Thermal decomposition of HNIW by TG-MS

Thermal decomposition of two kinds of hexanitrohexaazaisowurtzitane(HNIW) particles (230 μm, 40 μm) were studied by TG-MS. The isothermal decomposition residues of HNIW with larger particle (230 μm) were researched by FTIR spectra and elemental analysis. The results in the non-isothermal decomposition show that there are two steps for HNIW with larger particle and only one step for HNIW with small particle, the main products are NO, N₂O, CO₂, a small amount of NO₂ and C₂N₂H₂. Isothermal decomposition products of HNIW with large particle at 204°C are same as in the first step of the non-isothermal decomposition. The average molecular formulas of the residues at 204°C for 10 minutes and 60 minutes are C₃H_4.5N_5.5O, C₂H₄N₂O. The total of isothermal decomposition reaction at 204°C is C₆H₆N₁₂O₁₂ =6NO + N₂O +2CO₂ +2HCN + C₂H₄N₂O.