bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of 2-R-4,6-Dithiol-s-Triazine for Neoprene Vulcanization
Authors: Nakamura Y. , Mori K. , Nakamura T. 
Published: February 2011

Abstract
The most useful accelerator for neoprene (CR) vulcanization with magnesia and zinc oxide has been 2-mercaptoimidazoline (NA-22). However, an alternative accelerator or crosslinking agent that is almost completely devoid of toxic effects is required since toxicity investigation has indicated the danger of carcinogenicity arising from NA-22. Although thiol-s-triazine compounds have already been patented as accelerators in CR vulcanization, these must be reexamined with regard to the vulcanizing effect, since nontoxic dithiol-s-triazine compounds (Table I) have recently been produced on a commercial scale. Curing systems for poly (vinyl chloride) (PVC) or epichlorohydrin rubber (CO) with 2-R-4,6-dithiol-s-triazine (1, R: NHC6H5 or N(C4H9)2) have been found to give crosslinked products with excellent aging resistance; and thus a similar crosslinking effect might be observed in CR vulcanized with 1. The present studies were undertaken to confirm the crosslinking effect of 1 in CR vulcanization and then to show the antioxidative effects which remain after solvent extraction of CR vulcanized with 1 containing antioxidant substituent R.
Contribution to the Identification and Quantitative Determination of Carbon Black in Vulcanizates by Thermogravimetric Analysis
Authors: Pautrat R. , Metivier B. , Marteau J. 
Published: February 2011

Abstract
It has been verified that, in a number of cases, thermogravimetric analysis permits quantitative determination and identification of carbon blacks in the free state or in vulcanized compounds. The proper operating conditions can give sufficiently good repeatability and adequate precision for most routine analyses. As is the case in other methods for determining the loading, numerous difficulties were encountered with elastomers which graphitize on heating. However, quantitative analysis of black in nitrile rubbers remains possible, but the identification of different types of black is very difficult. The authors propose to continue this study, particularly into the new families of blacks, primarily into the function of the diameter of their elementary particles and their degree of structure.
High-Molecular-Weight, High-Unsaturation Copolymers of Isobutylene and Conjugated Dienes. I. Synthesis
Authors: Thaler W. A. , Buckley D. J. 
Published: February 2011

Abstract
This investigation has provided insight into the critical role of solution properties on the course of cationic polymerization and has led to a technique for reconciling the opposing demands for synthesis of isoolefin-diene copolymers both free from gel and high in molecular weight. By this technique, the synthesis of a broad range of intermediate-unsaturation elastomers of quality has been realized.
The Distribution of Olefinic Linkages in Elastomers
Authors: Anderson J. N. 
Published: February 2011

Abstract
A method for determining the distribution of olefinic bonds in elastomers has been developed using dual-detector gpc analysis of the polymer after derivatization with 2,4-dinitrobenzenesulfenyl chloride. The method is particularly useful for determining the distribution of olefinic bonds in hydrocarbon copolymers having small levels of unsaturation.
Functionality Distribution of Hydroxyl-Terminated Polybutadienes by Gel Permeation Chromatography. I. Method and Calibration Procedure
Authors: Anderson J. N. , Baczek S. K. , Adams H. E. , Vescelius L. E. 
Published: February 2011

Abstract
In recent years, considerable attention has been focused on the structural characterization of functionally terminated hydrocarbon prepolymers used in propellant binders and other applications. The molecular weight averages and molecular weight distributions of hydroxyl-and carboxyl-terminated poly butadienes have been determined by gel permeation chromatography (GPC). The functionality distribution of these prepolymers has also been previously studied by column fractionation and a procedure combining GPC and column fractionation of the polymer by stepwise elution from silica gel. The carboxyl or hydroxyl equivalent weights of the fractions were determined by infrared or near-infrared spectroscopy. The fractionation procedure is quite laborious, and multiple peaks were observed in the elution profile, making it difficult to decide how the fractions were to be grouped for subsequent analysis. Previously, a technique for determining the distribution of unsaturation in copolymers containing a small number of double bonds as a function of GPC elution volume was developed. The technique utilized a GPC equipped with uv photometer and differential refractometer detectors to determine the ratio of the weight fraction of olefinic bonds to the weight fraction of polymer by GPC analysis of the polymer after derivatization of the double bonds with 2,4-dinitrobenzenesulfenyl chloride. It was suggested that the technique should be applicable for the determination of the distribution of other functional groups with the choice of suitable reagents for derivatization. The purpose of this investigation was to attempt to extend our previous study to simultaneously determine the molecular weight averages, molecular weight distribution, hydroxyl equivalent weight, functionality averages, and functionality distribution of hydroxyl-terminated polybutadienes by a GPC technique.
Sequence Distribution of cis-1,4- and trans-1,4-Units in Polyisoprenes
Authors: Tanaka Y. , Sato H. 
Published: February 2011

