bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of the Color of Latex
Authors: Cotton F. H. 
Published: February 2011

Abstract
It has long been felt that there is a need for a standard method of measuring the color of latex, a feature of the utmost commercial significance in determining its value and suitability for certain manufacturing processes. The method to be described is the direct outcome of a recent discussion with members of the scientific staff of the London Advisory Committee for Rubber Research. Among the methods hitherto suggested for determining the color of latex are: (1) the use of standard tiles of varying tint with which the latex to be examined may be compared; (2) the use of a standard tintometer, such as that marketed under the trade name “Lovibond”; and (3) the employment of an apparatus embodying a photo-electric cell. Whereas the first of these methods is simple, there is some difficulty in ensuring that the standard color-tiles shall always be of exactly the same tint, and that their density shall undergo no change whatever with time. The color of latex is so largely a neutral gray tint that it hardly seems necessary to employ the wide range of color values incorporated in a tintometer of the Lovibond type. Though a photo-electric cell should be capable of giving an accurate measure of the relative whiteness of different grades of latex, it would not measure differences in tint and its cost would probably prove prohibitive.
Note on the Deterioration of Raw Rubber by Manganese Contamination
Authors: Hastings J. D. , Rhodes E. 
Published: February 2011

Abstract
The presence of excessive amounts of manganese has been found by Bruni and Pelizzola to be associated frequently with tackiness in raw rubber. Bishop and Sekar have described the development of unusual stickiness when rubber prepared from latex to which manganese salts had been added was subjected to a temperature of 50–55° C. for 300 hours. More recently Sackett has found that the use of manganese salts in the manufacture of crude rubber gives a product which becomes tacky and weak on storage, and which, when vulcanized, has a lower tensile strength, a poorer resistance to aging and a poorer abrasion resistance than normal rubber. Bruni and Pelizzola when examining various samples of very tacky estate rubber found amounts of manganese of the order of 0.02 per cent, but were not able to form firm conclusions as to the manner in which such large amounts of manganese find their way into various grades of estate rubber. The present note describes an instance in which it has been possible to trace the cause of serious manganese tackiness in a large consignment of estate rubber.
Rubber Production
Authors: Rhodes Edgar 
Published: February 2011

Abstract
The institute welcomes contact with users in America. There have been a few occasions when users have approached the institute direct on matters in which it could be of obvious assistance. A notable recent case was that of the manganese deterioration brought by Sackett's organization. In this case the institute was able to be of some assistance and was itself benefited. Such cooperation is excellent, and will be very welcome in Malaya. It would be well also to establish some single committee or organization as a channel through which samples, reports, complaints and suggestions could be circulated freely to American users from Malaya and the London organization, and received in both places from America. If there were a constant contact, for example, between a technical subcommittee of the American Chemical Society's Rubber Division, the technical subcommittee of the London Advisory Committee, and the Board of the Rubber Research Institute, users' requirements would always be known, views could be exchanged, suggestions could be made, word battles fought, and samples and batches of new materials passed forward from Malaya and London for American works test.
Determination of True Free Sulfur in Vulcanized Rubber. A Modification of the Thiocyanate Method
Authors: Minatoya Syukusaburô , Aoe Itirô , Nagai Idumi 
Published: February 2011

Abstract
The limit of quantity of potassium cyanide was determined as regards the interference with the end point of the titration of potassium thiocyanate with silver nitrate solution. Acetone was found to be a suitable solvent for the separation of potassium cyanide from potassium thiocyanate. A new modified method was proposed for the determination of true free sulfur in vulcanized rubber, by the use of acetone to remove the cyanide which renders obscure the end point of the titration of thiocyanate with silver nitrate solution. The proposed method was applied to the analysis of pure sulfur and some rubber goods, and was ascertained to be accurate and easy to carry out, requiring no special apparatus.
Organic Accelerators and Problems Connected with Their Use in the Factory
Authors: Jones Maldwyn 
Published: February 2011

