260 Propellants, Explosives, Pyrotechnics 24, 260Ä…265 (1999)
Spectroscopic and Thermal Studies on Pentaerythritol Tetranitrate
(PETN)
P. S. Makashir and E. M. Kurian
High Energy Materials Research Laboratory, Sutarwadi, PUNEÄ…411 021 (India)
Spektroskopische und thermische Untersuchungen an Pentaery- Analyses spectroscopiques et thermiques du pentaerythrittetra-
thrittetranitrat (PETN) nitrat (PETN)
  Á Â
Die Kinetik der thermischen Zersetzung von PETN im konden- La cinetique de la decomposition thermique du PETN a l'etat
     Á Â
sierten Zustand wurde untersucht durch Hochtemperatur-Infra- condense a ete etudiee par spectroscopie infrarouge a haute tempera-
Â
rotspektroskopie (IR) und Thermogravimetrie (TG) in Verbindung mit ture (IR) et par thermogravimetrie (TG) en liaison avec une analyse
Â
Pyrolyse-Gasanalyse, Differentialthermoanalyse (DTA) und Heiz- des gaz par pyrolyse, une analyse differentielle (DTA) et une micro-
Á Â Â Â
tisch-Mikroskopie. Die Kinetik der Thermolyse wurde weiterverfolgt scopie a platine chauffante. La cinetique de la thermolyse a ete
mittels IR-Spektroskopie nach Unterdruckung der Verdunstung in der poursuivie par spectroscopie IR apres elimination de l'evaporation
È Á Â Â
Matrix und durch isotherme TG ohne diese Unterdruckung, um die dans la matrice et par TG isotherme sans cette elimination, a®n de
È Â
È Â Â Â Â
Anwenderbedingungen zu simulieren. Die beste Linearitat wurde simuler les conditions d'utilisation. La meilleure linearite a ete obte-
erhalten nach der Avrami-Erofe'ev-Gleichung bei n ˆ 1 fur IR und nue d'apres l'equation d'Avrami-Erofe'ev a n ˆ 1 pour IR et TG
È Á Â Á
     Â
isotherme TG. Die Aktivierungsenergie wurde bestimmt durch IR zu isotherme. L'energie d'activation a ete determinee par IR comme etant
È Â Â
152 kJ=mol und log A zu 16.96 s 1. Die Wirkung von Zusatzen auf de 152 kJ=mol et log A de 16,96 s71. On a etudie l'effet d'additifs sur
  Â
den Thermolysebeginn con PETN wurde untersucht. Die Analyse der le debut de la thermolyse de PETN. L'analyse des gaz liberes par IR a
 Â
freigesetzten Gase durch IR zeigte, daû NO2 und H2CO in der montre que NO2 et H2CO etaient apparus durant la phase initiale de la
 Â
Anfangsstufe der Zersetzung entstanden sind gefolgt von NO, N2O, decomposition, suivis de NO, N2O, CO2, HCN et H2O. La decom-
à Â
CO2, HCN und H2O. Die Zersetzung in der KBr-Matrix zeigt einen position dans la matrice KBr fait apparaõtre une perte d'intensite
È Â Â
relative bevorzugten Verlust der Intensitat in der NO2-Bande, was relativement preferentielle dans la bande NO2, ce qui indique que la
Á Â
darauf hinweist, daû der Bruch der O-NO2 Bindung der erste Schritt rupture de la liaison O-NO2 est la premiere etape de la thermolyse du
bei der Thermolyse von PETN darstellt. PETN.
Summary additives has added signi®cance to its practical application.
