(714e) Kinetics and Thermodynamics of Energetic Materials: An Investigation to Understand and Control the Coarsening of PETN Single Crystals

A benchmark organic energetic material (OEM) such as Pentaerythritol tetranitrate (PETN)   is used in military and mining applications. The performances of PETN as an explosive strongly depend on the surface properties of the crystallites. Coarsening of particles in a long-term storage degrades the surface properties of PETN powder.  In this work, a comprehensive experimental investigation was conducted to understand and control the coarsening of PETN. To understand the coarsening of PETN, the kinetic and thermodynamic properties of solid-vapor equilibrium of PETN are experimentally obtained by using single crystals of PETN.  To the best of our knowledge, this work is the first demonstration of obtaining these properties from single crystals of an organic compound. The kinetic and thermodynamic properties of PETN obtained from single crystal are consistent with the theoretical values reported in the literature. To further understand the coarsening of PETN, single crystals of PETN are doped systematically with the PETN-homologs, diPEHN and triPEON. The kinetic and thermodynamic properties of the doped crystals shows that the rate of sublimation can be reduced by 35 % by doping PETN-homologs in the single crystals, thereby increase stability of PETN particle against the coarsening. This investigation shows that sublimation properties were reduced because of the change of surface property of the single crystal, which is studied with an Atomic Force Microscope. Distribution of impurities in the single crystal is also investigated in this study that shows impurities are incorporated both in the bulk material and on the surface of crystal.