Abstract
It may be said that there are three types of problems to be considered when selecting an accelerator: (1) To determine the approximate limits of curing temperatures and times within which it is desired to work. Questions of skill in handling accelerators and questions of the size and shape of the articles govern this. (2) To determine what are the specific qualities desired in the vulcanizate, and then to select appropriate accelerators coming within the limits specified in (1) above. (3) With the choice narrowed down to one or two products, questions purely of an economic nature will probably determine the final choice. In conclusion the author wishes to express his thanks to the Imperial Chemical Industries Ltd. for permission to publish the results embodied in this paper.
Studies on the Combined Use of Two Different Organic Accelerators. V. Mercaptobenzothiazole and Hexamethylenetetramine
Authors: Aoe Ichiro , Kitayama Hiroshi 
Published: February 2011

Abstract
1. Equal weights of a mixture of hexamethylenetetramine and mercaptobenzothiazole give the optimum accelerating activity and minimized scorching. 2. Scorching tests indicate that there should be no danger of scorching in practice; a comparison of the scorching tendencies of various proportions showed that a ratio of mercaptobenzothiazole 70 and hexamethylenetetramine 30 gives noticeable scorching. 3. The melting point curves, indicate some relation between the above proportion and the scorching phenomenon. 4. The heating curves of two sets of mixtures containing hexamethylenetetramine and sulfur, and hexamethylenetetramine, mercaptobenzothiazole and sulfur, respectively, in an oil bath at 150°, indicate that hexamethylenetetramine and sulfur react exothermically and that this reaction is accelerated by the presence of mercaptobenzothiazole. 5. The products of the reaction between hexamethylenetetramine and sulfur are carbon disulfide, ammonium thiocyanate, hydrogen sulfide, and ammonia. 6. The products of the reaction of two sets of samples heated in an oil bath at 150°, as indicated in 4, were determined quantitatively, and it was found that there was an increase of these products with an increase of time; which was also indicated by the loss of weight during the heating. 7. All of these reaction products had low accelerating power. Thiuram disulfide and ammonium thiocarbamate derived from carbon disulfide and ammonia and ammonium polysulfide derived from hydrogen sulfide, ammonium, and sulfur were tested, since they might have been formed during vulcanization, but they were found to be poor accelerators. 8. A preliminary test of combinations of mercaptobenzothiazole with ammonia, ammonium polysulfide, ammonium thiocyanate, and ammonium dithiocarbamate indicated that ammonia and ammonium polysulfide have some accelerating power, whereas all others are ineffective. 9. The combined use of ammonia and mercaptobenzothiazole forms a molecular compound which is effective as an accelerator, and this is true in an analogous way of the combined use of hexamethylenetetramine and mercaptobenzothiazole. 10. In order to prove experimentally the above theory, an attempt was made to treat a mixture of rubber, mercaptobenzothiazole, zinc oxide and sulfur with ammonia until the latter penetrated throughly the sample, after which the latter was vulcanized. Such treatment gives far better acceleration than does mercaptobenzothiazole without treatment with ammonia. 11. The accelerating power of ammonium polysulfide and mercaptobenzothiazole is attributed to the formation of ammonia from ammonium polysulfide and the reaction of ammonia and mercaptobenzothiazole.
Studies on the Acetone Extraction of Raw Rubber. V. The Influence of Heating at 100° C. and Storage of the Acetone Extract on the Saponification Value
Authors: Endô Hidemaro 
Published: February 2011

Abstract
(1) When the acetone extract was heated at 100° C., the saponification value (AT) first diminished and then increased. (2) When the acetone extract was stored, the saponification value (AT) first increased and then diminished and returned to the original value. (3) The determination of the saponification value was carried out as follows: The sample was extracted for the required time, the acetone was evaporated off as rapidly as possible and the flask was dried in a steam bath for as short a time as possible. The drying time must not be over 15 minutes, and usually 5 minutes is sufficient. The dried flask was cooled and weighed, after which 20 cc. of 0.2 N alcoholic KOH was added and the flask heated on a water bath for 60 minutes. The excess alkali was titrated with 0.1 N HCl solution, using phenolphthalein as indicator.
Thixotropy and Plasticity in the Rubber Industry
Authors: Freundlich H. 
Published: February 2011

