bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mass Spectrometric Identification of 2-Mercaptobenzothiazole Sulfenamide Accelerators in Rubber Vulcanizates
Authors: Hilton A. S. , Altenau A. G. 
Published: February 2011

Abstract
The identification of accelerators in rubber vulcanizates has traditionally been a difficult and tedious task. The mass spectrometric method described in this paper offers a simple and expedient approach to the identification of 2-mercaptobenzothiazole sulfenamides. Neither complicated sample preparation nor solvent extraction of the vulcanizates is required as in the more common methods employed. Only about one-half gram of vulcanizate is needed for the analysis. The sample tube is attached to the mass spectrometer, heated for 15–20 min at 150–200° C and then the mass spectrum of the volatiles is recorded. The characteristic amine fragment ions are utilized for identification of the amine portion while the presence of benzothiazole is indicated by a peak at m/e=135. Spectra obtained from analysis of seven vulcanizates containing different accelerators are presented and the results discussed. The identification of the accelerator in a competitor's tread is also discussed.
Alternating Copolymers by Complexed Copolymerization
Authors: Hirooka M. , Mashita K. , Imai S. , Kato T. 
Published: February 2011

Abstract
There have been few studies on how the nature of copolymers is affected by their sequential structure. This is because, in the past, the sequential structure of most copolymers could not be controlled at will. However, such studies have been realized since it was found that alternating sequential regulation can be attained from many monomer combinations, from which only random copolymers had been obtained previously, provided the copolymerization was carried out in the presence of a Lewis acid, such as an alkylaluminum halide. This kind of reaction is termed complexed copolymerization, as distinguished from the conventional alternating copolymerization. Furukawa and coworkers indicated that alternating butadiene—acrylonitrile copolymer is superior in various properties to the corresponding 1:1 random copolymer. Yabumoto and coworkers noticed that 1:1 styrene—acrylonitrile copolymer obtained in the presence of zinc chloride had a higher glass transition temperature than that of the corresponding 1:1 random copolymer made by radical copolymerization. Moreover, the former was hardly colored due to substantial absence of acrylonitrile—acrylonitrile bonds. Thus, it is very interesting how the properties of eopolymers are affected by sequential structure. The present paper describes various properties of alternating copolymers. The first part of this paper introduces a newly developed alternating copolymer of isobutylene and an acrylic ester and compares it with the corresponding homo-polymers. The latter part deals with comparison of alternating and random copolymers. Equimolar copolymers of styrene and acrylonitrile are compared in physical and mechanical properties. Glass transition temperatures of equimolar alternating and random copolymers of various vinyl compounds are compared. An interesting correlation is shown and discussed on the basis of a thermodynamic treatment.
Multiple Glass Transitions in Butadiene—Acrylonitrile Copolymers. II. Formation of Incompatible Phases during Copolymerization
Authors: Jorgensen A. H. , Chandler L. A. , Collins E. A. 
Published: February 2011

Abstract
Differential Thermal Analysis and Dynamic Mechanical measurements show that the presence of two glass transition temperatures in nitrile rubbers is not unusual. Two glass transition temperatures occur in all commercial non-crosslinked butadiene-acrylonitrile rubbers of less than 35 per cent acrylonitrile even though they have gone previously undetected. We have investigated the changes in composition and glass transition temperatures during the course of the copolymerization. The composition versus conversion results were in agreement with previously published data. Fractionation and polymer-polymer compatibility experiments were used to demonstrate the presence of two incompatible phases of different acrylonitrile content, corresponding to the glass transitions of the original co-polymer. The mechanism for the formation of these two phases is discussed.
An Analog Heat-Flow and Cure Controller Simulator for Rubber
Authors: Claxton W. E. , Holden H. C. 
Published: February 2011

Abstract
This paper has presented in rather general terms the results of experimentation with direct analog methods for simulating heat flow in rubber materials and calculating continuously the attained cure equivalence for interior points. Brief descriptions of both two-dimensional and of one-dimensional prototype instruments are given, along with various applications. Several upward compatible models of the cure simulator-controller are being considered for commercialization.
Accelerated Tire Wear under Controlled Conditions. I. Description of the Test System
Authors: Veith A. G. 
Published: February 2011

