bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure and Properties of Filled Stocks XVI. Polybutadiene Filled with Colloidal Silica
Authors: Dogadkin B. , Pechkovskaya K. , Gol'dman E. 
Published: February 2011

Abstract
1. Colloidal silica can be partially or completely removed from filled rubber stocks by boiling in 1% aqueous NaOH. 2. Degree and rate of extracting directly depend on the reinforcing effect of the silica. The higher the filler activity, the more complete its extractability from the rubber. Inactive samples of silica practically cannot be extracted from filled rubber stocks. 3. The active silica forms a thixotropic chain structure in the rubber, but inactive silica is distributed in rubber as isolated particles or aggregates. 4. The rubber portion that remains after extraction of the active silica is insoluble in common rubber solvents. 5. The equilibrium swelling value in binary solvents (butanol-toluene) is lower, the higher the reinforcing action of the silica. 6. The reinforcing effect of silica is proportional to its moisture takeup capacity, which may be determined by a simple method described. 7. Based on the experiments described, the type of linkages involved and the structure of the rubber stock filled with silica are considered.
Tensile Strength of Filled SBR Vulcanizates
Authors: Bueche F. 
Published: February 2011

Abstract
The molecular behavior responsible for the observed tensile strength properties of unfilled rubbers has been studied in a recent paper from this laboratory. In the present paper we intend to extend that work to the case of rubbers which are filled with carbon black. Measurements of the tensile strength of hot and cold SBR as a function of carbon black concentration, degree of vulcanization, and temperature are reported. An attempt is made to interpret the observed behavior in terms of molecular concepts. Some additional measurements with resin and calcium carbonate fillers are shown to lend support to the conclusions reached.
Oil Extended Styrene-Butadiene Rubber SKS-30M
Authors: Shatalov V. P. , Bashkatov T. V. , Kostiukov N. , Popova E. N. , Chuliukova T. A. , Krygina M. K. G. 
Published: February 2011

Abstract
The results indicate that there is a real possibility of obtaining oil extended SKS-30M-15 rubber with satisfactory physical and processing properties from high temperature, modified latex.
Vulcanization with TMTD
Authors: Bevilacqua E. M. 
Published: February 2011

Abstract
The mechanism reviewed in some detail here appears adequate to explain substantially all that is now known about vulcanization with TMTD. It has predicted accurately the stoichiometric relationships between the reagents entering into the vulcanization reaction and the known products formed. It presumes that vulcanization is a primary consequence of the interaction of rubber, TMTD, and zinc oxide and not an incidental result. It is not, however, fully established by the evidence now available. In particular the studies by Scheele and coworkers (as exemplified by Reference 33). on the reaction of zinc oxide with thiuram disulfides suggest the interesting possibility that primary attack during vulcanization is on the oxide rather than the hydrocarbon, as assumed in this discussion. There is at present no experimental basis on which to eliminate either of these two alternatives. The success of the mechanism reviewed here in delimiting stoichiometry of the reaction makes it a convenient framework from which to develop a complete understanding of the reaction.
The Structure and Properties of Rubbers Produced in Radiation Vulcanization
Authors: Dogadkin B. A. , Tarasova Z. N. , Kaplunov M. Ia , Karpov V. L. , Klauzen N. A. 
Published: February 2011

