Preparation of high-energy oxidant HMX/PTFE composite particles with enhanced safety and their impact on the energy release of TiH2

In recent years, metal hydrides have been extensively utilized in solid propellants due to their high hydrogen storage density, elevated combustion calorific value, and substantial gas production. However, optimizing and improving the energy release performance of metal hydrides remains challenging. This study prepared high-energy oxidizer 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane/polytetrafluoroethylene (HMX/PTFE) composite particles with enhanced safety using the emulsion-solvent evaporation method. The effect of PTFE content on the morphology of composite particles was analyzed, and their chemical structure, thermal decomposition characteristics, mechanical sensitivity, and oxidation-combustion behavior on metal hydrides were characterized and tested. Experimental results indicate that with 10 % PTFE content, the HMX/PTFE composite particles exhibit a dense surface, regular morphology, and uniform distribution of PTFE and binder around HMX. The crystal structure of HMX in the composite particles retains the β-type form, preserving its favorable application potential. Compared to raw HMX, the composite particles exhibited increased activation energy and critical temperature of thermal explosion by 40.05 kJ·mol⁻¹ and 17.26 K, respectively, and enhanced critical impact and friction values by 4.5 J and 40 N, respectively, demonstrating superior thermal stability and mechanical safety. Combustion experiments demonstrate that HMX/PTFE composite particles serve as an effective high-energy oxidant for TiH₂, providing more stable combustion and energy release compared to raw HMX. The oxidation-combustion mechanism of raw HMX and HMX/PTFE composite particles with TiH₂ is analyzed, offering a potential approach to enhance the combustion stability of novel propellants containing metal hydrides.