Thermal safety assessment and thermo-kinetic parameters of 5,5′-dinitramino-3,3′-bi[1,2,4-triazolate] carbohydrazide salt (CBNT)

The differential scanning calorimetry (DSC) was used to investigate the specific heat capacity of 5,5 '-dinitramino-3,3 '-bi[1,2,4-triazolate] carbohydrazide salt (CBNT) from 25 to 55 degrees C. The relationship can be described as C-p = 1.26324 + 0.0014 x T, 25 degrees C <= T <= 55 degrees C. Moreover, the thermal characteristics and kinetics of CBNT were studied using DSC and accelerating rate calorimetry (ARC). DSC results showed that the thermal decomposition occurred at 200.03, 203.75, 206.25 and 208.54 degrees C at different heating rates (0.5, 1.0, 1.5 and 2.0 degrees C min(-1)), respectively. The apparent activation energy (E-a) and pre-exponential factor (A), calculated using the Kissinger method, were 303.01 kJ mol(-1) and 2.37 x 10(32) s(-1), respectively. The apparent activation energy, calculated using the Ozawa equation, was 295.64 kJ mol(-1). ARC test indicated that the self-decomposition reaction of CBNT started at 180.8 degrees C and lasted for 497 min, during which the maximum temperature rise rate was 0.08 degrees C min(-1) and the pressure rise rate was 2.04 kPa min(-1). Moreover, rate constant method and mechanism functions method were applied to calculate kinetic parameters, among which the most possible mechanism functions were (1 - alpha)(2). The values of E-a for the decomposition of CBNT calculated by these two methods were 420.78 and 420.73 kJ mol(-1). The values of A were 5.13 x 10(43) and 3.04 x 10(45) s(-1), respectively. In addition, the self-accelerating decomposition temperature of CBNT based on ARC data in the packages of 25, 50 and 75 kg was 195.23, 194.10 and 193.10 degrees C, respectively.