Abstract
1. The structure and properties of irradiation vulcanizates of technical and purified SKB, NR, SKS-30A, SKS-30AM, and SKI rubbers with and without fillers, made by irradiation in a nuclear reactor and in a cobalt source, with integral doses of 107–108 r, have been studied. 2. The density of the network formed in irradiation vulcanization is determined by the quantity of energy absorbed, the type of rubber, the irradiation conditions (medium, temperature), and certain other factors. The yield of crosslinks per 100 ev in air is ∼12 for extracted butadiene-styrene rubber, ∼4 for extracted NR, and 2.5 for technical SKS-30A. The crosslinking effect increases with increase of temperature and decreases in presence of an oxidation inhibitor (phenyl-2-naphthylamine). 3. The thermomechanical stability of irradiation vulcanizates is superior to that of vulcanizates made with thiuram without sulfur, and such vulcanizates undergo the least changes in properties during chemical relaxation. In contrast to sulfur vulcanizates, the relative rate of stress relaxation in irradiation vulcanizates depends on the density of the vulcanization network. This indicates the C—C type bridges are formed in the course of irradiation vulcanization. The thermomechanical stability of irradiation vulcanizates is raised by the introduction of active blacks. 4. The presence of carboxyl, hydroxyl, ether, and ester groups in irradiation vulcanizates of natural, butadiene-styrene, and sodium butadiene rubbers vulcanized in presence of air has been demonstrated by infrared spectroscopy. A dose of 60·106 r causes almost complete disappearance of double bonds from extracted butadiene-styrene rubber. In the technical rubber, containing phenyl-2-naphthylamine inhibitor, this dose reduces the degree of unsaturation by about 30% of the initial value. 5. The tendency to crystallization on stretching was studied in irradiation vulcanizates of natural rubber. The crystallinity of irradiation vulcanizates made by irradiation with relatively small doses, up to 20–30·106 r, is the same as that of sulfur vulcanizates of the same network density. The degree of crystallization decreases with increasing radiation dose. 6. Conditions for the production of massive multilayer specimens by irradiation vulcanization were investigated. It was found that a uniform vulcanization network can be obtained irrespective of the thickness of the specimen (in the range 0.1–40 mm). 7. The physicomechanical and technical properties of irradiation vulcanizates were studied. In comparison with the best sulfur with the same filler contents, irradiation vulcanizates have a higher resistance to aging (4–5 times as high at 130°), low residual deformations, low hysteresis, high endurance to repeated deformation, and high heat resistance. The tensile strength of irradiation vulcanizates, as a function of the radiation dose, passes through a maximum, but does not reach the values found in the best sulfur vulcanizates.
Swelling Behavior of Rubbers Compounded with Reinforcing Pigments
Authors: Boonstra B. B. S. T. , Dannenberg Eli M. 
Published: February 2011

Abstract
Equilibrium swelling data are presented for vulcanizates of natural rubber, SBR 1500, butyl rubber, neoprene, and nitrile rubber containing fumed silica, precipitated silica, precipitated calcium metasilicate, hard clay and carbon black. Swelling media are chloroform, benzene, hexane, and acetone. It is observed that certain fillers, particularly carbon black, cause a reduction in the swelling of the rubber matrix which is commensurate with the volume loading of the filler. This effect is not specific for a particular solvent or elastomer. When a series of loadings of a filler shows this effect of reducing the matrix swelling in one solvent, it is also shown by the swelling data for the other solvents, but not to the same degree. The system SBR-benzene was studied to determine from the bound rubber measurements and the equilibrium swelling data for the corresponding vulcanizates the number of crosslinks per cubic centimeter in the unvulcanized and vulcanized states. It appears that the number of crosslinks estimated in the bound rubber gel is much too small to account for the increase in crosslink density in the rubber matrix that is caused by the presence of carbon black in the vulcanizate.
Colorimetric Determination of Amine Antioxidants
Authors: Hilton C. L. 
Published: February 2011

Abstract
A method is described for the qualitative identification and quantitative estimation of many of the more common amine antioxidants. The method is comparatively simple and requires less than one-half man hour per determination. The method is accurate and precise. Analyses with known stocks showed an average error of less than 2% relative.
Methods for Determination of Rubber to Cord Bond Strength
Authors: Uzina R. V. , Gromova L. S. , Vasil'eva S. A. 
Published: February 2011

