bluuebunny/crossref_metadata_2025_split huggingface dataset:
Angular Distribution of Intensity of Rayleigh Scattering from Comblike Branched Molecules
Authors: Casassa Edward F. , Berry Guy C. 
Published: February 2011

Abstract
The angular distribution function P(θ) for intensity of light scattered by a dilute solution of comblike branched molecules has been determined for three situations of some interest for evaluation of experimental data: (1) the molecules are identical with branches of equal length attached equidistantly along linear backbone chains; (2) the molecules are homogeneous in mass, with the same number of branches on each molecule, but the branches are distributed at random along the chain; (3) branches and main chains are still uniform, but the molecules are heterogeneous in mass with the number of branches per molecule distributed according to the binomial distribution and the branches in any molecule spaced randomly along the backbone. Examination of numerical results shows that the scattering functions for models (1) and (2) arc not very different. The function for case (3) is somewhat different from the others when the mean number of branches per molecule is small but they contain a large fraction of the mass of the molecule. Over a limited range of the pertinent variables (corresponding roughly to observations on typical vinyl polymers of molecular weights up to 106) all three functions agree quite well with P(θ) for homogeneous linear chains with the same mean square radius of gyration.
Influence of Test Conditions on Wet Skid Resistance of Tire Tread Compounds
Authors: Grosch K. A. , Maycock G. 
Published: February 2011

Abstract
This paper is primarily concerned with the skid behavior of tread compounds, and the extent to which testing parameters such as the type of road surface, the vehicle speed, or whether peak and sliding coefficients are considered, influence the skid behavior of one tread compound in relation to another. Whilst the actual braking coefficients depend profoundly on all these parameters the rating of two compounds is much less affected by them. Moreover, subject to the qualification given in the paper, the ranking of compounds will in many cases be predicted correctly by the RRL skid tester. The question arises how the rating of tread compounds will be affected by other testing methods. The three most commonly used are cornering, traction, and stopping distance tests. The first two are dominated by the peak value of the friction coefficient because the measurements are taken just before sliding occurs whilst the last reflects the sliding value of the braking coefficient. Since the rating is virtually the same for these two types of measurement it is likely to be independent of the measuring method. Although the ranking of compounds does not depend on the road surface, well drained road surfaces gave more reproducible results and larger ratings so that fewer readings are required on such a surface than on a flooded one. The following observations as to the nature of wet friction emerge from the present study. (a) Changes in coefficient of friction with tread compound and type of road surface texture confirm the findings of Miss Sabey, and Greenwood and Tabor, that the energy loss component of wet friction on coarse surfaces increases with the sharpness of the asperities, and thus with the pressure on the tops of the asperities. A mechanism for such energy losses based on elastic stored energy is suggested. (b) The decrease in the braking coefficient, as observed on well drained or dry road surfaces after the wheels have become locked, is explained by the frictional temperature rise in the area of contact. (c) It is suggested that in the case of the sliding tire, temperature increase in the contact region with increasing vehicle speed contributes to the observed fall in coefficient with increasing speed. This, together with the temperature dependence of the rubber properties, is used to explain small differences between the speed coefficients of various compounds in their rate of fall off with speed. (d) The mean braking coefficients of the compounds increase with their internal viscosity. It appears that the internal losses can be increased and therefore the skid resistance improved by incorporation of a heavy oil without an appreciable change in the glass transition temperature as measured by a torsion pendulum. This is strikingly demonstrated by the highly resilient natural rubber, whose skid resistance is greatly improved by oil extension without any significant loss in resistance to tire wear.
Incompatibility and Phase Formation in Solid Polymer Mixures and Graft and Block Copolymers
Authors: Bohn Lothar 
Published: February 2011

