bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Coagulation of Latices by Polar-Nonpolar Liquids
Authors: Daniel F. K. , Freundlich H. , Söllner K. 
Published: February 2011

Abstract
(1) Diluted latices—Abiarana gutta-percha latex was specially investigated—may be coagulated by shaking them with organic liquids, not miscible with water in all proportions, provided that the liquids form a second liquid phase and that their molecules have a polar-nonpolar structure (butyl alcohol, isobutyric acid, cyclohexanol, etc.). Nonpolar liquids (petroleum ether, chloroform, etc.) do not coagulate diluted latices on shaking under these conditions. (2) This coagulating action can be explained by assuming that the latex particles are strongly accumulated at the interfaces of polar-nonpolar liquids and water; this is not the case with nonpolar liquids. (3) Small concentrations of some polar-nonpolar substances of small molecular weight, soluble in water, can also coagulate Abiarana gutta-percha latex if they form unstable foams; this was observed with propanol and isopropanol. If the foam formed under these conditions is stable, as with small concentrations of dissolved butanol and isobutanol, no coagulation takes place. This behavior can be explained as in (2), the air bubbles behaving like the second liquid phase. (4) Jelutong latex is known to contain an excess of resins, compared with the amount of rubber. A method of coagulating this latex quickly and separating the resins from the rubber consists in shaking the latex for some seconds with certain polar-nonpolar liquids, forming a second liquid phase, such as isobutyl or isoamyl alcohol. A lump of rubber is accumulated at the interface of the two liquids; the resins are contained in the organic phase.
The Mechanism of the Action of Vulcanization Accelerators. Derivatives of Mercaptobenzothiazole. II. The Transformation of Mercaptobenzothiazyl Sulfide
Authors: Zeĭde O. A. , Petrov K. D. 
Published: February 2011

Abstract
1. During the vulcanization of rubber, mercaptobenzothiazyl sulfide is transformed into mercaptobenzothiazole and the zinc salt of the latter. 2. This transformation is effected by the interaction of mercaptobenzothiazyl sulfide with sulfur. As a result of this reaction unstable products of addition of sulfur and mercaptobenzothiazyl sulfide are formed, and when heated these are converted into benzothiazyl disulfide. 3. During vulcanization, benzothiazyl disulfide decomposes into mercaptobenzothiazole and the zinc salt of the latter. 4. The acceleration of vulcanization of rubber by mercaptobenzothiazyl sulfide, as well as by other derivatives of mercaptobenzothiazole in which the mercapto —SH group is substituted, is attributable to several causes, the chief of which is the formation of mercaptobenzothiazole and its zinc salt.
Research Coöoperation in the Rubber Industry
Authors: Geer William C. 
Published: February 2011

Abstract
One of the outstanding observations which one may make of the rubber industry of today is the high degree of technical competition. Research laboratories are large and their members are well trained and resourceful. The achievements of these groups of competing technologists find their way to the public as patented articles or methods and scientific articles in the literature. In the majority of cases the new products or methods are promptly studied by competing laboratories and ways are found to accomplish the same end by means which do not infringe a given patent. Therefore, much of the energy of research is expended merely in the effort to keep pace with competitors. Because of this price competition and the narrow margin of total profits, there is a constant pressure upon technical groups to apply their energies to the solution of immediate needs. The physical proximity of the laboratories to the factories and the force of competition usually lead these men to appraise new ideas in the light of practicability. Can the trick be turned within one or two years? If not, efforts should be expended in apparently more fruitful fields.
A Manometer for Measuring the Oxidizability of Rubber
Authors: Dufraisse Charles 
Published: February 2011

