Thermal and Pyrolysis Research on the Super Heat-Resistant Energetic Structure of Bis[1,2,4]triazolo[1,5-b;5’,1’-f][1,2,4,5]tetrazine-2,7-diamine

Thermal stability of energetic materials determines their applicability under high temperature conditions, while few energetic materials could achieve thermal decomposition peak temperatures above 450°C. Based on a novel nitrogen-rich fused heterocyclic skeleton, bis[1,2,4]triazolo[1,5-b;5’,1’-f][1,2,4,5]tetrazine-2,7-diamine (DATC) demonstrated super thermal stability compared to traditional heat-resistant energetic structures. Herein, a detailed exploration was conducted on the thermal decomposition behaviors and heat-resistant properties of DATC through conventional thermal decomposition methods combined with tandem techniques, including in-situ FTIR and DSC/TG-FTIR-MS quadruple analysis. The experimental results were compared with those of 2,2’,4,4’,6,6’-hexanitrostilbene (HNS) and 3,5-dinitro-N,N’-bis(2,4,6-trinitrophenyl)pyridine-2,6-diamine (PYX), two famous heat-resistant energetic materials widely applied. The major decomposition exothermic peak temperature of DATC was found around 479°C under the heating rate of 10°C ⋅min⁻¹ while corresponding onset decomposition temperature was around 430°C. The decomposition process of DATC was most likely initiated from the decompositions of amino groups and further destructed the molecular skeleton, which lead to a series of fragments of NH₂ (m/z=16), CN (m/z=26), HCN (m/z=27), N₂ (m/z=28), N₂H₂ (m/z=30), CN₂H₂ (m/z=42), HN₃ (m/z=43), and C₂N₂ (m/z=52). Obviously, the amino groups do not contribute much to DATC's heat-resistant performances, while the condensation of triazole moieties result in great thermal stability of the fused nitrogen-rich skeleton. Both the decomposition process and mechanism were much different from those of HNS and PYX.