Abstract
Tire wear is produced by a series of complex physical and chemical reactions occurring at the rubber-pavement interface. Because of this complexity a rather sophisticated test system is required to study this phenomenon. This paper describes such a system. It consists of an instrumented two wheeled trailer, a towing vehicle with appropriate control and recording instrumentation, and various supplementary measurement devices The conditions or factors that may be directly varied and controlled are tire slip angle and resulting cornering force, camber angle, load, and speed. Factors that may be controlled by suitable choice of test time and location are tire surface temperature and pavement texture. With this system, the three primary external factors that influence tire wear; tire force level, temperature, and pavement texture may be studied independently. This is in marked contrast to ordinary fleet tests where such factors are uncontrolled or mixed into a general matrix of conditions in unknown proportions. This independent factor variation is required for a realistic study of tire wear. The testing is done under accelerated conditions; sufficient losses are obtained in the range 50–500 miles depending upon the levels of the three primary factors. By appropriate choice of the levels of the three primary factors (mainly tire force) the rate of wear may be varied over a range of at least 50 to 1. The effects of tire load and speed on wear are, unlike their effects in ordinary vehicle use, due to the difference in tire force origin. In. trailer tests, the tire force is a sustained dynamic equilibrium force and is thus amenable to precise control. In vehicle use the forces are substantially transient and of an inertial character. The differences between these are pointed out. The system is completely described and operating procedures are outlined. A brief review of the basic factors involved in tire wear is given, including previous literature work on this topic.
Urethane Energy Absorbers for Automobile Bumpers
Authors: Weller P. A. 
Published: February 2011

Abstract
It is believed that the concepts and data presented here are not only useful for the design and application of urethane foam for bumpers, but demonstrate the inherent fitness of the material for this purpose. To review quickly the factors listed in the beginning of the paper: 1. Urethane-faced bumpers will not only prevent damage to the bumper or vehicle, but will eliminate or minimize damage to the object impacted. 2. Repeated tests at severe overloads have demonstrated the recoverability of the foam after repeated impacts. 3. High hysteresis of urethane results in minimum rebound. 4. The material is velocity responsive within the specification range. 5. A wide variety of usable arrangements plus ready moldability provide considerable styling freedom. 6. Temperature compensation features assure designable performance consistency. 7. High efficiency or form factor is achievable, resulting in minimum force and stroke. 8. No maintenance is required. 9. Urethane microcellular foam is among the lower cost plastic materials on a per pound basis. Low densities and discreet placement can result in very competitive systems. Steel stroking bumpers are designed to ward off blows with emphasis on protection of the vehicle on which they are mounted. As a result, they present a far more hostile motoring environment than ever before for anything or anyone except another similar bumper. Urethane bumpers have a great potential for creating a far less hostile environment for everyone and everything, including fronts and rears of current vehicles, sides of all vehicles, other objects, pedestrians, and occupants. The current specification severely inhibits the realization of that potential. Doing anything about it is no easy matter since it could easily lead into a specification of horrendous complexity. However, following is one suggested approach. In testing for occupant protection, a manikin or dummy is selected as a representative test device. It is by no means truly interchangeable with the real thing or all situations, but does provide a firm and representative means for reasonable evaluation and standardization. In like manner, it would be possible to select a reasonably typical front or rear current-model configuration to serve as a representative test device on the face of the pendulum, and simply specify “no damage to the test device” rather than “no contact to specified planes”. A manufacturer could be contracted with by the government to produce identical test devices for all who wished to run such tests. Such a specification could be amended to the current specification as an alternate, rather than attempting to revise what is already an excellent document for the steel stroking bumper.
An Elastomeric Impact-Absorbing Bumper System
Authors: Rusch K. C. , Slessor J. M. 
Published: February 2011