Abstract
In view of the practical interest in a method for measuring directly the rate of oxidation, i. e., the oxidizability of rubber, it has seemed worth while to devise an apparatus with which the technic of making such measurements is so simple that it is within the compass of operators with no particular training. With this in mind the author has been led to construct a new manometer for measuring oxidizability. Before describing the apparatus and its method of operation, however, it is necessary to explain its principles. Later on, it is intended to deal in a more thorough way with the significance of the measurements, with the various causes of errors arising from the nature of the substance studied and the technic employed, and finally with different ways of expressing the results obtained.
The Influence of Vulcanization on Oxidizability in Relation to Aging. A Preliminary Study
Authors: Dufraisse Charles , Étienne André 
Published: February 2011

Abstract
Because of its preliminary character, the present investigation does not admit any definite conclusions. Rather, by bringing out clearly the various complications which arise in studying the oxidizability of rubber, especially when the aim is to establish a parallelism between oxidizability and the ill-defined phenomenon of aging, the investigation has shown the many difficulties in general involved in the problem. These complications are to a certain extent attributable to the nature of the phenomenon itself which has been measured, i. e., the oxidizability; but for the most part they owe their origin to the nature of the substance studied, and especially to its heterogeneous character. For these reasons the uncertainty in the results is increased by vulcanization, and the more vigorous the treatment, the greater is this uncertainty. As a result, considerable fluctuation in the measurements occurred. This is the reason why, in the past as well as now, so much emphasis has has been laid on the advisability of considering as significant only relatively large differences in measurements when drawing conclusions from them. With these reservations in mind, the facts which emerge from this opening work may be reviewed briefly. First of all, it may be stated that, as a principle, the higher the percentage of combined sulfur, the greater is the oxidizability of rubber. In other words, it is, in a different guise, the principle accepted by the majority of technologists, and which Martin expressed in a particularly clear fashion, viz., that the lower its state of vulcanization, the more stable is rubber.
The Activating Influence of Metallic Oxides on Vulcanization in the Presence of Organic Accelerators
Authors: Cotton F. H. , Westhead J. 
Published: February 2011

Abstract
1. The activating influence of the oxides of six metals, zinc, cadmium, mercury, magnesium, calcium, and barium in Group 2 of the periodic table, has been investigated with raw and acetone-extracted rubber mixes containing accelerators representative of seven chemical classes. 2. Oxides of barium, calcium, and magnesium exert insignificant activating influence on vulcanization in the presence of all accelerators tested. 3. Cadmium oxide is superior to zinc oxide in activating effect when employed in normal rubber mixes accelerated with zinc isopropylxanthate, tetraethylthiuram disulfide, mercaptobenzothiazole, and ethylideneaniline. 4. Cadmium oxide proved superior to zinc oxide in activating all accelerators tested (other than diphenylguanidine) in a mix made from acetone-extracted rubber. 5. In a mercaptobenzothiazole stock, mercuric oxide gave greater activation than either zinc oxide or cadmium oxide. This superiority was more marked when using acetone-extracted rubber. 6. The activating influence of molar or semimolar proportions of twenty-four metallic oxides on vulcanization in the presence of diphenylguanidine and mercaptobenzothiazole was investigated and reported in the form of graphs showing the rigidity developed after varying times of vulcanization, with mixes containing either raw rubber or acetone-extracted rubber or rubber with additional stearic acid. 7. With mixes containing diphenylguanidine, the activating influence of oxides on vulcanization was more marked the lower the fat acid content. Most oxides gave the highest modulus in a mix containing acetone-extracted rubber and diphenylguanidine. 8. In mixes containing mercaptobenzothiazole, most oxides exhibited an increasing activating influence as the fat acid content of the rubber increased, although in several instances stearic acid in excess of that naturally present in the raw rubber merely acted as a softener. 9. Although development of modulus was retarded by increase in the fat acid content of a diphenylguanidine mix, it was frequently observed that the tensile strength and elongation at break were higher in the presence of stearic acid, suggesting that this improved dispersion of the oxide. 10. Of the twenty-four oxides tested, zinc oxide, cadmium oxide, red lead, and arsenious oxide proved most effective in the presence of diphenylguanidine, arsenious oxide giving greater rigidity than zinc oxide. 11. Bismuth trioxide, cadmium oxide, mercuric oxide, litharge, red lead, and zinc oxide were found satisfactory as activators in mixes incorporating mercaptobenzothiazole; and all the former gave stiffer vulcanizates than obtained with zinc oxide. 12. Cadmium oxide and red lead proved effective with both diphenylguanidine and mercaptobenzothiazole. 13. Cupric oxide showed distinct activating properties, but an equimolecular proportion of cuprous oxide caused such rapid deterioration during and subsequent to vulcanization that it was not practicable to complete physical tests.
Investigation of the Thermal Conductivity of Rubber
Authors: Frumkin L. , Dubinker Yu 
Published: February 2011

