Military carbon

Ammonia is a major concern for people working with military carbons. Due to its volatility, it is only weakly bound by physisorption, and there is very little indication of any chemisorption or catalytic activity of the copper, chromium or silver salts towards this gas. Some sources [40] suggest a slightly higlier uptake on ASC-wlietlerlte, compared to type AS. This would suggest a limited activity of the chromium. 

Of course, water is not a chemical warfare agent. However, it plays a major role in the various adsorption mechanisms, either directly, in a benevolent role (e.g. hydrolysis), or indirectly, usually influencing in a negative way the adsorption behaviour of the carbon (see sections 6.4 and 6.5). Therefore it is quite important to have a good understanding of the water adsorption behaviour of carbons in general, and military carbons in particular. This behaviour is characterised by two parameters, the water uptake and the time to reach this uptake. The water uptake depends on the structure and surface chemistry of the carbon. This is illustrated ly the water adsorption isotherm (see Fig. 13), that presents a very distinctive shape, especially when compared to the isotherms of other vapours such as chloropicrin (see Fig.l4). Even when... 

The protection against Chemicd Warferc Agents is a very small, but highly specialised field amongst activated carbon applications. Even after several decades of intensive use and elaborate research, many aspects of the military carbons, most of which are knovm as whetlerites, remain unclear. Much as is the case for other applications, activated carbon provides an adequate answer to a wide variety of problems, but raises a lot of questions as to the how and why of its excellent performance. This will, however, not prevent it from continuing to play its role as the first line of defence against the threat of CWAs in the near and even in the not so near future. 

Black Powder. Black powder is mainly used as an igniter for nitrocellulose gun propellant, and to some extent in safety blasting fuse, delay fuses, and in firecrackers. Potassium nitrate black powder (74 wt %, 15.6 wt % carbon, 10.4 wt % sulfur) is used for military appHcations. The slower-burning, less cosdy, and more hygroscopic sodium nitrate black powder (71.0 wt %, 16.5 wt % carbon, 12.5 wt % sulfur) is used industrially. The reaction products of black powder are complex (Table 12) and change with the conditions of initia tion, confinement, and density. The reported thermochemical and performance characteristics vary greatly and depend on the source of material, its physical form, and the method of determination. Typical values are Hsted in Table 13. 

Composites. Various composite materials have evolved over the years as a significant class of high performance textile products. The prototype composite is carbon fiber with an epoxy resin matrix for stmctural akcraft components and other aerospace and military appHcations. Carbon fiber composites ate also used in various leisure and spotting items such as golf clubs, tennis rackets, and lightweight bicycle frames. However, other types of appHcations and composites ate also entering the marketplace. For example, short ceUulose fiber/mbbet composites ate used for hoses, belting, and pneumatic tire components. 

The U.S. military specification, M1L-P-27201B, requires 95% para content, 99.995% minimum hydrogen by difference, 50 vppm maximum total imputities, 9 vppm maximum combined nitrogen, water, and volatile hydrocarbons, 1 vppm maximum combined oxygen and argon, 39 vppm maximum helium, 1 vppm maximum carbon monoxide and dioxide, and a 10/40 micrometers nominal /absolute particulate filtration level. Liquid hydrogen is stored in double-walled vessels with evacuated pedite or multilayer insulation and transported in similarly insulated 50,000-L trailers or 900,000-L barges. 

Epoxide resins reinforced with carbon and Aramid fibres have been used in small boats, where it is claimed that products of equal stiffness and more useable space may be produced with a 40% saving in weight over traditional polyester/ glass fibre composites. Aramid fibre-reinforced epoxide resins have been developed in the United States to replace steel helmets for military purposes. Printed circuit board bases also provide a substantial outlet for epoxide resins. One recent survey indicates that over one-quarter of epoxide resin production in Western Europe is used for this application. The laminates also find some use in chermical engineering plant and in tooling. 

The original drive for the development of modem carbon fibers, in the late-1950s, was the demand for improved strong, stiff and lightweight materials for aerospace (and aeronautical) applications, particularly by the military in the West. The seminal work on carbon fibers in this period, at Union Carbide in the U.S.A., by Shindo, et al, in Japan and Watt, et al, in the U.K., is well-documented [4-7]. It is always worth pointing out, however, that the first carbon fibers, prepared from cotton and bamboo by Thomas Edison and patented in the U.S.A. in 1880, were used as filaments in incandescent lamps. 

Myrite. An expl contg a mixt of nitrogen dioxide and carbon bisulfide. Its sensitivity to mechanical influences, brisance, rate of deton, and other expl characteristics were detd at PicArsn in 1940. In view of the fact that it is specially sensitive to rifle bullet impact, and has a rate of deton and brisance considerably lower than TNT, it was concluded that Myrite is not suitable for use as a military expl Ref C.J. Bain, Investigation of the Explosive Myrite , PATR 1030(1940)... 

The USA Military Specification (Ref 8) contains the following chemical criteria and requirements (1) As2Os by sodium thiosulfate—iodine titration 99.0% min, (2) As203 by carbonate-iodine titration 0.05% max, (3) Cl as AgCl turbidity 0.005% max, (4) heavy metals as PbS turbidity 0.010% max, (5) Fe as a Fe(CNS)3. 9KCNS.4H20 red coloration 0,010% max and (6) nitrate as an indigo carmen blue coloration which persists for over 5 mins... 

Experience has shown that the oxygen distribution in the products of a metallized military explosive favors the formation of the metal oxide. Any remaining oxygen then forms steam with the H of the expl. If any oxygen is still available it forms C02, and any unreacted C atoms then show up as free carbon in the products. (Confinement of the expls favors the formation of C02 and C at the expense of CO). In halogenated expls HX appears to be formed in preference to H20 and H2... 

Caibon-caibon has antigalling characteristic with the ability to slide against itself with very little wear, making it ideal for high-performance brakes. Such brakes are probably the maj or application of carbon-carbon and are found on most military aircraft, on the space shuttle. They are being introduced on civilian aircraft and racing cars. 

Katzenberg, M.A. 1991 Analysis of stable isotopes of carbon and nitrogen. In Pfeiffer, S. and Williamson, R.F., eds.. Snake Hill An Investigation of a Military Cemetery from the War of 1812. Toronto, Dundrun Press 247-255. 

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