Mechanism of the Improvement of the Energy of Host–Guest Explosives by Incorporation of Small Guest Molecules: HNO3 and H2 O2 Promoted C–N Bond Cleavage of the Ring of ICM-102

Abstract

Host–guest materials exhibit great potential applications as an insensitive high-energy-density explosive and low characteristic signal solid propellant. To investigate the mechanism of the improvement of the energy of host–guest explosives by guest molecules, ReaxFF-lg reactive molecular dynamics simulations were performed to calculate the thermal decomposition reactions of the host–guest explosives systems ICM-102/HNO3, ICM-102/H2O2, and pure ICM-102 under different constant high temperatures and different heating rates. Incorporation of guest molecules significantly increased the energy level of the host–guest system. However, the initial reaction path of the ICM-102 molecule was not changed by the guest molecules. The guest molecules did not initially participate in the host molecule reaction. After a period of time, the H2O2 and HNO3 guest molecules promoted cleavage of the C–N bond of the ICM-102 ring. Stronger oxidation and higher oxygen content resulted in the guest molecules more obviously accelerating destruction of the ICM-102 ring structure. The guest molecules accelerated the initial endothermic reaction of ICM-102, but they played a more important role in the intermediate exothermic reaction stage: incorporation of guest molecules (HNO3 and H2O2) greatly improved the heat release and exothermic reaction rate. Although the energies of the host–guest systems were clearly improved by incorporation of guest molecules, the guest molecules had little effect on the thermal stabilities of the systems.

Molecular dynamic insight into octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and the nano-HMX decomposition mechanism

“…Each possible atomic pair was assigned a different bond order cutoff value to properly identify chemical species (standard values in ReaxFF C/H/O/N high-energy simulations). 41 The original C/H/O/N ReaxFF has been used for several nitro explosives [41][42][43][44] and nanoparticles 45,46 and it correctly provided the 30-70 Å radius of nano-HMX, which was constructed from the original unit cell that was experimentally determined at room temperature. 47 The initial state of the system is shown in Fig.…”

Effects of Different Guests on Pyrolysis Mechanism of Α-CL-20/Guest at High Temperatures by Reactive Molecular Dynamics Simulations at High Temperatures

“…The results would provide fundamental to summarize the properties of guest for α-CL-20/guest with structural stability. Meanwhile, in order to deeply analyze the role of hydrogen-guest small molecules in the host-guest system, the initial decomposition reactions of ICM-102/HNO3 [10], ICM-102/H2O2 [11] with pure ICM-102 and CL-20/H2O2 [12] at several high temperatures were systematically studied by molecular dynamics simulations. It was found that the addition of guest small molecules significantly increased the energy levels of ICM-102 and CL-20, but had little effect on the thermal stability of the host-guest system.…”

“…ReaxFF-MD [10,12,13] can conduct in-depth and detailed research on the pyrolysis mechanism of host-guest explosive at the microscopic scale, and find that how guest molecules participate in the pyrolysis reaction of the guest is an important factor affecting the energy release and detonation performance of the host explosives. In this study, we investigated the initial reaction of CL-20/CO2, CL-20/N2O, CL-20/NH2OH and compared with the pure CL-20/H2O at various temperatures (2500, 2750, 3000, 3250, and 3500K) by Re-axFF-lg reactive MD simulations (MD/ReaxFF-lg).…”