Cent Of Sulfur Research Articles

The Minimum of Sulfur Required for Vulcanization. A Résumé

Abstract The problem of the minimum proportion of sulfur necessary to effect vulcanization is fundamental to an interpretation of the very nature of vulcanization itself. Since the introduction of ultra-accelerators, it has been recognized that very small quantities of sulfur are sufficient to bring about vulcanization. In experiments carried out in 1918 in collaboration with G. Menghi in the Laboratory of Chemical and Physical-Chemical Research of the Pirelli Company of Milan, the author found that by the aid of zinc dimethyldithiocarbamate or of similar substances there is an appreciable vulcanization with 0.2 per cent of sulfur. This fact was made public in patents applied for by the author the next year. On the other hand, it is generally recognized today that all vulcanization originates in a chemical reaction, though a fundamental difficulty lies in the fact that it has never been possible to give an exact definition of what is meant by vulcanization. When is a rubber considered vulcanized? From a technical point of view this question may be answered, but there has not been a satisfactory explanation up to this time.

Heat-Resisting Inner Tube Stocks

Abstract A large number of laboratory tests were carried out which showed that to resist deterioration due to heat in an inner tube stock successfully, the following points should be observed: 1. Sulfur ratios should be very low. One per cent on the rubber content is sufficient for most stocks; some will require 1.2 per cent. This is true provided no sulfur-producing material is present. 2. When P33 Black or a similar soft black is used, 20 to 25 volumes are necessary. In the case of zinc oxide, blanc fixe, barytes, and the like, lower volumes will be necessary to obtain satisfactory resistance to tear. 3. The stocks should not be markedly overcured, especially if the cure is carried out at 50 pounds steam pressure (298° F.) or above. This is the opposite of former practice with stocks of higher sulfur ratio. 4. The accelerator chosen must be strong enough to combine practically all of the sulfur present, and yet should not be too scorchy to handle safely in the plant. 5. Tests showed that the use of 2 per cent of a good anti-oxidant was justified. One per cent gave good results, but especially when agings longer than 18 hours were carried out the stocks containing 2 per cent were markedly superior. 6. Zinc oxide, blanc fixe, barytes, or precipitated whiting can be successfully employed in stocks of this type. The modulus and tensile figures are lower than when P33 Black is used, but the losses in tensile strength due to air-bomb aging are comparable to P33 Black, and these fillers would permit the manufacture of colored tubes such as red, green, and yellow. 7. Heat-resisting inner tube stocks of this type compared to the ordinary tread, carcass, and tube stocks will necessarily be more scorchy, and care must be taken to cool the stocks properly in processing through the factory. The possibility of the migration of sulfur from the carcass stocks to the inner tube, or the migration of accelerator from the inner tube stock to the carcass stock must be taken into account. Today tire manufacturers are using as low as 2 per cent sulfur in the carcass stocks of bus and truck tires. These low sulfur ratios in the carcass stock tend to prevent the migration of sulfur. The usual Geer oven migration tests were carried out on stocks containing Ureka C as accelerator. The Geer oven was maintained at 93.3° C. (200° F.) for 14-day periods, and in no case did these tests show appreciable migration of sulfur or accelerator. Controls were run during the migration tests and alone.

A Preliminary Report on Arsenical Substitutes for Peach Spraying

Since the insect pests of peaches are becoming increasingly important each year in Tennessee, a study of the newer spray materials such as cryolite and barium fluosilicate was made. These were compared with the standard lead arsenate. The latter material gave foliage injury at Kingston, Tennessee, whereas the fluorine compounds were found safe, when used at the rate of one pound to fifty gallons of water. The largest percentage of sound fruit, 81.11 per cent, was recorded for plot 7 receiving a dust of 50 per cent barium fluosilicate and 50 per cent sulphur. The plots sprayed with cryolite and barium fluosilicate showed 77.6 per cent sound fruit as compared with 68 per cent with lead arsenate and 5.8 per cent in the cheek plots. The fluorine sprays and dusts were decidedly more efficient than lead arsenate against the Oriental moth.

Studies on Zinc and Barium Ferrites

The formation of zinc ferrite by the direct addition of zinc and ferric oxides was studied at various temperatures between 580° and 660° C. During the first two or three hours of heating, the reaction obeys Tamman's logarithmic law on reactions between solid phases. An apparent equilibrium appears afterwards. At 580° C. the reaction takes place extremely slowly. It is found by thermal analysis that there is no evidence for the formation of a compound containing more zinc oxide than ZnFe2O4, at least not below 1,070° C. The solubility of zinc ferrite in normal and two‐normal sulfuric acid is studied. A mixture of 7.5 per cent sulfur dioxide in air, passed on zinc ferrite heated at 450° C., decomposes it slowly and liberates the zinc as zinc sulfate.The formation of barium ferrite resulting from the heating of a mixture of barium carbonate and ferric oxide was studied at 720° C. It also obeys Tamman's law. The apparent equilibrium towards which the reaction tends is destroyed when the mixture is stirred and heated again at the same temperature : the reaction goes on according to Tamman's law, the velocity of reaction being, however, considerably smaller than originally. The results are discussed and explained on the basis of diffusion.

