Synthesis and reactivity of aluminized fluorinated acrylic (AlFA) nanocomposites

Fluorinated materials, such as poly(tetrafluoroethylene) and its co-polymers, have attracted significant interest throughout the energetic materials community due to their strong reactivity with aluminum powders. Herein, we report the synthesis of a novel composite material produced through the in situ polymerization of 1H,1H,2H,2H-perfluorodecyl methacrylate in the presence of aluminum nanoparticles which have been previously functionalized with phosphoric acid 2-hydroxyethyl methacrylate ester to promote chemical integration into the polymer matrix. These materials, which we have termed aluminized fluorinated acrylic (AlFA) composites, have been prepared with particle contents ranging from 10% to 70% by weight. At particle loadings of 60 wt.% or less, the AlFA composites exhibited thermoplastic behavior and were able to be processed by melt extrusion. The AlFA-50 composite demonstrated the highest reactivity (most intense flame and shortest time to achieve complete deflagration) during air combustion experiments performed on consolidated pellets. Chemical analysis of the char indicated the presence of AlF₃, in addition to Al₂O₃, Al₄C₃ and residual Al, indicating that reaction with the fluoropolymer matrix does result in fluorination of the aluminum during the deflagration, however, this mechanism competes kinetically with air oxidation and carbide formation at higher particle loadings.