The thermal decomposition of PETN(1Ä…4) has been studied
Kinetics of the thermal decomposition of pentaerythritol tetranitrate
using gas manometric technique, differential scanning calori-
(PETN) in condensed state has been investigated by high temperature
metry, and isothermal weight loss method. Decomposition
infrared spectroscopy (IR) and thermogravimetry (TG) in conjunction
products(5) observed are N2O, NO2, NO, N2, CO and CO2.
with pyrolysis gas analysis, differential thermal analysis (DTA) and
hot-stage microscopy. Kinetics of thermolysis has been followed by IR Mechanisms for decomposition of PETN(6) have been pro-
after suppressing volatilization by matrixing and by isothermal TG
posed. The decomposition of PETN(7) is reported to be ®rst
without suppressing volatilization to simulate actual user conditions.
order over its entire course. Below and above melting point of
The best linearity was obtained for Avrami-Erofe'ev equation, n ˆ 1,
PETN(7) the decomposition is autocatalytic in the initial stage
in IR and isothermal TG. Activation energy was found to be 152 kJ
mol 1 and log A (in s 1) 16.96 by IR. The effect of additives on the and subsequently becomes ®rst order. Energy of activation
initial thermolysis of PETN has been studied. Evolved gas analysis by
reported is in the range of 132.7 to 197.5 kJ mol 1. Chemical
IR shows that NO2, H2CO are produced in the initial stage of
analysis technique(7) suggests that the primary decomposi-
decomposition followed by NO, N2O, CO2, HCN and H2O. The
tion mechanism is the breakage of O2NO2 bond leading to
2
decomposition in KBr matrix shows relative preferential loss in NO2
band intensity which indicates that the rupture of O NO2 bond is the
free radicals. Mass spectra(8) of detonation products of PETN
primary step in the thermolysis of PETN.
show that mass 18 ion, largely from H2O, is the dominant
product. Emission spectra(9) of PETN show only OH.
PETN(10) liberates mostly the side chain fragments NO2
1. Introduction and CH2O under subatmospheric argon pressure.
Roger(11) determined kinetic constants for the decomposi-
Nitro compounds and nitric esters, because of their tion of PETN. NQR=NMR studies(12) on PETN have also
inherent properties such as high energy content and ability been carried out. Oxides of nickel, lead, aluminium and TNT
to release large amounts of gas and energy on combustion at accelerate the decomposition of PETN(13). As such the
very rapid rate, have extensive civil and military applica- thermal decomposition of PETN is complex. In addition
tions. Nitric ester like pentaerythritol tetranitrate (PETN) is volatilization of the nitric ester at elevated temperatures
extensively used in shells, demolition charges and detonator. needs to be suppressed to arrive at the true kinetics in the
PETN is the most thermally stable nitric ester. Thermal condensed phase. This has been achieved by pelletiza-
decomposition data constitutes an essential component in tion(14,15) in KBr matrix. Infrared spectroscopy, in which
the studies of explosive properties of PETN. The mode of variation in the functional group band intensity with time can
thermal decomposition, both alone and in the presence of be followed, constitutes one of the most effective tools in the
# WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1999 0721-3115/99/0306Ä…0260 $17.50‡:50=0
Propellants, Explosives, Pyrotechnics 24, 260Ä…265 (1999) Studies on Pentaerythritol Tetranitrate (PETN) 261
kinetic investigation of explosives. High temperature IR 3.1 Kinetics by Isothermal TG
spectroscopy(16,17) has, therefore, been used successfully in
the present study to determine the kinetics, structural changes Kinetics(18) of the thermal decomposition of PETN in the
and mechanism of initial thermal decomposition of PETN in temperature range 149.8 C to 166 C, under static air atmo-
conjunction with pyrolysis gas analysis, hot-stage micro- sphere was studied using isothermal TG. Weight loss of
scopy and isothermal microthermogravity in which the mass PETN at de®nite time intervals was measured from the
and exothermicity effects on the kinetics are eliminated. respective isothermal TG curve. From these data, a, the
fraction decomposed with respect to the original weight, in
time, t, was calculated. Some representative plots obtained
2. Experimental are given in Figure 2. a t curves were analyzed using
various kinetic models using a computer program(19).
