[Study on thermal decomposition of HMX energetic materials by in-situ FTIR spectroscopy]

In-situ FTIR spectroscopy is a rising and dynamic technique. This technique, which combines the advantages of investigation in-situ and accurate structure analysis by FTIR spectsoscopy, can detect the chemical change of materials in different temperature with real time and obtain the relationship between micromechanism of materials and temperature. In the present paper, thermal decomposition of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) heated with 5 degrees C x min(-1) was investigated by in-situ FTIR spectroscopy. The results demonstrate that C-N bond cleavage and N-N bond cleavage of HMX occur at 205 degrees C. With increasing temperature, the rupture rate of C-N bond is faster than that of N-N bond, which verifies that the cleavage of C-N bond is the dominant rupture form. The augment in tension of HMX cyclic confirms that intramolecular cyclization occurs in breakage of HMX. Eight kinds of gaseous products such as CO2, N2O, CO, NO, HCHO, HONO, NO2 and HCN were determined. According to the structure change in condensed state and gaseous products, the decomposition mechanism was deduced that HCHO, N2O, HONO and HCN were released due to the cleavage of C-N bond, and NO2 was released due to the cleavage of N-N bond.