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Although new-type energetic materials have been investigated extensively, there is a challenge on how to integrate energy density and mechanical properties of energetic materials simultaneously. Herein, a versatile approach was proposed to design energetic materials with high energy density, reactivity, and flexibility based on a bio-inspired strategy. By mimicking the “brick-and-mortar” structure within a natural nacre, the energetic film with alternative layers of polytetrafluoroethylene (PTFE) and boron (B) was successfully fabricated. The nacre-mimetic PTFE/B energetic film exhibited excellent reaction heat (4413.9 J⋅g−1) and bright combustion flame, which may originate from the exothermic reaction mechanism between fluorine (F) and B. Even more remarkably, such PTFE/B energetic film revealed prominent mechanical flexibility reported for the first time. These findings indicate that the nacre-mimetic strategy provides an effective route to engineer energetic materials with high energy density, reactivity, and flexibility.

Recently, an emerging category green of energetic material ammonium dinitramide (ADN) has exhibited promising application in propellants due to its outstanding merits in energy release and environmental friendliness. It can be considered to substitute traditional oxidizer of ammonium perchlorate (AP) in military systems and aerospace. In this paper, a novel spherical energetic composite ADN/copper alginate (CA) with a microporous structure was designed and prepared by the W/O gel emulsion method, and a desirable porous microsphere structure was obtained. Multiple characterization techniques were used to investigate the structure and properties of ADN/CA composites. The results showed that ADN crystals were homogeneously encapsulated in an alginate-gel matrix. Thermal decomposition temperature was reduced to 151.7 °C compared to ADN, while the activation energy of them was reduced from 129.73 kJ/mol (ADN) to 107.50 kJ/mol (ADN/CA-4). In addition, as-prepared samples had lower impact and frictional sensitivity than ADN. The mechanism of sensitivity reduction and decomposition are also discussed. Constant-volume combustion tests show that peak pressure of the ADN/CA-4 achieves 253.4 kPa and pressurization rate of 2750.4 kPa/s. Hence, this has a promising application in improving the combustion performance and safety performance of solid propellants.

As a typical energetic composite, polytetrafluoroethylene (PTFE)/aluminum (Al) has been widely applied in explosives, pyrotechnics, and propellants due to its ultra-high energy density and intense exothermic reaction. In this work, the radial gradient (RG) structure of PTFE/Al cylinders with three different PTFE morphologies (200 nm and 5 μm particles and 5 μm fiber) and content changes are prepared by 3D printing technology. The effect of radial gradient structure on the pressure output of PTFE/Al has been studied. Compared with the morphology change of PTFE, the change of component content in the gradient structure has an obvious effect on the pressure output of the PTFE/Al cylinder. Furthermore, the relationships of the morphology, content of PTFE and the combustion reaction of the PTFE/Al cylinder reveal that the cylinder shows a more complex flame propagation process than others. These results could provide a strategy to improve the combustion and pressure output of PTFE/Al.