Abstract
Recently 13C NMR spectroscopy has been successfully applied to investigate the sequence distribution of 1,2- and 1,4-units or cis-1,4- and trans-1,4-units in polybutadienes. As for polyisoprenes, however, few investigations have been made on the sequence distribution of isomeric structures using this technique, although Duch and Grant have assigned the 13C NMR signals of cis-1,4- and trans-l,4-homopolyisoprenes. In previous work we have found new signals attributed to cis-trans linkages in the 13C NMR spectra of cis-trans isomerized polyisoprenes and assigned the signals using diad sequences of cis-1,4- and trans-l,4-units. We have also studied the 13C NMR spectra of hydrogenated polyisoprenes containing various amounts of 1,4- and 3,4-units and the sequence distribution of 1,4- and 3,4-units were discussed for n-BuLi-catalyzed polyisoprenes. In this work we have investigated the sequence distribution of chicle polyisoprene and cis-trans isomerized 1,4-polyisoprenes containing various ratios of cis-1,4- and trans-1,4-units.
Synthesis of Radial Thermoplastic Elastomers
Authors: Hsieh H. L. 
Published: February 2011

Abstract
The combination of anionic polymerization techniques and a subsequent coupling reaction created a versatile process for producing block polymers of not only controlled block length and block sequence but also with a controlled number of branches. This process has been successfully used in commercial production since 1967. Radial styrene-diene block polymers have properties significantly different from linear polymers of the same molecular weight, showing lower melt viscosities as well as lower solution viscosities. This feature is significant in adhesive applications because it allows the use of polymers of higher molecular weights with a corresponding improvement in shear resistance.
Rubber-Thermoplastic Compositions. Part I. EPDM-Polypropylene Thermoplastic Vulcanizates
Authors: Coran A. Y. , Patel R. 
Published: February 2011

Abstract
Thermoplastic elastomers are rubbery materials which can be fabricated by techniques usually associated with thermoplastic resins. Classical elastomers rely upon the crosslinked network, developed during vulcanization, to provide the retractive forces of rubber type elasticity. Thermoplastic elastomers contain rubber domains and resinous thermoplastic domains. The thermoplasticity results from the melting characteristics of the hard thermoplastic phase, while the rubber properties arise from the rubbery domains. Thermoplastic elastomers are, therefore, almost by definition, heterogeneous in their phase morphology. Such materials can be blends or block polymers. In the case of block polymers, the rubbery phase is not crosslinked chemically. However, hard or resinous phase domains occur as the hard segments of the block polymer which separate from the composition by agglomeration during cooling from the molten state. These domains act both as well-bonded reinforcing filler particles and as crosslinks. This is, of course, because the hard blocks are connected to the soft or rubbery segments by primary chemical bonds. In the case of the blend compositions, the hard and soft domains are separate polymeric species. However, there must be some form of interaction between the domains if useful properties are to be realized. Recently, uncured or partially cured EPDM rubber has been blended with polyolefin resin to make thermoplastic elastomer-like compositions. However, these compositions suffer deficiencies in performance as well as in certain aspects of fabricability. Only poor to fair performance at temperatures above 70°C in air or in oil has been achieved with the uncured to partially cured compositions. More recently, it has been found in our laboratories that fully cured EPDM compositions which are fabricable as thermoplastics can be prepared. Such compositions, referred to here as thermoplastic vulcanizates, have superior strength, high-temperature mechanical properties, hot oil and solvent resistance, better compression set, etc. This report outlines critical parameters associated with these unique materials.
Viscoelastic Characterization of Long Branching and Gel in Butadiene-Acrylonitrile Copolymer Elastomers
Authors: Nakajima N. , Harrell E. R. 
Published: February 2011

