The Chemistry of Powder and Explosives - Sciencemadness Dot Org

FLASHLESS CHARGES AND FLASHLESS POWDER 327
carbon monoxide along with substantially the same amount of the
other gaseous products. There will be more gas and cooler gas.
A colloided powder made from pyrocellulose 85 parts and hydrocellulose
15 parts is flashless in the 75-mm. gun, and gives practically
the same ballistic results as a hotter and more expensive
powder made from straight nitrocellulose. The strength of the
powder may be increased without affecting its flashlessness by
substituting part of the pyrocellulose by guncotton of a higher
nitrogen content.
Among the materials which have been incorporated into colloided
powder for the purpose of reducing or extinguishing the
flash are (1) substances, such as starch, hydrocellulose, and
anthracene, which are insoluble in the colloid and are nonexplosive.
They, of course, must exist in a state of fine subdivision
to be suitable for this use. Other anti-flash agents are
(2) solid or liquid non-explosive substances, such as diethyldiphenylurea
and dibutyl phthalate, which are solvents for nitrocellulose
and dissolve in the colloid. They reduce the hygroscopicity
of the powder and they reduce the amount of volatile
solvent which is needed for the manufacture. Still others are
(3) the explosive solid and liquid aromatic nitro compounds
which are solvents for nitrocellulose and are effective in reducing
both the flash and the hygroscopicity. All or any of the substances
in these three classes may be used either in a straight
nitrocellulose or in a nitrocellulose-nitroglycerin powder. Several
flashless powders have been described in the section on the "Classification
of Smokeless Powders." Many varieties have been
covered by numerous patents. We cite only a single example, 25
for a smokeless, flashless, non-hygroscopic propellent powder
made from about 76-79% nitrocellulose (of at least 13% nitrogen
content), about 21-24^O dinitrotoluene, and about 0.8-1.27o diphenylamine.
During the first World War the French and the
Italians used a swperattenuated ballistite, made without volatile
solvent, and containing enough aromatic dinitro compound (in
place of part of the nitroglycerin) to make it flashless. In a
typical case the powder was made from 30 parts CPi, 30 CP2,
15 DNT, and 25 nitroglycerin.
25 U. S. Pat. 2,228,309 (1941), Ellsworth S. Goodyear.