Decomposition mechanisms of insensitive 2D energetic polymer TAGP using ReaxFF molecular dynamics simulation combined with Pyro-GC/MS experiments

The two-dimensional energetic polymer triaminoguanidine–glyoxal (TAGP) has been used in modification of EMs to formation of various hybrid materials for higher density and better stability due to its excellent capability to desensitize high energetic crystals without any energy loss. In this paper, theoretical calculations based on ReaxFF-MD were performed to demonstrate the thermal decomposition mechanisms of TAGP, which has been further proved by experimental results from Pyro-GC/MS analysis. The results show that there are three dominant pathways for the initial decomposition of TAGP, i.e., the breakage of C-N bond with production of C₂H₃ON₂ (most likely to happen), the scission of N-N bond with release of C₂H₂ON, and the rupture of N-N bond accompanied with the proton transfer to release C₂H₃ON. Therefore, the C₂H₃ON₂, C₂H₂ON and C₂H₃ON are the dominant initial decomposition products of TAGP, which may gradually transform to the final gaseous products. The experimental results confirmed the presences of these substances. The major final gaseous products of TAGP include N₂, H₂, H₂O, NH₃, NH₄, NH₂, N₂H, N₂H₂, HCN and CO₂, among which the concentration of N₂ is the highest, relatively higher than H₂, H₂O and NH₃. Besides, the initial decomposition rate of TAGP largely depends on its MW. The activation energies for formation of C₂H₃ON₂ and N₂ under isothermal conditions has been obtained to further illustrate the effect of MW on the decomposition rate.