Study on the thermal decomposition and combustion of DAP-4 affected by copper(II) fluoride

Molecular perovskite energetic material (H₂dabco)[NH₄(ClO₄)₃] (DAP-4) has attracted significant attention. However, its high thermal decomposition temperature hinders its application in propellants. To reduce its reaction energy barrier and modulate its decomposition and combustion performance, the catalytic effect of copper fluoride (CuF₂) on the thermal decomposition and combustion behavior of DAP-4 was systematically investigated in this work. DAP-4/CuF₂ composites with different CuF₂ contents (1 wt%, 3 wt%, and 5 wt%) were prepared by a mechanical mixing method. Their morphology, thermal behavior, reaction products and combustion mechanism were comprehensively characterized by SEM, XRD, DSC, TG, high-speed combustion photography, XPS and MS. The results indicated that the CuF₂ significantly reduced the thermal decomposition temperature of DAP-4 with a maximum decrease of 35.2 °C and the apparent activation energy decreased markedly, dropping from 370.40 kJ/mol for pure DAP-4 to approximately 155.82 kJ/mol for the DAP-4/5 wt%CuF₂. Combustion experiments revealed that both the combustion pressure and pressurization rate were enhanced. A possibly reaction mechanism of energy release of DAP-4 with CuF₂ was proposed that CuF₂ accelerated the initial decomposition of DAP-4 through proton transfer reactions between ClO₄⁻/F⁻ and NH₄⁺, leading to enhancing the reaction kinetics. This study provided a new pathway for the design and fabrication of DAP-4-based energetic materials in solid propellants.