Comparison analysis of combustion performance and mechanism of Al/PVDF and Al/PTFE

• The effects of PVDF and PTFE on combustion mechanism of Al powder were compared. • Al/PVDF has shorter ignition delay than Al/PTFE at the same fluoropolymer content. • Al/PVDF system exhibits greater combustion heat than Al/PTFE at the same Al content. • The Al-F reaction is influenced by the specific surface area of the Al particle. • The penetrating H atoms enable internal Al atoms to break through the oxide layer. Although both aluminum/polyvinylidene fluoride (Al/PVDF) and aluminum/polytetrafluoroethylene (Al/PTFE) systems exhibit excellent combustion performance, the study on comparing their combustion behaviors and the underlying mechanisms responsible for their differences are still relatively limited. Therefore, the advantages and disadvantages of the Al/PVDF and Al/PTFE systems were compared through ignition experiments and molecular dynamics simulations. The Al/PTFE system exhibits higher combustion intensity, and the characteristic is attributed to the higher fluorine (F) content in PTFE, which triggers more Al-F reactions. In contrast, the Al/PVDF system exhibits a lower ignition delay time and higher combustion heat, which is attributed to the relatively lower initial decomposition temperature, the higher hydrogen (H) content, and the higher combustion heat in PVDF. Compared to oxygen (O) atoms, H atoms can penetrate the oxide film on the surface of Al particles more rapidly and react with the inner Al atoms, thereby reducing the temperature required for Al atoms to break through the oxide film and participate in reactions.