bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Simple Method for Estimating Viscosity of Highly Viscous Liquids
Authors: Graessley W. W. , Ver Strate G. 
Published: February 2011

Abstract
The results indicate that the hanging-strip method provides good values of η0 under favorable circumstances. The value of the method lies in the convenience and simplicity of the experiment. With little more than a meter stick and a clock, one can estimate zero-shear viscosities which are above 0.1 MPa·s. Careful testing is very important to avoid the effects of molding history and clamping, and to assure that the time-dependence of specimen elongation conforms to the Newtonian liquid model.
Environmental Degradation of Tire-Wear Particles
Authors: Cadle S. H. , Williams R. L. 
Published: February 2011

Abstract
Each of the three analysis methods contributes to an understanding of the degradation processes which occur in environmentally exposed tire-wear particles. Extraction-pyrolysis-GC is the most reliable method since it treats the whole sample rather than a few particles. In 16 months, 52% of the polymer in tread-wear particulate was degraded in soil samples. In glass beads, only 36% of the polymer in tread-wear particulate degraded, perhaps because soil microorganisms were not available to degrade sulfur linkages in the vulcanized portion of the polymer. Fresh tread particles of the same size showed no degradation. The pyrolysis-GC results showed wider scatter, presumably because only a few rubber particles could be analyzed and all the particles did not degrade at the same rate. However, this method showed that the unsaturated bonds of polybutadiene undergo oxidative degradation more rapidly than do the aromatic bonds of styrene units. These results strongly suggest that one important mode of degradation of tread-wear paniculate is atmospheric oxidation. The TGA results showed that biodegradation did not reduce the total carbon content of the tread-wear particulate in this 16-month study. However, more than half of the extender oil was oxidized sufficiently to increase its vaporization temperature to the polymer temperature range. Biooxidation may have detoxified some of the polynuclear aromatic hydrocarbon portion of the oil. Overall, these results suggest that microbial attack of tread-wear particulate is less significant than attack by-atmospheric oxygen. To match the amount of rubber observed at the California freeway site, the removal rate by all mechanisms must be 0.67% per day. For this high removal rate, the amount of rubber at the roadside would reach a steady-state value within the first two years of a freeway's use at a level equivalent to five months of tire-wear. The rate of environmental degradation found in this study is 0.15 per day, or 22% of the total removal rate found in the California study. Wind erosion and water runoff probably also contribute to the total removal rate. Most importantly, we have shown that tread-wear particles degrade at a faster rate than tread-rubber itself, and that environmental degradation plays an important role in the fate of tire-wear particulate.
Effect of Cure Temperature on Urethane Networks
Authors: Kimball M. E. , Fielding-Russell G. S. 
Published: February 2011

Abstract
The effect of cure temperature on the physical properties of two diamine-cured thermosetting polyurethanes was explained by differences in structure. The polymer cured at the higher temperature (140°C) exhibited properties more typical of a stable crosslinkedelastomer, whereas the behavior of the polymer cured at the lower temperature (80°C) was more typical of a domain-separated system.
N-Sulfonyl-Sulfilimines as Premature Vulcanization Inhibitors
Authors: Hopper R. J. 
Published: February 2011

Abstract
N-Sulfonyl-sulfilimines which undergo a thermal elimination to form N-alkyl (or aryl)thiosulfonamides act as premature vulcanization inhibitors, apparently by the same mechanism as the thiosulfonamides. S,S-di(isopropyl)-N-(p-toluenesulfonyl) sulfilimine was of particular interest due to its good inhibitory activity, ease of preparation, excellent stability, and resistance to bloom.
Comparing the Time and Rate Dependent Mechanical Properties of Elastomers
Authors: Meinecke E. A. 
Published: February 2011

Abstract
At attempt was made to show that the normally performed tests to evaluate the properties of elastomers (and compare different ones) are not necessarily the ones which govern failure due to small strain viscoelasticity. The easiest way to compare different rubber compounds as to their ability to keep their elastic properties is with the help of stress relaxation data. However, one has to perform loading-unloading creep experiments in order to be able to separate the permanent from the transient viscoelastic response.
Block and Graft Copolymers of Polypivalolactone : Poly(Acrylate-g-Pivalolactone)
Authors: Caywood S. W. 
Published: February 2011