PETN (JSS 1376-06: 1986) was obtained from Indian Correlation coef®cient was evaluated for eighteen equa-
Ordnance Factory and puri®ed by repeated recrystallization tions listed in Ref. 19 and eight equations where close
from acetone. Elemental analysis was carried out using correlation has been obtained are given in Table 1. The
Perkin-Elmer 240C. Thermal analysis and isothermal TG
were carried out on a Netzsch STA 409 thermal analyzer. In
isothermal TG the sample in platinum-iridium thermocup
was heated to the desired temperature using programmed
heating and the thermal cycle was kept practically the same
for different isothermal temperatures. Smooth gradual trans-
formation from dynamic to the desired isothermal tempera-
ture with no overshooting ensured temperature equilibrium
and uniformity without disturbing the equilibrium of the
microbalance.
Kinetics by IR was followed by a ratio recording IR
spectrophotometer, Perkin-Elmer 683. The high temperature
IR cell was fabricated in the laboratory(16) and temperature
programming was done using a Stanton-Redcroft universal
temperature programmer having chromel-alumel thermo-
couple. The temperature remained constant during the
experiment within 1 C of the set temperature.
Spectroscopic grade KBr was used as the matrix material.
Spectra of the sample in KBr matrix were recorded in the
frequency range 4000 cm 1 to 200 cm 1 at the desired
temperature at regular time intervals using medium speed
of scanning. It was veri®ed that the absorbency of the band at
1285 cm 1 corresponding to NO2 symmetric stretching
vibration of O2NO2 band, varied linearly with the amount
2
of sample in the concentration range of 0.1% to 0.75% PETN
in KBr matrix.
A specially designed experimental setup and IR gas cell
made of pyrex glass with KBr windows were used to study
the gas phase composition(17) during the thermal decomposi-
tion of PETN under isothermal and dynamic heating condi-
tions.
A Leitz-Orthoplan polarizing microscope with hot-stage
attachment was used under dynamic heating conditions to
observe the morphological sequence of the decomposition.
3. Results
Simultaneous TG-DTA results of PETN recorded at a
heating rate of 10 C min 1 are reproduced in Figure 1. TG
Figure 1. TG=DTA=DTG Curves of PETN.
curve yielded a very sharp change in weight of about 95% in
Sample weight: 5 mg
the temperature range 140 C to 237 C. DTA showed sharp
Atmosphere: dynamic nitrogen
endothermic change at 140 C followed by pronounced
Reference: calcined alumina
Heating rate: 10 C=min
exothermic change with peak maximum at 201.5 C.
262 P. S. Makashir and E. M. Kurian Propellants, Explosives, Pyrotechnics 24, 260Ä…265 (1999)
Figure 3. IR Spectra of PETN at 162 C, (a) after 0.0, (b) 6.4, (c) 13.5,
(d) 20.5, (e) 30.0 and (f) 41.0 min.
Figure 2. a t Plots for the thermal decomposition of PETN by
isothermal TG.
however, not that prominent at higher temperatures, which
is characteristic of some metastable systems. At higher
decomposition of PETN was found to be best described by
temperatures the obedience to Avrami-Erofe'ev equation,
Avrami-Erofe'ev equation for n ˆ 1. The activation energy
n ˆ 1, similar to pseudo ®rst order behaviour as reported by
was found to be 162 kJ mole 1 with log A (in s 1) 17.85.
earlier workers was better. This type of kinetic obedience was
interestingly also noted for TNT(14) and nitromethane
decompositions(20). Table 2 gives the eight rate expressions
3.2 Kinetics by IR Spectroscopy
which gave better correlation. The decomposition of PETN
was found to be best described by Avrami-Erofe'ev equation
IR spectra of PETN in KBr matrix at room temperature and
for n ˆ 1. The energy of activation was found to be 152 kJ
at desired elevated temperatures at regular time intervals 1
mol and log A (in s 1) 16.96 by IR. The difference in the
were recorded. Figure 3 presents the variation of band
rate parameters arrived at by TG and IR may be due to the fact
intensity for different groups with time at 162 C with
that the kinetics of thermolysis has been followed by IR after
progressive decomposition.
suppressing volatilization by matrixing.