Abstract
Sole and gels are characteristic colloidal systems. In sole the continuous phase or dispersion medium is a liquid and is in excess; the disperse phase is distributed in this medium in the form of small particles invisible in the ordinary microscope, and having diameters below 0.5 µ. The particles may be liquid or solid or have a more complicated structure. The term colloidal may be used in a somewhat broader sense, to include for instance, latex which contains a certain percentage of larger particles visible in an ordinary microscope, and with diameters up to about 5 µ. It is arbitrary to draw the line of demarcation between colloidal and non-colloidal systems at 0.5 µ most properties of colloidal systems may be found in systems containing larger particles (up to about 6–7 µ) and most methods used in colloid science may be applied to them. The term gel is not so easy to define. The conception favored in the earlier days of colloid chemistry that gels are the counterpart to sols, having a solid medium of dispersion and a disperse phase consisting of small drops of liquid, is not now popular and does not seem probable. It is assumed by many investigators that gels have a structure similar to that of foams or concentrated emulsions, the disperse phase consisting of small solid particles and the dispersion medium being liquid as in the case of sole; but it is present in very thin layers, generally only a few mµ thick, separating the solid particles from each other.
The Oil Resistance of Rubber. I Study of the Swelling of Vulcanized Rubber
Authors: Tanaka Yoshio , Kambara Shû , Noto Jirô 
Published: February 2011

Abstract
To study the effect of solvents on the elastic properties of vulcanized rubber, the following three points were investigated. 1. The swelling maximum obtained by various mixed solvents. 2. The stress-strain curves of rubber swollen to different degrees. 3. Time-swelling and time-deswelling curves. The spiral theory of molecular structure of rubber proposed by Fikentscher and Mark is utilized to explain the experimental results.
The Influence of Mastication on the Oxido-Aging of Rubber. A Comparison with the Influence of Heating
Authors: Dufraisse Charles , Vieillefosse Roger 
Published: February 2011

Abstract
It may rightly be said that vulcanization improves all the properties of rubber except its tendency to deteriorate. We have undertaken a systematic study with a view to ascertaining why raw rubber, which shows so little tendency to oxidize and is so stable, loses its resistance upon being vulcanized and becomes both more easily oxidized and more easily altered. To this end, we have studied successively each of the factors which may have an influence on its oxidizability. In a previous article we settled the question of metallic impurities, particularly iron, which ordinarily is introduced into rubber either by means of the ingredients added or by removal from the steel rolls during the mechanical action. Under ordinary conditions the deleterious effect of iron, without being zero, is not great; it simply merits attention. In any case, it is not sufficient to explain the undesirable change in stability which is found after vulcanization. Taking the factors in order, mastication was next studied. This treatment, which is almost always necessary and the discovery of which has made possible the development of the rubber industry, would seem, a priori, to be rather dangerous from the point of view with which we are concerned. In the first place, it disrupts the substance, a condition which cannot be favorable to its subsequent equilibrium. But above all there is the danger that it may be an “inductor” of autoöxidation.
Heat Capacity, Entropy, and Free Energy of Rubber Hydrocarbon
Authors: Bekkedahl Norman , Matheson Harry 
Published: February 2011

