Nitrogen-Rich Heterocycles as Reactivity Retardants in Shocked Insensitive Explosives

Abstract

We report the first quantum-based multiscale simulations to study the reactivity of shocked perfect crystals of the insensitive energetic material triaminotrinitrobenzene (TATB). Tracking chemical transformations of TATB experiencing overdriven shock speeds of 9 km/s for up to 0.43 ns and 10 km/s for up to 0.2 ns reveal high concentrations of nitrogen-rich heterocyclic clusters. Further reactivity of TATB toward the final decomposition products of fluid N(2) and solid carbon is inhibited due to the formation of these heterocycles. Our results thus suggest a new mechanism for carbon-rich explosive materials that precedes the slow diffusion-limited process of forming the bulk solid from carbon clusters and provide fundamental insight at the atomistic level into the long reaction zone of shocked TATB.

Improved reactive flow modeling of the LX-17 double shock experiments

“…The current Cheetah models of LX-17 detonation includes a chemical kinetic rate model for the decomposition of the explosive as the detonation waves passes through, and keeps all product species, including the carbon condensate as well as the gas species, in chemical equilibrium. The carbon condensate is taken to be a solid mixture of carbon, nitrogen, and oxygen, roughly based on the nitrogen-rich heterocycle clusters of Manaa et al [21]. All reactions in the product species "freeze-out" below a pressure of around 10 GPa.…”

Multistage reaction pathways in detonating RDX

“…The length of this reaction zone, as well the associated reaction time, is a fundamental quality that dictates various important properties of HEs such as sensitivity. 6 The reaction time in turn is essentially determined by what intermediated reaction products are produced, i.e., the reaction pathways. [6][7][8] It has been suggested that the slow formation time of certain products play an essential role in determining the reaction time of some HEs.…”

“…6 The reaction time in turn is essentially determined by what intermediated reaction products are produced, i.e., the reaction pathways. [6][7][8] It has been suggested that the slow formation time of certain products play an essential role in determining the reaction time of some HEs. 6,9,10 However, the molecular process that determine the reaction time are largely unknown.…”

“…[6][7][8] It has been suggested that the slow formation time of certain products play an essential role in determining the reaction time of some HEs. 6,9,10 However, the molecular process that determine the reaction time are largely unknown. 6 RDX (C 3 H 6 N 6 O 6 ) or Cyclotrimethylenetrinitramine is one of the most powerful HEs, yet with good stability under ambient conditions.…”

Self-consistent tight-binding molecular dynamics simulations of shock-induced reactions in hydrocarbons

“…The reaction pathways accessed by shock compression are difficult to track experimentally owing to the inherently short time scales and the rapid onset of optical opacity. Nevertheless, the initial steps in shock-induced chemistry are important to the understanding of the performance of energetic materials [3] and routes toward the synthesis of new materials.…”