bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure-Property Relations in Amorphous and Crystallizable ABA Triblock Copolymers
Authors: Morton Maurice 
Published: February 2011

Abstract
The properties of the thermoplastic elastomers derived from ABA triblock copolymers depend largely on the nature of the A blocks, which form rigid, thermoplastic domains holding the elastic network together. These domains may be either amorphous or crystalline in nature, the former resulting from an inherent incompatibility between the A and B blocks, while the latter form by normal crystallization processes. It can be demonstrated convincingly that the formation of the amorphous (glassy) domains is enhanced by a higher degree of incompatibility between the A and B blocks and that the strength of the material depends on the degree of phase separation and on the integrity of the amorphous domains. However, the viscosity increases with increasing incompatibility between the two phases, presumably because the two-phase morphology persists even in the melt. On the other hand, the presence of crystallizable A blocks, which do not phase separate in the melt, leads to good flow properties. However, the strength of the material and other mechanical properties are strongly dependent on the molecular weight and crystallization of the A blocks.
Improved Particle Size Measurements on Pigments for Rubber
Authors: Hess W. M. , McDonald G. C. 
Published: February 2011

Abstract
High shear mixes of carbon black and many other pigments in a cellulose acetate butyrate paint chip formulation have provided superior specimens for analysis by automated electron microscope image analysis. Specimens prepared from these mixes exhibit reduced aggregation and improved dispersion. Testing accuracy, precision, and sampling are significantly improved in comparison to previous techniques. The CAB method is applicable to carbon blacks, silica, precipitated calcium carbonate, red iron oxide, titanium dioxide, and any rubber grade pigment that is composed of stable particles that are reasonably isotropic in nature. Certain ground pigments or those containing highly anisotropic particles may give erroneous results due to breakage (e.g., clay, acicular zinc oxide). An improved particle size analysis program for automated electron microscope image analysis was developed. This utilizes a self-determining factor to correct for particle aggregation. The method provided good grade classification for a broad range of carbon blacks in CAB and is also suitable for screening blacks in the dry state or extracted from rubber.
Fracto-Emission from Filled and Unfilled Elastomers
Authors: Dickinson J. T. , Jensen L. C. , Jahan-Latibari A. 
Published: February 2011

Abstract
We have tried to show a variety of EE and PIE results on a number of systems involving fracture of filled and unfilled elastomers and consider some of the parameters that influence this emission. The need for careful studies of the physics and chemistry of these phenomena is obvious. The usefulness of FE as a tool for investigation of failure mechanisms and fracture phenomena in elastomers requires a broad-based attack combining fracture mechanics, materials science, and fundamental fracto-emission studies on well characterized elastomer. Since the field is relatively unexplored, we will conclude by speculating on some potential areas of usefulness of FE, many of which depend critically on further understanding of FE itself.
Ionic Crosslinking of Carboxylated SBR
Authors: Sato Kyosaku 
Published: February 2011

Abstract
1. Ionic bonding of carboxylated SBR with zinc oxide is detectable by means of measurements of the temperature dependence of tan δ. There is an α peak in the region of 60°C at 3.5 Hz. The position and shape of the α peak are strongly dependent on the state of cure of the vulcanizates. Without permanent crosslinking, the α peak is a plateau; as the crosslink density increases, the α peak becomes sharper and shifts to lower temperatures. The presence of carbon black causes the α peak to shift to higher temperatures, regardless of the presence of permanent crosslinks. 2. Ionic bonds in carboxylated SBR reacted with zinc oxide are in the form of ion clusters which function as crosslinks at room temperature. The ionic crosslinks provide carboxylated SBR with high tensile strength in the absence of reinforcing fillers. The presence of carbon black causes the 300% modulus to increase. The ionic crosslinks are labile, and the strength is lost at moderately elevated temperatures. A mixed cure system consisting of both sulfur and zinc oxide provides higher heat resistance than either of the single cure systems.
On the Small Strain Behavior of Peroxide Crosslinked Natural Rubber
Authors: McKenna Gregory B. , Zapas Louis J. 
Published: February 2011