Abstract
Compatibility in the sense of a tendency to molecular mixture and mutual solubility is rare for two solid polymeric components. Thus, not only mixtures but also graft and block copolymers constitute two phase systems. Possibilities for identification of separate phases are discussed, including optical methods and determination of freezing and melting temperatures of the individual phases. Problems of preparation of two phase mixtures and the phase distribution arising thereby, including identification of disperse and continuous phases are discussed. Examples are given of little known polymer mixtures for which complete or partial compatibility exists.
Reinforcement of Fluoroelastomers with Halopolymers
Authors: Kaufman Martin H. , Gonzales John 
Published: February 2011

Abstract
This study demonstrated the utility of Teflon as a reinforcing agent. Elastomeric compositions prepared with Teflon powder by milling or extrusion have very large increases in tensile strength when measured parallel to the direction of shear, and high tear strength when measured perpendicular to the direction of shear. Teflon powder sheared in a fluoroelastomer matrix coalesces to form fibrils. The hypothesis that free radicals, and therefore branching, are produced when Viton and Teflon mixtures are sheared at ambient temperature is supported by the increase in slope of curves of ηsp/c as a function of c. However, the principal cause of the large improvement in tensile and tear strength is believed to be formation of oriented Teflon fibers and films in the elastomer matrix. The formation of these fibers and films would explain the rough surface of milled material as well as the poor consolidation of these materials when they are compression molded. Reinforcement by fibrillation does not occur with Kcl-F resin or fluorinated ethylene propylene.
Freezing and Relaxation of Elastooptical Effects in Polymers
Authors: Sheyanova A. I. , Sokolov S. I. , Shchegolevskaya N. 
Published: February 2011

Abstract
It is known that stress birefringence in optically isotropic, amorphous substances in the elastomeric state is firmly fixed by transition into the glass state. Only a small change is observed as a rule, upon reducing the load. This phenomenon is used in studying stress with polarized light and three dimensional models by the “freezing” method. The freezing process and its reverse, relaxation of birefringence, as complex processes characteristic of polymers, merit more detailed study. In our first investigations, two materials were used having three dimensional, network structures and practicable for stress studies by polarized light (1) epoxy resin E-40 set up by maleic anhydride and (2) an oligomeric copolymer (trademark MIRhM-IMASh) of poly(diethylene glycol sebacate fumarate) with styrene and methyl methacrylate and later, two linear polymers of polystyrene and poly-(methyl methacrylate), produced on a laboratory scale with benzoyl peroxide and completely stabilized by long, stepwise heating.
Thermodynamic Properties and Polymer Solvent Interaction Parameters for Silicone Rubber Networks
Authors: Seeley R. D. 
Published: February 2011

Abstract
The relationships of the volume fraction of rubber (silica reinforced silicone rubber vulcanizates) at equilibrium swelling to a corresponding solvent-rubber interaction parameter have been found to agree quite well with theory throughout the entire range of volume fractions investigated. Composite sigmoidal curves were constructed from the ϕrs versus μ data for the different vulcanizates. Temperature and solvent effects were found to merely shift the plotting points along the curves for the respective vulcanizates. Contrary to other work linear relationships between ϕrs and μ were found in this investigation only in the range of moderate dilations. Such relationships could lead to serious misinterpretations if the investigations involved ϕrs versus μ data near an inflection point. Thus, the value of μ relative to a corresponding ϕrs not only depend upon solvent (s) and temperature, but also upon the level of vulcanization at moderate to high dilations. The entropy, enthalpy, and free energy changes associated with the configurational changes occurring in the network structure of the rubber were calculated. The thermodynamic properties were found to be consistent and uniform throughout the dilation range. Limiting osmotic pressures were determined to obtain effective number average molecular weights of the crosslinked chains. The molecular weight values were found to average slightly less than three times those obtainable from ve/Vr data. Finally, this investigation has shown that reinforced silicone rubber vulcanizates at equilibrium swelling in a variety of solvents exhibit the swelling behavior predicted by theory. However, swelling behavior at moderate to high swelling was found to be unrelated to the rubber in general, but related more specifically to the network structure of the vulcanizate. At low dilations, the characteristics of the silicone rubber species control the swelling behavior.
Identification of Antioxidants, Accelerators and Plasticizers in Rubber Compounds by Column Chromatography and Ultraviolet and Infrared Spectrophotometry
Authors: Fiorenza A. , Bonomi G. , Saredi A. 
Published: February 2011

