Thermal decomposition mechanism and energy release law of polynitrogen compound 4,4′-azobis (1,2,4-triazole) and its composite system

Abstract

4,4′-Azo-1,2,4-triazole (ATRZ) is a polynitrogen compound with broad application prospects. In this study, the first principles method was employed to analyse the thermal decomposition process and mechanism of ATRZ and its composite system at high temperatures. The decomposition process of ATRZ includes two stages: gas production and molecular agglomeration. The primary decomposition products are nitrogen and CN clusters, which contain unreleased energy. To examine the promoting effect of additional oxidants on ATRZ energy release, we added 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and ammonium perchlorate (AP) as oxidants. The findings demonstrate that the addition of CL-20 and AP can collapse the CN clusters formed by ATRZ decomposition, convert C and N into small molecular products like CO2 and N2, and promote the complete energy release of ATRZ. The NO2 in CL-20 can oxidise C2H2N3, forming C2H2N, small fragments of HCN and CN clusters formed by the combination of various CN species, and eventually small oxygen-containing molecules such as CO2. AP undergoes thermal decomposition, forming OH, which subsequently oxidises other CN substances to form oxygen-containing small-molecule products like CO2. Moreover, some of the produced NO2 participates in the further oxidation of CN. The thermal decomposition kinetics and mechanism of ATRZ and its composites were studied by TG-DSC, TG-FTIR and PY-GCMS. A comprehensive understanding of the reaction mechanism and energy release law significantly promotes the application and synthesis of novel ATRZ-based nitrogen-rich energetic materials.