The Electrical Conductivities of Sulfur Dioxide-Water Mixtures between 8 and 22 Per Cent Sulfur Dioxide and from 0° to 40° C.

The Electrical Conductivities of Sulfur Dioxide-Water Mixtures between 8 and 22 Per Cent Sulfur Dioxide and from 0° to 40° C.

Effect of High vs. Low Sulfur in Vulcanizing Reclaim

Abstract To obtain the optimum results in curing compounded stocks containing whole tire reclaim, a minimum of 2.0 and a maximum of 2.5 per cent sulfur are required. This range of sulfur content, based on the total weight of reclaim in the compound besides the 4 per cent added for curing the crude rubber present, gives the flattest and longest curing range in conjunction with the highest physical qualities. Three per cent of sulfur on the straight reclaim-sulfur mix gives the maximum physical properties.

ON THE STORAGE OF SULPHUR IN THE ADRENAL GLANDS

Recent work, both abroad and in our own laboratory, has pointed to some relationship between the adrenal glands and sulphur metabolism. Data gathered from the literature seemed to indicate that the content of sulphur found in the adrenals is higher than in the other organs. To quote briefly some of these references, we mention Schultz (1) who found 0.964 per cent sulphur in the liver, 0.7797 per cent in the spleen, and 0.8608 per cent in the muscle tissue. Other figures (2) show that the sulphur content in the liver varies from 0.75 to 1.1028 per cent in man, while in the ox it might be as high as 1.86 per cent. In the liver from 0.9643 to 2.5 per cent in man, and 1.75 per cent in the ox. In the spleen (3) the figures seem to vary from 0.7797 per cent in man to from 1.72 to 2.23 per cent in the ox. Work done by Katz (4) seems to give more uniform figures for the various species inasmuch as the percentage of sulphur content of muscle tissue is as follows : In man, 0.75 ; pig, 0.85 ; ox, 0.77 ; rabbit, 0.85...

Gold Preparations in Therapy.

Gold preparations have recently found clinical application in tuberculosis and certain diseases of the skin. Among these preparations are Sanocrysin or gold and sodium thiosulfate, Krysolgan and Triphal.Sanocrysin or gold and sodium thiosulfate was originally prepared by Fordos and Gellis in 1845. It has been improved on by Mollgaard and contains about 37.5 per cent gold and 26.2 per cent sulphur, which would correspond to the formula 3Na2S2O3Au2S2O3 4H2O.Triphal, one of the other preparations studied by us from a toxicological point of view, contains approximately 44 per cent gold and 7.1 per cent sulphur, nd this corresponds to the chemical formula C6H3N-NH-CSAu-COONa 2H2O or the sodium salt of Aurothiobenzimidazolcarboxylic acid.Previous investigations1 have shown that under some conditions, gold salts tend to produce marked kidney and liver damage as well as urticaria, pruritus and erythematous eruptions. With these possibilities in mind, the present report deals with a toxicological study of the thre...

Westbrook Field, Mitchell County, Texas

The Westbrook oil field is doubly worthy of description because it is the discovery field of western Texas and because oil was found in Permian strata, previously not seriously considered as oil-producing beds. Since the first producer in 1920, a 10-barrel well at 2,498 feet, 77 wells have been drilled, averaging 40 barrels each. Early in 1926, 8 were producing. The Triassic extends from the surface to 500 feet in depth; the remainder of the section is Permian. Several key beds in the Permian are used to map the subsurface structure which is that of a northeast-southwest anticline. The 2,400-foot pay and the 3,000-foot Morrison sand are themselves good markers, occurring along porous zones within definite vertical limits. The productive reservoir is dolomitic limestone. The oil has a gravity of 25.8 degrees Baume, and contains 4 per cent sulphur, and 32 per cent gasoline. Its source is probably the Permian limestones and shales. Two kinds of gas occur in the field: (1) non-inflammable gas at depths between 1,000 and 1,300 feet, and (2) wet petroleum gas in both oil zones.

The Preparation and Use of Colloidal Sulfur as a cControl for Red Spider

Two types of colloidal sulfur have been prepared, (1) by running hydrogen sulfide into a solution of sulfur dioxid; (2) by precipitating lime-sulfur solution with acid. The former (hydrophilic colloidal sulfur solution) shows the finest stage of division of sulfur particles. The latter (hydrophobic colloidal sulfur or precipitated sulfur) has a coarser sulfur grain which precipitates in a few days. The sulfur particles in both of the colloid forms are smaller than those of high grade dusting sulfur and hence oxidize more quickly, making them more active in the control of red spider than other forms of sulfur. Comparison of the toxic properties of the colloidal solutions with a two per cent lime sulfur solution containing 0.6 per cent sulfur showed that the former were more effective especially at low temperatures. The addition of five pounds of ground or flowers of sulfur will probably prolong the length of time which such solutions would remain effective both as acaricides and fungicides.