Abstract
Difficulties in relating long-chain branching to processability may be attributable to two causes: one is the definition, pertinent to processability, of what long branches are and the other is a method of determining long branching which is free from interference by other material variables, such as molecular weight distribution, gel, and “short” branches. Measurements of the dilute solution properties are tedious, time-consuming, and require skill for precision. In addition, the requirement for filtering the solution practically obliterates the result, regardless of how precise the measurement may be, because elastomers, as a general rule, have or are suspected to have an insoluble gel fraction. Recent advances in viscoelastic studies of model polymers show that the branches must be 2–3 times longer than the “entanglement coupling” distance in order to exhibit enhancement of viscosity in the Newtonian flow. Whereas Newtonian flow provides a precise definition of the long branches, it is not accessible for most of the elastomers. In the observed time scale, the linear viscoelastic properties as well as the steady-state viscosities are affected not only by branches but also by gels and molecular weight distribution. When these material variables are changed one at a time in the properly designed model systems, their effects are separately observable. On the other hand with a sample of unknown background, the effect of long branching is usually inseparable from those of other variables.
Enthalpic Analysis of Vulcanization by Calorimetry. Thiuram Monosulfide/Sulfur Vulcanization of NR, BR and SBR
Authors: Brazier D. W. , Nickel G. H. , Szentgyorgyi Z. 
Published: February 2011

Abstract
As demonstrated in the foregoing discussion, the chemical complexity of accelerated sulfur vulcanization reactions prevents detailed interpretation of the enthalpy-temperature and enthalpy-time relationship. Nevertheless, the following conclusions can be reached regarding the origin of the enthalpy terms observed under scanning and isothermal temperature regimes. (1) The total enthalpy observed under scanning conditions is the sum of all reactions occurring. This includes (among others) crosslink formation, formation of non-crosslinking sulfidic products and maturation or subsequent polysulfide reactions. (2) In the isothermal experiment, the major contribution to the observed enthalpy arises from reactions resulting in the formation of sulfidic products (although some maturation must be expected and its extent will depend upon the temperature and time of cure). (3) When a precured sample is scanned, the observation of an enthalpic term depends upon the original cure system used. It is small or unobserved, for example, when the sulfur/TMTM ratio is small or with sulfur donor cure systems. On this basis, the DSC scan of a vulcanizate is potentially useful for characterizing that vulcanizate, and in particular, for the rapid quality control assessment of the state of sulfidic products in the vulcanizate. (4) Evidence has been discussed which suggests that the origin of the enthalpy term obtained with vulcanizates which have been precured can be related to the polysulfidic products in the sample. In laboratory experiments, not reported here, the magnitude of this term is reduced as the vulcanizate is heat aged or over-cured, which again supports the conclusion that we are observing the maturation of polysulfidic products. (5) Finally, comparison of rheometer and calorimeter data indicates that, as expected, we are observing all, reactions accompanying cure in the calorimeter; whereas, the rheometer responds only to crosslinking and chain scission, factors having a large effect on viscosity. DSC does not detect chain scission reactions at normal cure temperatures because the rate of scission is too small.
Wear of Metal by Rubber
Authors: Gent A. N. , Pulford C. T. R. 
Published: February 2011

Abstract
Rates of wear have been determined for steel and bronze scrapers sliding over rubber surfaces. The wear rates were found to depend strongly upon the particular elastomer used, varying by orders of magnitude even though the other ingredients in the compound and the physical properties of the rubber were largely unchanged. In the absence of oxygen the metal scrapers were found to wear away much faster in general; by a factor of 5 to 50 times, depending upon the elastomer. Butyl rubber was anomalous in this respect, however, causing three times greater wear in air than in nitrogen. These diverse observations are attributed to the direct attack upon metals of free radical species generated by mechanical rupture of elastomer molecules during abrasion. The rate of metal wear is closely correlated with the stability of polymeric radicals formed in this way. When the radical is highly reactive it is thought to take part primarily in internal reactions and thus cause little wear of the scraper. On the other hand, relatively stable polymer radicals appear to attack metals vigorously.
Synthesis and Properties of Polyoxazolidone Elastomers from Diepoxides and Diisocyanates
Authors: Kitayama M. , Isda Y. , Odaka F. , Anzai S. , Irako K. 
Published: February 2011