Abstract
In selecting methods for determination of rubber to cord bond strength it is necessary to consider the factors which are subject to variation in the system— the type of cord, the composition of the vulcanized rubber, or the composition of the impregnant. The selection (composition) of the methods of assessment of bond strength was carried out in the present study while keeping the type of cord and the rubber compositions constant ; only the composition of the impregnant was varied. Up to the present there has been no single laboratory method for evaluating rubber to cord bond strength for the determination of the service quality of rubber-fabric structures. The bond strength in such a system is assessed in the majority of cases by the use of a series of methods. The existing methods may be systematized according to the nature of the deformation (static or dynamic), the nature of the specimen (with single thread of cord or with cord fabric) and so on. We adopted the following classification of methods: 1). Determination of bond strength of a single thread of cord with the rubber; 2). Determination of bond strength of rubber to fabric model specimens. Determination of bond strength of a single thread of cord with rubber is an exceptionally widely used type of testing in the rubber industry. It is based either on the principle of stripping of a single thread of cord from the rubber under pressure, or on the principle of pull-out of a thread of cord from a rubber specimen.
Thermoelastic Phenomena in SKS-30A and SKB Rubber Compounds in Adiabatic Deformation
Authors: Votinov M. P. , Kuvshinskiĭ E. V. 
Published: February 2011

Abstract
1. The stretching of vulcanizates of SKS-30A and SKB before break accompanied by the generation of heat equivalent to the work of stretching indicates the kinetic nature of the elastic forces in these vulcanizates. 2. Change in the degree of vulcanization of the compound and the addition of fillers leads only to a change in the modulus of elasticity of the rubber compound. The rules of conversion of work into heat do not change. The absence of crystallization processes even at high elongation (λ=6−7.5) is evidently a result of the irregular structure of the hydrocarbon skeleton of the original rubbers, SKS-30A and SKB. 3. For rubbers containing active fillers (channel black and silica gel) and obtained by optimum vulcanization, there is observed a decrease in heat evolution caused by hardening of the material in the region of high elongation just before break.
Cis-Trans Isomerization of Natural Rubber under the Influence of Organo-Aluminum Compounds and Titanium Tetrachloride
Authors: Dolgoplosk B. A. , Kropacheva E. N. , Nelson K. V. 
Published: February 2011

Abstract
Ziegler catalysts have become of prime importance for synthesis of polymers with regular structure, particularly cis-polyisoprene. The disruption of the structure of the chain by the formation of trans units was, until now, connected only with the influence of the physical and chemical properties of the catalyst on the nature of the addition of the diene monomers during the polymerization process. In the present work it is shown that destruction of regularity of structure can be caused by isomerization of cis units in complete polymer chains into trans units under the influence of the compounds used for initiating the polymerization process. Attempts to isomerize natural rubber by means of ultraviolet light and iodine did not give the expected effect. Ferri established for the first time that under the influence of zinc chloride and titanium tetrachloride natural rubber undergoes changes accompanied by disappearence of crystallization on stretching as shown by x-ray structure analysis. On the basis of these results the authors presumed that under the influence of these agents isomerization of cis units to trans units occurs in the natural rubber chain. The isomerization of cis-1,4 units to trans units in polybutadiene by means of ultraviolet light in the presence of organic bromine or sulfur compounds was first accomplished and proved by Golub. The formation of trans units in natural rubber under similar conditions was not observed. The study of the isomerizing effect of TiCl4 and organo-aluminum compounds was conducted by us on solutions of milled natural rubber (NK) in benzene in sealed glass ampoules. The benzene used was dried and distilled over sodium. All work was conducted in an atmosphere of dry argon. Unsaturation and microstructure of the chain was determined on each sample. The study of microstructure of polyisoprenes was carried out by means of infrared spectra, the relative content of the different configurations of the polymer chain being determined by the absorption in the 800–1000 cm−1 region. The method previously developed by one of us was used for this purpose.
Ozone Resistance of Elastomeric Vulcanizates
Authors: Ossefort Z. T. 
Published: February 2011

