rubbery state can be obtained from the Jacobian table, Table I. Numerical data that have been obtained under conditions of optimum reversibility have the same significance as has been assigned by Krigbaum and Roe and previous authors. However, with a thermodynamics specifically designed for rubbery solids, it is possible to apply directly the equations of heat and work to obtain the specific heat at constant length. This quantity should be related to molecular vibrations and molecular structure. If so, rubber thermodynamics may help increase our understanding of polymers in the rubbery state.
Tracer Diffusion in Rubber and Benzene Mixtures and its Relation to Mutual Diffusion
Authors: Pattle R. E. , Smith P. J. A. , Hill R. W. 
Published: February 2011

Abstract
The tracer diffusion coefficient of radioactive benzene in mixtures of benzene and rubber at 25° C has been measured over the whole range of composition. Variation of diffusion coefficient with composition can be described by a formula of the Fujita type. Results have been combined with published values of the mutual diffusion coefficient and the thermodynamic properties. They are interpreted in terms of a “one-process” theory and show that mobility of benzene molecules in mutual diffusion at low concentrations of rubber is greater than that in tracer diffusion by a factor which rises to 4.2 when the concentration of rubber is 5%. Results are incompatible with the “two-process” theory of diffusion, unless this theory is modified by inclusion of an adjustable parameter.
Diffusion of Liquids in Crosslinked Rubbers
Authors: Southern E. , Thomas A. G. 
Published: February 2011

Abstract
Diffusion of various liquids in natural rubber vulcanizates has been studied by following the kinetics of the mass uptake of a rubber sheet immersed in the liquid. An anomaly in the mass uptake-time relation is due to stresses set up in the sheet during swelling and to their variation as swelling proceeds. This anomaly has been eliminated by using specimens constrained laterally, by bonding to metal backing plates, which maintains boundary conditions constant during swelling. At the liquid concentrations used, the diffusion coefficient depends mainly on the liquid viscosity rather than compatibility of the rubber and liquid. Neither amount of carbon black filler nor of crosslinking of the rubber has a significant effect on the diffusion coefficient measured at relatively high liquid concentrations.
Effect of Network Breakdown and Re-Formation on the Swelling of Rubbers in Compression
Authors: Treloar L. R. G. 
Published: February 2011

Abstract
Effect of changes in network structure on equilibrium swelling of a crosslinked rubber subjected to uniaxial compressive stress is calculated on the basis of the ‘two-network’ hypothesis. Equations are also derived for compressive force and amount of elastic recovery after removal of the stress. Numerical examples are given to illustrate effects predicted by the theory for a rubber in a good swelling agent.
Problems Concerning Adhesion of Steel Wire and Steel Cord in Rubber
Authors: Maeseele A. , Debruyne E. 
Published: February 2011

Abstract
A research program, employing specially adapted techniques, was conducted on the bonding phenomena of steel reinforcements in rubber. Most of this work has a bearing on the problem of steel wire and cord in varying compounds. In most cases the metal-to-rubber bonding agent used was a copper alloy, especially brass. Some experiments were also made with nonmetallic adhesives. The influence of numerous possible variables of steel wire and cord on the adhesion in several well-defined rubber compounds was examined thoroughly. It was found that the compound itself played an important part in the process of metal-to-rubber bonding. Hence the research program was extended to the influence of rubber compounding on wire adhesion. The research on adhesion phenomena is far from finished. The reaction mechanism of bonding metals to rubber looks very complex. Both metal and rubber are responsible for the actual measured bond strength. Research on adhesion therefore appears to belong to the field of the metallurgist as well as to the field of the rubber chemist and the tire maker. A close cooperation on this problem might prove as fruitful to the wire as to the tire manufacturer. We should appreciate any information or suggestion that might be offered.
Identification of Organic Compounding Ingredients in Vulcanized Rubbers by Thin Layer Chromatography
Authors: Nagasawa K. , Ohta K. 
Published: February 2011

Abstract
As a result of a search for a method for the simultaneous analysis of organic compounding ingredients in vulcanized rubber by one dimensional and two dimensional thin layer chromatography, a method was discovered by which it was possible to identify directly 24 accelerators and 19 antioxidants. The sample was developed on a Wakogel B-5 (silica gel) plate with chloroform/benzene (10/9) in one direction and then with ethanol in the other direction. The plate was sprayed with formalin/sulfuric acid (1/4) and then heated for one hour at 120° C. It was found that the 43 compounding ingredients could all be identified from their Rƒ values and the colors of the spots. Good results were also obtained in the actual analysis of the organic compounding ingredients in vulcanized rubbers. Investigation of interference by the base rubbers showed that the organic compounding ingredients could be identified. Translator's note: According to the English summary, the silica gel contains 5% of calcined gypsum. This is not mentioned in the Japanese text.
Basic Principles of Hose Design
Authors: Harkleroad W. I. 
Published: February 2011