In IR the variation of the intensity of the nitro band at
1285 cm 1 was used to monitor the decomposition by KBr
pellet method. For calculating the fraction of PETN decom-
posed the peak absorbency after attaining the selected 3.3 Effect of Additives
isothermal temperature was taken as the initial concentration.
a t curves thus obtained are given in Figure 4 which were Effect of additives incorporated to the extent of 10% on the
then analyzed using the computerized method for various kinetics of the thermal decomposition of PETN, has been
kinetic expressions as in isoTG to evaluate the rate constants. studied using IR spectroscopy. IR spectra of pure PETN and
a t curves are characterized by long induction period at PETN mixed with 10% additives in KBr matrix were
lower temperatures and are sigmoidal in nature. Long recorded at 150 C at regular intervals. Variation in the
induction period also indicates that the volatilization has absorbency of NO2 symmetric stretching vibration at
been effectively suppressed. The induction period was 1285 cm 1 was used to monitor the decomposition. a t
Table 1. Correlation Coefficient `R' obtained for various F(a) by Isothermal TG.
S.No. F (a) `R' Isothermal temperature ( C)
149.8 152.3 156 161 166
1 a2 0.9853 0.8989 0.9932 0.9615 0.9445
2 1 1 aÄ…1y2 0.9924 0.9397 0.9971 0.9499 0.9385
3 1 1 aÄ…1y3 0.9945 0.9273 0.9981 0.9613 0.9507
4 ‰ 1n1 aÄ…Š 0.9946 0.9990 0.9962 0.9789 0.9711
5 ‰ 1n1 aÄ…Š3y2 0.9919 0.9385 0.9979 0.9566 0.9509
6 ‰ 1n1 aÄ…Š1y2 0.9823 0.9540 0.9939 0.9388 0.9382
7 ‰ 1n1 aÄ…Š1y3 0.9659 0.9661 0.9865 0.9159 0.9238
8 1n‰ay1 aÄ…Š 0.9492 0.9658 0.9836 0.9106 0.9303
Propellants, Explosives, Pyrotechnics 24, 260Ä…265 (1999) Studies on Pentaerythritol Tetranitrate (PETN) 263
Figure 5. IR Spectra of the gaseous decomposition products of PETN
at 145 CÄ…220 C.
stage followed by NO, CO2, CO and then N2O, HCN and
H2O.
3.5 Microscopic Studies
Figure 4. a t Plots for the thermal decomposition of PETN by IR.
Microscopic studies on the thermal decomposition of
PETN under dynamic temperature conditions reveal that at
normal temperature PETN crystals are fairly transparent and
plots of pure PETN and those of PETN mixed with 10%
the transparency gradually decreased with increase in tem-
carbamite, calcium carbonate and magnesium oxide at 150 C
perature. At about 140 C melting sets in, accompanied by a
show that there is an accelerating effect by these additives on
sudden change, similar to shattering, occurring in crystals.
the ®rst stage of decomposition of PETN. Similar results
After this, evolution of gases sets in and increases in intensity
were also obtained from dynamic TG-DTA studies on the
at localized points and ®nally a black charred residue is left
effect of additives.
behind.