Abstract
Polyoxazolidone elastomers are obtained by reacting at 150°C. bisphenol-A-diglycidylether and polyoxytetramethylene-glycol having terminal isocyanate groups in the presence of new diepoxide-soluble catalysts. Among these catalysts, MgCl2/HMPA2 yields an excellent polyoxazolidone elastomer having low modulus and high tensile strength. The stress-strain data of the elastomers show stress-induced crystallisation. The reaction proceeds selectively and completely in one hour at 150°C. The pot life is long enough to ease the handling before curing. The properties of polyoxazolidone elastomer, especially heat resistant properties, are compared to those of polyetherurethane, also a castable elastomer. This comparison has shown (1) a somewhat higher melting point, (2) appreciably better retention of tensile properties after aging at 170°C (3) lower, high-temperature tensile properties and (4) tear energy, stress-relaxation and the creep behavior about the same or somewhat lower.
The Effect of Biaxial Orientation on the Thermal Conductivity of Vulcanized and Unvulcanized Rubber
Authors: Hands D. 
Published: February 2011

Abstract
Experiments have been carried out to investigate the effect of equibiaxial orientation on the thermal conductivity of a series of natural rubber compounds. The conductivity was measured normal to the direction of stretch. The main effect has been explained quantitatively and an equation obtained which relates the conductivity to the extension ratio. The effect of orientation is not only of intrinsic interest but is also technologically significant, since the conductivity can decrease by a factor of 4 for quite modest extension ratios. The size of the effect indicates that it should be taken into account in mixing and extrusion theories, since in such processes the orientation is comparable to or greater than that of our experiments, but so far all theories have ignored any possible change in the thermal transport properties. We have also observed that crosslinking causes a significant decrease in the thermal conductivity.
Halogen-Containing Aminimide Compounds as Tire Cord Adhesives
Authors: Throckmorton P. E. , Luckman E. R. 
Published: February 2011

Abstract
Aminimides derived from dibasic acids such as sebacic acid have proven to be very good adhesives when used in the first dip of a two-dip tire cord system. These aminimide materials have the advantage of being water soluble for easy application. They give effective adhesion of rubber to polyester tire cord. Although they offer process advantages, their performance is only approximately as good as present commercial art. It would be a further advantage if aminimides for tire cord bonding were improved over the best tire cord adhesive. Consequently, a means to effect bonding improvement was sought. Halogenated aminimides were prepared to effect tire cord bonding improvement to polyester cord. Various compounds derived by synthesis procedures for polyhalo aromatic or norbornene aminimide compounds were prepared. The preparations were designed so that the starting materials were readily available. The aminimide precursors avoided base-displaceable halogen because strong base is needed to make aminimides. Thus, aliphatic halogenated starting materials were not used because they contain base-displaceable halogen. Two of the model aminimides prepared were polyhalo aromatic aminimides and five were polychloronorbornene nuclear or side chain aminimides. In a two-dip system, aminimide compounds derived from hexachlorocyclopentadiene showed adhesion values of up to 164.6 newtons and 100% rubber coverage remaining after extracting the polyester cord from the rubber test specimen. This was equal to the best aminimide dibasic acid polyester tire cord adhesion and coverage. But although the bonding with the halogen-containing aminimides was good, the goal of improved adhesion was not met. Although the chlorinated compounds of this study were promising in bonding rubber to polyester tire cords, the first ones lacked water solubility. Water solubility is considered desirable from the process dip viewpoint. A water soluble version was made where each of two of the chlorine atoms were replaced by a methoxy group. However, tire-cord-to-rubber bonding tests of the water-soluble version of the polyhaloaminimide type was not found to be an improvement over the several oil-soluble versions prepared and tested.
1H NMR Study of Polyisoprenes
Authors: Sato H. , Tanaka Y. 
Published: February 2011

