bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abrasion Resistance of Pre-Stressed and Stressed Rubber Vulcanizates
Authors: Lambert D. H. , Boonstra B. B. 
Published: February 2011

Abstract
The abrasion resistance of carbon black-reinforced SBR-1500 vulcanizates has been shown to be drastically reduced by the application of tensile strain during the abrasion process. Pre-stressing of similar vulcanizates, however, has no effect upon the abrasion resistance.
Adsorption and Calorimetric Investigations on Carbon Black Surfaces I. Immersional Energetics of Heat Treated Channel and Furnace Blacks
Authors: Wade W. H. , Deviney M. L. 
Published: February 2011

Abstract
Adsorption of gases under reversible conditions on carbon blacks can provide important basic information revealing the highly heterogeneous nature of the surface electronic fields and relating to physical interactions between the black and elastomeric molecules. Precise, immersional, calorimetric measurements likewise document the strongly heterogeneous surface energies and provide a powerful technique for measuring both physical and chemisorptive interactions between the surface and organic adsorbates. In the first phase of this study a broad spectrum of channel and reinforcing furnace blacks has been studied by immersional calorimetry to provide a survey of both integral and, to a lesser extent, differential heats of adsorption using methanol, n-decane, benzene, and water as adsorbates. The blacks studied were thermally treated at appropriate temperatures so that a wide span of surface conditions could be investigated, including the entire range of coverage by oxygenated functional groups and the regions of maximum hydrogen evolution and incipient graphitization. With these heat-treated blacks, marked integral immersional heat differences between channel and furnace blacks were observed with some adsorbates but not with others, and these results are discussed in terms of black surface conditions. Subtle differences between furnace blacks revealed by differential immersional heats are also presented.
Vulcanizate Performance as a Function of Carbon Black Morphology
Authors: Burgess K. A. , Scott C. E. , Hess W. M. 
Published: February 2011

Abstract
A new nomenclature is proposed for carbon black morphology to be based on actual quantitative electron microscopical measurements. Carbon black is now defined in terms of “paracrystalline graphitic units” which are composed of interlocking “domains of rotational graphitic layer orientation”. The measurement of “unit” or “domain” dimensions replaces the earlier imprecise concepts of structure and particle size. Automated measuring procedures have been developed for determining carbon black unit and domain size functions using a Quantimet Image Analyzing Computer. Unit dimensions are expressed in terms of total projected length (L), average width (W), two-dimensional projected area (A), and form factor (L/W). Domain size (d) measurements have been programmed to give comparable results to earlier carbon black “particle” size determinations using a Zeiss Particle Size Analyzer. The new program enables measurement of similar classes of blacks (e.g., tread grades) under identical instrumental conditions, thus greatly reducing the problem of operator subjectivity. Meaningful correlations have been determined for several vulcanizate properties in terms of the above carbon black parameters. Domain size was found to be the most significant variable in the correlations with resilience, showing a positive relationship. Increasing unit form factor, indicated a depressing effect on resilience and was also the most significant single variable in regard to heat build-up and hardness, showing a positive relationship with both of these properties. A significant inverse correlation with heat build-up and hardness was observed for unit or domain size, when the full range of rubber grade carbon blacks were evaluated. Tensile strength showed an inverse relationship with unit or domain size in the SBR and SBR/BR systems that were studied. In natural rubber, however, there was also a significant depressing effect on tensile strength, attributable to increasing unit form factor. Modulus showed a strong positive correlation with unit length or form factor and an inverse relationship with domain or unit size. High unit form factor was also the most significant variable in reducing extrusion swell. High abrasion resistance (treadwear) was favored by high form factor, low unit size, and low domain size in that order of significance.
The Effect of Compositional and Testing Variations on the Dynamic Properties of Compounds Based on Styrene-Butadiene and Polybutadiene Elastomers
Authors: Meyer D. A. , Sommer J. G. 
Published: February 2011

