Enhanced shockwave-absorption ability of the molecular disorder rooting for the reactivity elevation of energetic materials

Abstract

It is universally believed that the molecular disorder possesses a high reactivity compared to the molecular order and can start the ignition of shocked energetic materials (EMs) from defects, interfaces, and surfaces. However, the origin of this high reactivity is still not fully understood. To this end, this study performs a series of simulations of reactive molecular dynamics on a solid model and a liquid model of 1,3,5-trinitro-1,3,5-triazinane (RDX), which are the representatives of ordered and disordered energetic molecules with ReaxFF potentials, respectively. A total of five heating conditions and three shock conditions are considered. The high reactivity of the molecular disorder in liquid RDX is remarkably discriminated under shock, with the discrimination degree depending on shock strength, followed by adiabatic heating. This high reactivity is attributed to the increase in internal energy induced by stronger shock, which is originated from a high shockwave-absorption ability of the liquid RDX with amorphous structures compared to the solid RDX with ordered structures. Therefore, the high shockwave-absorption ability is just the root of the high reactivity of molecular disorder in defected EMs and usually starts the ignition. Thereby, for the first time, the high reactivity of molecular disorder in shocked EMs can be well understood through its high shockwave-absorption ability.