The kinetics of the thermal decomposition of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) in condensed state has been investigated by high temperature infrared spectroscopy (IR) and thermogravimetry (TG) in conjunction with pyrolysis gas analysis, differential thermal analysis (DTA) and hot stage microscopy. The decomposition proceeds in two main stages under isothermal conditions and the initial stage involving about 24% loss in weight obeys Avrami-Erofe'ev equation (n = 1), and is governed by an activation energy (E) of 150.58 kJ.mol -l and log(A in s -l) 12.06. The second stage corresponding to 24 to 90% loss in weight gave best fit for Avrami-Erofe'ev equation, n=2, with E=239.56 kJ.mol -~ and log(A in s <) 19.88 by isothermal TG. The effect of additives, on the initial thermolysis of TATB has also been studied. Evolved gas analysis by IR showed that NH3, CO2, NO2, HCN and H20 are produced in the initial stage of decomposition. The decomposition in KBr matrix in the temperature range 272 to 311.5~ shows relative preferential loss in the -NH2 to -NOz band intensity which indicates that the rupture of C-NHz bond, weakened also by the interaction of the NH2 with the neighbouring NOz group, appears to be the primary step in the thermolysis of TATB.

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Kinetics of the thermal decomposition of pentaerythritol tetranitrate (PETN) in condensed state has been investigated by high temperature infrared spectroscopy (IR) and thermogravimetry (TG) in conjunction with pyrolysis gas analysis, differential thermal analysis (DTA) and hot-stage microscopy. Kinetics of thermolysis has been followed by IR after suppressing volatilization by matrixing and by isothermal TG without suppressing volatilization to simulate actual user conditions. The best linearity was obtained for Avrami-Erofe'ev equation, n 1, in IR and isothermal TG. Activation energy was found to be 152 kJ mol À1 and log A (in s À1 ) 16.96 by IR. The effect of additives on the initial thermolysis of PETN has been studied. Evolved gas analysis by IR shows that NO 2 , H 2 CO are produced in the initial stage of decomposition followed by NO, N 2 O, CO 2 , HCN and H 2 O. The decomposition in KBr matrix shows relative preferential loss in NO 2 band intensity which indicates that the rupture of OÀNO 2 bond is the primary step in the thermolysis of PETN.

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