Abstract
Torque and normal force measurements on a cylinder subjected to torsion at constant length were used to study the behavior of NR crosslinked with 5 phr dicumyl peroxide. The derivatives of the strain-energy density function ∂W/∂I1 and ∂W/∂I2 were calculated from the data using the scaling law of Penn and Kearsley. The new results extend the limit of small strains at which the strain-energy density function derivatives have been measured to γ&lt;0.005 and further confirm our previous results that for peroxide-crosslinked NR, ∂W/∂I2 does not become negative at small strain, contrary to several reports in the literature. Reduced stress was determined for the rubber by using the approach of Kearsley and Zapas to calculate the derivative w′(λ) of the Valanis-Landel form of the strain energy function. The results were compared with the measured values for reduced stress in tension and compression at small strains. While the deviation between the predictions and the experimental behavior do not exceed 6%, the characters of the calculated and measured reduced stress plots are different. The measurements in torsion were not obtained at small enough strains to enable direct comparison with the extension/compression behavior at |ε|&lt;0.002. Extrapolation of the results did not produce the anomalous cusp observed in the reduced stress for 0.998&lt;1/λ&lt;1.002 which was reported in our previous study. The fact that torsional data do not show the cusp offers support to the Kearsley suggestion that at these extremely small deformations, rubber compressibility may play an important role in the stress-strain behavior. This could also explain the apparent discrepancy between the predicted Valanis-Landel behavior and the observed behavior. Future work involving higher precision experiments is required to resolve the matter.
Application of Flow Behavior to Design of Rubber Extrusion Dies
Authors: Kannabiran R. 
Published: February 2011

Abstract
It is common in the tire industry to extrude profiles like treads using a hot-feed dual extrusion line. There is a need to extrude the profiles with zero drawdown in the extrusion line after exiting from the die. Also, the extrudate from the two extruders in a dual extrusion must knit together to form a well-defined and reproducible junction line. A contoured flow channel called a preform is customarily used to achieve a desired junction line and to roughly preshape the stream before passing it through the final die. In practice, several trials are usually required to arrive at an optimum die combination to obtain desired size and shape of extrudate after due allowance for extrudate swell, as well as uniform velocity across the width of the extrudate profile. It is helpful to eliminate some of these trials by developing calculation methods for estimating pressure profile, velocity and swell distribution. There are a number of articles on calculating pressure drop from flow rate for non-Newtonian fluids in odd shaped ducts and tapered channels. Also, many simple techniques are available for analyzing non-Newtonian flow of polymer melts in simple extrusion dies. Most of these calculations assume a one-dimensional flow. More recently, there has been much work on developing finite element and other numerical methods for computing complex die flows. This paper describes and tests the utility of a quick and easy method of estimating extrusion pressures and velocities in and at the exit of extrusion dies using material properties and geometry. This method allows for abrupt changes in geometry such as sudden contractions in the flow channel.
Empirical Equations for Tire Footprint Area
Authors: Pillai P. S. , Fielding-Russell G. S. 
Published: February 2011

Abstract
Two simple predictive equations for tire footprint area in terms of tire deflection and tire and wheel dimensional parameters found on the tire sidewall, have been empirically developed. Footprint areas calculated using these equations agreed with measured areas for a number of passenger, truck, and off-the-road tires, of both radial and bias belted constructions, indicating the general predictive usefulness of the equations. The form of one of the equations is similar to that of equations presented in the literature that were derived using different assumptions.
Sequence Distribution of Commercial SBR by Ozonolysis-GPC Measurement
Authors: Tanaka Yasuyuki , Sato Hisaya , Adachi Junichi 
Published: February 2011

Abstract
Sequence distribution of commercially obtained styrene-butadiene copolymers (SBR) was investigated by high-resolution-GPC measurement of ozonolysis products. The ozonolysis-GPC of emulsion SBR samples showed peaks corresponding to 1 to 4 styrene sequences and styrene-1,2-butadiene sequences flanked by 1,4-butadiene units. In random SBR samples with anionic polymerization, long styrene sequences of from 8 to 19% were detected in addition to the short styrene sequences. So-called tapered-block structure was clearly observed in partially block SBR samples; a broad peak derived from block styrene sequences in a relative intensity of 49 to 55% was overlapped by peaks due to styrene sequences longer than 10 styrene units. The content of pure-block styrene sequences in S-B-S type triblock SBR samples was found to be 85 to 99% or above.
Effects of Salt Corrosion on the Adhesion of Brass Plated Steel Cord to Rubber
Authors: Ishikawa Yasuhiro , Kawakami Shinji 
Published: February 2011