Abstract
An elastomeric impact absorber was selected from a variety of mechanical designs involving a mechanical strut (Torshok), a buckling-column flat spring and an involute spring, several hydraulic shock absorbers, and various concepts utilizing elastomeric polyurethane foam. Functional and economic criteria as well as manufacturing considerations dictated the choice. The following list outlines the functional attributes that favored a rubber shear spring in the elastomeric impact absorber: 1) Simple, rugged design—all parts except rubber blocks are conventional steel stampings. 2) The device is capable of accepting high angular impacts. Due to the rugged I-beam arm, comer impacts and large torsion loads are tolerated. 3) Mounting requirements are incorporated in the case of the unit. This eliminates the need for separate brackets which results in a cost savings as well as a stronger, more integrated attachment between device and structure. 4) The device has very high compliance in skewed loading. This refers to the bumper geometry resulting from an in-line impact on one unit causing it to stroke fully while the other unit remains unstroked. Since the I-beam arm is unrestricted in the lateral direction except by the rubber blocks, the arm of the unstroked unit can assume an angular position in the plan view and does not bind up the bumper system nor does it unnecessarily load absorber faceplate or bumper reinforcement. 5) A high degree of interchangeability could be achieved with this device. In 1973, four basic designs satisfy the front bumper requirements of fourteen (14) different car lines, including attachment requirements. In addition to the many functional attributes for which this unit was selected, there are also several non-functional factors that were of significance. Some of these are: 1 ) The unit, with the exception of the rubber blocks, requiring only stamping plant facilities and technologies to fabricate, can be contained within existing facilities at moderate investment costs. 2 ) Only limited training is required for the work force. The typical automotive worker can be easily trained to produce this unit. 3) The only critical part in the device, the rubber block, can be obtained from a sufficient number of rubber suppliers to ensure adequate supply protection and complete rubber technology support. In summary, high volume production of a bumper impact absorbing device makes necessary a design that is simple yet rugged and reliable.
The Effect of Carbon Black Type on the Dynamic Properties of Natural Rubber
Authors: Ulmer J. D. , Chirico V. E. , Scott C. E. 
Published: February 2011

Abstract
The influence of carbon black type on the dynamic properties of natural rubber is examined for nine carbon blacks, encompassing a wide range of structure and surface area. The dynamic properties are measured at 23° C and 100° C, over a 2 decade range of log frequency, and over a range of 1 to 25 per cent dynamic strain. The effect of carbon black structure and surface area on dynamic properties of a natural rubber compound are dependent on the combination of strain amplitude and frequency test conditions. The effect of carbon black surface area and structure at different temperatures varies on an absolute basis but not necessarily on a relative basis. Correlations of forced non resonant measurements of dynamic properties with dynamic measurements using other instruments confirms the strain amplitude and frequency interaction with carbon black type. Also, the Goodyear-Healy Rebound machine, the Goodrich Flexometer, and the Pirelli Hysteresimeter can be used to estimate basic dynamic properties over limited strain amplitude and frequency conditions. In addition, mixing procedure was found to have a significant effect on the dynamic properties of a natural rubber compound filled with N-327.
Some Observations on the Mechanism of Cure Retardation
Authors: Son P. N. 
Published: February 2011

Abstract
1. A good retarder reacts fast with MBT and forms a non-scorchy accelerator. 2. The decrease in cure rate (k2.) is attributable to the slow cure rate of 2-cyclohexyldithiobenzothiazole (CDB). 3. Cyclohexyl polysulfides (CPS) and cyclohexylthioamine are believed to be also involved in the cure retardation. 4. The new retarder can stop crosslinking by intercepting the crosslink precursors. 5. Formation of cyclohexyl polysulfides (CTP) and their lack of curing property may be responsible for the low state of cure when the new retarder is used. These results are schematically summarized in Figure 7.
Electron Spin Resonance Study of Phenolic Antioxidants. II. Free Radical Structures Arising from Antioxidants Containing the 3,5-DI-Tert.-Butyl-4-Hydroxy-Benzyl Group
Authors: Westfahl J. C. 
Published: February 2011

