Microscopic Chemical Reaction Mechanism and Kinetic Model of Al/PTFE

Area of Science:

• Materials Science
• Chemical Engineering
• Computational Chemistry

Background:

• Aluminum/Polytetrafluoroethylene (Al/PTFE) is a reactive material system.
• Understanding its microscopic reaction mechanisms is crucial for controlling energy release.
• Oxide layer properties can influence the reactivity of energetic materials.

Purpose of the Study:

• To investigate the microscopic reaction mechanism and kinetic model of Al/PTFE.
• To analyze the effect of oxide layer thickness on the thermochemical behavior of Al/PTFE.
• To determine the kinetic parameters (activation energy and pre-exponential factor) of the Al/PTFE reaction.

Main Methods:

• Simulations using a reactive force field (ReaxFF) for Al/PTFE interface models with varying oxide layer thicknesses (0 Å, 5 Å, 10 Å).
• Simultaneous thermal analysis (TG-DSC) to study thermochemical behavior at different heating rates.
• Kinetic analysis using the shrinkage volume (R3) and three-dimensional diffusion (D3) models.

Main Results:

• Oxide layer thickness significantly affects the Al/PTFE reaction process.
• A 5 Å oxide layer allows reactant diffusion and core reactions; a 10 Å layer shows interface reactions and oxide layer movement.
• The study obtained the mechanism function and determined activation energy (258.8 kJ/mol) and pre-exponential factor (2.495 × 10^15 min^-1).

Conclusions:

• The oxide layer's thickness is a critical factor in Al/PTFE reactivity.
• The findings provide insights into the microscopic reaction pathways and macroscopic energy release of Al/PTFE.
• This research offers theoretical significance for understanding and quantifying the behavior of Al/PTFE reactive materials.