R. Meyer J. Köhler A. Homburg Explosives

55 CDB Propellants
Since W TNT is pourable at 80 °C (176°F), it is highly important in
military technology. Since a considerable contraction takes place when
the liquid explosive solidifies, good care must be taken during casting
to ensure free access to all parts of the cast which have not yet
solidified, in order to ensure proper replenishment of liquid material.
Formerly, this was done by simple manual poking, but many automatic
devices have been developed which do not involve any manual labor
and which yield cavity-free casts.
Pure TNT tends to form very long, needle-shaped friable crystals, with
a loose texture which does not correspond to the maximum density.
Cast TNT charges must be fine-crystalline, mechanically firm and
dense, with numerous crystallization nuclei; i.e., solid TNT must be
finely dispersed in the cast. According to BOFORS, the texture of the
cast can be improved by the addition of W Hexanitrostilbene.
Casting of Propellants
Giessen von Triebsätzen; coulée de propergols
Casting processes are needed especially in rocketry for the shaping of
large propellant grains. Unlike in the casting of explosives, processes
which cause shrinking and yield friable crystals cannot be applied.
There are two solutions to this problem:
a) hardening of polycondensates (e.g. polyurethanes or epoxys) with
mechanically incorporated oxidizers, e.g. ammonium perchlorate
(W Composite Propellants); the hardened plastic material acts as fuel
for the oxidizer;
b) converting of pourable nitrocellulose granules by treatment with
liquid nitrate esters (e.g. with nitroglycerine). The granules can be
poured dispersed in the liquid (“slurry casting”), or filled in the rocket
motor shell and gelled in situ with the added nitrate ester.
CDB Propellants
W Composite Propellants.