(688f) Influence of Organic Acid Coatings On Energetic Nanocomposite Combustion Performance

Aluminum fuel particles, with and without self-assembled monolayers of two different organic acids: perfluoro tetradecanoic acid (PFTD) and perfluoro sebacic acid (PFS) were combined with  molybdenum trioxide (MoO₃) to obtain three different energetic nanocomposites: Al-PFTD/MoO₃, Al-PFS/MoO₃ and Al/MoO₃. Combustion analysis using flame propagation tube and thermoequilibrium tests using DSC/TGA were performed for these nanocomposites. Flame speeds of Al-PFTD/MoO₃ was 86% higher than Al/MoO₃ whereas that of Al-PFS/MoO₃, almost half of Al/MoO₃. Results from the DSC showed that the apparent activation energy of the nanocomposites had an inverse relationship with the flame propagation velocity. This went on to show that the combustion behavior of nanocomposites could be influenced by coating them with organic acids. The Al−PFTD structure is more sterically hindered and exhibits lower bond dissociation energy. This chemistry promotes increased flame speeds. This study shows that surface functionalization can be used as an approach to control the reactivity of Al particles.