Chemistry Reference
In-Depth Information
E
= 200 kJ mol
−
1
and
Qk
0
= 10
23
Jg
−
1
s
−
1
. The values obtained are in a good agree-
ment with the literature data on
k
02
and
E
2
for the decomposition of nitrocellulose
[12, 13, 14, 15]. The results of kinetic studies of nitrocellulose are summarized in
Table 8.1, Chap. 8.
The kinetic constants of the limiting reaction of high-temperature decompo-
sition of ammonium bichromate at
T
0
= 518-559 K (
E
= 166 kJ mol
−
1
,
Qk
0
=
8
.
3
10
17
Jg
−
1
s
−
1
) and organic azide-APU at
T
0
= 525-619 K (
E
= 180 kJ mol
−
1
,
Qk
0
= 10
.
4
×
10
18
Jg
−
1
s
−
1
) were determined from ignition experiments using the
“flash-block” device. The data obtained for organic azide-APU are in good agree-
ment with the corresponding data for low-temperature (
T
0
= 420-489 K) decompo-
sition:
E
= 175 kJ mol
−
1
,
Qk
0
= 6
.
2
×
10
18
Jg
−
1
s
−
1
0
.
8). This confirms
the applicability of the flash-block technique to the study of the initial stage kinetics
of fast exothermal reactions in homogeneous condensed systems.
×
(up to
η
≈
5.4 Studying the Initial Stage Kinetics for the High-Temperature
Decomposition of Model and Commercial Composite Solid
Propellants
5.4.1 Method Verification for the Ignition of Polyurethane-Based
Composite Solid Propellant
The decomposition of polyurethane-based (grade P) composite solid propellant was
the first process studied using the flash-block device due to availability of some data on
the low-temperature decomposition kinetics of this system [16] and a few experimen-
tal data on the kinetics of heat release (obtained thermographically in a hot gas flow)
[17]. Since it is a typical representative of commercial AP-containing composite solid
propellants (based on its composition and ignition patterns), the polyurethane-based
energetic material was found to exhibit ignition behavior qualitatively similar to that
of a number of commercial and model “AP-fuel binder” systems.
The samples (10 mm in diameter, 6 mm long) were chopped from hollow rods
made by a standard molding method using a special cutter (ensuring strictly parallel
and smooth end-surfaces). The sample composition is shown in Table 5.1.
Table 5.1
Composition of the polyurethane-based (P) fuel
Component
wt %
70
.
86
Monodisperse AP
18
.
84
Polyester
Toluylenediisocyanate
2
.
8
Aluminum powder
7
.
0
Lithium fluoride
0
.
5
