Thermal Research on the Melt⁃cast Explosive of 3-Azido-1,3-dinitroazetidine (ADNAZ)

The systematical thermal behaviors of 3⁃azido⁃1,3⁃dinitroazetidine (ADNAZ) was investigated in this research and compared with those of 1,3,3-trinitroazetidine (TNAZ). The results showed that ADNAZ has a low melting temperature at 78 °C. The final mass loss of ADNAZ under atmospheric pressure is 88.2%. Compared to TNAZ, the replacement of gem-dinitro group with gemazidonitro group makes greatly reduce vapor pressure, melting point as well as the thermal decomposition temperature. The in-situ FTIR spectroscopy of ADNAZ proved the strength of nitro group decreases faster than that of azide group, and a carbonyl group (C=O) was formed at the quaternary carbon center on the azetidine skeleton during heating process. TG/DSC–FTIR–MS quadruple technology was applied, finding small molecular fragments from ADNAZ’s thermolysis includes H2 (m/z = 2), H2O (m/z = 18), CN (m/z = 26), HCN (m/z = 27), N2 (m/z = 28), NO (m/z = 30), C2H2O (m/z = 42), HN3 (m/z = 43), CO2 (m/z = 44), and NO2 (m/z = 46). A detailed decomposition mechanism was proposed based on the experimental results.