Abstract
Important factors of potential use for manipulating static and dynamic stiffness and the damping characteristics of compounds based on styrene-butadiene and polybutadiene elastomers and their blends have been outlined. Their characteristics have been compared with those of IIR and EPDM compounds. The effects of variations in composition are quantitatively defined to assist the compounder in combining these effects in a manner that will lead to a desired combination of properties. In addition to the expected increase in static spring rate and dynamic spring rate with carbon black level, the following responses to compositional variations were found important: 1. The complex dynamic spring rate is more sharply dependent upon carbon black level than the static spring rate. 2. The complex dynamic spring rate is essentially independent of the level of crosslinking while static spring rate increases. 3. Damping coefficient is directly proportional to the level of carbon black and inversely proportional to the level of crosslinking. 4. Styrene level in a polymer blend and plasticizer composition can be used to adjust loss modulus and storage modulus at a given temperature and also to modify the rate of change of these properties with temperature. 5. The strain dependency of storage modulus was found in one instance to vary with the elastomer composition. The IIR vulcanizate, when formulated to the same static modulus, exhibited a larger strain dependence than the SBR, BR, and EPDM composition.
Carboxy Nitroso Rubber, Chemistry, Properties, and Applications
Authors: Levine N. B. 
Published: February 2011

Abstract
The nitroso copolymer shows excellent promise which has not been realized due to a lack of ability to achieve a suitable cure. The CNR terpolymer, on the other hand, retains the excellent solvent and oxidizer resistance, nonflammability, and wide useful temperature range of the copolymer and can, in addition, be easily fabricated and cured by several techniques into many useful products.
Structure-Property Relationships in Elastomer-Modified Terpolymer Systems
Authors: Hagerman E. M. 
Published: February 2011

Abstract
A number of terpolymers, incorporating as the elastomer phase polybutadiene, polyisoprene, poly-2,3-dimethylbutadiene, poly(butadiene-co-styrene), and poly(butadiene-co-2-methyl-5-vinylpyridine), were studied. Matrices were composed of poly(styrene-co-aerylonitrile) (SAN), poly(α-methylstyrene-eo-acrylonitrile), and poly(styrene-co-acenaphthylene). At constant elastomer content and elastomer molecular weight in systems employing a SAN matrix, Izod impact resistance was found to vary inversely with rising elastomer-glass transition temperature. In systems of various matrix composition, using a polybutadiene elastomer, heat deflection temperatures were found to vary directly and impact resistance inversely with rising matrix-glass transition temperature. In acrylonitrile-butadiene-styrene (ABS), systems of constant matrix composition and elastomer content, varying the elastomer molecular weight from 0.6 to 2.6×105 resulted in increasing the Izod impact resistance from 0.67 to 12.8 ft-1b/in. of notch.
Raman Spectrographic Studies of the Vulcanization of Rubbers. I. Raman Spectra of Vulcanized Rubbers
Authors: Koenig J. L. , Coleman M. M. , Shelton J. R. , Starmer P. H. 
Published: February 2011

Abstract
We have demonstrated that good quality Raman spectra can be obtained from vulcanizates prepared from cis-l,4-polybutadiene. Furthermore, significant differences are seen in the spectra of extracted vulcanizates prepared from various recipes. Tentative assignments have been made for many of the following Raman lines observed in the spectra. 1. The 1633, 1187, 734, and 720 cm−1 lines are thought to be associated with dialkenyl sulfide crosslinks. 2. Lines occurring at 440 and 505 cm−1 are assigned to polysulfidic and disulfidic structures respectively. 3. The 635, 690, and 708 cm−1 lines are thought to be associated with cyclic sulfides. In particular, the 635 cm−1 line with six membered thioalkenes, the 690 cm−1 line with five membered thioalkanes and the 708 cm−1 line with five membered thioalkenes. 4. Pendent side groups derived from TMTD are thought to have lines occurring at 1142 and 577 cm−1. Other lines occurring in the Raman spectra of the vulcanizates examined cannot be assigned with the same degree of confidence. The line occurring at 1606 cm−1 may be associated with conjugation but further work is necessary to verify it. The recipes chosen do not necessarily reflect those used currently in industry but were designed to accentuate certain structural features in the network. Consequently, the weak band at 1587 cm−1, observed only in systems with large amounts of TMTD and associated with vinyl thioether type structures, should not be overemphasized. Lines occurring at 558, 852, and 872 cm−1 are unassigned at present. Although the initial results are encouraging, it must be stated that many problems exist. Due to difficulties associated with fluorescence and degradation, Raman spectra of many important rubber systems will be difficult to obtain. Low levels of fluorescence cause serious problems when weak lines are present and when quantitative measurements of line intensities are made.
The Migration of Extender Oil in Natural and Synthetic Rubber. V. Dependence of Diffusion Rates on Oil Concentration and Elastomer Blend Ratios. The Locus of Oil in a Simulated Tire during Service
Authors: Deviney M. L. , Whittington L. E. , Corman B. G. 
Published: February 2011