Abstract
Fundamentals of hose design have not changed with the introduction of new and improved component materials. Hose consists of three basic elements which are tube, reinforcement, and outer cover—with each serving a primary function. The tube or inner liner contains and resists the fluid conveyed and transmits forces created by the internal pressures to the strength member. The reinforcement or strength member contains the forces created by the fluid pressure. The outer cover protects hose reinforcement and resists external environment and damage. This paper is primarily concerned with the design concepts of the strength member or reinforcement as a functional component to resist and control forces created in service. Design principles relating to reinforcement angle, burst strength, and length change under pressure are presented for various hose styles. Braided, spiral, wrapped, loomed, wrapped ply and knitted hose styles are reviewed and compared. Reinforcement materials, their types, relative strengths and advantages are summarized. Examples of specific applications of hose are presented to illustrate hose design principles in action in industry.
Extrusion of Polymer Melts and Melt Flow Instabilities. I. Experimental Study of Capillary Flow and Extrudate Distortion
Authors: Bialas Gene A. , White James L. 
Published: February 2011

Abstract
The extrusion of molten plastics, elastomers and fibers represent an important industrial operation. The rate of extrusion of melts through dies is limited by the onset of a flow instability. This phenomenon consists of a change in flow from uniform to irregular that results in the production of rough and distorted extradates drastically different from the smooth cylinders obtained at lower rates. Extrusion melt flow instability is observed in the entire spectrum of polymer melts ranging from silicone gums through nylon and polyolefin plastics to raw elastomers. Since the first descriptions of this phenomena in the 1940's considerable research effort has been expended in this area with limited agreement. It is the purpose of part I to: (1) present new experimental data on capillary flow of polymer melts and extrudate distortion, and (2) to review critically the literature on extrudate distortion.
Extrusion of Polymer Melts and Melt Flow Instabilities. III. Theoretical Analysis of Extrusion through a Slit Die
Authors: White James L. 
Published: February 2011

Abstract
In the previous sections of this paper we have discussed our own and other experimental studies of flow instabilities in the extrusion of polymer melts as well as various theories of the mechanism of initiation of the instability. It is our belief that one of the keys to a deeper understanding of this phenomenon is a fuller analytical understanding of the stress and velocity fields in the composite reservoir, capillary, and extrudate system. It is to this problem that we turn our attention here. The velocity, stress-field problem in the entrance region of a conduit being fed from a reservoir has received considerable attention for Newtonian fluids. Most authors have followed Schlichting and Goldstein in using boundary-layer theory to analyze this problem. While there are a number of such solutions for viscous non-Newtonian and viscoelastic fluids, they are of little interest for polymer melts. This is not only because they represent a high Reynolds number, inertia-dominated asymptote but because they neglect all phenomena occurring in the reservoir feeding the conduit. Of more interest are the low Reynolds number creeping flow solutions for Newtonian fluids which are based upon the work of Sampson (see also Roscoe and Weissberg). A decade ago Tomita published a pioneering analysis of the creeping flow of a viscous non-Newtonian (power-law) fluid into a sharp edge entrance of a capillary. More recently LaNieve and Bogue have analyzed the creeping flow of a Coleman-Noll second order into the capillary entrance. A recent study of the entry problem has been made by Metzner, Uebler, and Chan Man Fong. The related problem of creeping flow of a viscoelastic fluid in a converging channel or cone has been analyzed by Adams, Whitehead, and Bogue and Kaloni. While the former authors computed the stress field for a second-order fluid and an integral constitutive equation in a presumed velocity field, Kaloni actually evaluated velocity profiles and predicted the formation of secondary flows. A more intuitive, but far less rigorous approach to extrusion of a viscoelastic fluid has been taken by Dexter and Dienes and Smith. These authors presume a virgin material to enter a capillary die in fully developed flow and utilize the theory of linear viscoelasticity to evaluate the stress field.
Processibility of Rubbers and Usefulness of the Mooney Viscometer
Authors: Ninomiya Kazuhiko , Yasuda Genichi 
Published: February 2011