Abstract
1. The apparatus for the determination of the coefficients of thermal conductivity which is described is satisfactory for the investigation of rubber mixtures. 2. A review of the results of the determinations of K values of various mixtures leads to the following conclusions: (a) The thermal conductivity of rubber mixtures containing synthetic rubber is greater than that of mixtures containing natural rubber. (b) The addition of zinc oxide even in considerable quantities to rubber mixtures containing a large percentage (55 per cent) of carbon black does not substantially increase thermal conductivity. (c) In the case of carcass mixtures a considerable increase in the coefficient of thermal conductivity is observed when the content of zinc oxide is increased from 7.5 to 15 per cent by weight; on further increase in the zinc oxide K increases but little. (d) The K value of carcass mixtures before vulcanization is smaller than that of the same mixtures after vulcanization by an average of 23 per cent. (e) The thermal conductivity of uncured tread mixtures is the same as that of vulcanized mixtures. (f) The coefficient of vulcanization has no effect on the K value of unloaded mixtures and mixtures containing fillers. (g) The K value of rubber mixtures increases sharply with addition up to 60 per cent by volume of fillers with good thermal conductivity (zinc oxide and graphite), but only slowly with the addition of fillers of medium thermal conductivity (carbon black). In other words, the curve of the relation between the coefficient of thermal conductivity and the percentage by volume of graphite and of zinc oxide is convex to the filler axis and is concave in the case of carbon black.
Comparative Viscometric Studies of Solutions of Crepe Rubber and of Buna
Authors: Philippoff W. 
Published: February 2011

Abstract
Measurements and their representation as flow curves of solutions of Buna-115 in tetrachloroethane give a means of obtaining an insight into the properties of Buna-115 in solution. By measurements of the viscosity as a function of temperature, it was proved that the temperature coefficient is similar in magnitude to that of natural rubber and that of polystyrene. A comparison of the flow curves of Buna, masticated rubber, pyroxylin, and Cellit leads to certain conclusions regarding the elasticity of colloids in solution and the role of the distribution curve. At low temperatures, i. e., below −40° C., both Buna and natural rubber show transformation points, which are manifest by increases in the otherwise very small temperature coefficients. The measurements reveal no property of natural rubber and of Buna which is peculiar to these two substances alone.
Water Resistance of Neoprene
Authors: Starkweather Howard W. , Walker Herbert W. 
Published: February 2011

Abstract
Superior water resistance of well-cured Neoprene, like that of natural rubber, depends upon the absence of water-soluble ingredients and agents that are capable of absorbing water. It has been shown that the water resistance of Neoprene varies greatly with different activating agents. This paper includes a more detailed study of the water absorption of Neoprene—magnesia—zinc oxide compounds and describes certain loaded stocks with improved water resistance. The water absorption was determined by the method already outlined, using slabs 0.20 cm. thick. Calculation of Water Absorption The water absorption can be calculated from the increase in weight or from the increase in volume of a stock during immersion in water. A difference between these values is an indication of chemically combined water. This is based upon the assumption that water undergoes no significant change in volume during absorption but that there is a change in volume during a chemical reaction. The two methods of calculating the absorption of water are shown by the equations:
A New Method for the Direct Determination of Rubber. A Preliminary Communication
Authors: Kheraskova E. , Korsunskaya E. 
Published: February 2011