Abstract
Thermoplastic poly(acrylate-g-pivalolactone) elastomers depend upon the crystallization of polypivalolactone side chains into discrete domains for the reversible formation of elastomeric networks. The high crystallinity of the grafted polyPVL chains and their chemical inertness leads to a highly reinforced, effectively crosslinked copolymer of unusual stability. The physical properties of the graft copolymer are similar to those of elastomeric polyacrylates compounded with carbon black and chemically crosslinked. At high deformation, as on a two-roll mill, the crystalline domains are sufficiently disrupted to allow the polymer to flow easily. At low deformation, for example in the compression-set test, there is very little flow, as shown by resistance to compression set fully equivalent to that of covalently crosslinked elastomers. The synthesis of polyacrylate-g-PVL copolymers is remarkably simple and subject to few limitations. Grafting efficiency is high and should approach 100% under slightly more rigorous conditions than employed in this work. These copolymers are unique in the ease and precision with which both hard and soft segment length can be varied to control the physical properties of the product.
Design and Engineering with Natural Rubber
Authors: Meyer D. A. , Welch J. A. 
Published: February 2011

Abstract
NR continues to be the preferred general-purpose elastomer for many important engineering applications. Although its stress-strain behavior is similar to most other rubbers, it possesses several unique characteristics which makes it a good or preferred candidate for a large number of applications. These include outstanding fatigue life, high rupture strength, excellent relaxation properties, and stable characteristics over a wide temperature range along with a greater flexibility for manipulating dynamic properties. Many of its apparent limitations can be overcome with proper design and sufficient consideration to end-use conditions. A few well-established engineering applications as well as the design principles involved are presented along with reasons for the use of NR.
The Poisson Ratio for Rubber—Cord Composites
Authors: Pósfalvi Ö 
Published: February 2011

Abstract
Elasticity equations have been devised for an orthotropic rubber-cord system based on nonlinearly elastic rubber and linearly elastic cord. The problem involves the mechanics of nonlinear, elastic, composite materials under large deformations. The Poisson ratios and Young's moduli characteristic of such a composite system under uniaxial stress can be derived. For this computation it is necessary to establish the moduli of elasticity of the cord imbedded in the rubber and the critical cord angle.
Phase Morphology of High-Impact-Strength Blends of EPDM and Polypropylene. Knit-Line Behavior
Authors: Thamm R. C. 
Published: February 2011

Abstract
The blend morphologies of injection moldings of high-impact-strength blends of EPDM or mixtures of EPDM and high-density polyethylene (HDPE) in polypropylene have been elucidated by the use of several classical microscopic techniques. It is demonstrated that, when present, HDPE is located within the EPDM phase, where it probably functions predominantly as a viscosity modifier. Within the core, the dispersed phase has an equilibrium globular shape, whose size can be related to impact strength. Elsewhere, the shape of the dispersed phase accurately reflects the shear forces of viscous flow through the mold cavity. In effect, these small domains serve as tracer elements and provide visual evidence and verification for previously postulated flow patterns. Fast, laminar flow through the center of the cavity to the advancing front and then in a curved path to the wall creates shear patterns such that the dispersed phase is in sheetlike or disk-shaped domains at the melt front and in rapidly crystallized regions near the cold mold wall. When knit lines are formed by union of two melt fronts, these flattened domains are oriented perpendicularly to the flow direction, where they prevent adequate matrix union and probably act as stress concentrators which can provide additional loss of knit line strength. Less easily dispersed, higher viscosity EPDM compositions are recommended where knit-line strength is required.
13C NMR Characterization of Polychloroprene Microstructure I. Spectral Assignments
Authors: Coleman M. M. , Tabb D. L. , Brame E. G. 
Published: February 2011

Abstract
13C NMR spectroscopy has proved to be a very powerful tool for the characterization of polychloroprene microstructure. We have identified and assigned the lines associated with diad and triad sequences involving the predominant trans-1,4 placement, together with other lines associated with cis-1,4, 1,2, isomerized 1,2, and 3,4 structural irregularities. Currently, we are performing 13C NMR, relaxation studies on the chloroprene polymers and will be presenting quantitative data in the near future.
Elastomer Blend Properties—Influence of Carbon Black Type and Location
Authors: Hess W. M. , Chirico V. E. 
Published: February 2011

Abstract
Criteria for minimizing hysteresis in carbon-black-filled elastomer blends are: (1) large black unit size, wide distribution, and low structure; (2) higher black loading in the discrete polymer phase (large zones); and (3) polymer of lower hysteresis as the continuous phase (low black loading). Of the different strength properties that were evaluated, tear and fatigue resistance showed the greatest dependence on black location in NR-BR and NR-SBR blends. Both properties were markedly higher for NR-BR, with most of the black in the NR phase. In NR-SBR, tear strength was higher with high loadings of black in the SBR. Fatigue life showed a reverse pattern, but the variations were not as great in this system. Criteria for maximizing tear resistance are: (1) small black unit size, low structure; (2) higher loading of carbon black in the continuous polymer phase ; and (3) the polymer of higher strength as the continuous phase. There may also be optimum levels of polymer zone size and black size distribution which affect tear strength. Optimized performance in a 50:50 NR-BR radial truck tire tread stock was obtained with a wide-distribution N-375 (50:50 N-351-N-110 blend) black with 75% location in the NR phase. This black gave 5–6°C lower heat buildup, equivalent modulus, 35% higher tear strength, and almost double the fatigue life of a conventionally mixed N-220 at essentially equivalent tread wear resistance (−4%). Optimized performance in 50:50 NR-SBR was indicated for a wide-distribution N-231 type (50:50 blend of N-351-N-119) with 75% of the black in the SBR phase. In comparison to conventionally mixed N-234 and N-220, this black gave about 8–10°C lower heat buildup, about 15% lower modulus, and essentially equal tensile, tear, and fatigue properties. Alternatively, a standard N-231 type with 75% location in the NR phase showed about 5–6°C lower heat buildup, about 20% lower modulus, equivalent tensile strength, 60% higher tear resistance, and 75–120% higher fatigue life.
SEM Study of a Cyclized Rubber Surface
Authors: Bascom W. D. 
Published: February 2011