Abstract
Processibility is best for any kind of rubber when it exhibits the same rheological behavior as a properly masticated natural rubber. The relaxation spectrum was proposed as a most influential material factor in describing the rheological material characteristics in the processibility of rubbers. A standard shape of relaxation spectrum of the raw rubber which would give the processibility close to the best was suggested, and the effects of molecular weight distribution on the processibility was discussed in terms of the relaxation spectrum. A semi-quantitative interrelation was given between the Mooney viscosity and the relaxation spectrum and the validity of this relation illustrated with experimental data. It was shown that the Mooney viscometer can be used not only for the fundamental test but also for the performance test for processibility of raw rubbers. The time-dependent shear stress at constant shear rate and the subsequent stress relaxation were analyzed in terms of the relaxation spectrum, the strain-at-break, and the elastic strain at steady flow using the concepts of the critical relaxation time, the rupture process in the physically crosslinked molecular network, and the existence of the Mooney's rheological unit. It was then shown that six time-independent material parameters are necessary to describe the mechanical behavior of raw rubbers as measured with a Mooney viscometer. Interrelations between those six parameters and the relaxation spectrum and two other material factors were given and verified. It was shown that three of the six parameters are related only to the relaxation spectrum and the remaining ones also depends at least partly on the relaxation spectrum. This indicates that the relaxation spectrum is the most influential material factor in determining processibility. In the appendix, the shearing period dependence of viscous and elastic components of the shear stress, the delta Mooney and the qualitative similarity between the dynamic and the stead-fiow non-Newtonian viscosities were briefly discussed.
Polymer Crystallization History and Resultant Properties
Authors: Collier John R. 
Published: February 2011

Abstract
Mechanical properties of semicrystalline polymeric materials are strongly influenced by the morphology into which these materials crystallize. In addition the morphology can be altered by changes in crystallization temperature and regime, crystallization pressure, melt treatment conditions, shear history, and probably other processing conditions. The mechanical properties reflect the changes in morphology not only in the initial moduli values but also the overall stress-strain relationships, including the fracture mechanism. A strong influence is noted, at least in the polymers cited, even when slight changes occur in average spherulite size, spherulitic fine structure, and in the nature of interlamellar ties. Smaller, finer textured spherulites with higher interconnections arc apparently more susceptible to yielding by neck formation and elongation to high values than are the larger, coarser textured spherulites than tend to fail by random brittle failure mechanisms at low elongations. In addition, if the chlorinated polyether (Penton) is typical of slowly crystallizing polymers, the change from spherulitic morphology obtained during crystallization from the melt to the small platelet morphology obtained during slow crystallization from quenched glassy state has a complex effect on mechanical properties. The specimens slowly crystallized from the glass exhibit initial shear and tensile moduli values higher than those exhibited for rapid crystallization from the melt and rapid crystallization from the glass, but lower than the corresponding values for slow crystallization from the melt. In addition, the only specimens of this chlorinated polyether that exhibited the ability to draw to high degrees of elongation (as a result of yielding by a necking phenomenon) were those crystallized slowly from the quenched glassy state.
The Formulation of a Mathematical Model for Plasticating Screw Extrusion
Authors: Tadmor Zehev , Klein Imrich 
Published: February 2011

Abstract
The theory of plasticating extrusion has reached the stage where scientific design methods can replace the empirical ones. It is possible today to build a mathematical model comprising the whole plasticating extruder. This model predicts the temperature and pressure profiles along the extruder, the solids content everywhere in the extruder, the total power requirements and even the temperature fluctuations of the extruder. These developments were made possible by the recent mathematical formulation of the melting mechanism in the extruders, by a more accurate formulation of the melt conveying theories and by the availability of high speed digital computers. The development of such a mathematical model is discussed in this paper. The model has been built by a stepwise process of improving existing theories and eliminating critical simplifying assumptions and undue complexities. This has been accomplished by comparing the computer simulated results with their experimental counterparts. The application of the mathematical model to screw design, and to critical analysis of working extruders is also discussed.
Oxidative Aging of Natural Rubber Vulcanizates. Part III. Crosslink Scission in Monosulfidic Networks
Authors: Colclough T. , Cunneen J. I. , Hrggins G. M. C. 
Published: February 2011

Abstract
A natural rubber vulcanizate containing almost entirely monosulfidic crosslinks was oxidized in oxygen and with tert-butyl hydroperoxide. The changes in physical properties due to oxidation were followed by stress—strain measurements, and the changes in chemical structure were investigated with chemical probes, and by spectroscopic methods. The results show that when the oxidized vulcanizates are heated at 75° C, the monosulfidic crosslinks are broken, that crosslinks containing two sulfur atoms are formed, and that conjugated diene and triene structures are introduced into the main polyisoprene chains.
Volume Change Measurements in the Study of Rubber-Filler Interactions
Authors: Shuttleworth R. 
Published: February 2011

