Comparison study of the ignition and combustion characteristics of directly-written Al/PVDF, Al/Viton and Al/THV composites

摘要

The aluminum-fluorine reaction is attracting growing interest due to its higher density over aluminum oxygen. Fluorine rich polymers are particularly interesting for their applications as an energetic binder in advanced additive manufacturing of energetic materials. In this paper, three soluble polymers of PVDF (59 wt% F), Viton (66 wt% F) and THV (73 wt% F) are incorporated with aluminum nanoparticles (Al NPs) and prepared as free-standing films using solvent-based direct writing. The three composite films are compared for their mechanical properties as well as the ignition and combustion performance. Tensile stress was found to order as Al/PVDF Al/THV Al/Viton while the elasticity of Al/Viton is much higher than the other two. The burn rate of different composite films increases with Al content, while the flame temperature peaks slightly fuel-rich. The Al/PVDF had the highest burn rate, however, the flame temperature ordered as AI/THV (similar to 2500 K) Al/Viton (similar to 2000 K) Al/PVDF (similar to 1500K), consistent with fluorine content. With higher fluorine and lower hydrogen content, THV releases more CFx gas than HF, which generates higher temperature. However, HF which is predominantly produced from PVDF has the lowest ignition by far and may be responsible for its high flame speed. (C) 2018 Published by Elsevier Inc. on behalf of The Combustion Institute.