Abstract
Adhesion loss caused by salt corrosion is proposed to occur by the following process: 1) During a salt corrosion test, the NaCl solution rises in the cavity located at the steel-cord center. 2) An electrochemical oxygen concentration cell is formed. 3) OH− is produced by the reduction of oxygen. 4) An increase of the NaOH concentration causes the reverse of ion tendency between brass and steel. 5) Dezincification and dissolution of brass take place in the brass plating. The same process also occurs in the corrosion of a bare brass plated steel cord immersed in NaCl solution. Compounds containing cobalt stearate and a compound free from cobalt show adhesion deterioration by the process described above. Many other cobalt salts suppress the corrosion of brass in NaCl solution. At the same time, the underlying steel changes to become ignoble compared with brass, leading to the production of a large amount of rust. In view of the above considerations, it is desirable to remove the cavity located at the steel-cord center in order to suppress the steel-cord corrosion. Use of an open type of steel cord is useful in this respect.
Prediction of Equilibrium Swelling in Fuel and Lubricant Ingredients
Authors: Neppel A. 
Published: February 2011

Abstract
In accord with the Porter equation, linear relationship has been found between the apparent and actual network-chain concentrations of DCP-cured NBR reference elastomers containing 18–39% ACN and 0–70 phr N550 black while Porter's k factors and, therefore, the extent of the restriction of swelling by the filler vary somewhat with the diluent. Taking this variation into account, a self-consistent relationship has been obtained between data on swelling in MEK (24 h) and those on equilibrium swelling in some fuel and lubricant ingredients (2 to 4 weeks). By using this relationship and the modified Flory-Rehner equation, the equilibrium swelling in fuel and lubricant ingredients of NBR test vulcanizates can be estimated from determining their nitrile content and from an MEK immersion test if these vulcanizates are filled with only N550 black, and if the only variables in their compositions are nitrile content, state of peroxide cure, and carbon black loading. The development of a similar technique to predict the swelling in mixed solvents of unknown NBR vulcanizates would probably involve serious difficulties which would stem from the presence of plasticizers, antioxidants, and fillers other than N550 black as well as from the assessment of the polymer-solvent interaction factor.
Diffusion of Heavy Oil in a Swelling Elastomer
Authors: Bouvier J. M. , Gelus M. 
Published: February 2011

Abstract
The swelling of SBR by an aromatic oil has been experimentally studied at temperatures ranging from ambient to 200°C with thermally stable networks. A model based on Fick's law was developed, and the change of geometry of the elastomer sample was taken into account. The proposed approach is global or macroscopic, and a constant diffusion coefficient has been defined. The diffusion number, ND, defined by two characteristics of a solvent-polymer system, tf the swelling time and tD the diffusion time, represents an important result for engineering applications; it allows prediction of the behavior of amorphous elastomers in contact with a diffusing organic liquid.
Differential Dynamic Shear Moduli of Carbon Black-Filled Styrene-Butadiene Rubber Subjected to Large Shear Strain Histories
Authors: Arai Koichi , Ferry John D. 
Published: February 2011

