(189ce) Reactive Molecular Dynamics Simulation of Disintegration of Cross-Linked Epoxy-Resin Polymers upon Atomic Oxygen Bombardment

Ultraviolent radiation from the sun results in dissociation of molecular oxygen into atomic oxygen (AO) which is abundant in lower earth orbit. Re-entry vehicles entering earth atmosphere experience significant impact by these atomic oxygens, which cause both physical and chemical damage on the surface of the vehicle. The vehicle surface is normally made of polymer composites and evaluating these composites for AO impact requires an extensive experimental setup to simulate low earth orbit (LEO) conditions and is therefore expensive. Alternative to experiments, molecular dynamics is a powerful tool to examine the behavior of polymers with potential aerospace applications under harsh environmental conditions. In this study, we investigate the AO impact on various thermoset polymers using ReaxFF^1,2 reactive force field simulation. These cross-linked polymers are generated using our recently introduced accelerated cross-link methodology in ReaxFF. Since ReaxFF can simulate chemical reactions on-the-fly, both physical and chemical damages on polymers can be captured using ReaxFF simulations, which in turn, can be used in designing next generation polymer composites for aerospace application.

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