Efficient preparation of core–shell Al@PFHP@fluoropolymer energetic composites combining corrosion resistance and high energy release properties

Abstract

The study employed a two-step synthesis method to prepare Al@PFHP@fluoropolymer energetic composites with a core–shell structure. PFHP and HF acid are used for surface etching and modification of raw Al powder. PFHP bonds to the surface of Al powder, with redundant C-F providing hydrogen bonding sites, driving dissolved PVDF and P(VDF-HFP) polymer chains in the liquid phase to migrate, nucleate, and grow on the surface of the Al powder, and consequently the formation of a continuous shell layer through hydrogen-bonding self-assembly. The Al powder coated with fluoropolymer exhibited strong hydrophobic and corrosion-resistant properties, ensuring long-term storage and environmental adaptability. Compared to mechanically mixed Al@PFHP/fluoropolymer, the Al@PFHP@fluoropolymer composites show significant improvements in thermal reactivity, ignition, and combustion performance. The close integration of fluoropolymer and Al shortens the mass and heat transfer distances during the reaction process. Additionally, the low-boiling-point AlF3 does not hinder diffusion process in the combustion zone, which is conducive to the alleviation of the reaction sintering phenomenon and the rapid and concentrated release of energy. Therefore, through the dual strategy of using fluorine-containing oxidizers and structure optimization, efficient reaction of Al@PFHP@fluoropolymer is achieved, also promoting efficient combustion of Al powder. The synthesis process of this energetic composite is simple yet yields exceptionally high performance, enabling large-scale production and application potential in military ammunition and rocket propulsion systems.