Designing of corrosion resistant epoxy coatings embedded with polypyrrole/SiO_2 composite

摘要

Polypyrrole/SiO_2 composite was synthesized by chemical oxidative polymerization of pyrrole using FeCl_3. The synthesized polymer composite was loaded in epoxy resin to develop coatings for mild steel substrates using powder coating technique. SEM and TEM images reveal homogenous dispersion of SiO_2 particles in polypyrrole matrix. TGA analysis confirms good thermal stability of the polymer composite. Tafel polarization and electrochemical impedance spectroscopy (EIS) results exhibit remarkably high corrosion protection efficiency of epoxy coatings with polymer composite in 3.5% NaCl solution. Corrosion studies of coatings with an artificial defect reveal the passivation of defect by the polymer composite present in the epoxy coatings. Salt spray test results revealed superior corrosion resistance offered by the polymer composite.