Substantially enhanced durability of polyhedral oligomeric silsequioxane-polyimide nanocomposites against atomic oxygen erosion
XB Li and A Al-Ostaz and M Jaradat and F Rahmani and S Nouranian and G Rushing and A Manasrah and H Alkhateb and M Finckenor and J Lichtenhan, EUROPEAN POLYMER JOURNAL, 92, 233-249 (2017).
Several groups of polyimide (PI)-based nanomaterials reinforced with polyhedral oligomeric silsequioxane (POSS) nanoparticles were subjected to atomic oxygen (AO) exposure to investigate the effects of POSS and glassification plasma pre-treatment. Various characterizations revealed the clear effects of AO degradation, such as decreased transmissions of all tested films. POSS significantly enhanced the stability of PI in terms of mass loss under an AO environment. One polyimide film sample containing 10 wt% POSS also exhibited excellent stability in mechanical properties measured by dynamic mechanical analyzer (DMA). Surface topography and roughness of all films were qualitatively and quantitatively analyzed using the atomic force microscope (AFM). After AO irradiation the POSS-filled films showed a much smoother surface than that of neat PI film. The results of mass loss, mechanical property and AFM topography collectively indicate the exceptional self-healing capability of the POSS nanoparticles upon AO erosion that enables it to protect polyimide due to the formation of a thin glass layer. A further molecular dynamics simulation of the neat PI and PI-POSS system revealed reduced mass loss, damage propagation depth, and erosion yield of the nanocomposites with increasing POSS concentration, which are consistent with the experimental findings.
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