Synergistic effect of Ag and ZnO nanoparticles on polypyrrole-incorporated epoxy/2pack coatings and their corrosion performances in chloride solutions

Abstract

In this study, two formulae (F1 and F2) of epoxy/2pack coatings incorporated with polypyrrole (PPy)-conducting polymer were produced from bisphenol-A type of epoxy resin (DGEBA) with the addition of Ag and ZnO nanoparticles. The synergism effect of Ag and ZnO nanoparticles on the mechanical and corrosion resistance properties was reported. The curing agent 2,4,6-tris (dimethylaminomethyl) phenol (ARADUR 3282-BD) was used under optimized stoichiometry values. The nanoparticles ratio in different wt.% were first dispersed in solvent by the sonication process and then added to epoxy/PPy composition. All the coated steel panels were cured at room temperature in a controlled dust free environment for 7 days in order to obtain a hard and intact coating. The dispersion of nano-size ZnO and Ag pigments was investigated using scanning electron microscopy (SEM) and its composition through an energy dispersive X-ray (EDX) technique. Conventional techniques and nano-indentation were also performed to observe the effect of ZnO and Ag synergism content on the hardness and modulus of elasticity at nano scale. The corrosion behavior of the coated samples was investigated at room temperature in 3.5% NaCl solution using electrochemical impedance spectroscopy (EIS). The synergism effect of nanoparticles along with PPy resulted in an enhancement of mechanical and corrosion-resistant properties.