bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Use of Radio-Frequency Activated Gas Treatment to Improve Bondability
Authors: DeLollis N. J. 
Published: February 2011

Abstract
Two apparent contradictions are indicated in comparing recent work with previous work in the field of adhesion. The first contradiction concerns the significance of a weak boundary layer in adhesion failure. Bikerman and Hansen infer the presence of a weak boundary layer and imply that its removal is necessary to improve adhesion. Yet, neither its presence nor its removal are confirmed experimentally. Recent work with RTV silicone confirms experimentally the presence of a material meeting the definition of a weak boundary layer before and after the radio—frequency activated oxygen treatment, which improves adhesion. These results indicate that a possible bonding mechanism involves desorption or displacement of the weak bondary layer and preferential adsorption of the adhesive to form the bond. The other contradiction involves the report by Hansen and Schonhorn that the “CASING” treatment improves adhesion to poly (ethylene) without changing surface energy characteristics. Three laboratories report relatively large changes in contact angle on poly (ethylene) even after exposure to an activated gas for as little as 5 sec. Malpass and Bright report that, while there may be no change in contact angle immediately after removal from the activated inert gas environment, the contact angle rapidly decreases to very low values. This indicates that the low energy state is rather transitory in nature. These results along with those of Sowell and Westerdahl indicate that there may be no serious contradiction to the rule of energetics in bonding, i.e., the adhesive in the liquid state shall have a lower surface tension or surface free energy in order to wet, spread, and adhere to the higher surface energy adherend. Recent findings by Hudis, confirmed by Sowell, indicate that the ultraviolet emission from the radio—frequency gas plasma is the basic factor in the cross-linking of poly(ethylene). Sowell has shown that exposure to ultraviolet radiation also causes increase in critical surface energy and improvement in bondability of poly (ethylene).
Infrared Studies of Oxygen-Containing Groups on the Surface of Carbon Black
Authors: Studebaker M. L. , Rinehart R. W. 
Published: February 2011

Abstract
Results of this infrared study give strong qualitative support for the presence of quinones and support the presence of lactones. Considerable chemical reactivity is associated with the presence of these two groups. Absorption typical of phenols and ethers was obtained in the 1205–1195 cm−1 and 1275-1265 cm−1 regions; and it is suggested by this study that the oxygen not present in quinone, lactone, or phenolic form is present as aromatic ring-type ether groups.
Large Particle Oil Furnace Black. A New Type of Carbon Black
Authors: Johnson P. H. , Cooper W. T. , Forseth G. J. 
Published: February 2011

Abstract
Continuous-oil-furnace blacks have dominated the tire-black portion of the carbon black spectrum while the large particle blacks have been produced by the older gas-furnace and thermal processes. New technology has led to the extension of the oil-furnace-black process to include the Thermal black portion of the spectrum. Amenability to control of structure, particle size, and extractables are important features of the process which produces new carbon blacks called LPF for Large Particle Furnace blacks. These new blacks are in the 100–350 nanometer particle size span and can be produced in a range of Dibutyl Phthalate Absorption numbers (ASTM) from about 25 to 120. LPF blacks appear to be similar to existing large particle types, based on general physical properties. However, detailed examination of LPF black morphology with the electron microscope shows unique differences in microstructure. Compared directly in compounds, the new blacks are often more reinforcing than existing counterparts, yielding higher modulus and tensile strength. Substitution of some LPF blacks for Thermal types in mechanical rubber goods can result in substantial savings in terms of plasticizer oil and curative use. Often LPF types can be used to an advantage by replacing blends comprising Thermal types and more reinforcing blacks.
Wire Adhesion Testing
Authors: Coates L. C. , Lauer C. 
Published: February 2011