Abstract
1H NMR spectra of polyisoprene were assigned using polymers of isoprene-1,1,4,4-d4, isoprene-1,1,5,5,5-d5, and isoprene-4,4-d2 polymerized with various catalysts. The methylene-proton signal at 2.1 ppm in cis-1,4- and trans-1,4-polyisoprenes was divided into H4- and H1-proton signals; H4 resonated at 2.21 ppm in both cis-1,4 and trans-1,4 units, whereas H1 resonated at 2.05, 2.21, and 2.15 ppm. Splitting due to the dyad sequences of 1,4 and 3,4 units was apparent. The methine-proton (H3) in a 3,4 unit showed a broad peak centered around 1.5 ppm in C6D6. The overlapping of this signal with the methyl-proton signals at 1.73 and 1.63 ppm resulted in some uncertainty in the determination of the microstructure of polyisoprene which contained a considerable amount of 3,4 unit.
An Elastomeric Energy Storage Device for Automotive Engine Restart
Authors: Killgoar P. C. , Pett R. A. , Tabar R. J. , Foote L. R. 
Published: February 2011

Abstract
An elastomeric spring starter using rubber in shear has been designed. Design criteria have been established and used to develop potential compounds for use in the device. Natural rubber proved to be the elastomer of choice primarily because of its excellent fatigue resistance. To reconcile bonding requirements and requirements for low hysteresis, the individual rings were fabricated from two elastomer compounds. Limitations on the thermal stability of the adhesive system were identified which put constraints on the operating conditions for the starter. A prototype starter has been assembled and installed in a vehicle. This prototype starter provides quiet, rapid starting of the test car. Questions of cost effectiveness, reliability, durability or manufacturing feasibility of this device have not been addressed. The starter was built for experimental purposes only and development of such a concept for mass production has not been explored.
Characterization of Aniline-Acetone Condensation Products by Liquid Chromatography and Mass Spectroscopy
Authors: Lattimer Robert P. , Hooser E. Ray , Zakriski Paul M. 
Published: February 2011

Abstract
Liquid chromatography has proven to be an extremely valuable tool for many separations involving polymers and polymer chemicals, especially when used in conjunction with mass spectroscopy for chemical identification. The complex products of the condensation reaction of aniline with acetone have been characterized by liquid chromatography and mass spectroscopy. The LC separation procedure utilized a C18 Micro Bondapak (reverse phase) column with a water/tetrahydrofuran gradient system. Eluted peaks were trapped individually for field desorption mass spectral identification. Syringe deposition was used to transfer the isolated components to the field emitter. The major components found in the reaction mixture were oligomers of 2,2,4-trimethyl-l,2-dihydroquinoline (TMDQ), although several other monomeric and oligomeric side-products were observed and characterized. Forty-two components were identified in the product resin. These can be classified into eight major series of oligomers; all series have oligomers separated by the TMDQ monomer unit (173 amu).
S-N Compounds as Delayed Action Chemicals in Vulcanization
Authors: Morita E. 
Published: February 2011

Abstract
Since the discovery by Goodyear in 1839 that the physical properties of rubber may be improved with sulfur, it has been the most commonly used crosslinking agent. The rubber industry is concerned with the production of homogeneous products with appropriate physical properties, by compounding rubber with ingredients, including crosslinking agents, followed by processing, molding, and introduction of chemical bonds. Economically, it is advantageous to apply high temperature which reduces processing and curing time. However, application of high temperatures frequently causes premature cure. Compounding adjustments are often required in the plants to prevent scorch, especially by the use of compounds with S—N bonds as accelerators, vulcanizing agents, and also as prevulcanization inhibitors or retarders which delay the crosslinking reaction of sulfur and rubber. There are several reviews relating to accelerators, retarders, and vulcanization, which discuss S—N compounds as delayed action curing agents. This review covers the development of S—N compounds as delayed action chemicals for vulcanizing rubber, the various structural types, properties, applications, and the mechanism of their function during vulcanization.