Abstract
Combined measurements of shear-stress relaxation and differential dynamic storage and loss shear moduli G′ and G″ following a single-step shear strain of 0.4, as well as measurements of dynamic moduli in on-off strain and stress histories, have been made on styrene-butadiene rubber (type 1502) filled with carbon black (N299) at loadings of 40, 50, 60, and 70 phr, with 10 phr Sundex 790 oil. Both cured and uncured compounds were studied at temperatures of 25.0° and −0.5°C respectively. The maximum oscillatory shear strain was 0.005, and the frequency was from 0.4 to 1.8 Hz. The storage shear modulus G′(ω, 0) measured without imposition of static strain was approximately proportional to the fourth power of the volume fraction of black. With imposition of single-step strain, the differential storage modulus G′(ω, γ; t) fell 25% to 35% but slowly recovered somewhat while the strain was maintained for 4 to 5 h. During this period, the static stress relaxed continuously. At the highest content of black, the drop in log G′ was the least, and the final recovery was closest to the initial value of G′(ω, 0). In on-off experiments on uncured compounds, when the strain was “on” for 250 s and then “off” (either stress or strain returned to zero), G′ decreased when the strain was imposed as before and decreased further when it was removed. In the “off” state, G′ recovered partially but did not attain the initial value of G′(ω, 0) even after 7 d. In on-off experiments on cured compounds, removal of stress caused G′ to either increase or decrease depending on the content of black; in any case, in the “off” state, G′ recovered completely to its initial value. Other strain histories involved on-off sequences with different “on” periods and multiple on-off sequences with different “on” periods and multiple on-off sequences. The results are interpreted in terms of a network of black particle aggregates whose contacts can slowly rearrange even in the absence of stress as shown by stress relaxation at very small strains in earlier studies. In large strains, it is postulated that some contacts are broken but can partially reform, especially in the stress-free state; the rate of reformation is similar to that of small-strain stress relaxation. Only in cured compounds is the network fully recovered, presumably because in these the particles are imbedded in a crosslinked matrix and have crosslinked bridges that facilitate reestablishment of interparticle contacts, whereas in uncured compounds the matrix has no crosslinks and the bound rubber on adjacent particles may be merely entangled.
A Quantitative Determination of the Damping Behavior of Acrylic Based Interpenetrating Polymer Networks
Authors: Fradkin D. G. , Foster J. N. , Sperling L. H. , Thomas D. A. 
Published: February 2011

Abstract
The damping function, D.F., as derived from the area under the linearE″— temperature curve, expresses the amount of mechanical energy converted to heat per unit volume of material. Sometimes characteristics of the damping behavior of homopolymers and IPN's are more apparent in the linear E″—temperature plot, such as glass transitions and secondary transitions. Decrosslinking and/or annealing the IPN's have no effect on the D.F.'s, although these treatments significantly modify the shape of the E″—temperature curves as a result of molecular and phase rearrangements. Thus, to a first approximation, the area expressed by D.F. is a polymer chain characteristic, depending on the chain structure itself but not on crosslinking and/or annealing.
Curing SBR with Thiocarbamyl Sulfenamide Accelerators
Authors: Layer Robert W. 
Published: February 2011

Abstract
We have found that the physical properties of conventional SBR/BR tire tread vulcanizates obtained with benzothiazole sulfenamide accelerators can more efficiently be obtained using a thiocarbamyl sulfenamide accelerator. Since thiocarbamyl sulfenamides utilize sulfur more efficiently than benzothiazole sulfenamide accelerators, they should be used at 15 to 20% higher sulfur levels compared to those used with the benzothiazole sulfenamides. The combination of greater efficiency and higher sulfur level used with the thiocarbamyl sulfenamides allows the accelerator level to be reduced by about 40%. Vulcanizate properties as well as the crosslink networks of these two systems are the same when used in this manner.
Recent Developments in the Flammability of Elastomeric Materials
Authors: Lawson David F. 
Published: February 2011

Abstract
Most of the flame-retardant technology now used with elastomers has been known for some time. Advances have been made in recent years in the understanding of elastomer combustion and inhibition mechanisms, in the measurement and control of visible smoke generation from elastomers, and the toxic effects of combustion atmospheres. By integrating existing technology with recent developments and the likely advances of the future, elastomeric materials will continue to receive acceptance for a wide variety of applications. Author's note: A review stressing quantitative aspects of polymer combustion has recently appeared.
Engineering with Rubber
Authors: Mullins Leonard 
Published: February 2011

