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

Abstract

AbstractThermal 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.