Abstract
The conventional methods for the direct determination of rubber cannot be used for determining natural rubber in the presence of sodium-butadiene rubber. These methods are based either on precipitation of the rubber from solution or on the determination, by one method or another, of the double bonds in the rubber molecule. Since natural rubber and synthetic rubber differ in their solubilities but little, the method of precipitation obviously cannot be used for their separation. Nor are methods which involve determining the double bonds adequate to distinguish them, because both kinds of rubber are unsaturated compounds. It was therefore of interest to develop a method of analysis based on the determination of the methyl groups, which are present only in the natural rubber molecule. Kuhn and L'Orsa (Z. angew. Chem., 44, 847 (1931)) have shown that, in the oxidation of organic compounds, a methyl group connected with a carbon atom is partially oxidized to acetic acid. The object was to develop this reaction into a method of rubber analysis by establishing the optimum conditions for the quantitative oxidation to acetic acid of all the methyl groups in the rubber hydrocarbon.
The Marking of Uncured Rubber Mixes
Authors: Stern H. J. 
Published: February 2011

Abstract
One of the problems which confront almost every rubber manufacturer is to avoid confusion between the various qualities of mixings which he uses. Few indeed are the factories where the qualities are not so numerous and difficult to distinguish from their appearance as to provide a possible source of troublesome and costly errors. Rubbers which have received different mastication treatments and pure gum mixings are most difficult to recognize. In some cases, of course, the uncured mixings may be readily distinguished by their color. Even where this is not so, it is frequently possible to add, during the mixing process, a small quantity of coloring matter, which, though sufficient to prevent errors, is unnoticeable in the vulcanized result. This method is an excellent one, but its use is restricted to neutral tinted goods, which are not sold on color. Goods which are colored, or of a good white, and of course all black mixings, will require a different means of identification. After a mixing has been made, it may be necessary to store it for some time before it is used. A system of storage bins or shelves, divided into sections which are labelled and reserved for the various mixings, is helpful, but by no means foolproof. Unless the greatest care is taken, mixings will find their way into the wrong compartment, and the marking or labelling of each batch is therefore an essential safeguard.
The Preparation of Latex and Determination of Quality
Authors: Davey W. S. , Coker F. J. 
Published: February 2011

Abstract
Latex production has steadily increased during the last few years, as shown by the figures in Table I, which have been extracted from data published by the International Rubber Regulation Committee. Since 1934, output has nearly doubled, and for this year it is estimated, from the average figures for the first nine months of the year, that it will amount to approximately 35,000 tons. No statistics are published as to the respective amounts of preserved field latex and concentrated latex which comprise this 35,000 tons, but assuming the latex to contain an average of 50 per cent dry rubber, this quantity would represent approximately 16,000,000 gallons. Almost the whole of this latex is exported from Malaya and the Netherlands East Indies, only a negligible quantity being shipped from other rubber-growing countries. This production is confined to relatively few estates and in this respect affords a strong contrast to the production of estate rubber in the form of sheet or crepe, which is spread over many estates and small holdings (in Ceylon alone it is computed that rubber is produced on 100,000 estates and small holdings, mostly the latter). Latex production must of necessity be limited to the larger estates for both technical and commercial reasons, as the smallest consignments which are conveniently handled by European importers are around 500 gallons, and for some estates even the production of this quantity entails bulking several days' crop. On the other hand, some large estates export regularly 20,000 gallons or more every month, and the practice is growing of bulking supplies from individual small estates at central factories.
Some Properties of Rubber Latex
Authors: Schmidt Ernst , Stamberger Paul 
Published: February 2011

Abstract
Rubber latex of the commercial type preserved by ammonia was freed almost completely of its serum components by a method involving two steps: 1. Electrophoretic deposition of the rubber particles on a membrane, followed by 2. Dispersion of the resultant paste in a 0.6-per cent solution of ammonia in distilled water. This process was repeated until the aqueous phase obtained from this separation was free of non-rubber components in the latex.
The Gough-Joule Effect in Vulcanizates
Authors: Gleichentheil S. , Neumann W. 
Published: February 2011

