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in the presence of water than when water is absent. Diphenylamine is dissolved in the ethyl acetate before the latter is added to the water and nitrocellulose in the still. At the same time, centralite or DNT or any other substance which it may be desired to incorporate in the powder is also dissolved and added. The water phase and the lacquer arc then stirred for 30 minutes by which operation the nitrocellulose is stabilized.'-7 Starch or gum arabic solution to secure the requisite colloidal behavior is then introduced into the still, the still is closed, the temperature is raised so that the lacquer becomes less viscous, and the mixture

Figure 82. Cross Section of Ball Grain, Double Base. Deterrent Coated (U2X). (Courtesy Western Cartridge Company.)

under pressure is agitated vigorously until the lacquer is broken up into small globules of the correct size. The pressure is then reduced, and the ethyl acetate is distilled off and recovered. If the distillation is carried out too rapidly, the grains are shaped like kernels of popcorn. If it is carried out at such a rate that the volatile solvent is evaporated from the surface of the globules no faster than it moves from the interior to the surface, if the distillation is slow at first and more rapid afterwards, then smooth ball grains are formed, dense and of homogeneous structure.

11 Diphenylamine in the presence of water thus has an action beyond that which it has when it is added to the nitrocellulose gel (in the absence of a separate water phase) during the manufacture of smokeless powder by the usual process. Being preferentially adsorbed by the nitrocellulose, it drives any acid which may be present out of the nitrocellulose and into the water. After that it fulfils its usual function in the powder.

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