R. Meyer J. Köhler A. Homburg Explosives

221 Nitrocellulose
the following data refer to 13.3% N:
oxygen balance: –28.7%
volume of explosion gases: 871 l/kg
heat of explosion
(H2O liq.): 1031 kcal/kg = 4312 kJ/kg
(H2O gas): 954 kcal/kg = 3991 kJ/kg
density: 1.67 g/cm3 (maximum value attainable
by pressing: 1.3 g/cm3 )
lead block test: 370 cm3 /10 g
impact sensitivity: 0.3 kp m = 3 N m
friction sensitivity:
up to 36 kp = 353 N pistil load no reaction
critical diameter of steel sleeve test: 20 mm
Nitrocellulose is the commonly employed designation for nitrate esters
of cellulose (cellulose nitrates). Nitrocellulose is prepared by the action
of a nitrating mixture (a mixture of nitric and sulfuric acids) on wellcleaned
cotton linters or on high-quality cellulose prepared from wood
pulp. The concentration and composition of the nitrating mixture determine
the resulting degree of esterification, which is measured by
determining the nitrogen content of the product.
The crude nitration product is first centrifuged to remove the bulk of
the acid, after which it is stabilized by preliminary and final boiling
operations. The spent acid is adjusted by addition of concentrated
nitric acid and anhydrous sulfuric acid and recycled for further nitration
operations. The original form and appearance of the cellulose remains
unchanged during the nitration. Subsequent boiling of the nitrocellulose
under pressure finally yields a product with the desired viscosity
level. The nitrated fibers are cut to a definite fiber length in hollanders
or refiners. Apart from the numerous types of lacquer nitrocelluloses,
which include ester- and alcohol-soluble products with a nitrogen
content of 10.3–12.3% at all viscosity levels used in technology,
standard nitrocellulose types are manufactured and blended to the
desired nitrogen content. Blasting soluble nitrocotton (dynamite nitrocotton;
12.2–12.3% N) is held at a high viscosity to maintain good
gelatinizing properties.
All nitrocelluloses are soluble in acetone. The viscosity of the solutions
is very variable. (For its adjustment by pressure boiling see above.)
Nitrocellulose is transported in tightly closed drums or in pasteboard
drums lined with plastic bags inside, which contain at least 25% of a
moisturizing agent (water, alcohol, isopropanol, butanol, etc.). Spherical
NC particles are precipitated from solution under vigorous stirring,
and preferably used for manufacturing of cast or composite double
base propellants.