Atomic Oxygen-Induced Surface Erosion Behavior and Mechanical Degradation of Polyether Ether Ketone via Reactive Molecular Dynamics Simulations

GX Li and JJ Wang and B Niu and Y Xing and XB Liang and YY Zhang and DH Long, JOURNAL OF PHYSICAL CHEMISTRY B, 127, 5509-5520 (2023).

DOI: 10.1021/acs.jpcb.3c02074

Atomic oxygen (AO) collision is one of the most seriousthreatsto polymeric materials exposed to the space environment, yet understandingthe structural changes and degradation of materials caused by AO impactremains a tremendous issue. Herein, we systematically evaluate theerosion collision and mechanical degradation of polyether ether ketone(PEEK) resin under hypervelocity AO impact using reactive moleculardynamics simulations. The interaction process and local evolutionmechanism between high-speed AO and PEEK are investigated for thefirst time, suggesting that AO will either be scattered or adsorbedby PEEK, which is strongly correlated with the main degraded speciesevolution including O-2, OH, CO, and CO2. DifferentAO fluxes and AO incidence angle simulations indicate that high-energyAO collision on the surface transfers kinetic energy to PEEK'sthermal energy, thus inducing mass loss and surface penetration mechanisms.Vertically impacted AO causes less erosion on the PEEK matrix, ratherthan obliquely. Furthermore, PEEK chains modified with functionalside groups are comprehensively investigated by 200 AO impact andhigh strain rate (10(10) s(-1)) tensile simulations,demonstrating that the spatial configuration and stable benzene functionalityof phenyl side groups can significantly improve the AO resistanceand mechanical properties of PEEK at 300 and 800 K. This work revealeduseful insights into the interaction mechanisms between AO and PEEKat the atomic scale and may provide a protocol for screening and designingnew polymers of high AO tolerance.

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