Abstract
The results of this study are conclusive. The ASTM D-2229 Test Method is not a reliable test for measuring adhesion of wire cords to rubber compounds. However, by using the basic design and modifying it, an accurate measurement of bond strength on a macroscopic level can be obtained. This test is insensitive for all practical purposes to compound physical properties and changes in cord diameter and embedded length—for both stranded and rod-like cords. It is also possible with this test to calculate the amount of stress that is exerted on the surface of the wire cord to determine the relationship between failing stress and the material strength of the rubber compound. Properly used, this new test should give the compounder a better tool to study the adhesion of compounds to metal.
The Chemistry and Technology of Rubber-Bound and Related Novel Antioxidants
Authors: Cain M. E. , Gazeley K. F. , Gelling I. R. , Lewis P. M. 
Published: February 2011

Abstract
The discovery that C-nitrosoanilines react with olefins to give p-phenylenediamines has made possible the synthesis of powerful antioxidants from a wide range of naturally occurring and synthetic unsaturated compounds. Simple alkenes, vegetable oils, and factices may be converted to antidegradants whose behavior parallels that of commercially available materials. The reaction of 4-nitrosoanilines or 4-nitrosophenols with natural and synthetic rubber or latices gives rubber-bound antioxidants which are completely resistant to extraction by water or organic solvents. No major modification of technological processing or fabrication techniques is necessary, and the reaction takes place conveniently during vulcanization. Attachment of the protective group to the rubber molecule does not affect its antioxidant activity, but reduces its effectiveness when migration to the surface is required, e.g., in protection against ozone. Although faster at elevated temperatures, the nitroso-olefin reaction will occur at room temperature, and this allows the preparation of chemically modified raw rubbers by carrying out the reaction in latex before coagulation and drying.
Phase Stability in Heterogeneous Compositions of Butadiene-Acrylonitrile Copolymer
Authors: Landi V. R. 
Published: February 2011

Abstract
Multiple glass transitions in emulsion polymerized butadiene—acrylonitrile copolymer at leass than 36% acrylonitrile by weight were studied using the Differential Scanning Calorimeter. The appearance of two rather than one transition was shown to be related to the drift in composition with degree of monomer conversion, when all monomer was introduced initially. Material responsible for either glass transition in 29% ACN copolymer was concentrated by phase separation in solution. Phase separation in the butadiene—acrylonitrile copolymer system when the width of the distribution of compositions is above a critical value is shown to be predicted by Scott's thermodynamic treatment of multi-component copolymer mixtures. The partitioning of species of different compositions between phases was calculated for a model distribution of polymeric compositions.
Mechanical Fatigue of Rubber
Authors: Lake G. J. 
Published: February 2011

Abstract
Fatigue failure of rubber under repeated loading is reviewed. The process considered is that occurring in the absence of appreciable temperature rise as a result of the development of one or more cracks. A fracture mechanics approach, based on the elastic energy available for crack propagation, enables the crack growth and fatigue behavior to be interrelated quantitatively and is helpful from both basic and applied viewpoints. Initiation of mechanical crack growth is governed by a critical value of the available energy, which is of similar magnitude for various elastomers and can be related approximately to the primary bond strength and molecular structure. Once this value is exceeded, the characteristics of growth vary markedly for different elastomers and appear to be influenced primarily by the elastic hysteresis of the rubber at high strains. Although the mechanical deformations are the basic driving force, the crack growth and fatigue behavior can also be strongly affected by atmospheric oxygen and ozone and the mechanisms of action of these gases are described. Implications of the work from the testing and service viewpoints are considered. A major problem in applying the fracture mechanics approach is to determine the energy available for crack growth in a component of complex shape. Recently-developed methods of doing this are discussed and the quantitative application of the approach to predict service performance is illustrated.
Constitutive Equations for Elastomers
Authors: Tschoegl N. W. 
Published: February 2011

Abstract
General relations were derived by expanding the strain-energy density function in terms of the invariants of the deformation tensor. Some constitutive equations obtained by keeping a third term in the expanson in addition to the two terms retained in the Mooney-Rivlin equation were tested in the light of currently available experimental data. It is shown that by the retention of the third term the upswing in the Mooney stress at low values of γ−1 is successfully predicted, and the stress—strain behavior can be described with excellent accuracy up to break, even in carbon black-filled rubber which is difficult to describe by the Mooney-Rivlin equation.
Low Temperature Relaxation Phenomena in Rubber-Like Polymers Subjected to Low Deformation
Authors: Bartenev G. M. , Kucherskii A. M. 
Published: February 2011

