bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Protective Action of Some Antioxidants II. The Metal Halide Compounds of Some Protective Agents against Aging, with Special Reference to Aldol-Alpha-Naphthylamine
Authors: Kirchhof F. 
Published: February 2011

Abstract
The results described in the present paper can be summarized as follows: 1. Certain antioxidants containing nitrogen, like aldol-α-naphthylamine and Stabilite Alba, give in alcoholic solution with higher halides of certain metals, especially those of iron and copper, unstable intense blue-violet as well as stable carmine-red colorations, which may be regarded as more or less stable complex compounds of these antioxidants. A series of other heavy metal halides of which similar behavior would be expected (for example, SnCl4, CoCl3, etc.) give no color reactions of this kind. 2. Both the chemical and the optical behavior of these colored solutions indicate that they contain complexes of ferric chloride and cupric chloride groups attached to tertiary nitrogen, as in the haemin of blood pigment. 3. Of the antioxidants studied here, aldol-α-naphthylamine reacts quickest with the metal halides named above, Agerite the slowest and Stabilite Alba somewhere between the two. The reaction with cupric chloride occurs in every case much more rapidly than that with ferric chloride. It is obvious that this behavior might be utilized to distinguish analytically small quantities of these substances. 4. The complex metal halide compounds show strong oxygen-transporting action, as does the haemin of the blood, which contains iron. This is many times greater with the compounds of antioxidants which contain copper than with those which contain iron compounds, and this agrees with the similar behavior of compounds of these metals with rubber, as has long been known. 5. Since the antioxidants are oxidized in the course of time, as the result of autoöxidation, they protect an autoöxidizable substance like rubber only so long as they are not rendered inactive. Since traces of soluble heavy metal compounds, especially of iron, are invariably present in rubber compounding ingredients, it can be understood why rubber mixtures containing protective agents are more or less strongly and more or less rapidly discolored as a result of the formation of dark-colored metal complex compounds and their oxidation products. 6. Finally it was possible to show that the complex metal halide compounds of the antioxidants studied are remarkably sensitive toward certain catalytic poisons such as hydrocyanic acid, in quite an analogous fashion to known biological oxygen carriers. It is entirely possible that this phenomenon may also be of significance in the use of protective agents in technical rubber mixtures.
Reënforcing Action of Pigment Mixtures on Rubber Compounds
Authors: Beaver D. J. , MacKay J. W. 
Published: February 2011

Abstract
Mixtures of varying ratios of either channel black or a soft carbon black with whiting, lithopone, or clay show additive physical properties. Mixtures of soft carbon with zinc oxide also show additive properties, while mixtures of channel black and zinc oxide show poorer resistance to abrasion, higher modulus, and higher tensile strength than would be shown by purely additive mixtures. The explanation of these results appears to be found in the chemical reaction between the basic zinc oxide and the acidic compounds in the rubber or on the black. These results have been applied to the formulation of a solid-tire stock which will give a better resistance to abrasion and blow-out when using a soft black than when using a channel black.
Determination of pH of Ammonia Latex
Authors: McGavack J. , Rumbold J. S. 
Published: February 2011

Abstract
The pH of latex has been determined at various concentrations of ammonia (1) by the use of indicators, and (2) by the application of the glass electrode. The two curves thus obtained were comparable but not identical. It is shown that the glass electrode gives results reproducible with a high degree of accuracy up to pH 9.5 and a fair degree of accuracy up to pH 11.0. Above pH 11.0 it is necessary to calibrate each electrode. An ordinary galvanometer allowed measurement of the e. m. f. to 1 millivolt. The assymetry of the glass was so small as to be negligible. This paper covers the work done so far in these laboratories on the development of an accurate and rapid method for determining the pH of latex. From a practical viewpoint one of the most troublesome features of the direct use of a hydrogen electrode is the deposition of a film of rubber on the platinum, which by increasing the internal resistance of the cell, so reduces the sensitivity of the null point instrument that after a few determinations the apparatus must become inoperative. A more serious objection to this electrode is the uncertainty attached to measurements made in solutions containing proteins.
Determination of Alkalinity of Reclaimed Rubber
Authors: Palmer Henry F. , Miller George W. 
Published: February 2011