Abstract
Using carbon-14 labelled aromatic extender oil as a penetrant species, diffusion rates were measured in practical elastomeric compounds of high oil concentration, and in elastomer compounds based on blended polymers. These results, combined with earlier data, allow the calculation of the locus of oil during the service life of the rubber product. Increasing the concentration of oil increases the rate of diffusion of oil. Butyl rubber was the most sensitive to this effect, albeit the slowest in rate of migration, with a 2-fold increase in migration rate over the range of oil concentration of 2–27%, followed by polybutadiene, 1.53; natural rubber, 1.27; and ethylene-propylene-diene rubber, 1.26, and SBR, 1.00. Polymer blends display no synergism in their effect on diffusion; the diffusivity of oil in the blends was predicted exactly by the weighted average of polymer composition. Further studies of the effect of dynamic flexing indicated that, at constant temperature, static and dynamic conditions gave equal diffusivities. Calculations were made of the locus of the oil in a simulated tire section at 3000, 6000, 9000, and 24,000 miles. These agree very closely with experi mental results on a vulcanized, aged simulated tire segment.
Thin Layer Chromatographic Identification of Rubber Compounding Ingredients
Authors: Kreiner J. G. 
Published: February 2011

Abstract
The many examples related above should provide the rubber analyst with systems well suited to some of his problems and, if not, certainly with direction for the evolution of custom systems for his specific needs. The Rƒ values and colors resulting from the chromatographic conditions employed by the experimenters have generally been well related for the compounds examined. These values and colors are useful as guides to another analyst but cannot be trusted for reliable identifications. Rƒ values are difficult to reproduce from one laboratory to another since the factors influencing Rƒ are not always readily reproduced within the different laboratories. Colors are difficult, if not impossible, to describe accurately or to reproduce faithfully with color photography. In addition, many colors may vary (some quite rapidly) with time after or conditions of indication. An identification is best and most reliably made by comparison to known compounds. An unknown is identified when, after adjusting the sample spot size to match that of the known, it travels the same distance and gives the same color and shape as the known. The use of a chromogenic indicator is advisable, if one suitable is available, since differentiation of samples by both a wide range of colors and Rƒ values makes identification much easier. TLC has been shown to be of great utility for the identification of rubber compounding ingredients by the many examples related above. In addition, TLC has proven a rapid, reliable, relatively simple, and inexpensive technique. Undoubtedly many new papers will appear in the future. Some will enlarge or improve on applications already existent. Hopefully, a quantity will tap areas of rubber analysis yet untouched by TLC.
Micro-Evaluation
Authors: Humpidge R. T. , Maclean A. , Morrell S. H. 
Published: February 2011

Abstract
The work at RAPRA has shown that it is perfectly possible to mix 1 g batches of compound and obtain a variety of physical measurements on the products. This especially of value when only a small amount of the polymer is available as in studies on experimental materials, where the polymer itself is costly, or where it is required to investigate the effect of costly additives. For a number of years, work of this nature has been continued in the authors' laboratories, continually perfecting the apparatus and techniques, and the results quoted above are typical of those obtained on a range of experimental polymers and additives.
Crosslink Density Evaluation of EPDM Vulcanizates
Authors: Zamboni V. , Flisi U. , Giunchi G. 
Published: February 2011