Abstract
First I must thank you Mr. Chairman for your most generous introduction. I understand that there will be another opportunity later today to thank the Executive Committee of the Rubber Division of the American Chemical Society for nominating me as the Charles Goodyear Medalist for 1986, for the pleasure of being here today, and for the privilege of addressing you. But I would wish to say, at this stage, how deeply honored I am to receive this most distinguished award. It is a tradition that this address should reflect the author's special interests and his own contribution to rubber science and technology, and they have tended to be autobiographical in nature. However the title which I have chosen, “Engineering with Rubber,” covers a broad field of activity, but in the relatively short time at my disposal I will perforce have to restrict myself to those areas in which I have been personally involved. Like so many recent Charles Goodyear Medalists it was my good fortune to be active during the period of almost explosive growth of polymer science and technology which occurred during the 1940's and 1950's and which provided a proper scientific basis for the polymer industries created during this period. The rubber industry is, of course, much older, but hitherto it had relied upon an essentially empirical approach to provide practical answers to most of its problems. It was also my good fortune to work with and alongside many outstanding individuals both at the Research Association of British Rubber Manufacturers (now the Rubber and Plastics Research Association) and at the Malaysian Rubber Producers' Research Association (formerly the British Rubber Producers' Research Association). To these I owe much and I would wish to share this recognition with my colleagues.
Effect of Cyclohexyl Thiophthalimide on NR Vulcanization Accelerated by Thiocarbamyl Sulfenamide-Dibenzothiazyl Disulfide System
Authors: Datta Rabindra Nath , Das Prasanta Kumar , Basu Dipak Kumar 
Published: February 2011

Abstract
Investigations have been carried out on the effect of CTP on thiocarbamyl sulfenamides, either alone or in combination with MBTS, in the vulcanization of NR. It has been observed that CM, CP, CPTCD, OTCD, and CDB formed from various thiocarbamyl sulfenamides like OTOS, OTCS, and CTOS in the presence of CTP play a vital role in cure retardation. CM and CDB under the experimental conditions have been found to prolong the onset of cure, while CP, CPTCD, and OTCD reduce scorch time. The presence of a substituent on the carbamate N-atom of thiocarbamyl sulfenamides greatly influences cure retardation. OTOS and CTOS give rise to CM and CP respectively in the presence of CTP. OTCS, however, generates both CM and CP under the identical conditions and thus differs from OTOS and CTOS. CPTCD and OTCD formed from thiuramdisulfides have been shown to be poor and scorchy accelerators, and these, like CM and CP, play a significant role in cure retardation.
Characterization of Polymers by GPC-Lalls. II. Concentration Effect of Polydisperse Polymers in GPC
Authors: Shiga S. , Sato Y. 
Published: February 2011

Abstract
The concentration effect in a GPC is studied on the following polydisperse polymers: HDPE, EVA, EPM, and EPDM. The GPC is equipped with a dual detector system consisting of a LALLS and a differential refractometer. A proportional relationship is widely observed between the degree of the concentration effect and the elution concentration, and classified in two groups according to the molecular weight: in the first where the molecular weight is larger than 100–200 thousand, the effect becomes more severe as the molecular weight increases; and in the second where the molecular weight is smaller, the effect is less apparent with the molecular weight. The branched molecule is more gently influenced than the linear one. Hypothetical equations are proposed for the molecular coil-size-reduction effect and the viscosity effect under the experimental conditions. In combination they would constitute most of the concentration effect, though the estimation of the latter effect would remain uncertain because of the optional character of the equation constant. It is indicated that the correction of the concentration effect is necessary to measure long chain branches exactly by GPC.
Analysis of EPM Elastomers by Infrared and NMR Methods
Authors: Johnson-Plaumann M. E. , Plaumann H. P. , Keeler S. E. 
Published: February 2011

Abstract
The IR absorbances at 1465 and 1378 cm−1 formed the basis of an infrared method for estimating the ethylene/propylene ratio in EPM polymers. Calibration curves were set up for both self-supporting and silver chloride supported films of ASTM EPM polymers. The adequacy of the calibration curves was verified by 1H and 13C NMR data and by testing the methods on several commercial polymers. The self-supporting film method provided more reproducible data than the silver chloride film method. Even so, the confidence intervals for predicting the composition of new polymers were rather broad. They could be reduced to about ±2 wt.% ethylene on polymers of 40 to 70 wt.% ethylene by running five analyses. We have illustrated some of the problems which face the analytical chemist in setting up calibration curves with particular focus on the quality of new data arising from the calibration.