Abstract
1. A new relaxation process was discovered which explains the change, at critical tensile stresses (0.1–0.5 kg/cm2), in the elasticity of rubber-like polymers subjected to small deformations. This new process is characterized by relatively low activation energies (weak dependence of temperature on relaxation time) and kinetic units that are large (strong dependence of relaxation time on stress). The kinetic stress is a function of the temperature and for rubbery polymers it is reduced to zero, at 40° –60° C. 2. The mechanism of this phenomenon is elucidated by the existence of ordered, supermolecular microregions forming, with the free chains of 3-dimensional networks, supplementary bundles of non-chemical origin which disintegrate under, critical stresses. The activities observed are analogous to the processes of forced-elastic deformation in the same polymers in the glassy state. The critical stress is analogous to the limit of forced elasticity at low second order (glass) transition temperatures.
Electron Spin Resonance Study of Phenolic Antioxidants. Correlations of Organic Free Radical Stability with Antioxidant Activity
Authors: Westfahl J. C. , Carman C. J. , Layer R. W. 
Published: February 2011

Abstract
Electron spin resonance (ESR) is a well established, sensitive spectroscopic technique for determining the molecular structure, as well as the lifetime or stability of organic free radicals. Consequently, ESR spectroscopy provides a logical method for gaining insight into the role that free radicals play in the stabilization of rubber by organic antioxidants. We used ESR spectroscopy to determine the molecular structure of the phenoxyl free radicals derived from a series of twelve phenolic antioxidants. We also used ESR to measure relative radical concentrations of the free radicals and evaluated the twelve phenolic antioxidants relative to each other. We have found that the ESR measurement of relative radical concentration is a measure of relative radical stability, and that the relative radical stability is temperature dependent. By plotting relative radical concentration (or stability) as a function of temperature, we can rank these twelve antioxidants relative to each other. This ranking is in good agreement with the activity of these antioxidants in EPDM. These data were discussed in relation to antioxidant mechanism.
Polydiene Oxidations with Singlet Oxygen
Authors: Kaplan M. L. , Kelleher P. G. 
Published: February 2011

Abstract
Excited molecular oxygen in its singlet delta (1Δg) state can be made chemically in homogeneous solution and in the gas-phase by the electrodeless discharge of ground state oxygen. Both techniques have been used to perform oxidations of polydiene systems. Solutions of high cis, trans, and vinyl polybutadienes have been treated with singlet oxygen produced in situ. Only the high cis and high trans were oxidized, apparently by different mechanisms. Squalene, a model for polyisoprene, has been oxidized in solution and the initially formed hydroperoxides reduced and analyzed and found identical to the product from a photosensitized oxidation. Cis-polybutadiene films were treated with gas-phase singlet oxygen and the extent of surface oxidation was monitored spectroscopically and chemically.
The Oxidative Hardening of SBR
Authors: Studebaker M. L. , Beatty J. R. 
Published: February 2011

Abstract
During aging, SBR hardens. This hardening can be followed by swelling volume, hardness, and modulus measurements. Crosslink properties are important in determining the amount of oxidative hardening. The quantity of Sx-type sulfur in the R−S−Sx−S−R polysulfide crosslinks correlates well with the extent of hardening. A drastic reduction in ultimate elongation accompanies hardening, and this is believed to be intimately related to the severe reduction in resistance to cut growth and flexing.
Pendent Accelerator Groups in the Aging of Rubber
Authors: Parks C. R. , Parker D. K. , Chapman D. A. 
Published: February 2011

