PTFE–Al2O3 reactive interaction at high heating rates

Differential scanning calorimetry and a high-speed temperature scanner were used to characterize dynamic features of the reaction between polytetrafluoroethylene (PTFE) and Al2O3 under heating rates ranging between 20 and 780 °C min−1. Exothermic reaction behavior between PTFE and Al2O3 was observed at heating rates of 150 °C min−1 and higher. Thermodynamic calculations predicted an adiabatic temperature of 1,425 K for the PTFE/Al2O3 stoichiometric ratio. At lower heating rates, endothermic decomposition of PTFE dominated the interaction, where PTFE decomposes into gaseous products that escape the system without interacting with alumina. The enthalpy of the PTFE–Al2O3 exothermic reaction was estimated to be −103 kJ mol−1 with activation energy of 21 kJ mol−1. This study shows that, for energetic formulation of Al–PTFE, the Al2O3 layer on the aluminum particles can exothermically react with PTFE, producing AlF3 and carbon monoxide.