Abstract
This paper deals with separation of antioxidants, accelerators, and plasticizers in rubber compounds by column chromatography. The chromatographic diagrams obtained by a special ultraviolet detector and the spectra of the various fractions obtained from the extracts of eleven compounds are reported. With suitable reference samples, many other antioxidants and some other accelerators can be identified in addition to those tested in the present work. The identification of the components of the extract is improved examining the fractions also by IR spectrophotometry, employing either the technique of NaCl plates or, better, that of KBr pellets. Other very useful auxiliary techniques are paper and thin layer chromatography and gas chromatography.
Effect of Sulfur Crosslinks on Radical Recombination in Irradiated Elastomers
Authors: Kvashenko Yu Yu , Kuzminskii A. S. , Fedoseeva T. S. 
Published: February 2011

Abstract
It was found that sulfur crosslinks intensified radical decay in glassy polymers. The process follows a migration mechanism, free valency being transmitted both along and between molecular chains.
Rapid Method for Studying Molecular Weight Distribution of Isoprene Polymers
Authors: Polyakova G. R. , Pravikova N. A. 
Published: February 2011

Abstract
A nomogram was plotted for low molecular weight isoprene polymers of 1,4-cis- and 3,4-structures, which made it possible to obtain MWD curves of the polymers from titration curves. A study was made by turbidimetric titration of the MWD of isoprene polymers having 3,4-structure obtained in tetrahydrofuran at low temperatures, and 1,4-cis-isoprene polymers, obtained in a hydrocarbon solution with LiC2H5. It was found that MWD of isoprene polymers with 3,4-structure was considerably wider than that of 1,4-cis-polymers; this is in satisfactory agreement with kinetic views on the molecular distribution of such polymers.
Rubber Chemicals from Cyclic Amines. II Dithioamines and Sulfenamides as Accelerators and Curing Agents
Authors: Morita Eiichi , D'Amico John J. , Young Evan J. 
Published: February 2011

Abstract
Dithioamines and sulfenamides derived from various cyclic amines were evaluated as accelerators and vulcanizing agents. Structural variations of these compounds are correlated with their scorch delaying properties, accelerating activity and vulcanization efficiency, employing the Mooney Viscometer and the Monsanto Oscillating Disk Rheometer. The relative cure characteristics differed with changes in the basic structure of the compounds, and with the size and type of the cyclic amine moiety. However, the piperidine derivatives consistently showed longer scorch delay and slower mean cure rate than the corresponding derivatives of pyrrolidine, hexamethylenimine or heptamethylenimine. In the case of the thiazolyl sulfenamides, the type of substitution in the thiazolyl group also influenced scorch delay. An empirical relation was observed between the effect of concentration of the thiazolyl sulfenamides on scorch delay and the results of differential thermal analyses of sulfenamide and sulfur blends.
Reinforcement and Abrasion
Authors: Westlinning H. 
Published: February 2011

Abstract
Physical properties, and also abrasion resistance of vulcanizates are determined essentially by: the polymer, the network (crosslink density), and the molecular superstructure of the crosslinked network (reinforcement) introduced by the amount and type of filler. To establish the relation between reinforcement and abrasion one must first elucidate effects of polymer crosslink density. EXPERIMENTAL Measurement techniques.—Difficulties in determining the laboratory abrasion of rubber are well known. For the problem at hand, a method should be used which will give reproducible results with minimum effort. In addition, abrasion measurements should be possible for compounds ranging from unfilled to highly filled vulcanizates. Two basic principles had to be observed in developing an apparatus to fulfill these requirements: (1) surface velocity of the test specimens was selected to be commensurate with the rolling speed of tires, e.g. approximately 80 km/hr; (2) a relatively large amount of rubber should be worn off, to increase the accuracy of the determinations.
Advances in Tire Technology Introduction to Symposium. (Cleveland, Ohio, April 24, 1968)
Authors: Sjothun Irvin J. 
Published: February 2011

