The Chemistry of Powder and Explosives - Sciencemadness Dot Org

PENTRYL 231
tetryl by one of 27.5 cm., and one of picric acid by a drop of
42.5 cm., while TNT was not exploded by a drop of 100 cm.
It is somewhat more sensitive to friction than tetryl, and much
more sensitive than picric acid and TNT. Pentryl explodes in
3 seconds at 235°.
The results of Clark's experiments to determine the minimum
amounts of primary explosive necessary to initiate the explosion
of pentryl and of other high explosives are tabulated below. For
Pentryl ....
Picric acid ... .
TNT
Tetryl
Trimtroresorcinol
Trinitrobenzaldehyde
Tetranitroamline
MINIMUM INITIATING CHARGE (GRAMS) OF
Diazodinitrophenol
0 095
0115
0.163
0.075
0.110
0.075
0.085
Mercury
Fulminate
0.150
0.225
0240
0165
0225
0.165
0.175
Lead Azide
0.025
0.12
0.16
0.03
0.075
0.05
0.05
Hexanitrodiphenylamine 0.075 0.165 0.05
the.purpose of these experiments a half-gram portion of the high
explosive was weighed into a No. 8 detonator shell, a weighed
amount of primary explosive was introduced on top of it, and
both were compressed under a reeoforcing capsule at a pressure
of 3400 pounds per square inch. Without the reenforcing capsule
diazodinitrophenol did not cause detonation, and pentryl required
0.035 gram of lead azide and more than 0.4 gram of fulminate.
The results show that pentryl has about the same sensitivity to
initiation as tetryl and hexanitrodiphenylamine.
In the small Trauzl test pentryl caused an expansion of 15.8
cc, while the same weight of tetryl caused one of 13.8 cc, TNT
12.2 cc, and picric acid 12.4 cc. In the small lead block compression
test, in which 50 grams of the explosive was exploded by
means of a detonator on top of a lead cylinder 64 mm. long, it
was found that pentryl produced a shortening of the block of
18.5 mm., tetryl 16.6 mm., picric acid 16.4 mm., TNT 14.8 mm,,
and diazodinitrophenol 10.5 mm. Determinations of velocity of
detonation made with half-meter lengths, the explosives being
contained in extra light lead tubing y2 inch internal diameter
and weighing 12 ounces to the foot, gave the following figures.