Abstract
The best method for obtaining the free energy of formation of rubber is by making use of the third law of thermodynamics. This makes necessary the determination of heat-capacity values of rubber from room temperature down to temperatures sufficiently low to apply an empirical formula for obtaining the values below this lower temperature. From these heat-capacity values the entropy may be obtained. Then from this latter value, along with the entropy values of carbon (graphite) and gaseous hydrogen and the heat of formation of rubber, a reliable value for the free energy of formation of rubber may be calculated. Several investigators have previously determined the heat capacities of rubber, but their observations were not made at temperatures sufficiently low to permit accurate extrapolation to the absolute zero in order to apply the third law. Furthermore, in the previous work the possibility that rubber at low temperatures might exist either as a metastable amorphous form or as a crystalline form was not clearly recognized. In the present investigation the aim was not only to extend the temperature range but also to obtain data of a higher order of accuracy than that previously reported.
Corrosive Action of Sulfur against Metallic Copper during Vulcanization
Authors: Satake Shozo 
Published: February 2011

Abstract
The use of copper wire electroplated with tin for insulated electric wires was originated by Siemens eighty-five years ago (through Saito, J. Soc. Chem. Ind. Japan, 18, 248 (1915)), and its merits lie in the fact that it prevents a lowering of the electrical conductivity and mechanical strength from corrosion of copper by the sulfur in the rubber, and also prevents the rubber from deteriorating abnormally fast by contact with the copper. The manufacture of rubber for coating wire has improved rapidly since the appearance of organic accelerators and combined accelerating and vulcanizing agents, such as the polynitrobenzenes and benzoyl peroxide of Ostromislensky, the selenium of Boggs and tetramethylthiuram tetrasulfide and tetramethylthiuram disulfide. Recently, it was reported (India Rubber World, 87, 38 (1933)) that rubber compounded with 2 per cent of 1,3,5-trinitrobenzene as vulcanizer does not corrode wire conductors and does not deteriorate abnormally fast when the rubber mixture is covered directly on the wire and vulcanized. The prediction was also made that tin-coated copper wire will disappear entirely from the cable world. As a matter of fact, marine cables have for a long time been covered with an insulator consisting chiefly of gutta-percha or balata hydrocarbon, in direct contact with the copper conductor, and have given good service. The para-gutta insulation of marine cables, recently developed by the Western Electric Company, U. S. A., is composed partly of rubber, with no tin coating on the copper conductor. Nevertheless, the principal factor which decides the “electrical life” of rubber submerged in water is, according to Curtis (J. Res. Natl. Bur. Standards, 5, 539 (1930)) the deterioration of the rubber by copper salts, and Asano (J. Soc. Chem. Ind. Japan, 24, 336 (1921)) reported that smoked sheet became so sticky that it required considerable strength to separate after it had been held between two copper plates for six months. The status of the electric insulating wire industry today is such that a thorough investigation of the tin coating of copper wire and the methods of tin coating in connection with the deterioration of rubber by the copper wire is desirable. The investigation described in the present paper was carried on with this object, and it deals with experiments on the corrosion of metallic copper by sulfur during vulcanization, and shows the formation of copper sulfides as corrosion products.
The Formation of High Polymers by Condensation between Metallic Polysulfides and Dihalogenated Hydrocarbons and Ethers
Authors: Patrick J. C. 
Published: February 2011

Abstract
The general theory of formation of high molecular weight linear polymers by condensation between bifunctional compounds of low molecular weight to form products of large molecular mass has been so thoroughly reported in the literature that no extensive citation is believed to be advisable here. A very thorough study of this type of reaction has been made by Carothers and his co-workers on the formation of polyesters, the reaction being of the general type: One can, without taxing the imagination, conceive of the polymerization of isoprene or butadiene as belonging to the same general type of phenomenon, differing only in the fact that the reacting molecules are alike instead of different and that the “condensate” is one double bond per molecule. Therefore, no attempt will be made in this paper to distinguish between condensation and polymerization. When organic dihalides having CH2X terminals, in which “X” denotes a halogen, are caused to react with metallic polysulfides, MSxM, there usually results a linear polymer of high molecular weight.
Investigation of the Structure of Rubber by Means of Electron Diffraction
Authors: Kruilov K. I. 
Published: February 2011