Abstract
A new method is given for determining the relative alkalinity of reclaimed rubber. The extraction of the alkaline material is based on a digestion of the sample in a mixture of ethanol, benzene, and water. The method is compared with the previous method described by the authors in 1928. The experimental figures given show that the new method gives results which are dependable, and approximately four times as accurate as the previous method. The higher degree of accuracy is due to the elimination of much of the personal error, the extraction of a larger percentage of alkaline material, and a more accurate titration end point. The purpose of this paper is to present a method for determining the relative alkalinity of reclaimed rubber which, in the authors??? opinion, has certain advantages over other methods in use at present.
The Effect of Organic Accelerators on the Temperature Coefficient of Vulcanization
Authors: Eliel K. W. 
Published: February 2011

Abstract
(1) The temperature coefficient of vulcanization to a standard modulus is 2.0 in the presence of mercaptobenzothiazole, Ureka, Ureka White, and Vulcafor D. A. (2) The temperature coefficients of vulcanization in the presence of all accelerators tested, including those of delayed action type, are constant over a wide temperature range (110–150° C). None of the accelerators appears to have a critical temperature. (3) Differences between the rates at which modulus develops with accelerators of similar activity may account for the fact that some induce scorching on the compounding mill, whereas others do not. (4) At all temperatures investigated, the period of delay of a delayed action accelerator may represent a constant proportion of the total time required to reach a definite state of cure, as indicated by modulus.
Mechanism of Rubber Vulcanization with Sulfur
Authors: Lewis W. K. , Squires Lombard , Nutting Robert D. 
Published: February 2011

Abstract
THAT vulcanization of rubber with sulfur always involves a chemical reaction consisting in the addition of sulfur to the double bonds of the rubber molecule has been conclusively established (18, 28). The facts indicate that this addition of sulfur to rubber is an irreversible reaction (31). The temperature coefficient of the reaction is high, increasing about 2.65 fold per 10° C. at ordinary curing temperatures (31). Furthermore, the reaction is apparently exothermic (4, 24). It is noteworthy that catalysts are apparently necessary, since synthetic rubbers prepared from pure materials add sulfur slowly, if at all. The proteins and perhaps the resins in natural rubber undoubtedly serve as accelerators. The curves for combined sulfur vs. time of cure for typical mixes are shown in Figures 1 and 2. Figure 1 is taken from the data of Kratz and Flower (16); the composition and temperature of cure for this mix are shown in Cranor's Table I (9). Figure 2, curve 1, is from Table I of Eaton and Day (10), and curve 2 from data obtained in this laboratory (27, Table I). Superficial inspection of these curves shows extraordinary divergence of type. Figure 1 is a typical fadeaway curve, characteristic of most chemical reactions, where the reaction rate decreases with decreasing concentration of the reacting materials. Curve 1, Figure 2, is an entirely different type, where the rate of sulfur addition is constant until nearly 70 per cent of the initial sulfur has reacted. Curve 2, Figure 2, shows even more complex behavior. Again the rate is constant in the initial portions of the cure. However, following this period, the rate increases markedly but later falls off, approaching zero, to give an S-shaped eurve.
Rapid Detection of Accelerators
Authors: Slepushkina E. P. 
Published: February 2011

