Synthesis of ultrathin α-zirconium phosphate functionalized with polypyrrole for reinforcing the anticorrosive property of waterborne epoxy coating

Abstract

As a classical two-dimension nanomaterial, α-zirconium phosphate (α-ZrP) with outstanding barrier property and non-conductivity has great potential application in anticorrosion field. However, the thicker layer thickness and lack of long-term anticorrosion property limit the application of α-ZrP. In this work, α-ZrP with the diameter of about 500 nm was prepared and then exfoliated to enhance the dispersion in waterborne epoxy coatings(WEC). Then polypyrrole (PPy) was used to encapsulate the exfoliated α-ZrP (E-ZrP) to obtain final nanomaterial(PPy-ZrP). XRD, FTIR, EDS mapping, SEM, TEM were employed to characterize the as-prepared nanomaterials. WECs with those as-prepared nanomaterials were fabricated by spray and the anticorrosion performance of WECs were tested by electrochemical impedance spectroscopy(EIS) test and salt spray test. At the end of the EIS test (60 days of immersion in 3.5 wt% NaCl solution), the PPy-ZrP/WEC exhibited the highest value of |Z|0.01 Hz (4.5 × 107 Ω·cm2), which is about two orders of magnitude higher than blank WEC. During the EIS test period, PPy-ZrP/WEC displayed better corrosion resistance than other WECs. As a two-dimension nanosheet with good dispersion in WEC, PPy-ZrP provided outstanding barrier property for WEC. And the passivation effect of PPy further enhanced the corrosion resistance of WEC.