Abstract
Crosslink density of EPDM vulcanizates, both gum and filled, has been evaluated from stress-strain measurements on both dry and swollen samples, by plotting the data according to the Mooney-Rivlin diagram. Values of the C1 constant of swollen specimens were generally found to be much higher than those of the dry ones, and the difference was ascribed to the effect of entanglements, which probably act as stable crosslinks in swollen networks. The Flory-Huggins equation has also been studied and its applicability to EPDM vulcanizates examined ; a large degree of uncertainty was found for the polymer-solvent interaction parameter, μ, that suggests the use of this equation with reservation in the case of EPDM elastomers. Many data of the Mooney-Rivlin C2 constant being available, its dependence on various parameters has been investigated and the hypothesis has been confirmed that it is associated with entanglements and intermolecular structure. The stress-strain curves of samples filled with both mineral and black fillers were analysed using the Mullins and Tobin “strain amplification factor.” This technique, which allows one to describe the behavior of the rubber phase in filled vulcanizates, has given good results that endorse the use of the Mooney-Rivlin plot for the characterization of rubbery networks. The Mooney-Rivlin constants also gave very interesting results for the investigation of the networks obtained from curing elastomer blends.
EPDM Elastomers in Rubber Modified Plastics
Authors: Meredith C. L. 
Published: February 2011

Abstract
The superior resistance of EPDM to thermal and ultraviolet degradation makes the use of this elastomer particularly attractive in rubber modified plastics. Because of difficulty in grafting onto EPDM compared to polybutadiene or SBR, conventional emulsion polymerization processes do not give products with the desired balance of physical properties. In order to obtain the necessary degree of grafting and desired rubber particle size in the plastic matrix, a solution-precipitation polymerization was developed. This process is particularly well adapted for the preparation of EPDM modified styrene-acrylonitrile. Properties are quite dependent upon the EPDM composition used to modify the plastic. The amount and choice of third monomer are the most critical parameters with 5 to 12 C = C/1000 of 5-ethylidene-2-norbornene giving the best balance of properties. Relatively poor plastics result with dicyclopentadiene or 1, 4-hexadiene EPDM. while the physical properties of the EPDM-SAN plastic compare very favorably with commercial ABS, the chief advantage is a much greater resistance to the deleterious effects of aging. This is shown by comparative tests of oxygen uptake, accelerated aging, property retention and discoloration at elevated temperatures and during outside exposure, and rheological stability under severe processing conditions.
Rubber Chemicals from Cyclic Amines. V. Thiocarbamyl Sulfenamide Accelerators Derived from 3-Azabicyclo(3.2.2)Nonane
Authors: D'Amico J. J. , Morita E. 
Published: February 2011

Abstract
Evaluation of thiocarbamyl sulfenamides (I) prepared from 3-azabicyclo-(3.2.2) nonane and other amines indicates that the curing properties of stocks accelerated by (I) are influenced by the amino groups which constitute the thiocarbamyl and sulfenamide moieties, R and R′, respectively, and also vary with the formulation of the rubber stocks. The fastest cures are obtained when R is pyrrolidinyl or dimethyl and slowest cure when R′ is N-tert-butyl or N-morpholino. The lowest maximum crosslink density is obtained with morpholino- or piperidinothiocarbonyl sulfenamide. In a non-extended SBR black stock the crosslinking reaction generally proceeds as a second order reaction. The major part of the crosslinking reaction of the slower curing stocks proceeds by a fast first order rate followed by a slower first order rate.
Ambient Curing of Unsaturated Elastomers with Halomethyl Phenolic Resins
Authors: Petersen K. C. 
Published: February 2011

Abstract
A new vulcanizing agent, CRJ-328, has been developed which is activated at low temperatures by zinc oxide. This material, a phenolic heat reactive which contains bromomethyl groups (28% bromine), vulcanizes unsaturated elastomers of both the functional group containing variety, and those containing unsaturation as the sole reactive moiety. Fillers have their usual effects on the vulcanizates. At the present time, most of the work has been done on liquid elastomers although work is currently progressing on the higher strength solid elastomers. We envision initial application of this new cure system in caulking compounds, sealants, adhesives, coatings, propellant binders, potting, and encapsulating compounds. The advantages of this system are a low temperature vulcanization and formation of light colored stocks. Perhaps the scorchy nature of this cure system can be put to use in applications requiring faster cure times at lower temperatures.
Tread Wear and Wet Skid Resistance of Butadiene-Styrene Elastomers and Blends
Authors: Kienle R. N. , Dizon E. S. , Brett T. J. , Eckert C. F. 
Published: February 2011

