Thermal Decomposition Parameters of PBXN-111 Plastic Bonded Explosive

PBXN-111 is a cast cured underwater explosive containing RDX, ammonium perchlorate, aluminium powder and HTPB binder. In this research, the kinetics and thermodynamic properties of thermal decomposition of this PBX investigated by Kissinger and Flynn-Wall-Ozawa (FWO) methods based on differential scanning calorimetry under non-isothermal condition with heating rate of 5, 10, 15 and 20 °C/min. Results showed that this charge has thermal stability exceed 200°C. As heating rate in thermal analysis increased, decomposition temperature of RDX, as first unstable ingredient in PBX, increased slightly. Activation energy of RDX decomposition reaction in PBXN-111 increased 16% in comparison with pure RDX. Average enthalpy, Gibbs free energy and entropy of thermal activation were 311.34 kJ/mol, 122.57 kJ/mol and -373.69 J/mol.K, respectively. In addition, average amounts of critical temperature for thermal explosion and 500-day cookoff temperature of PBXN-111 are 198.35 °C and 120.95 °C, respectively.