Thermal Decomposition of Petn/Nano-Al and Petn/Nano-Alh3 by Reaxff Simulation

Abstract

Reactive molecular dynamics simulations with ReaxFF-lg force field parameters were performed on the thermal decompositions of pentaerythritol tetranitrate (PETN), PETN/nano-Al, PETN/nano-AlH3. The unpassivated AlH3 with smaller particle size promote the PETN decomposition greatly. The adsorption of PETN on AlH3 is so strong that PETN deforms seriously and its nitro N-O bond ruptures firstly. There are no energy barriers in the thermal decompositions of PETN when AlH3 is added, while the systems release 502.09 ~ 488.18 kcal·mol−1 more energies than pure PETN. The surface passivation of AlH3 greatly reduces the thermal release of PETN/AlH3. The additives increase H2O productions, but decrease N2 and CO2 productions. The total numbers of main gaseous products (H2O, N2 and CO2) increase when AlH3 or passivated AlH3 are added. The prolonged time span of gas producing and energy release are agreeable with the experimental facts.

Keywords: Reactive molecular dynamics simulations, Pentaerythritol tetranitrate (PETN), Aluminum, Aluminum hydride, Composites of energetic materials, nano-particle