Energetic metastable n-Al@PVDF/EMOF composite nanofibers with improved combustion performances

Combustion is a kind of reacting process involves fluid mechanics and chemical reactions at the same time. In the past decades, little attention has been paid to the improvement on the heat and mass transfer rate of EMs, especially for metastable intermixed composites (MICs). In this paper, an Al-based MIC (EF@EMOF) with modified chemical kinetics as well as improved heat and mass transfer rate was prepared by precisely designing the reaction process and introducing energetic metal organic frameworks (EMOF) with high specific surface area as the reactants. The overall reaction process includes the activation of n-Al by eliminating Al₂O₃, decomposition of EMOF producing metal oxide, followed by exothermic reactions between the activated n-Al with metal oxide and PVDF. Results show that obtained MIC has significantly increased heat release (3464 J g⁻¹), burning rate (more than 5 times faster than that of mechanically mixed one), and improved combustion efficiency. Furthermore, it is found that the decomposition of EMOF as well as the etching reaction generates massive gas products on the interface layer which avoid the sintering and form lots of holes. Those holes, in return, provide new channels for the further reaction, thus significantly improving the energy output and chemical reaction kinetics.