ELECTROCHEMICAL PROPERTIES OF MULTIFUNCTIONAL CARBON NANOFIBER/POLYIMIDE NANOCOMPOSITE COATINGS

摘要

Polymer nanocomposite coatings constituted of polyamide imide matrix (Pyralin) and surface modified vapor grown carbon nanofibers have been developed. The nanocomposite coatings were cast onto aluminum alloy, Al 2024-T3 coupons by solution casting followed by imidization at 250C for 3 h. Hybrid polymer nanocomposite coatings containing intrinsically conducting polymer modofied nanofibers and polyimide resin were also synthesized and evaluated. The weight percent of the surface modified nanofibers was varied from 0.3- 6 weight percent in order to determine the effect of nanofiber loading on the electrochemical and electrical properties of the composite coatings. The corrosion performance and electrical conductivity of the nanocomposite coatings and free standing films were measured by electrochemical impedance spectroscopy, EIS, and 4-point probe method, respectively. Our results show that the polarization resistance, Rp of the coatings is dependent on the composition, thickness and uniformity of the coatings. Coatings containing voids and flaws show lower coatings resistance than uniform void free coatings by over 3 orders of magnitude (10~5-10~8 OMEGA).