Abstract
This review has attempted to categorize and describe the degree of ozone resistance available both within and among the various elastomers. Some of the factors affecting ozone resistance and means for obtaining ozone-resistant vulcanizates have been discussed. It has been indicated that by judicious selection of elastomer and compounding ingredients, resistance to very severe ozone conditions may be obtained with the currently available elastomers. The dependence of ozone resistance on proper compounding of the ozone susceptible rubbers has been emphasized. This has led to the conclusion that certain rubbers considered to be ozone resistant behave in the expected manner only if proper attention is given to compounding variables.
Ozone Cracking in the Los Angeles Area
Authors: Haagen-Smit A. J. , Brunelle M. F. , Haagen-Smit J. W. 
Published: February 2011

Abstract
Cracking of rubber, due to the presence of ozone, was determined in the Los Angeles area by measuring the number of cracks and the crack depth after exposure of standardized bent rubber strips to the atmosphere. The cracking shows a daily and seasonal variation due to the difference in ozone concentration as well as difference in temperature. Results over a three year test period are presented, as well as a comparison with oxidant and ozone values measured in the same area. The ozone concentration usually reaches a maximum during the day and is highest during the summer months. Its origin has been traced to the action of sunlight on mixtures of organic material and oxides of nitrogen, common air pollutants in urban areas. A comparison with chemical measurements of the oxidizing power of the air shows a similar trend. The rubber test is useful in the correct interpretation of outdoor exposure tests of rubber goods, since it integrates the variable action of ozone due to large fluctuations in its concentration and the reaction rate due to climatological factors. The application of the test to area surveys in air pollution studies is suggested.
Weather Aging of Elastomers on Military Vehicles
Authors: England W. D. , Krimian J. A. , Heinrich R. H. 
Published: February 2011

Abstract
The results of the Ordnance Corps Pasadena exposure tests may be summarized as follows: 1. The ozone resistance of synthetic elastomers, particularly SBR, can be substantially improved by the addition of suitable antiozonants and waxes to the rubber compound. 2. The one to two years protection at Pasadena appears to be equivalent to 3–5 years protection in other areas where ozone concentrations are low. 3. Butyl and neoprene rubbers which have inherent high ozone resistance become less effective when plasticized to meet the military's low temperature requirements and require the addition of suitable antiozonants and careful compounding in order to regain their ozone resistance. 4. Polyurethane rubbers promise to play an important role in the manufacture of many end items used on military vehicles when it becomes economically available. 5. For storage purposes a surface coating with a 50/50 mixture of dioctyl-p-phenylenediamine and acetone promises to impart good ozone resistance to tires that were not protected against ozone during manufacture.
Carbon Black Structure and the Tear Resistance of Vulcanizates
Authors: Epshtein V. G. 
Published: February 2011

Abstract
1. The increase in tear resistance of vulcanizates, where carbon blacks are added in considerable amounts, is related to the formation of secondary black structures and is manifested especially when certain blacks are used (channel, anthracene and acetylene). 2. The presence of secondary black structures brings about an increase in the tear resistance at elevated temperatures.
γ-Irradiation of Rubber and Styrene. Graft Polymer Formation
Authors: Turner D. T. 
Published: February 2011

Abstract
In a previous investigation, radiation was used to initiate a free radical reaction in a rubber-monomer mixture, the main object being the separation and characterization of the polymeric products. For this, the most suitable monomer was methyl methacrylate. The present investigation extends this work to quantitative aspects of energy absorption, and, for experimental reasons, styrene is a more convenient monomer. The polymerization of styrene on exposure to high energy radiation has been previously studied. Styrene has also been polymerized in the presence of polyisoprenes, including rubber, but not by irradiation.
Polarographic Determination of Accelerators, Antioxidants, and Other Rubber Chemicals. I.
Authors: Mocker F. 
Published: February 2011