Abstract
As pendent accelerator groups are believed to be precursors to the formation of crosslinks in accelerated sulfur vulcanization, their original composition and concentration are largely responsible for the characteristics and properties of the final vulcanizate, including aging. This means that aging of rubber vulcanizates is inherently tied into the curing system. Dual labeled experiments using tritium-labeled accelerator and sulfur-35 were carried out to determine the number of sulfur atoms in the original pendent groups. As attached pendent accelerator groups are built up in the initial part of the vulcanization reaction before a network is formed, a dual vulcanization system was used, first curing with dicumyl peroxide followed by the addition of labeled sulfur and accelerator by infusion from benzene solution. Analyses were made by liquid scintillation counting after degrading the vulcanizates in p-xylene solution with t-butyl hydroperoxide using osmium tetroxide as a catalyst. The initial number of sulfur atoms in the pendent groups was found to be 3 for an efficient low sulfur system and 16–17 for a conventional high sulfur system. Oxygen absorption measurements have shown that vulcanizates having a low amount of sulfur in the original pendent groups resulted in superior aging. The presently proposed scheme of vulcanization requires the formation of a zinc perthiomercaptide as the actual sulfurating agent. Reaction with rubber gives rise to attached pendent groups which are the precursors to the formation of crosslinks. Results have shown, however, that pendent accelerator groups were formed not only in the presence of zinc but also in its absence where no zinc complex is possible. This would mean that the mechanism for the formation of pendent groups, at least in the absence of zinc, may be different from that presently accepted.
Fractionation of Polymers
Authors: Smith W. V. 
Published: February 2011

Abstract
Fractionation is an important tool for obtaining structural information on polymers. It is also important for isolating relatively homogeneous samples of polymer to use in determining relationships between structure and properties. The most common structural information obtained from fractionation is molecular weight distribution (MWD). This is a very important factor in determining processing behavior. To a lesser extent MWD affects the properties of finished polymer products. It is quite important in helping to elucidate mechanisms of polymer formation. Development of gel permeation chromatography (GPC) over the past few years has provided a fast convenient tool for comparing molecular weight distributions. GPC is fast enough that it may even be considered as a potential means of controlling polymerization processes. The chemical composition of copolymers can be determined using fractionation techniques. For this the fractionations based on polymer solubility are particularly suitable. Thin layer chromatography also shows promise in this area. This information is of importance in respect to some physical properties such as solvent and oil resistance and crystallinity. It is also useful in elucidating mechanisms of polymerization. While the ultracentrifuge has not been used extensively in the investigation of industrial polymers, it does have the advantage of being capable of providing absolute moleclar weight information. When it is desired to establish relationships between the structure of polymers and their physical properties it is always desirable to work with polymers having a narrow molecular weight distribution and a homogeneous composition. This can frequently best be accomplished by using fractionated polymer samples. At the present time fractionations based on solubility are the principal ones used through preparative fractionations based on GPC are now possible and a limited amount of literature in this area is now appearing.
Influence of Lubricating Oil Additives on Swell-Resistant Elastomers
Authors: Bertram H. H. , Brandt D. 
Published: February 2011

Abstract
In the last few decades the demands made on lubricating oils have become increasingly severe; corresponding improvements in the quality of oils have been achieved primarily by adding additives of widely different composition and function. These substances, however, may severely attack elastomers which come into contact with lubricating oils, possibly making the elastomers useless within a short time. The influences of chemically defined lubricating oil additives on nitrile-butadiene, chloroprene, silicone, and acrylic rubbers are investigated at 140° C, ASTM Oil No. 1 being used as the medium. The various substances are found to have strong influences on the condition of the elastomers, depending on the structure of the polymer. See Figure 16. Sulfonated and chlorosulfonated fatty oils and hydrocarbons cause surface hardening in nitrile rubber, which results in crack formation under flexure or elongation. However, after pronounced initial deterioration of the mechanical properties, further penetration of the additive is prevented by the protective layer thus formed. Chloroprene rubber also takes part in a crosslinking reaction with these additives, though without undergoing surface hardening. Silicone and acrylic rubber, which have no double bonds in the polymer chain, are not attacked by these additives. Owing to a crosslinking reaction compounds which release hydrogen chloride, e.g., chlorinated paraffin, cause severe surface hardening in nitrile and chloroprene rubber vulcanizates, which is not restricted to the surfaces. In the case of nitrile rubber, hydrogen chloride combines with the vulcanizate. In the presence of chlorinated paraffin, acrylic rubber first softens but this is afterwards obscured by hardening. Chlorinated paraffin does not attack silicone rubber. Lead naphthenate damages acrylic and silicone rubber but stabilizes nitrile and chloroprene rubber. With reference to nitrile rubber, as an example, it is shown that the resistance of the elastomers greatly depends on the temperature and concentration of the additive and that both synergistic and antagonistic effects are possible when additives are used in conjunction with one another. The purposes of this study have been, firstly, to show that the differences in the behavior of elastomers in technical lubricating oils are usually due to the influence exerted by additives, and, secondly, to encourage the lubricating oils industry to consider and make allowances for the problems of the rubber industry.
Elastomer Abrasion at high Velocity
Authors: Staklis A. A. 
Published: February 2011

