Fabrication of ZnO/rGO and ZnO/MWCNT nanohybrids to reinforce the anticorrosion performance of polyurethane coating

Abstract

Polyurethane (PU) has been widely utilized in different applications due to its unique properties. Substantial attempts have been made to enhance the corrosion resistance and mechanical properties of PU coating through the addition of nanomaterials. In this study, zinc oxide/reduced graphene oxide (ZnO/rGO) and zinc oxide/multiwalled carbon nanotube (ZnO/MWCNT) nanohybrids were synthesized and incorporated into the PU matrix to enhance the anti-corrosion property of the PU coating. The synthesized nanofillers were thoroughly characterized through Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive X-ray spectroscopy (EDX). The rGO/ZnO-PU and MWCNT/ZnO-PU nanocomposites, and also neat PU were coated on the mild steel (MS) substrate, and the surfaces of the coated samples were probed by Contact angle technique, Atomic Force Microscopy (AFM), and SEM analysis. Electrochemical impedance spectroscopy and potentiodynamic polarization tests were carried out to examine the effects of rGO/ZnO and CNT/ZnO nanofillers in improving the protection and barrier properties of pure PU coating. Electrochemical corrosion data revealed the superior anticorrosion efficiency for rGO/ZnO decorated PU coating (99.09%) compared to that of MWCNT/ZnO dispersed PU coating (95.24%). The high surface area and aspect ratio of rGO make it an effective nanofiller in reinforcing the PU matrix for anticorrosion application.