Abstract
The present paper shows that the Polarographic method for the determination of rubber additives (rubber chemicals) delivers fully usable results. The following points are discussed : 1. The method is qualified for a rapid quantitative determination of MBT and 2-mercaptobenzimidazole in raw materials control. 2. The zinc salt of MBT can be indirectly determined after its decomposition with acid. 3. MBT and 2-mercaptobenzimidazole can be determined directly in the methanolic extracts of masterbatches. 4. As with the masterbatches, MBT can be determined directly in the extracts of rubber stocks and vulcanizates when zinc oxide is absent. Magnesium oxide or zinc stearate do not interfere. 5. Experimental conditions are given which permit quantitative determinations of MBT in the presence of zinc oxide in uncured and cured rubber compounds. 6. The experiments have shown that the method is applicable to complex recipes containing MBT as the only accelerator. Of course, the limit of error is higher, that is, around −5%. The investigations are being continued and the results will be presented at a later date.
Sulfur Group Analyses in Natural Rubber Vulcanizates
Authors: Studebaker Merton L. , Nabors Lester G. 
Published: February 2011

Abstract
Uncertainty as to the nature of the crosslinks in vulcanized rubber has been a tremendous handicap to chemical studies of vulcanization. A direct result is that physical methods have been the most successful in providing definite information about the nature of vulcanized rubber. However, these physical methods also possess serious limitations. A brief review may be in order on the methods which have provided insight into the chemical nature of the crosslinks. A tremendous amount of information has been obtained on the reactions between sulfur and various olefins at vulcanizing temperatures. Much, but not all, of this work has been carried out in the laboratories of the British Rubber Producers' Research Association. These studies are too extensive to review in detail here. But some of the impressions gained from studying them are: (1) There is no evidence that reaction with sulfur produces any carbon-to-carbon bonds. (2) The linkages produced between different molecules (intermolecular) are monosulfides, disulfides and polysulfides. The dominant linkage and the amount of polysulfide sulfur depends on the nature of the olefin, the reaction conditions and the presence of auxiliary materials such as accelerators, zinc oxide and fatty acids. (3) In the initial stages of the reaction, more polysulfide groups are present than in the later stages. Some of the sulfur in these polysulfide groups appears to react with the rubber to form five- and/or six-membered rings, and is referred to as “cyclic sulfur”. The intermolecular sulfur-containing groups which survive contain less sulfur on the average than those present during the early part of the reaction.
Derivatives of 2-Mercaptobenzothiazole and Dimethyldithiocarbamic Acid as Vulcanization Accelerators
Authors: Fel'dshteĭn M. S. , Eĭtingon I. I. , Pevzner D. M. , Strel'nikova N. P. , Dogadkin B. A. 
Published: February 2011

Abstract
1. We have synthesized and investigated as vulcanization accelerators the derivatives of 2-mercaptobenzothiazole (MBT) in which the thiol hydrogen is replaced by the nonpolar methyl radical, as well as compounds in which methyl hydrogen of the methyl derivative is replaced by various functional groups. 2. It has been shown that methyl-2-thiolbenzothiazole is not an accelerator. The replacement in this compound of one of the methyl hydrogens by a polar hydroxyl group substantially enhances the activity (see, however, editors note in the text). The substitution of hydrogen by a carboxyl group does not increase vulcanizing activity. 3. We have determined that replacement of a methyl hydrogen by an amino radical increases sharply the accelerating activity. The structure obtained as a result of this reaction, benzothiazolyl-2-thiolmethyldiethylamine (BTMA), is of great practical interest as an accelerator. 4. The accelerator BTMA in stocks of natural and SKS rubber gives vulcanizates which are substantially superior in their properties to rubbers cured with MBT, and are practically equal to vulcanizates obtained with sulfenamide accelerators—sulfenamide BT and sulfenamide Z (Santocure). 5. The accelerator BTMA is much cheaper than sulfenamide BT since its production requires much less diethylamine. 6. It has been determined that, just as in the case of 2-mercaptobenzothiazole derivatives, for the derivatives of dimethyldithiocarbamic acid containing analogous functional groups the same results are obtained for the change in activity depending upon the chemical structure of the accelerator.