Abstract
Oxidation of a series of phenolic antioxidants, or compounds related to antioxidants, was carried out using ferricyanide ion in dimethylsulfoxide solution. The free radicals produced were studied by ESR spectroscopy. Most of the antioxidants examined contained one or more 3,5-di-tert-butyl-4-hy-droxybenzyl groups. Based on their behavior on oxidation, the compounds can be divided into two classes. One class forms a relatively unstable primary radical which decomposes to give 2,6-di-tert-butyl quinone methide.
Analysis of Chain Unit Structure of Poly(Butadiene) by Means of the HR-300 NMR Spectrometer
Authors: Santee E. R. , Malotky L. O. , Morton M. 
Published: February 2011

Abstract
The data presented in this paper can best be summarized as follows: 1. With present equipment 13C-NMR cannot distinguish cis—trans junctures in BuLi catalyzed poly(butadiene). 2. Cis—trans content in poly(butadiene) can now be determined by 1HNMR at 300 MHz. 3. The cis—trans content in low vinyl n-BuLi catalyzed polymers is best determined in the olefinic region. 4. The cis—trans content in high vinyl is best determined in the aliphatic region, although contents above 60 per cent become difficult to determine because of overlap with the methine proton of the vinyl unit. 5. Cis—trans ratios are constant over the measurable range of vinyl content. 6. The cis—trans triad sequence distribution and hence the mole fraction of triads can be determined by 1HNMR at 300 MHz. 7. The triad sequences best fit a random distribution. 8. The 1,2 unit is inserted in a random manner, i.e., the unit enters the chain with no preference for any triad sequence.
The Dependence of Processability on Molecular Weight Distribution of Elastomers
Authors: Tokita N. , Pliskin I. 
Published: February 2011

Abstract
After examining the mechanism of mixing of elastomer with filler by both internal mixers and open mills, the failure characteristics of an elastomer (extension to break and ratio of elasticity to plasticity) were found to be important properties affecting the filler wetting and dispersion rates. The failure characteristics have also been shown to depend on the polymer MWD, branching, and microstructure. A quantitative characterization of deformational behavior and failure of uncured material has been presented. Also, an attempt has been made to establish a link between the more basic properties of elastomers and processability, particularly the rate of filler dispersion in mixing. The variation of compound Mooney torque and die swell with mixing time can be explained theoretically by taking account of the occluded rubber trapped by the carbon black agglomerates. As filler dispersion increases, the amount of such occluded rubber decreases, Mooney torque decreases, and die swell increases as expected from the theory of rheology of composites.
Effect of the Compatibility of Rubbers on the Viscous Flow Properties of Their Binary Mixtures
Authors: Kongarov G. S. , Bartenev G. M. 
Published: February 2011

Abstract
The viscosity of binary systems of incompatible polymers is lower than that of the individual rubbers. In the case of compatible polymers, the viscosity of the systems changes additively with its composition or may increase somewhat. The degree of compatibility of the polymers affects the size of the entrance effect and the character of its dependence on strain rate.
Rheology of Elastomer Blends
Authors: Folt V. L. , Smith R. W. 
Published: February 2011

