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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 (Ea) and pre-exponential factor (A) of the exothermic decomposition, and the free energy of activation, activation enthalpy, and activation entropy at initial decomposition temperature (Tp0) 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 (Tbp0) 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 Ea and A under adiabatic condition were also calculated. In addition, the self-accelerating decomposition temperature (TSADT, 50kg) was calculated as 175.37 °C. These results could contribute to improve the safety in the reaction, transportation, and storage processes of DNABT.

TKX-50-based PBX (PBX-T) is prepared by solution–water suspension method using dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate (TKX-50) as the explosive. The thermal behavior of PBX-T is investigated under a nonisothermal condition by using TG-DTG and DSC method. The kinetic parameters (E a = 167.98 kJ mol−1 and A = 1016.05 s−1) for the main thermal decomposition reaction of PBX-T are calculated from the analysis of DSC curves by differential method and integral method, and the nonisothermal kinetic equation of the exothermic process is $${\text{d}}\alpha /{\text{d}}T = \left( {10^{16.05} /2\beta } \right)5\left( {1 - \alpha } \right)\left[ { - \ln \left( {1 - \alpha } \right)} \right]^{3/5} \exp ( - 2.0204 \times 10^{4} /T)$$ , suggesting that the main exothermic decomposition reaction mechanism of PBX-T is classified as Avrami–Erofeev equation. The specific heat capacity (C p) of PBX-T is measured using continuous C p mode of C80 micro-calorimeter. Depending on the thermal decomposition parameters and Chinese Military Standards GJB 772A-97 method, the adiabatic time, self-accelerating decomposition temperature, sensitivities, and 5-second flash point on of PBX-T are obtained.

The enthalpies of dissolution for dihydroxylammonium 5, 5′-bistetrazole-1,1′-diolate (TKX-50) in water were measured using a C-80 Calvet microcalorimeter at four different temperatures under atmospheric pressure. Differential enthalpies (Δdif H) and molar enthalpies (Δdiss H) of dissolution were calculated. The corresponding kinetic equations that describe the dissolution rate at the four experimental temperatures are dα/dt = 10−3.06(1 − α)0.59 (T = 298.15 K), dα/dt = 10−2.98(1 − α)0.37 (T = 303.15 K), dα/dt = 10−2.90(1 − α)0.37 (T = 308.15 K), dα/dt = 10−2.85(1 − α)0.43 (T = 313.15 K). In addition, the determined values of the activation energy E and pre-exponential factor A for the dissolution process are 25.08 kJ mol−1 and 21.98 s−1, respectively.

The enthalpies of dissolution for 5,5′-Bistetrazole-1, 1′-dihydroxy ((H2O)2BTO) and disodium 5,5′-Bistetrazole-1,1′-diolate ([Na2(H2O)4]BTO) in dimethyl sulfoxide (DMSO) at 298.15 K were studied by using a C-80 Calvet microcalorimeter. Empirical formulae for the calculation of the molar enthalpies of dissolution (Δdiss H), relative partial molar enthalpies (Δdiss H partial), and relative apparent molar enthalpies (Δdiss H apparent) were deduced by the experimental results of the dissolution processes of (H2O)2BTO and [Na2(H2O)4]BTO in DMSO. Finally, the corresponding kinetic equations describing the dissolution processes were dα/dt = 10−2.60(1−α)0.61 for the dissolution of (H2O)2BTO in DMSO, and dα/dt = 10−2.69(1−α)0.62 for the dissolution of [Na2(H2O)4]BTO in DMSO.