Advanced anti-corrosion coatings prepared from alpha-zirconium phosphate/polyurethane nanocomposites

This paper presents the first successful application of alpha-zirconium phosphate/polyurethane (ZrP/PU) nanocomposites for corrosion protection. ZrP nanoplatelets were synthesized using a reflux method and modified with a polyetheramine surfactant (Jeffamine M1000) to form organic ZrP nanoplatelets. ZrP/PU nanocomposite films were based on PU and ZrP with different ZrP contents from 0.5-5 wt%. To probe the internal morphology of ZrP/PU nanocomposites, their cross-sections were examined by scanning and transmission electron microscopy. The results reveal that ZrP dispersed very well in PU films and that no substantial agglomeration occurred. Well-dispersed ZrP nanoplatelets in a PU matrix could effectively enhance the moisture barrier properties of ZrP/PU films. The water vapor transmission rate was significantly reduced to 84 g m(-2) per day for ZrP/PU films compared to 194 g m(-2) per day for pure PU films. Using a series of electrochemical measurements of corrosion potential (E-corr), polarization resistance (R-p), corrosion current (I-corr), and electrochemical impedance spectroscopy, ZrP/PU coatings on cold-rolled steel electrodes were also found to exhibit enhanced corrosion protection properties compared to pure PU coatings.