Abstract
Where doubt exists rubber technologists may at times require a prompt answer as to whether accelerators are present in a rubber compound. It was necessary therefore to develop specific reactions and methods of procedure which make it possible to determine each individual accelerator in the presence of other accelerators. The procedures developed by us for the detection of accelerators in uncured rubber compounds and for mixed accelerators are extremely simple, and require not more than 10–15 minutes for completion of a test. By these methods a technologist can obtain a quick answer, and thus prevent possible spoilage and rejection of finished rubber goods. The additional advantage of these methods is that each individual accelerator can be detected in any combination of accelerators present in the rubber compound. Qualitative identification is performed almost exclusively in aqueous extracts, and is based on the differing solubilities of accelerators in water. The tests, described here in detail, were confirmed by tests of all rubber mixes used at the Yaroslav Rubber and Asbestos Works. These mixes contain the accelerators most commonly used in the rubber industry, such as diphenylguanidine, mercaptobenzothiazole, tetramethylthiuram disulfide, K-1 (a condensation product of aniline 2 mols and acetaldehyde 3 mols), and A-19 (formaldehydeacetaldehydeaniline).
The Falling-Weight Impact Test for Ebonite
Authors: Church H. F. , Daynes H. A. 
Published: February 2011

Abstract
1. With unnotched test-pieces, although impact strength is uninfluenced by variations of width of test-piece, the depth must be fixed. 2. With notched test-pieces, impact strength is independent of the depth of the notch with deep notches, provided the depth of the material above the notch is kept constant. Impact strength is, however, very sensitive to variations of notch radius. 3. Impact strength increases slightly with velocity of the striker, so that this should be kept within reasonably narrow limits for accurate work. 4. The falling weight type of apparatus provides a simple and convenient method of testing the resistance of ebonite and similar materials to damage or fracture by impact. 5. Three variations of the method of use of this apparatus are described which involve the factor of fatigue to different extents. 6. Results with a number of pure ebonites of different compositions and vulcanization times are given to show the influence of those factors on impact strength.
The T-50 Test Applied to Zinc Oxide Compounds
Authors: Haslam George S. , Klaman Clarence A. 
Published: February 2011

Abstract
The T-50 test is an extremely satisfactory tool for the study of the curing rate of zinc oxides. There are small differences in the curing rates of various zinc oxides when used in activation amounts in gum stocks and stocks loaded with inert extenders. In the presence of carbon black, these differences are not detectable. There are marked differences in curing rate between the various zine oxides in stocks containing more than 10 parts of pigment in 100 parts of rubber. The oxides containing sulfur show marked retardation, as do the fine oxides, at high loadings. In the first case, this retardation is caused by the chemical nature of the pigment; in the second case, by the absorption of sulfur and accelerator.
A Study of the Formation of Rubber in the Plant
Authors: Ambros Otto 
Published: February 2011

Abstract
The hypothesis is advanced that the natural polymerization of isoprene in plant cells is induced and accelerated by an oxidation which in turn is brought about through the agency of a system of enzymes. Experiments in a laboratory in the tropics show that the serum of latex has an accelerating action on the polymerization of emulsions of isoprene in water containing hydrogen peroxide, and that this effect is nullified if the action of the enzymes is arrested by an acid or by a poison such as hydrocyanic acid.
Natural and Synthetic Rubber. XVIII. The Protein from Natural Rubber and Its Amino Acid Constituents
Authors: Midgley Thomas , Henne Albert L. , Renoll Mary W. 
Published: February 2011

Abstract
The protein constituent of rubber has been extracted from the natural rubber by removal of the rubber hydrocarbon with solvents followed by electrodialysis of the residue. This material has been analyzed, subjected to hydrolysis, and its amino acid constituents have been separated and identified.
The Kinetics of the Coagulation of Latex of Hevea Brasiliensis and the Separation of the Hydratant Acid
Authors: van Harpen N. H. 
Published: February 2011