Abstract
The current interest in tires, transportation, and passenger safety in highway vehicles, prompted this symposium on advances in tire technology. Everyone is familiar with tires, at least to the degree that he recognizes them on his car. It seems the average layman thinks a tire is something that is somehow put together and thrown into a mold where it is given shape, but he has little conception of the compound, construction, or design engineering required. We are also hearing new as well as old names. Of tire types there are such names as bias, bias belted, and radial; of cord types such names as rayon, Tyrex, nylon, polyester, glass, and wire. You hear other terms such as wide oval, wide tread, aspect ratio, rim diameter, white wall, red ring, high performance, and many more. The tire carries the load, absorbs shocks, withstands impacts, goes through mud, ice and snow, and gives the consumer a minimum concern and minimum cost in spite of the ever increasing requirements placed on it.
Demographic Study of Tire Hazard Failures
Authors: Dobie W. J. 
Published: February 2011

Abstract
We have shown through the results of a detailed in-depth, nation-wide survey of tire road hazard damage a number of significant factors: (1) Tire cutting by glass is the most frequent cause of road hazard damage in all types of service and for all types of tires. (2) Road hazard damage due to rupture occurs more frequently on high speed highways than in any other type of service. Rupture damage is a more frequent occurrence in 4 ply nylon tires than in 2 ply rayon. (3) The relative incidence of road hazard damage is a function of both population density and precipitation.
Skid Resistance of Passenger Car Tires on Wet Surfaces
Authors: Maycock G. 
Published: February 2011

Abstract
This paper reports investigations into the effect of tread pattern, pattern modifications, tread material, and tire casing construction, on skid resistance of passenger-car tires at speeds between 25 and 80 mph on a range of wet road surfaces. The technique was to brake the front wheels of a car until they locked, and to record deceleration of the vehicle. From the deceleration record, both peak and locked-wheel values of braking force coefficients were obtained. The method is described and an assessment of the errors is given. The experiments showed the importance of adequate drainage of the region of contact between tire and road, particularly at higher speeds, in order to remove the lubricating film of water. Such drainage can be provided either by a tread pattern or a coarse road surface. The results indicate the importance of each and their inter-relation. Results of various modifications to a standard tread pattern are given; these show that on smooth surfaces worthwhile increases in wet road adhesion at high speeds can be obtained by suitable design of tire tread patterns. Magnitude of increases in friction due to changes in tread material are given for both peak and locked-wheel coefficients. Ratios of peak to locked-wheel coefficients have been calculated over a wide range of surface and tire combinations. They show the potential value of devices enabling a vehicle to make use of these high coefficients.
Lubricated Friction of Rubber. IV. Characteristics of Roads
Authors: Percarpio E. P. , Bevilacqua E. M. 
Published: February 2011

Abstract
We have described evidence showing that wet friction of rubber on hard surfaces is affected by two components in the hard surface—one deformation, the other abrasion. In this report we relate this to the properties of road surfaces and show that with appropriate simple measurements it is possible to estimate the relative importance of these two contributions in roads. SLIPPERINESS OF ROADS Data on slipperiness of roads taken under controlled conditions with a standard reference are rather limited, the most extensive material available applying. to European roads. We have therefore made a survey, which is continuing, in which we measure the properties of roads in use. Results reported here give us considerable confidence that roads are so similar in character that our sample is representative and that quantitative analysis of their surface characteristics can be made. It is well established that roads become slippery by polishing in use; the methods described here make it possible to estimate that extent of polishing in a quantitative way.
Kinetics of Alkyllithium Initiated Polymerizations
Authors: Hsieh H. L. , Glaze W. H. 
Published: February 2011

