Polyimide/nanoclay coatings: corrosion inhibition behavior

Polyimide clay hybrid nanocomposite coatings have been synthesized and fully imidized. The properties of clay/polyimide coatings such as corrosion inhibition, rubbery plateau modulus and glass transition temperature, Tg, are affected by the weight percent of filler, curing temperature and the weight percent of clay. Increasing the weight percent of clay increases the extent of imidization and decreased the corrosion rate for composite coatings. The glass-rubber transition temperature decreased with increasing filler concentration. The Tg of the composite coatings containing 0.25% filler was, however, slightly higher than that for the neat polyimide film. The rubbery plateau modulus of the nanocomposite coating containing high clay concentration (wt% clay > 5%), increased by about three orders of magnitude to 1 GPa. By incorporating well-dispersed and high concentration of clay into the polyimide/clay coatings, the corrosion inhibition and thermo-mechanical properties of the coatings are drastically improved beyond what is possible through the conventional state-of-the-art coating processing methods.