4. Discussion
3.4 Evolved Gas Analysis by IR
When alkyl nitrates(21) are heated, they produce organic
In order to get an insight into the mechanism of the thermal free radicals, which indicate the breakage of O2N bond, as
2
decomposition, gaseous species evolved, when 10 mg of the primary step. Decomposition of simple nitrate esters(22,23)
sample was decomposed at controlled heating rate of 5 C involved endothermic and exothermic reactions. First step,
min 1, was examined and identi®ed using IR spectroscopy the breakage of O N bond is endothermic and second step,
(Fig. 5). Around 145 CÄ…155 CNO2 (1625 cm 1) and HCHO the disproportionation of free radicals is exothermic. The
(H2CO) aldehyde (1740Ä…1760 cm 1) were the ®rst gases that cleavage of CO2NO2 bond constitutes the primary step in
2
could be detected. Bands of medium intensity due to CO2 the thermal decomposition of nitrate esters(7,24Ä…28). The high
(2320Ä…2340 cm 1), N2O (2220 cm 1), NO (1790 and sensitivity and low stability of compounds containing nitrate
1805 cm 1), HONO (1790Ä…1800 cm 1), CO (2140 cm 1), ester groups is accounted for by the low energy of O2NO2
2
HCN (710 cm 1) are noticed between 145 CÄ…220 C. Iso- bond.
thermal gas evolution studies have also been carried out Infrared spectroscopic studies of the decomposition under
which show that NO2 and H2CO are produced in the initial isothermal conditions reveal that the band intensities due to
Table 2. Correlation Coefficient `R' obtained for various F(a) by IR
S.No. F(a) `R' Isothermal temperature ( C)
145 150 157.5 162 164.5 167 175
1 a2 0.9406 0.9558 0.9508 0.9697 0.9754 0.9297 0.9450
2 1 1 aÄ…1y2 0.9641 0.9583 0.9747 0.9903 0.9876 0.9437 0.9532
3 1 1 aÄ…1y3 0.9737 0.9705 0.9738 0.9897 0.9817 0.9528 0.9644
4 ‰ 1n1 aÄ…Š 0.9856 0.9908 0.9840 0.9918 0.9748 0.9602 0.9975
5 ‰ 1n1 aÄ…3y2 0.9601 0.9720 0.9795 0.9942 0.9838 0.9593 0.9678
6 ‰ 1n1 aÄ…Š1y2 0.9653 0.9698 0.9709 0.9914 0.9911 0.9491 0.9535
7 ‰ 1n1 aÄ…Š1y3 0.9310 0.9271 0.9468 0.9812 0.9925 0.9284 0.9311
8 1n‰ay1 aÄ…Š 0.9943 0.9791 0.9153 0.9721 0.9835 0.9290 0.9299
264 P. S. Makashir and E. M. Kurian Propellants, Explosives, Pyrotechnics 24, 260Ä…265 (1999)
nitro and other groups decrease but additional band at NO, CO2, N2O, HCN and H2O. The primary radical gener-
1840 cm 1 is observed which may be due to NO in NOBr, ated during the initial thermolysis can interact with the parent
formed in situ by the interaction of NO2 with KBr matrix. molecule resulting in hydrogen abstraction thus generating
This suggests the formation of NO2 in the ®rst stage of additional radicals which can set up a chain process. Iso-
decomposition of PETN which reacts with matrix KBr(30) thermal calorimetry and UV spectroscopic studies(33) have
giving NOBr. The disappearance of this additional band at brought out the inŻuence of surface area upon the rate
1840 cm 1 with continued heating is due to dissociation of determining step controlling PETN stability. In simple O-
NOBr to 1=2Br2 and NO. Appearance of additional peak at nitro molecule CH3O2NO2, the bond dissociation energy(29)
2
2320Ä…2340 cm 1 during isothermal decomposition of PETN calculated is 166.7 kJ mole 1 which implies that PETN,
can be attributed to species like CO2 trapped in the matrix, being a poly O-nitro molecule will have a corresponding
suggesting the formation of CO2, during the decomposition bond dissociation energy less than in simple nitrate esters.