Abstract
The melt flow properties of certain elastomer blends are shown to be a function of the mixing history and the morphology of the blends. And, more significantly, the melt flow properties are found to be non-additive functions of the melt flow properties of the homopolymers comprising the blends. Mixing studies using a Brabender Plastograph show that blends of certain elastomers generate much higher temperatures while, simultaneously, generating much higher torques than either of the homopolymers over time cycles of practical interest in elastomer processing operations. A sharp minimum in the early stages of the torque/time relationship in the mixing operation, followed by an abrupt maximum, is correlated with abrupt changes in the morphology of the blends as determined by electron microscopy. The morphological structure of certain well mixed elastomer blends consists of domains of the lesser component dispersed into a matrix of the major component. For well mixed blends near 50/50 weight per cent composition the morphological structure appears to consist of two continuous interpenetrating phases. Mooney values as well as Plastograph torque values are observed to be non-additive functions of the corresponding properties of the homopolymers. A minimum in the Mooney/blend ratio relationship over a rather narrow range of blend compositions is observed for certain systems. In contrast, the Plastograph torque values for the identical compositions are observed to be higher in all instances than those for the homopolymers. A phenomenological description of these apparent contradictions is obtained from a simple analysis of capillary melt viscosity measurements carried out on the same blends. These melt viscosities are also a non-additive function of the viscosities of the homopolymers. Minimum and/or maximum viscosities for specific blend ratios are observed for a given rate of shear. The minimum or maximum shift (s) to different blend ratios with changes in the rate of shear. Viscosity/composition plots similar to the Mooney/composition plot are observed at low rates of shear and plots similar to the torque/composition plot are observed at high rates of shear. These behavior patterns remain unexplained at this time.
Dependence of the Glass Transition Temperature on the Composition of Elastomer Mixtures
Authors: Zlatkevich L. Yu , Nikolskii V. G. 
Published: February 2011

Abstract
The dependence of the glass transition temperature on the composition of some compatible, partially compatible, and incompatible elastomer mixtures have been investigated by means of the radiothermoluminescence method. It has been established that the glass temperature of a homogeneous mixture of two elastomers, Tgm, is related to the glass temperature of these elastomers, Tg1 and Tg2, by Tgm=Tg2−(Tg2−Tg1)⋅W1c, where C is lower than unity for each investigated mixture. Incompatible mixtures are characterized by two glass temperatures practically equal (to within 0.5° C) to that of initial components in a rather wide range of concentrations. Two Tg's are also characteristic of partially compatible systems though their values are different from those of the individual components.
Observations of Die Swell Behavior of Filled Elastomers Measured Automatically with a New “Die Swell Tester”
Authors: Pliskin Irwin 
Published: February 2011

Abstract
A new instrument has been developed to measure the elastic memory of rubber or plastic compounds by automatically indicating the die swell of the material when a small amount is extruded. It has the potential to be used as a quality control instrument in a manufacturing plant. The new Die Swell Tester measures the time (in sec.) necessary to extrude a fixed length of extrudate at a constant volumetric flow rate. The time measurement is directly proportional to the die swell when expressed as an area ratio, and it can be made equal to the die swell by choosing the extrudate length judiciously. Furthermore, it is measured electronically and has a digital readout in hundredths of a second. Measurements made on tire tread compounds using the Die Swell Tester correlate well with die swell measurements made using a more conventional gravimetric method. The die swell of filled elastomers generally decreases with increase in filler loading and structure. When a composite of fixed filler loading is mixed, its die swell first increases due to the dispersing of filler, but it eventually reaches a maximum and begins to decrease. The composite viscosity, on the other hand, decreases monotonically as it is mixed. These variations can be explained by taking into account changes in the amount of rubber occluded by filler agglomerates and simultaneous degradation of free rubber during the mixing process. The time to reach the peak in die swell is a simple macroscopic measure of the filler dispersion rate for a given elastomer-carbon black composition.
Investigation of the Molecular Structure of Synthetic Cis-Polyisoprene
Authors: Grechanovskii V. A. , Ivanova L. S. , Poddubnyi I. Ya 
Published: February 2011

Abstract
Some thermodynamic and hydrodynamic properties of solutions of a series of commercial samples of cis-poly(isoprene) (SKI-3 rubber) were studied. Data on solubility, gel content, and its swelling in different solvents was obtained. It was shown that the intrinsic viscosity of the whole rubbers, as a rule, diminishes with transfer of the gel into solution. The obtained experimental data confirm the supposition made earlier about an aggregate and not a network structure of synthetic cis-poly (isoprene) gel.An approximate equation for finding the average number of macromolecules entering into the gel aggregates was obtained. It was shown that the average content of macromolecules in one aggregate varies from several tens to several hundreds for the investigated samples and that the aggregates are characterized by an extremely broad distribution with respect to the number of macromolecules entering into them.