Synthesis and characterization of polypyrrole-fly-ash-adenosine composite reinforced epoxy coating for anticorrosive applications

Abstract

Polypyrrole (PPy), PPy-fly ash, and PPy-fly ash-adenosine composite in an epoxy resin system were studied for potential applications in the field of corrosion protection. The composite was prepared using a simple and cost-effective in-situ chemical oxidative method by interfacial polymerization technique. The synthesized composites were added into the epoxy coating matrix. All the studied formulations show excellent adhesion (5B) and good chemical resistance and passed flexibility test without any crack formation. Pencil hardness increases from 2H to 4H while scratch resistance increases from 1.5 to 2 kg for both PPy-Ash 3wt% and PPy-Ash-adenosine 3 wt% as compared to plain epoxy. The contact angle observed to be 80.4° for plain epoxy and with PPy-Ash-adenosine 5 wt% it is 98.75°. Anticorrosive properties of the coatings were evaluated using electrochemical impedance spectroscopy bode plot analysis and salt spray tests. There was an increase in impedance from 2.5 to 4.25 ohm, as the addition of PPy-Ash-adenosine composite. The results indicated that the composite coatings exhibited significantly higher corrosion protection properties compared to the pure epoxy coating. The enhanced corrosion protection performance of the composite coatings was attributed to the synergistic effect of PPy, fly ash, and adenosine.