Rational Design of Al@PVDF@HMX Composite Energetic Material Exhibits Ultra-high Heat of Explosion

Enhancing the combustion efficiency of aluminum (Al) is a crucial research direction for solid propellants. Constructing an efficient fuel-oxidizer interaction environment through interfacial regulation is an effective approach. In this work, a synergistic strategy integrating polyvinylidene fluoride (PVDF)-mediated interface regulation with core-shell structuring was adopted to fabricate a dual-layer core-shell Al@PVDF@HMX composite energetic materials (EMs). This composite exhibits an ultra-high heat of explosion (8416.8 J·g⁻¹), which is over 52.8% higher than that of the Al+HMX physical mixture. Explosion residue measurements show that the primary combustion products were AlN and Al₂O₃, and no large Al agglomerations were detected, meaning that the inhibition of Al particle agglomeration by the dual-layer core-shell structure and the shell-breaking combustion effect induced by PVDF should be the key factors for the heat of explosion enhancement. Simultaneously, it was demonstrated that the composite is superior safety to HMX, as its impact sensitivity (8%) and friction sensitivity (36%) are decreased by 91% and 64%, respectively. This work indicates that the dual-layer core-shell structured Al@PVDF@HMX can synergistically improve the reaction between Al and HMX, providing a new approach to improve the energy efficiency and safety of EMs.