Abstract
1. Car, wheel position, driver, inflation pressure, and shoulder drop have a statistically significant effect upon wear loss and need to bo taken into consideration before material factors affecting wear can be studied. 2. Variations in macrostructure of the polymers are not found to have a significant effect on wear as compared to microstructure variations. 3. At least two material factors control wear loss of tire treads. 4. When polymers are tested near their glass transition temperature (within 80° C), wear loss is dominated by viscoelastic properties. Viscoelastic properties can be related to wear loss through Tg or the combined effect of the cis, trans, vinyl, and styrene content. 5. At higher test temperatures (over 100° C above Tg) wear loss is dominated by a material factor that has a positive correlation with temperature. This is particularly noticeable when treads are worn under mild conditions. However, there is evidence that this wear factor is present at the testing nearer to Tg but is masked by the dominant viscoelastic effect. 6. The combined effect upon wear of the different material factors leads to an optimum wear resistance for any polymer in the butadiene—styrene system in the range of 75°–105° C above the Tg for that polymer. 7. For polymers tested at the same ambient temperature, (T), the effect of viscoelastic properties decreases non-linearly as T−Tg increases. 8. In the range of test severity studied, severity has little effect upon the inter-relationship of material factors. 9. In the range of test temperature where Tg dominates wear loss, skid distance on wet asphalt pavement is inversely related to wear rating.
Organic Peroxides for Cure of Ethylene-Propylene Rubbers
Authors: Harpell G. A. , Walrod D. H. 
Published: February 2011

Abstract
The reactivity of crosslinking peroxides decreases in the order 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, dicumyl peroxide, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(t-butylperoxide)-3-hexyne. First order decomposition rate constants for these peroxides were inferred from oscillating disk rheometer studies in poly(ethylene). The cure reaction in EPR and EPDM is more complex than in poly(ethylene) and the conventional measure of cure time leaves significant unreacted peroxide in the vulcanizate. Quinoline type antioxidants are preferred because they interfere least with the cure reaction.
Determination of Ethylidenenorbornene in EPDM Terpolymers
Authors: Gardner I. J. , Ver Strate G. 
Published: February 2011

Abstract
Ethylidenenorbornene (ENB) is a diene often employed as the third monomer in the commercial production of ethylene-propylene terpolymers (EPDM). A number of spectroscopic, chemical, and physical property procedures were examined as potential methods for determining ENB content. These included the use of iodine monochloride (ICI) and borane chemistry, nuclear magnetic resonance (NMR), and infrared (IR) analyses, as well as refractive index determinations. To evaluate the accuracy and reproducibility of the various methods, we prepared 24 EPDM terpolymers containing carbon-14 labeled ENB. The labeled diene was prepared via the Wittig synthesis. The ENB content of the EPDM's varied from 1.17 to 17.40 weight per cent. Catalyst systems for terpolymer preparation were employed that were representative of those used commercially in the production of EPDM. The refractive index method was found to combine adequate precision with speed of operation and proved to be the most reliable of the methods studied for determination of ENB content. An iodine number method was equally precise but suffered from the standpoint of speed. Two IR methods employing the 1685 cm−1 and 805 cm−1 absorption bands were not acceptable because of various structural interferences arising from compositional variations within the polymers. Proton NMR requires the use of time averaging and borane. chemistry proves to be a more cumbersome wet method than ICI, although presumably it involves reactions with olefins less complicated by side reactions than with ICI. Interrelationships of the various techniques are examined with regard to information concerning branching reactions. It is concluded that the data are consistent with the idea that commercial EPDM is a highly branched, partially gelled polymer. The basic contribution here is the refractive index technique which we referred to previously.