Reactive Molecular Dynamics Simulations of the Atomic Oxygen Impact on Epoxies with Different Chemistries
C Ashraf and A Vashisth and CE Bakis and ACT van Duin, JOURNAL OF PHYSICAL CHEMISTRY C, 123, 15145-15156 (2019).
Atomic oxygen (AO) is one of the most abundant species present in the lower earth orbit and is responsible for the aggressive degradation of polymers used in spacecraft structures. In this investigation, we use ReaxFF reactive force field molecular dynamics simulations to evaluate the disintegration of several different thermosetting epoxy polymers subjected to hypervelocity AO impact. Our simulations indicate that epoxy with aromatic curative displays higher resistance to the AO impact because of its stable benzene functionality. Decreased cross-linking density and increased simulation temperature both lead to faster disintegration of the polymer. Our simulation results indicate that ReaxFF force field simulations can be a useful tool to evaluate the response of various thermosetting epoxies to AO impact and identify promising candidate materials for spacecraft applications.
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