ReaxFF molecular dynamics simulations on thermal decomposition of RDX-based CMDB propellants

ReaxFF molecular dynamics (ReaxFF MD) simulations were performed to study the thermal decomposition property of cyclotrimethylenetrinitramine (RDX)-based composite modified double base (CMDB) propellants. The intermediate products and final products of the decomposition of RDX-based CMDB propellants at 2000 K, 2500 K, and 3000 K are obtained. The simulation results show that the decomposition of RDX and RDX/HTPB/Al is primary triggered by N-NO₂ rupture, and then, the intermedia products undergo a series of complex interactions to form final products. The final products of RDX/HTPB/Al are H₂ and N₂, while the final products of pure RDX are H₂, N₂, and H₂O. In addition, the abundance of the main intermediate products generated by RDX/HTPB/Al is lower than that of RDX, in that the reaction between intermediate products is more complex for RDX/HTPB/Al. Moreover, the decomposition rate of RDX/HTPB/Al increases with the increasing temperature.