Abstract
In the present work, an attempt is made to study the process of coagulation of Hevea brasiliensis latex, so familiar to every rubber expert, from a general colloid-chemical point of view, and to ascertain the physical conditions under which the kenetic phenomena take place. Hevea Brasiliensis Latex as a Physical System In “The Electrometric Determination of the Hydrogen Ion Concentration in the Latex of Hevea brasiliensis and Its Applicability to Technical Problems” the true character of Hevea brasiliensis latex as a physical system and the phenomena which take place during coagulation of this system are discussed in the light of investigations and observations of various rubber experts. Latex is a dispersion composed of polydispersed rubber hydrocarbon, serum components, and water. The rubber component consists of microscopically visible solid or semi-solid particles, in Brownian movement, and judged by the degree of affinity of rubber for water these particles are unquestionably lyophobic. Since the serum components are in a colloidal state, they are present as sols or emulsions, and they impart to the latex its lyophilic properties. It is possible, however, to choose the conditions of coagulation so that, for a given concentration of dispersed substances and at a given temperature, the dispersion will be predominantly lyophobic or lyophilic. This dual standard leads to the conclusion that Hevea brasiliensis latex is a pseudo-lyophilic dispersion. In saying this, it should be noted that, although the dispersion has several lyophilic properties, it is nevertheless essentially a lyophobic system, the properties of which become manifest under the right conditions.
The Concentration of Latex by Creaming
Authors: Baker H. C. 
Published: February 2011

Abstract
Latex consists of a suspension of microscopic particles of rubber, bearing an adsorbed layer of protein, in an aqueous serum containing principally l-methyl inositol, so-called rubber resins, and saline substances. The rubber particles are in continuous oscillatory motion, which may be seen under the microscope. Brownian movement is due to the bombardment of the suspended particles by the molecules of the dispersion medium, and it can be demonstrated that the smaller particles are in more violent oscillatory movement than the larger particles. The rubber particles in latex are sufficiently small to remain in suspension in the aqueous serum for an indefinite period, but if latex is left to stand, a concentration gradient will develop throughout its bulk, leading to the formation of an upper concentrated layer of closely packed rubber globules in a manner analogous to the formation of cream on milk. This behavior is shown by all types of latex, field, preserved, and concentrated, but the effect is stated to be much greater with preserved latex than with field latex (Bishop and Fullerton, Latex Preservation and Shipment Planting Manual, No. 4, Rubber Research Institute of Malaya, July, 1932). The same authors give figures (Table I) which show the magnitude of this effect for freshly ammoniated latices which had remained undisturbed for a period of two months. It will be observed that creaming occurred to a considerable extent in all samples, accompanied by a diminution in the ammonia contents of the surface layers.
Highly Reactive Sulfur or the Reaction of Ammonia and Sulfur Chloride in Rubber Solutions
Authors: Menadue F. B. 
Published: February 2011

Abstract
When sulfur chloride and ammonia gas react in the presence of rubber in a benzine solution, a precipitate is formed which contains, in addition to NH4Cl, sulfur, etc., sulfur combined with the rubber in varying proportions according to the amount of S2Cl2 used and thus the amount of this active form of sulfur produced. A limit is reached, however, beyond which no additional rubber-sulfur product is obtained. The sulfur in the precipitate is classifiable into: (a) uncombined, and soluble in acetone and NaOH solutions. (b) combined with the rubber, not extractable with acetone on extraction for standard periods of time of 8 hours for soft vulcanizates to 60 hours for ebonites, but slowly extractable with 10 per cent NaOH solutions. (c) present in the precipitate as S2Cl2 additive product and as nitride. As much as 39.5 per cent of (b) plus (c) was obtained, the product in such case resembling ordinary ebonite. The nitrogen content in this case was 2.8 per cent, equivalent to 9.2 per cent N4S4, and the S2Cl2 as the additive rubber product was 1.52 per cent. These figures were the highest obtained in any precipitate. Nitrogen was fairly constant between 2.17 and 2.8 per cent for ebonites, and obviously occurred in accordance with some law of equilibrium.
The Isomerization of Rubber
Authors: Ferri Cesare 
Published: February 2011

