Pyrometry in the reaction zone of PETN- and RDX-based polymer bound explosives

Initial hot spot temperatures and temperature evolutions for PETN and RDX-based polymer-bound explosives under shock compression by laser-driven flyer plates at speeds from 1.5 – 4.5 km/s are presented. The PBX formulations studied here consist of either pentaerythritol tetranitrate (PETN) or 1,3,5-trinitro-1,3,5-triazinane (RDX) in a 80/20 wt.% mixture with a silicone elastomer binder. The temperature dynamics and are modeled well by a single exponential cooling term for all impact velocities in both PETN and RDX, while RDX at low velocities additionally requires a single Gaussian heating term to capture its slow energy release. When shocked to near the characteristic von Neumann spike pressure cooling rates rapidly increase and the heating term is no longer required in RDX due to heat generation being out competed by heat loss and adiabatic expansion of product gasses.