Thermal decomposition and safety assessment of 3,3'-dinitrimino-5,5'-bis(1H-1,2,4-triazole) by DTA and ARC

Thermal decomposition and safety assessment of 3,3'-dinitrimino-5,5'-bis(1H-1,2,4-triazole) (DNABT) were investigated by thermogravimetry–derivative thermogravimetry–differential scanning calorimetry (TG-DTG-DSC), differential thermal analysis (DTA), and accelerating rate calorimetry (ARC). The result of TG-DTG-DSC at a heating rate of 10 °C min^-1 indicated that an endothermic decomposition and an exothermic decomposition occurred at 133.98 and 210.86 °C, respectively. The apparent activation energy (E_a) and pre-exponential factor (A) of the exothermic decomposition, and the free energy of activation, activation enthalpy, and activation entropy at initial decomposition temperature (T_p0) were calculated from the DTA curves recorded at the heating rates of 1, 2, 4, 8 °C min^-1. The critical temperature of thermal explosion (T_bp0) obtained by Ozawa’s and Kissinger’s methods were calculated as 205.01 and 205.14 °C, respectively. The result of ARC indicated that the self-heating decomposition started at 200.22 °C and ended at 232.66 °C. The self-heating decomposition parameters, including the onset temperature, final temperature, temperature at maximum rate, maximum temperature rate, adiabatic temperature rise, and time to maximum rate were obtained, and these parameters were corrected by thermal inertia factor. The E_a and A under adiabatic condition were also calculated. In addition, the self-accelerating decomposition temperature (T_{SADT, 50kg}) was calculated as 175.37 °C. These results could contribute to improve the safety in the reaction, transportation, and storage processes of DNABT.