Abstract
It has been shown that cyclization of a nitrile rubber produces a brittle surface layer. Microcracks develop when the rubber is flexed and, when stressed, severely deform the underlying rubber into an open, fibrous network. These microcracks offer easy penetration and interlocking of the adhesive into the rubber. Evidence was also presented for entrapment of electrolyte solution in the cyclized layer.
Fine-Particle Silicas in Tire Treads, Carcass, and Steel-Belt Skim
Authors: Wagner M. P. 
Published: February 2011

Abstract
HS-200 silicas, modified with the coupling agents, performed in tire treads equivalent to N-200 type carbon blacks. Tread wear and traction in contemporary tire tread compounds could be obtained with HS-200 silica equivalent to those with carbon black. In passenger-car treads containing higher than normal butadiene rubber, HS-200 silica could be compounded for excellent mileage and improved wet road traction. These results are encouraging, but considerably more tire testing would be required for absolute certainty that silicas could, in fact, replace contemporary tread fillers. The data indicate that silicas together with silane coupling agents provide extreme flexibility in the design of tread properties. Although tested only to a limited extent in tires, silicas can be used in sidewall, carcass, and radial-belt compounds of tires, as well. The various filler sizes available, and the flexibility of adjusting surface activity, permits a wide range of rubber properties to be obtained. In a limited number of cases, these properties are virtually identical to those obtained with contemporary carcass and sidewall fillers. Tire performance in carcass and belt-skim compounds showed that silicas could provide tire performance equivalent to conventional fillers in these applications. Based on our observations, we confidently believe the technology exists to meet the performance of today's tire components entirely with inorganic fillers. Obviously, to put these components together in a practical tire requires some development work. Satisfactory performance in individual components is encouraging, but the incorporation of all components into a single harmonious product is still necessary. Fine-particle silicas are truly oil-independent fillers that can be used for tires as well as other quality rubber products.
Chain Scission in the Oxidation of Polyisoprene
Authors: Morand J. L. 
Published: February 2011

Abstract
The composition of the mixture of volatile products formed during the oxidation in air of natural rubber or synthetic cis-polyisoprene in the raw state was investigated in order to obtain further information on the mechanism of chain scission. An important observation was made: in order to obtain, by means of gas chromatography, the peaks of all the constituents, a completely anhydrous solution of the trapped mixture must be used. If the water liberated by the oxidized polyisoprene is present, the peaks of some constituents do not appear. By removing this difficulty, four new less volatile compounds which could result from chain scission were detected on heating extracted polyisoprenes which do not contain protective agents. The concentrations of these four compounds are similar to those of levulinaldehyde, methacrolein, or methyl vinyl ketone, and the structures which were identified correspond to a γ-substituted γ-butyrolactone, a primary γ-ketol, and probably a tertiary γ-aldol and a secondary γ-ketol. These components could arise from a chain scission between two isoprene units, due to a β-scission process of an alkoxy radical. Natural rubber or synthetic polyisoprene which contain protective agents give off mainly the lactone and the tertiary γ-aldol, but levulinaldehyde is produced in small amounts, and methacrolein and methyl vinyl ketone are absent.
A New Fluoroelastomer Derived from Tetrafluoroethylene and Propylene
Authors: Kojima G. , Kojima H. , Tabata Y. 
Published: February 2011

Abstract
(1) A process to produce C2F4-C3H6 copolymer of molecular weight over 150 000 was established by exploiting a new catalyst which permits low temperature polymerization. (2) A vulcanization recipe, comprised of peroxide and TAIC, was established to give the copolymer superior vulcanizate properties. (3) Polymer structure and properties were elucidated, and the high potential as a heat-resistant elastomer was shown. (4) The resultant vulcanizate has been proved to be a unique fluoroelastomer with outstanding heat and chemical resistance as well as mechanical properties which are adequate in practice.
The Polymer-Solvent Interaction Parameter X
Authors: Orwoll R. A. 
Published: February 2011

