The Chemistry of Powder and Explosives - Sciencemadness Dot Org

320 SMOKELESS POWDER
the methyl or the ethyl compound, and is likely to find more
extensive use in the future.
Gelatinizing Agents
Gelatinizing agents, of which the centralites are examples, are
often incorporated in colloided straight nitrocellulose and douhlebase
powders where they cause the materials to burn more slowly,
where they serve as flash reducing agents, and where they reduce
the tendency of the powders to take up moisture. They reduce
the amount of volatile solvent which is needed in the manufacture
of nitrocellulose powders, and facilitate the manufacture of
double-base powders without any volatile solvent at all. The
centralites happen also to be effective stabilizers, but this is not
a general property of gelatinizing agents.
Marqueyrol and Florentin M have published a list of patents
for gelatinizing agents, esters, amides, urea derivatives, halogen
compounds, ketones, and alcohols, and have reported their study
of many of them with respect to their effectiveness on the CPi
and CP2, insoluble and soluble nitrocellulose respectively, which
were standard in the French service. To a weighed quantity of
the dry nitrocellulose a dilute solution of the gelatinizing agent
in 95% alcohol was added in portions of 1 cc. at a time, the alcohol
was then evaporated at a temperature of 35-40°, more of the
alcohol solution was added, and the evaporation was repealed
until gelatinization was complete. The results with the best gelatinizing
agents are shown in the table below, where the numbers
CPi (INSOLUBLE) CP2 (SOLUBLE)
Ethyl sebacate 320 65
Dimethylphenyl-o-tolylurea 260 65
Dimethyldiphenylurea 80
Ethyl succinate 400 90
Ethyl phthalate 360 95
represent the amounts by weight of the several substances which
were needed for the complete gelatinization of 100 parts of the
nitrocellulose. Ninety parts of ethyl citrate or of benzyl benzoate
almost completely gelatinized 100 parts of CP2, 90 of ethyl malonate
incompletely, 90 of ethyl oxalate or of ethyl stearate more
incompletely, and 90 of ethyl acetoacetate or of ethyl ricinoleate
20M6m. povdres, 18, 150, 163 (1921)