Abstract
It is already known that rubber and gutta-percha behave as if they were cis and trans isomers. Judged by the roentgenographic observations of Meyer and Mark, of Mark and von Susich, and of Lotmar and Meyer, rubber has the cis form and gutta-percha, the trans form. Numerous attempts have been made to transform rubber into gutta-percha. As is well known, isomerization from the cis to the trans form is often induced by light, and for this reason Meyer and Ferri studied the action of ultra-violet radiation on rubber. They were unable to prove that isomerization took place, but rather found a ‘reticulation’ resulting from polymerization. This latter phenomenon was manifest by the irreversible formation of a gel. Sievers obtained the same result by exposing to visible light, with rigorous exclusion of air, a benzene solution of rubber in the presence of a little iodine. Under these conditions likewise, gelatinization took place, without appreciable polymerization. On the other hand, the technical and patent literature describes a series of reaction products of rubber having physical properties similar to those of gutta-percha; at ordinary temperature they are solids, and at elevated temperatures they become plastic. These substances are formed by treatment of rubber with zinc chloride, toluenesulfonyl chloride, titanium tetrachloride, etc.
An X-ray Study of Stretched Rubber
Authors: Morss Henry A. 
Published: February 2011

Abstract
With the more extensive data from new x-ray films of the diffraction pattern of stretched rubber made in a cylindrical camera, an attempt has been made to find the true unit cell. No really satisfactory solution has been reached. The leading possibilities are described. They are characterized by a change of the angle between the two independent sets of planes which reflect the two strong equatorial spots from 90°, the value which first suggests itself, to 109.5°. The new choice is shown to be consistent with all the evidence. It has the great advantage of resolving fairly well the familiar discrepancy between measured and calculated values of the density of the crystals in stretched rubber. The new value from the unit cell is 1.00. A necessary consequence of the x-ray data is that the carbon atoms of a molecular chain are not co-planar in stretched rubber. The reason appears to be the large repulsive forces which would have to exist in that configuration. In rotations on the single bonds during stretching and retraction the interatomic forces are probably repulsions in the dominating pairs. Repulsions give a plausible explanation of the form of the outer part of the stress-strain curve.
Purification and Concentration of Rubber Latex, with Special Reference to Dialysis
Authors: Stevens H. P. , Dyer J. W. W. , Rowe J. W. 
Published: February 2011

Abstract
Constructional details and methods of operation are described of a pressure dialyzer capable of treating 4 gallons of latex. The removal by dialysis of various substances from latex maintained at constant volume is shown to cause the segregation of a concentrated, pasty layer of latex at the dialyzing membrane. A preliminary investigation of this hitherto unrecorded phenomenon indicates that the degree of paste formation is related to the molecular weight of the diffusing substance. It can be avoided by allowing some dilution of the latex to occur. It is considered that the segregation at the membrane is caused by a bombardment of the colloidal particles of rubber by the diffusing molecules of the solute, and that this effect will be of interest in many cases of diffusion through colloidal dispersions. Concentration of ordinary and dialyzed latex by simple evaporation and by evaporation in a spray dryer is described, and dialyzed latex is shown to have an advantage in giving a concentrate of lower viscosity.
Studies of the System Latex-Colloidal Clay
Authors: van Rossem A. , Plaizier J. A. 
Published: February 2011

Abstract
In the literature of rubber and latex, several references to studies on the use of colloidal clay in latex mixtures are to be found but, surprising as it may seem, the various purposes for which colloidal clay is employed are merely indicated, without any scientific explanation based on quantitative data being offered in a single case. For example, colloidal clay is used for increasing the viscosity of latex, but quantitative data have not been available. for this reason it was considered of importance to undertake a scientific and more nearly quantitative study of the latex-colloidal clay system. Some of the results of this investigation are described in the present communication which deals with experiments on the increase in viscosity brought about by colloidal clay, the diminution in tackiness of a dried latex film, the reinforcement of dried latex rubber by colloidal clay, and the flocculation of the system latex-colloidal clay.