Porous powders, esp. of nitrocellulose - obtd. by addn. of porogenic agents and leaching out with water esp. useful in prepn. of more active gun powders

Prodn. of porous powders, esp. of nitrocellulose, involves addn., at the time mixing, of a porogenic agent chosen from (Me)2C(CN)N2C(CN)(Me)2, C6H5SO2NHNH2 and organic di- or tri-carbonates whose decompsn. point as 100 degrees C, and mixing, drawing and cutting and drying the powder in the open air at room temp. to yield a residual solvent content of approx. 10 wt. % based on the amt. of dry matter. The dried prod. is passed into water at >60 degrees C and leached at 90-100 degrees C. The pref. porogenic agent is t-butyl tricarbonate. The max. leading temp. is pref. achieved after 1/2 hour and the leaching stage is usually 1/4-1 hour, pref. 1/2 hour. The porous powder may be a nitrocellulose having a polyvinyl nitrate additive. The porogenic agent is pref. present as 2-20 wt. % of total dry matter. The process avoids the need to remove large amts. of salts e.g. KNO3, by dissolution in water, as in the prior art and gives macroporous powders c.f. fine powders previously obtd. The combustion speed of the nitrocellulose is increased.