SYNERGISTIC EFFECT OF SIMULATED HYPERVELOCITY SPACE DEBRIS AND ATOMIC OXYGEN ON DURABILITY OF POSS-POLYIMIDE NANOCOMPOSITE

摘要

The combined effect of hypervelocity space debris impacts and atomic oxygen (AO) on the fracture of polyimide films reinforced with polyhedral oligomeric silsesquioxanes (POSS) was studied. A laser-driven flyer (LDF) system was used to accelerate aluminum flyers to impact velocities of up to 3 km/s, and the impacted films were exposed to an RF plasma AO source. Scanning electron microscopy (SEM) was used to characterize the fracture morphology. The extent of damage in POSS-polyimide impacted films was found to be much smaller compared to POSS-free films, insinuating on a toughening mechanism developed due to POSS incorporation. When exposed to AO, the impacted POSS-free film revealed synergistic effect associated with a large increase in the erosion rate, while impacted POSScontaining samples showed improved resistance toward AO. The increased erosion rate of the impacted POSSfree film is explained by formation of residual stresses that affect the oxidation mainly by increasing the diffusivity of oxygen.