Impregnation with sulphur

One method of overcoming some of the instability and loss in strength of oxychloride cements when exposed to water has been to modify them by impregnation with sulphur (Beaudoin, Ramachandran Feldman, 1977). The resulting material appears to be a composite in which the respective components complement each other. The magnesium oxychloride part has relatively poor resistance to water as initially formed, whereas the sulphur is difficult to wet and is completely insoluble in water. 

For the native cement exposed first to water, there was a dramatic and rapid drop in microhardness, 30-40 % in the first hour, and 55-60 % at eight hours. Compressive strength was assumed to have undergone a similar decrease, since it is linearly related to microhardness for cementitious materials (Beaudoin Feldman, 1975). Scanning electron microscopy revealed clearly the differences that occurred on soaking in water. 

Modulus of elasticity showed similar behaviour. Impregnated samples were found to have initially a higher modulus value than unimpregnated ones the decrease in modulus was less for the impregnated cements following the 88 days immersion in water. 

The mechanism by which sulphur has these observed effects is as follows. Immersion of native magnesium oxychloride cement in water brings about a slow dissolution which creates pores. When those pores are filled with sulphur, sites of possible stress concentration at points of contact between particles are modified. Similar effects occur when sulphur is used to impregnate hydraulic cements based on Portland cement and silica (Beaudoin, Ramachandran Feldman, 1977). 

Overall, these studies showed that sulphur could be used to impregnate magnesium oxychloride cements thereby yielding materials of superior 

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There are two types of tantalum electrolytic capacitor wet and solid . Both varieties consist of a porous anode made by sintering tantalum powder at 1800 °C in vacuum. In the wet type the porous structure is impregnated with sulphuric acid, anodized to form a thin layer of Ta205 and encapsulated in a tantalum container that also serves as the cathode. The use of sulphuric acid gives a lower e.s.r. than that of the aluminium electrolytic and increases the temperature range within which the unit can be run. In the solid type the liquid... 

Three U-tubes are connected in series, the first filled with granular potassium hydroxide, the second with pumice impregnated with sulphuric acid, and the third with pure anhydrous iodic acid which should not liberate iodine when pure air is passed through.2 This last U-tube is connected by glass-to-glass connections with a boiling-tube containing sufficient concentrated potassium iodide solution to ensure complete absorption of the iodine. 

Sulphate To treat or Impregnate with sulphuric acid or a sulphate to convert Into a sulphate. 

Air was filtered on a quartz fiber filter and drowned through a polyurethane foams at a flow rate of 100 1 min . The foam was extracted with toluene. The sample was then cleaned by chromatography on silica gel impregnated with sulphuric acid... 

Hair is characterised by the appearance of a new type of X-ray pattern when it is stretched, showing that the keratin chains occur normally in a folded state. Hair protein resembles muscle protein that has been vulcanised, or impregnated with sulphur, to decrease plasticity and increase resistance to wear (Astbury, 1936). 

Carbon disulphide is an excellent solvent for fats, oils, rubber, sulphur, bromine and iodine, and is used industrially as a solvent for extraction. It is also used in the production of viscose silk, when added to wood cellulose impregnated with sodium hydroxide solution, a viscous solution of cellulose xanthate is formed, and this can be extruded through a fine nozzle into acid, which decomposes the xanthate to give a glossy thread of cellulose. 

The spring water issuing through fissures in the hills, which are only masses of coal, is so impregnated with bituminous and sulphurous particles as to be frequently nauseous to the taste and prejudicial to the health. (T. M. Morris, 1803, in Mac-Kenthum, 1969)... 

Beaudoin, J. J., Ramachandran, V. S. Feldman, R. F. (1977). Impregnation of magnesium oxychloride cement with sulphur. Ceramic Bulletin, 56, 424-7. 

Nakagami and Yokota (1983) impregnated wood with a solution containing methacrylic acid, trifluoracetic acid and sulphuric acid, to form a covalent bond with the cell wall polymers. The methacrylic-reacted wood was then impregnated with styrene, or methylmethacrylate, to form cross-links with the reacted cell wall polymers. Improved dimensional stability was obtained, although degradation of the wood was also observed. 

In the fifth edition of his Cours de Chymie, Nicolas Lemery confused bismuth with zinc. Bismuth, said he, is a Sulphureous Marcassite that is found in the Tinn Mines many do think it is an imperfect Tinn which partakes of good store of Arsenick its pores are disposed in another manner than those of Tinn, which is evident enough because the Menstruum which dissolves Bismuth cannot intirely dissolve Tinn. There is another sort of Marcassite, called Zinch, that much resembles Bismuth.. . Marcassite is nothing else but the excrement of a Metal, or an Earth impregnated with Metallick parts. The Pewterers do mix Bismuth and Zinch in their Tinn to make it found the better (52). 

Sulphide of liyclrogon is highly inflammable if burned in a limited quantity of air, the hydrogen is consumed, whilst most of the sulphur is deposited. By means of chlorine or nitric acid, it may he completely decomposed hence, chlorine acts as a disinfectant and purifier of sewers or rooms impregnated. with the odor of sulphide of hydrogen. The annexed represents the decomposition... 

Adulteration,—Should it be desired to ascertain whether ordinary carded cotton has not been added to sophisticate the gun-cotton, it may be arrived at by the following micro-chemical process. A small portion of the cotton Is impregnated with a solution of iodine, and a drop of sulphuric acid added, and then submitted to the lens the gun-cotton is very feebly affected by this treatment, and reteins the yellow coloration communicated by the iodine only slightly intensified after some time, whilst under the same treatment the fibres of ordinary cotton would quickly disintegrate, and partake of a lively violet hue, The intensity of the latter will be a comparative indication of the probahio amount of the adulterants. 

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