of PETN, after the formation of NO. Activation energy of 152 kJ mole 1 is thus of the right order
In evolved gas analysis, nitrogen dioxide and formalde- vis-a-vis the expected bond dissociation energy of O2NO2
2
hyde(27) were the ®rst gaseous decomposition products bond in PETN consistent with the proposed primary rupture
detected. Subsequently nitric oxide (NO), nitrous oxide of this O2NO2 bond, as also observed for N2NO2 bond
2 2
(N2O), carbon dioxide (CO2), carbon monoxide (CO), and rupture in TNP(34). In nitrocellulose, another polynitrate, the
hydrogen cyanide were also observed. From a perusal of thermal decomposition proceeds with loss of NO2 forming an
intensities of the various bands it seems that nitrogen dioxide, organic free radical, which can undergo carbon-carbon bond
formaldehyde and nitric oxide are the major decomposition cleavage in the skeleton and this is more reactive than the
products. NO2(35). X-ray photoelectron spectroscopic studies on nitro-
Spectra of the residue at the end of the isothermal TG cellulose also indicate that cleavage of O2N bond with NO2
2
experiments show bands at 1725Ä…1750 cm 1 and 1150Ä… loss is the initial step at the surface as well as bulk(36).
1170 cm 1 due to CO and CH2, respectively which are
characteristic of the formaldehyde structural grouping (Fig.
6). Thermal decompositions of mononitrated nitrocellulose
Kinetics of Initial Thermolysis and Velocity of
and double base propellants have been studied(27). Formation
Detonation:
of NO2 and formaldehyde in the decomposition has been
noticed suggesting reaction of NO2 with formaldehyde as the
Correlation observed between the kinetics of initial ther-
rate controlling ®zz zone reaction.
molysis and velocity of detonation has also been found to be
Thus the primary step in the decomposition of PETN is the
valid in the case of PETN too, vide Figure 10 in Ref. 17.
breakage of O2NO2 bond(7,27,29,31,32) leading to the forma-
2
tion of RCH2O free radical(7,27)
5. References
_
RCH2ONO2 !RCH2O ‡ NO2 primary reactionÄ…
PETNÄ… (1) M. A. Cook and M. T. Abegg, Ind. Eng. Chem. 48, 1090 (1956).
(2) J. Harris, Thermochim. Acta 14, 183 (1976).
_ _
RCH2O ‡ RCH2ONO2 !RCH2OH ‡ RCH ONO2
(3) R. N. Roger and E. D. Morris, Anal. Chem. 38, 412 (1966).
(4) K. K. Andreev and B. I. Kaidymov, Russian J. Phys. Chem. 35,
This free radical may get converted into intermediate
1324 (1961).
(5) A. J. B. Robertson, J. Soc. Chem. Ind. (London), 67, 221 (1948).
decomposition products such as H2CO which may further
(6) R. N. Roger and D. M. Colman, ``Technical Report on Com-
react with NO2 liberated(27,31) producing gases including
patibility of Propellants, Explosives and Pyrotechnics with
Plastics and Additives'', Dec. 3Ä…4, 1974, II-B-1.
(7) J. Roth, in ``Encyclopedia of Explosives and Related Items'',
Picatinny Arsenal Dover, New Jersey, Part 2700, 1978, P107.
(8) N. C. Blais, N. R. Greiner, and W. J. Fernandez, in ``Chemistry
and Physics of Energetic Materials'', S. N. Bulusu, (Ed.), Kluwer
Academic Publishers, Boston, (1990) pp. 498.
(9) B. J. Van der Meer, in ``Chemistry and Physics of Energetic
Materials'', S. N. Bulusu, (Ed.), Kluwer Academic Publishers,
Boston, (1990) pp. 671.
(10) Y. Oyumi and T. B. Brill, Combustion and Flame 66, 9 (1988).
(11) R. N. Rogers, Thermochim. Acta 11, 131 (1975).
(12) R. A. Marino, in ``Chemistry and Physics of Energetic Materi-
als'', S. N. Bulusu, (Ed.), Kluwer Academic Publishers, Boston,
(1990) pp. 736.
(13) C. E. H. Bawn and G. Rotter, ``Science of Explosives'', London,
1956, Part 2, pp. 749.