Abstract
The kinetics of alkyllithium initiated polymerizations is reviewed for publication in Rubber Reviews for 1970. It contains nine sections: introduction, the structure of organolithium compounds, rate of polymerization, rate of propagation, rate of initiation, molecular weight and molecular weight distribution, polymerization of diene and vinyl monomers in polar solvents, copolymerizations, and polymerizations of polar monomers. A total of 205 references are cited.
Mechanism of Emulsion Polymerization
Authors: Gardon J. L. 
Published: February 2011

Abstract
Emulsion polymerization is one of the most important processes for the manufacture of polymers for rubbers, plastics, coatings, finishes, and adhesives. By the correct choice of comonomers, initiators, surfactants, and reaction conditions, a great variety of latex products are manufactured which meet many specific requirements in their applications. However, there is a great gap between this mostly empirically developed and sophisticated technology and our scientific understanding of it. The present paper presents a theory based on a single internally consistent model which predicts several experimentally available data of emulsion polymerization: the particle size, the conversion—time relationship, the dependence of particle size and molecular weight on conversion, and the influence of surfactant, of initiator and of monomer. This theory is based on extension of the assumptions first proposed by Smith and Ewart and Haward, and later modified by Stockmayer and O'Toole. It differs from these earlier theories in that the derived relationships are quantitative and contain no adjustable parameters. Also, the validity limits of the predictions are defined. The present form of the theory does not apply to all monomers, initiators, surfactants and reaction conditions commonly used in the practice of emulsion polymerization although its predictions are in good accord with experimental results obtained with model systems complying with the assumed conditions.
Glass Transitions in Polymers
Authors: Shen M. C. , Eisenberg A. 
Published: February 2011

Abstract
We hope that the preceding presentation has made it clear that the glass transition is not a simple phenomenon, but a very complicated process which is still not understood in all of its ramifications. The nature of the glass transition temperature (Tg), to begin with, has been the source cf considerable controversy for many years. The observation of its rate effects, on the other hand, and its similarity to second-order transition, on the other, has caused much confusion. It is not until recently that there is promise for reconciliation. It appears at present that Tg is what one experimentally observes when the material is on its “slow boat” to T2 In other words, Tg is a kinetic manifestation of a thermodynamic process (T2). There is, in fact, no inherent controversy between these two views, since each explains one aspect of the “many-faced” transition. The solution of this problem was actually alluded to in the classical paper of Kauzmann, although it was not recognized as such. The credit of explicit clarification goes to Gibbs and DiMarzio, who first argued the case in quantitative terms.
Polychloroalicyclic Ketones as Promoters for Crosslinking Polymers
Authors: Morita E. 
Published: February 2011

Abstract
Polychloroalicyclic ketones are chlorine liberating compounds which in combination with activators and coagents promote crosslinking of saturated and unsaturated polymers. One of the most active ketone is octachloro-3-cyclohexen-l-one (OCTA). During the curing process the alicyclic ketones transform into phenols and probably some phenates. The most effective activators are magnesium and calcium hydroxides and oxides. These curing systems are also activated by acidic and basic fillers. Active coagents are sulfur, p-benzoquinones and maleimides. EPM of superior thermal stability is obtained with the chlorinated p-benzoquinones as the coagent. The apparent order of crosslink formation in EPM using these curing systems is pseudo first order. In case of OCTA/MgO/coagent system, the specific rate of crosslink formation is directly proportional to (MgO)1/2/(OCTA) and the maximum crosslinks formed vary linearly with (MgO)1/2/(OCTA). The OCTA system is most suitable for curing saturated polymers or their blends, and not for black stocks of high unsaturation polymers because of its high reactivity. Saturated polymers may be heated with OCTA and MgO and modified to unsaturated polymers which are curable by the conventional sulfur-accelerator system.