Abstract
1. Irradiation of unstretched rubber with an electron beam gives electronograms in the form of three amorphous rings with identity periods of 4.15, 2.05, 1.25 A. U. The third identity period closely approaches the distance between the carbon atoms of the carbon chain of a rubber molecule. 2. An electronogram obtained by the irradiation of stretched rubber with an electron beam discloses interference points, and the whole pattern has the character of a fiber diagram. 3. An electronogram contains more details (rings, points) than the corresponding x-ray diagram. Thus electron analysis makes it possible to obtain more information relating to the structure of rubber, and in this respect has an advantage over x-ray analysis. 4. Calculation of the electronograms shows that the elementary cell of rubber has orthorhombic symmetry with edge dimensions of a=12.3, b=8.3, c=8.1 A. U. These results agree with the model of the elementary cell of rubber constructed by von Susich, Mark, and Meyer on the basis of x-ray analysis. 5. Highly oriented rubber preparations give in addition to a large number of points, a certain number of spots which do not fit into the scheme of points of oriented rubber. This phenomenon requires a further study. 6. Spot interference appears, as a rule, only with stretched films. The localized maxima on the interference rings of irradiated unstretched films observed in some cases are explained by a partial orientation formed in the process of drying the film.
Inorganic Substances with Rubber-like Properties
Authors: Meyer Kurt H. 
Published: February 2011

Abstract
Two inorganic substances with elasticity similar to that of rubber are described in the literature of the subject, viz., elastic sulfur and polyphosphonitrilic chloride. In this paper we shall deal with investigations of both. It is common knowledge that sulfur heated to 170° becomes highly viscous; if then cooled, e. g., by plunging into water, it yields an amorphous elastic product. If threads of this amorphous product are stretched, they show a double refraction, and, as Trilat has found, develop a fiber-diagram. With Go the author has examined this diagram, and deduced from it the following arrangement of the sulfur atoms: long chains of sulfur atoms, linked by strong homeopolar valences, are arranged parallel to the direction of stretching. Their special position in the elementary cell is shown in Fig. 1. In a recent publication, Warren has made it clear that ordinary sulfur is made up of 8-atom rings. The molecular weight of the elastic form Sn is not known, but seems to be very high. We know from earlier work that the melting of sulfur produces an equilibrium between the two forms, and this shifts, at higher temperatures, in favor of the chain-sulfur. About 1000 calories per gram atom S are consumed in the transformation of S8 into Sn.
Plasticization of Rubber
Authors: Garner T. L. , Blow C. M. 
Published: February 2011

Abstract
The effect of oxygen in the mastication process of raw rubber has been demonstrated by Cotton (Trans. Inst. Rubber Ind., 6, 487 (1931) and Busse (Ind. Eng. Chem., 24, 140–146 (1932), who obtained a considerable reduction in the rate of plasticization of raw rubber when milled in the absence of oxygen. In a recent paper (Blow and Garner, Trans. Inst. Rubber Ind., 10, 465 (1935)) it was suggested that work on similar lines with rubber-carbon black stocks and rubber-softener mixtures might yield interesting results. The opportunity to carry out some experiments presented itself, and the results form the subject of this note. Experimental.—A small Werner-Pfleiderer enclosed mixer, suitably modified to render it as gas-tight as possible, was employed. The weight of rubber taken for each test was 14 ounces. This was fed into the mixer piece by piece, over a period of two minutes, and milled for a further 5 1/2 minutes; the atmosphere in the mixer was in one series nitrogen, freed from oxygen by passing through pyrogallol, and in another series oxygen. Sufficient gas was supplied to the mixer to maintain a pressure of about 5 cm. of water. The conditions of temperature, time, etc., were as accurately controlled as possible. Plasticity measurements were made 30 hours after the milling process, the plasticity figure being the time in seconds taken to compress a pellet (1 sq. cm. in cross-section and 1 cm. long) between platens 1 sq. cm. cross-section from a thickness of 7.5 to a thickness of 5 mm. under a load of 1000 gms. at 100° C.