Self-passivation of polymer-layered silicate nanocomposites

Nanoscale dispersion of only a few weight percentage. of layered silicate ( montmorillonite) in nylon 6 and epoxy results in the formation of a uniform passivating and self-healing inorganic surface region upon exposure to oxy gen plasma. The enrichment of inorganic is compositionally graded with resp ect to the surface and is due to the preferential oxidation of the polymer from the nanocomposite and the corresponding enhancement of the nanoscale l ayered silicate on the surface. The structure of the inorganic region is tu rbostratic, with an average distance between layered silicates of 1-4 Lm. T his ceramic-like silicate layer provides an overcoat to the nanocomposite a nd can significantly retard the penetration of oxygen plasma. Thus, layered silicate containing nanocomposites may enhance the survivability of polyme ric materials in aggressive oxidative environments, such as atomic oxygen i n low earth orbit (LEO). The formed inorganic region was characterized chem ically and morphologically by X-ray photoelectron spectroscopy (XPS), atten uated total reflection infrared (ATR), transmission electron microscopy (TE A), and X-ray scattering.