Search

A new nitrogen-rich energetic material, hydrazinium 3,5-dinitroamino-1,2,4-triazole (HDNAT), was synthesized. Thermal behavior and non-isothermal decomposition kinetics of HDNAT were studied with DSC and TG/DTG methods. The non-isothermal decomposition kinetic equation is $$\frac{{{\text{d}}\alpha }}{{{\text{d}}T}} = \frac{{10^{19.37} }}{\beta }6(1 - \alpha )^{{{2 \mathord{\left/ {\vphantom {2 3}} \right. \kern-0pt} 3}}} [1 - (1 - \alpha )^{{{1 \mathord{\left/ {\vphantom {1 3}} \right. \kern-0pt} 3}}} ]^{{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-0pt} 2}}} \exp ( - 188.6 \times 10^{3} /RT)$$ . Self-accelerating decomposition temperature and critical temperature of thermal explosion of HDNAT are 168.1 and 178.1 °C, respectively. Specific heat capacity of HDNAT was determined with a micro-DSC method and the molar heat capacity is 258.96 J mol K at 298.15 K. Adiabatic time-to-explosion of HDNAT is about 100 s. The impact sensitivity, friction sensitivity, detonation velocity and detonation pressure of HDNAT are >13.1 J, 84 %, 9.0 km s and 36.0 GPa, respectively. [ABSTRACT FROM AUTHOR]

The high nitrogen compound 3,6-bis(1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine and the high energy density material hexanitrohexaazaisowurtzitane (HNIW), were used as substitute of hexogen (RDX) in the composite modified double base (CMDB) propellant formulations, the propellant samples were prepared, the thermal behaviors, nonisothermal reaction kinetics, and thermal safety were carried out, and the eight important parameters were calculated and obtained as the self-accelerating decomposition temperature ( T), thermal ignition temperature ( T), critical temperatures of thermal explosion ( T), critical temperature of hot-spot initiation ( T), characteristic drop height of impact sensitivity ( H), critical thermal explosion ambient temperature ( T), safety degree ( S), and thermal explosion probability ( P). It shows that the content of HNIW has a large effect on the decomposition reaction mechanism of the CMDB propellant, when the content of HNIW is 10 %, the decomposition reaction are controlled by the random nucleation and subsequent growth ( n = l), and the reaction mechanism obeys Mampel law; but when the content of HNIW is 20 %, the decomposition reaction are controlled by the chemical reaction ( n = 1/4). The mechanism can not be changed by the catalysts, and they just make the apparent activation energy change slightly. For the sample, from BC01 to BC04, the values of T and T making an upward tendency, show the resistivity to heat: BC04 > BC03 > BC02 > BC01; the values of T and S, BC01 are the maximum and BC02 are the minimum, show the heat sensitivity: BC01 > BC03 > BC04 > BC02. For the same radius, the thermal safety of the sphere sample is greater than that of the infinite cylinder one. [ABSTRACT FROM AUTHOR]

Nitrosyl cation (NO+) generating reaction HONO + H+ → NO+ + H2O has been theoretically investigated by B3LYP and high-electron-correlation QCISD methods with 6-31G (d,p) basis set. The solvent effects on the geometries, reaction path properties, energies, thermodynamic, and kinetic characters in four solvents (benzene, tetrahydrofuran, acetonitrile, and water) have been calculated using self-consistent reaction field (SCRF) approach with the polarizable continuum model (PCM). The results show that the activation energy barriers and the relative energies of the products are decreased with increase of the polarities of the solvents, and the reaction is favored in polar solvents thermodynamically and kinetically. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011 [ABSTRACT FROM AUTHOR]

Abstract: The composite modified double base (CMDB) propellants (nos. RB0601 and RB0602) containing 3,6-bis (1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz) without and with the ballistic modifier were prepared and their thermal behaviors, nonisothermal decomposition reaction kinetics, thermal safety and burning rates were investigated. The results show that there are three mass-loss stages in TG curve and two exothermic peaks in DSC curve for the BTATz-CMDB propellant. The first two mass-loss stages occur in succession and the temperature ranges are near apart, and the decomposition peaks of the two stages overlap each other, inducing only one visible exothermic peak appear in DSC curve during 350–550K. The reaction mechanisms of the main exothermal decomposition processes of RB0601 and RB0602 are all classified as chemical reaction, the mechanism functions are f(α)=(1− α)2, and the kinetic equations are and . The thermal safety evaluation on the BTATz-CMDB propellants was obtained. With the substitution of 26% RDX by BTATz and with the help of the ballistic modifier in the CMDB propellant formulation, the burning rate can be improved by 89.0% at 8MPa and 47.1% at 22MPa, the pressure exponent can be reduced to 0.353 at 14–20MPa. [Copyright &y& Elsevier]