Abstract
A new type of measurement using an extension-dilatometer is described and used in an attempt to provide a more adequate understanding of the mechanism of reinforcement. A description of the dilatometer is given together with some of the results obtained. These results are discussed in the light of a recently proposed mechanism of reinforcement.
Structure of Vulcanized and Unvulcanized SBR/BR Blends
Authors: Yoshimura N. , Fujimoto K. 
Published: February 2011

Abstract
Mainly from the temperature dependence of transitions in dynamic modulus, loss tangent, and dielectric loss, associated with microbrownian motions of main chains, it was concluded that blends of NR and BR are microheterogeneous and those of SBR and BR are almost microhomogeneous. Furthermore, even SBR/BR blends tended to be heterogeneous if the styrene content in SBR was increased. On the other hand, unvulcanized SBR/BR blends have been reported to be heterogeneous from observation of phase contrast micrographs. To investigate this vulcanization effect further, measurements of temperature dependence of dynamic modulus and tan δ of unvulcanized blends were compared with those of vulcanized blends.
Physics of the Slipping Wheel. I. Force and Torque Calculations for Various Pressure Distributions
Authors: Livingston D. I. , Brown J. E. 
Published: February 2011

Abstract
Slipping wheel theory has been extended to predict the dependence of the lateral force and of the aligning torque on the nature of the pressure distribution over the contact patch between the wheel and the ground. Expressions have been derived for both side force and aligning torque as functions of the slip angle under: uniform pressure distribution, which applies to the behavior of an inflated membrane wheel; elliptical distribution, which describes the behavior of a solid wheel; and parabolic distribution. All appear appropriate in some respect to the actual tire.
Preparation of Epoxide Rubber Containing Allylic Chloride
Authors: Gurgiolo A. E. 
Published: February 2011

Abstract
New epoxide monomers have been prepared that contain allylic chlorine. These have been copolymerized with propylene oxide to give polymers that also contain allylic chlorine. This type of propylene oxide rubber can be vulcanized with a mixture of magnesium oxide and zinc oxide eliminating the need for sulfur in the vulcanization recipe. This work presents an indirect proof of the allylic structure of neoprene and substantiates the theory of vulcanization of neoprene by magnesium and zinc oxides.
General Method for Approximating the Tire Contour Integral for Arbitrary Cord Path
Authors: Mavrigian G. , Gehman S. D. 
Published: February 2011

Abstract
It has been shown that the tire contour integral can only be evaluated exactly in terms of elementary functions and elliptic integrals in special cases. Approximate numerical methods, with computer programming, have been used heretofore to calculate contours which result from conventional, bias-angle tire construction, by assuming the cord path: ρ/cos α=ρ0/cos α0. In calculating the contours, for deflected tires having such a cord path, a new approximate method of evaluating the contour integral was described which expressed the contours in terms of elliptic integrals.
Measurement of Curative Diffusion Between Rubbers by Microinterferometry
Authors: Gardiner J. Brooke 
Published: February 2011

Abstract
Diffusion of sulfur and MBTS across interfaces between dissimilar rubbers has been measured by microinterferometry. This technique involves the comparison of optical path length through refractive index gradients, due to diffusion, against that of a reference area. Differential diffusion coefficients are obtained showing considerable change in coefficient with curative concentration. Diffusion of sulfur between NR, SBR, and BR is quite similar to diffusion in the homo-polymer. Butyl rubber has a much lower diffusivity and limits diffusion of a curative from another rubber. The method also can be used for dissolution measurements on curatives. Microinterferometry is particularly useful in obtaining concentration and diffusion data at short distances from an interface.
A New Tire Expansion Rule and Its Use in Tire Design Computations
Authors: Leibee J. B. , Schaffers W. J. 
Published: February 2011

Abstract
The carcasses of most early automobile tires were built by stretching bias cut, rubberized, square woven fabric more than once around the major circumference of a toroidal core. By 1914, two crossed rubber coated cord warps had been substituted for each layer of fabric. In the twenties, the core was replaced by a cylindrical building drum and the tires were subsequently expanded by air pressure to the toroidal shape. In all of these cases an initially flat fabric or crossed warps were made to conform to the surface of a toroid without folding or appreciable cord length change. Close examination showed that the tiny rhombuses between adjacent cords were stretched more in the circumferential direction in the crown than in the sidewall. The obvious analogy to a pantograph with hinged members of constant length provided the key to cord angle and drum set calculations needed for carcass design. The geometrical consequence of the assumption of constant rhombus side length is the well known cosine rule