Abstract
Since the phenomenon now known as the Joule effect was first measured, only a few investigators have concerned themselves with this phenomenon. Hock, one of these investigators, measured the heat which is evolved by raw rubber when stretched, and found that the quantity of heat evolved is proportional to the degree of elongation. When, therefore, the quantity of heat is plotted against the percentage elongation, a straight line is obtained. The present authors have measured the heat evolved when vulcanized rubber is stretched, the method being to stretch a strip of rubber in a calorimeter filled with mercury.
Oxidation Products of Rubber: Rubbone
Authors: Stevens H. P. , Popham F. J. 
Published: February 2011

Abstract
(1) The methods of making Rubbone are described and data given regarding the “dry” method in which rubber containing catalyst is milled with cellulosic materials and fillers. (2) The properties of Rubbone are described, including the polymerized products, the resistance of films to weak acids as for lacquering tins, and the electrical properties. (3) Rubbone can be vulcanized with sulfur. The products have applications as cements. (4) The method of preparation and properties of the hydrochloride and chlorinated Rubbone, and their use as a basis for alkali-resistant paints are described. These products have a tendency to gel, but this may be prevented by the incorporation of coumarone.
Difficulties in the Thorough Impregnation of Textiles with Latex
Authors: Bongrand J.-Ch 
Published: February 2011

Abstract
In a patent of 1920 by Hopkinson, there appears the claim that cotton thread need only be immersed in latex to bring about complete impregnation and even penetration of the latex into the canals of the fibers. This is a quite unwarranted claim, and it can be explained by the fact that Hopkinson was primarily a lawyer as far as patents are concerned, and there is a natural tendency in this profession to place a mortgage on future accomplishments. As a matter of fact, in spite of its very low viscosity (200 times less than that of benzene solutions containing the same percentage of rubber), latex does not penetrate spontaneously into textiles in the same way that clear solutions of rubber do. The work of Hauser and Hünemörder (cf. Rubber Chem. and Tech., 5, 685(1932)) has more or less settled this question. According to their technic, rubberized threads to be examined are immersed in gelatin, the preparation is frozen by carbon dioxide, and fine sections are cut by means of a microtome. The gelatin and also the cotton structure which has not been impregnated are then destroyed by concentrated sulfuric acid, and are eliminated by washing. The remaining rubber has a red-brown color. In this way Hauser and Hünemörder established definitely that whereas clear solutions containing, for example, five per cent of rubber, penetrate cotton threads, latex only coats them superficially and does not penetrate them.
Flocculation of Pigment in Carbon Black—Rubber Mixtures
Authors: Park C. R. , McClellan Paul P. 
Published: February 2011

Abstract
NUMEROUS references occur in the literature as to the cause of so-called scorching or burning in rubber-pigment mixes containing no vulcanizing agent. It was suggested (6) that this stiffening effect may be caused by flocculation of the pigment particles. Green (8) demonstrated a relation between the stiffness and flocculating tendency of pigments in paint mixtures, and Depew and Ruby (4) and Green (7) suggested that the phenomenon of flocculation may have some relation to the properties of cured rubber mixes which contain pigments, especially carbon black pigments. Grenquist (9) reported that carbon black exists in a more or less flocculated condition in vulcanized rubber, and some evidence was presented by Park and Morris (11) that mill-scorched batches which exhibit abnormal stiffness possess a structure which suggests that the black has been flocculated. The increase in stiffness of unvulcanized rubber—carbon black mixes upon standing for periods of several days was mentioned by Stamberger (13). Busse and Davies (2) presented data showing the effect of heat upon the stiffness of such mixes and mentioned the possible relation between flocculation and increase in stiffness. In order to throw more light upon the behavior of carbon black in the stiffening of rubber, a series of experiments was planned following the general methods of Busse and Davies, which include heating the sample for various periods of time and attempting to follow the changes in gross physical properties and in the minute structure of the mix.