Explosion Control of Nanobomb via Modifying Nanocontainer and Adding Detonating Molecule

Abstract

High-energy materials (HEMs), which show the excellent performance for explosion, have been applied for propellants, explosives, and pyrotechnics. Especially for explosives, high detonation velocity and pressure are needed to initiate rapid reaction, while low sensitivity to external stimuli is required. However, low sensitivity inevitably leads to a decrease in detonating power. Therefore, we investigated alternative ways to facilitate bursting of HEM (e.g., nitromethane (NM)), which are particularly confined in the nanocontainer (e.g., carbon nanotube (CNT)) by multi-scale molecular modeling and simulation methods. For the enhancement of performance of nanobomb, physicochemical modification of CNT and introduction of detonating molecule into nanobomb system were considered. For the modifications, chirality variation, nitrogen-doping, and mono-vacancy defect were introduced into CNT. All modifications brought time reduction in bursting of nanobomb while bursting mechanism was similarly kept. Among the modifications, mono-vacancy defect exhibited the most enhancing effect for bursting because chemical reactivity was dramatically increased around the defect sites. This was because the formation of Stone-Wales defect and attachment of the products, which are preceding bursting, were much favorable with mono-vacancy defect than those in other modified CNTs. In addition, the synergistic effects of NM and detonating molecule on bursting of nanobomb were investigated. Candidates of detonating molecules were initially filtered by comparing detonation velocity and pressure derived from Kamlet–Jacobs equations. In bulk mixtures of NM and detonating molecules, HMX or RDX showed superior rapid decomposition rate and supported the acceleration of NM decomposition. Subsequently, nanobombs with HMX or RDX were heated and their decomposition processes were compared with those in pure nanobomb. Upon heating, detonating molecules were decomposed prior to NM and their reaction intermediates contributed to enhanced decomposition of NM, inducing fast burst of nanobomb.