(14) P. S. Makashir and E. M. Kurian, J. Therm. Anal. Calorimetry 55,
173 (1999).
(15) J. Hayhurst and E. Kaisersberger, Proc. 3rd National Seminar on
High Energy Materials, HEMRL, Pune, 1984 pp. 136.
Figure 6. IR Spectra of the solid residue obtained in the thermolysis
(16) P. S. Makashir, ``Studies on the Thermal Decomposition of Some
of PETN at different temperatures.
Nitro Compounds'', M.Sc. Thesis, University of Pune, 1985.
Propellants, Explosives, Pyrotechnics 24, 260Ä…265 (1999) Studies on Pentaerythritol Tetranitrate (PETN) 265
(17) P. S. Makashir and E. M. Kurian, J. Therm. Anal. 46, 225 (1996). (28) Wee Lam Ng, J. E. Field, and H. M. Hauser, J. Chem. Soc.,
(18) E. M. Kurian, J. Therm. Anal. 35, 1111 (1989). Perkin Trans. 2, 637 (1976).
(19) K. V. Prabhakaran, N. M. Bhide, and E. M. Kurian, Thermochim. (29) C. F. Melius, in ``Chemistry and Physics of Energetic Materials'',
Acta 220, 169 (1993). S. N. Bulusu, (Ed.), Kluwer Academic Publishers, Boston,
(20) C. J. Piermarini, S. Block, and P. J. Miller, in ``Chemistry and (1990), pp. 21.
Physics of Energetic Materials'', S. N. Bulusu, (Ed.), Kluwer (30) H. A. Bent and B. Crawford, Jr., J. Am. chem. Soc. 79, 1793
Academic Publishers, Boston, (1990) pp. 391. (1957).
(21) J. B. Levy, J. Am. Chem. Soc. 76, 3254 & 3790 (1954). (31) G. Lengelle, A. Bizot, J. Duterque, and J. F. Trubert, in: ``Fun-
(22) R. E. Wilfong, S. S. Penner, and F. Daniels, J. Phys. Chem. 54, damentals of Solid Propellant Combustion'', K. K. Kuo and M.
863 (1950). Summer®eld (eds.), American Institute of Aeronautics and
(23) G. K. Adams and L. A. Wiseman, ``Selected Combustion Pro- Astronautics, Inc., Publishers, New York (1984) pp. 361.
blems'', Butterworth's Scienti®c Publications, London, 1954, pp. (32) T. B. Brill, in ``Chemistry and Physics of Energetic Materials'',
277. S. N. Bulusu, (Ed.), Kluwer Academic Publishers, Boston, (1990)
(24) M. Caire-Maurisier and J. Tranchant, 4th Symposium on Che- pp. 277.
mical Problems Connected with the Stability of Explosives'', (33) R. D. Larry and M. P. James, Thermochim. Acta 226, 187 (1993).
(1976), [Proc.], pp. 249. (34) K. V. Prabhakaran, S. R. Naidu, and E. M. Kurian Propellants,
(25) T. Yoshida, N. Tsumagiri, and K. Namba, Kogyo Kayaku 23, 325 Explos., Pyrotech. 20, 238 (1995).
(1972). (35) C. W. Saunders and L. T. Taylor, J. Energetic Materials 8, 149
(26) B. B. D. Schor and J. E. Toni, Thermochim. Acta 27, 347 (1978). (1990).
(27) R. A. Fifer, in ``Fundamentals of Solid Propellant Combustion'', (36) B. C. Beard and J. Sharma, 1987 JANNAF Propellant Char-
K. K. Kuo and M. Summer®eld (eds.), American Institute of acterization Subcommittee Meeting, CPIA Pub. #470, pp. 259.
Aeronautics and Astronautics, Inc., Publishers, New York
(1984), pp. 177.
(Received September 11, 1997; Ms 46=97)