Abstract
The interaction parameter X has been defined as a measure of the chemical potential of the solvent in solutions with a polymeric solute. Consequently a number of equilibrium properties can be expressed as functions of X. Values of X determined from these properties reveal that for most systems this quantity increases with the volume fraction of polymer in the solution. Accordingly, values of the interaction parameter have been tabulated as a function of concentration, as well as of temperature. The values of X obtained either from experiment or theory can be utilized for predicting the colligative properties and determining the solubility characteristics of polymer-solvent systems.
Continuous Emulsion Polymerization
Authors: Poehlein G. W. , Dougherty D. J. 
Published: February 2011

Abstract
The theories presented can be used for prediction of particle size, particle formation, rate of polymerization, and molecular weight for the emulsion polymerization of styrene in continuous stirred-tank reactors. The incorporation of Stockmayer's modification of the Smith-Ewart theory into Gershberg's continuous reactor model has helped to account for the formation of fewer but larger particles when the reactor is operated at long mean residence times. The use of a different particle generation relation by Nomura and coworkers has led to better agreement between theory and experiment for particle number and polymerization rate at low values of mean, residence time. Their model also fits transient data better than Gershberg's. However, the prediction that free-radical movement into particles is independent of particle size is not very satisfactory. Perhaps the better agreement between theory and experiment results because of the introduction of an additional experimentally determined parameter. Data for other monomers do not follow theoretical predictions as closely as styrene. For methyl acrylate the particle number data are in reasonable agreement with theory but the polymerization rate data show completely different trends. An improved, more general, theory will undoubtedly require a more complete understanding of particle formation and particle growth mechanisms. Particle size distribution measurements would be a valuable asset in developing improved competitive particle growth models.
Fun and Frustrations with Synthetic Rubber
Authors: D'Ianni James D. 
Published: February 2011

Abstract
It is a great pleasure and honor to have this opportunity to share with you some of my experiences in synthetic rubber over the past forty years. I am deeply appreciative of my selection as the thirty-fourth recipient of the Charles Goodyear Medal by the Rubber Division of the American Chemical Society and accept it only as a representative of my many associates at Goodyear who have participated with me in significant developments in synthetic rubber during this period. As the title of this talk indicates, we had both successes and disappointments in our endeavors to develop improved synthetic rubbers. These efforts were greatly stimulated by shortages of natural rubber which occurred in times of national emergencies such as World War II and the Korean War. When we successfully met these challenges it was fun, but to the extent that we were not able to achieve all of our objectives, we suffered a number of frustrations.
Use of Azo Foaming Agents to Produce Reinforced Elastomeric Foams
Authors: Harpell G. A. , Gallagher R. B. , Novits M. F. 
Published: February 2011

Abstract
It is highly desirable to produce elastomeric foams directly from liquid components. Flexible urethanes, the only technologically important elastomeric foams that are commercially available, are enjoying rapid growth. An essential feature of a successful foam system is the ability to attain the appropriate balance between gas generation and cure reaction. We report here a completely new system which allows syrups, consisting of polymer dissolved in free-radically polymerizable monomers, to be foamed directly using certain azo compounds. Our preliminary results show that a number of different azo compounds may be utilized to produce elastomeric foams over a wide density range. The variables which can effectively control the foaming and curing reaction are discussed, but there has been no attempt to optimize the physical properties of the flexible foams. Physical property evaluations will be the subject of future publications. We illustrate the versatility of the system and believe that properties may be easily tailored to end-use needs by appropriate selection of formulation components.
Elastomeric Polyether-Ester Block Copolymers. I. Structure-Property Relationships of Tetramethylene Terephthalate/Polyether Terephthalate Copolymers
Authors: Wolfe J. R. 
Published: February 2011

Abstract
The properties of elastomeric tetramethylene terephthalate/polyether terephthalate copolymers have been related to the chemical structure, chain length, and concentration in the copolymers of the PTMEG-, PEG-, and PPG-derived polyether units. Low-temperature properties and tear strength are dependent on all three polyether-related variables. Melting point, hardness, and stress at 100% elongation appear to be independent of polyether structure. Polyether glycols of low MW volatilize during copolymer preparation. High-MW polyethers tend to crystallize when present in the copolymers. Polyether glycols of intermediate MW (∼ 1000) yield copolymers with the best resistance to low-temperature stiffening. Copolymer synthesis is most difficult with PPG as the polyether glycol. Inherent viscosities are low, and phase separation occurs at lower polyether MW than with PTMEG or PEG. The PEG-based copolymers exhibit high water swell, particularly at intermediate and high PEG MW. The PTMEG-based copolymers are easiest to synthesize and exhibit the best overall combination of properties.