Abstract
The series of abrasion runs conducted indicated several trends in rubber abrasion or wear in tests conducted under conditions representative of ACLS braking. Major effects were found for variations in filler level and experimental or abrasion conditions. Optimum filler (SAF) level was found to be between 55 and 65 phr in Butyl-HT. Beneficial effects in terms of reducing rubber adhesion to the braking surface were provided by steel fibers and by talc at 2-8 phr. Rubber abrasion mechanism was found to be predominantly mechanical. The rate of wear, however, was strongly affected by heating at the abrasion interface.
Kinetics and Mechanism of the Reaction of 2-Mercaptobenzothiazole with N-(Cyclohexylthio)Phthalimide and Related Compounds
Authors: Son P. N. , Andrews K. E. , Schooley A. T. 
Published: February 2011

Abstract
Kinetic studies show that 2-mercaptobenzothiazole (MBT) reacts faster with N-(cyclohexylthio)phthalimide (CPT) than with such accelerators as N-t-butyl-2-benzothiozolesulfenamide (BBTS) or 2-(4-morpholinothio)benzothiazole (OBTS). Furthermore, the reaction between N-(cyclohexylthio)-o-benzoic sulfimide (CTBS) and MBT is so fast that it reacts almost instantaneously even at room temperature. However, CTBS is not a good retarder due to its thermal instability.
Acrylonitrile Copolymerizations. IV. Butadiene Copolymerization
Authors: Vialle J. , Guillot J. , Guyot A. 
Published: February 2011

Abstract
The kinetics of the acrylonitrile-butadiene radical copolymerization, carried out in solution at 60° C, have been followed using gas chromatographic analysis. Remote unit effects are observed only on the butadiene-ended radicals, but they seem to involve a quite long sequence of butadiene units. The following values of the reactivity ratios are proposed: rA=0.067, rAB=0.70, rABB=0.66, rABBB=0.17, rBi→0.01 to 0.06 for large values of i. The results are discussed in terms of either polarity effects, or differences in reactivities between 1,4- or 1,2-butadiene radicals, or finally of charge transfer complexes between the monomers.
New Polymer Systems: Chain Extension by Dianhydrides
Authors: Rhein R. A. , Ingham J. D. 
Published: February 2011

Abstract
New highly stable polymers are required for materials applications on future long-term planetary missions. This article presents the results of a systematic investigation on the use of anhydrides to prepare stable elastomeric materials using mild reaction conditions. The three anhydrides investigated were found to provide effective chain extension of hydroxy-terminated poly(alkylene oxide)s and poly(butadiene)s. These were tetrahydrofuran tetracarboxylic dianhydride, pyromellitic dianhydride, and benzophenone tetracarboxylic dianhydride. The most effective catalyst investigated was ferric acetylacetonate, which resulted in chain extension at 333 K (60° C). A novel feature of these anhydride reactants is that they are difunctional as anhydrides, but tetrafunctional if conditions are selected that lead to reaction of all carboxyl groups. Therefore, chain extension can be effected and then followed by crosslinking via the residual carboxyl groups.