| Organic coating can provide barrier protection for metal matrix,and is the most widely used and economical method among many metal corrosion protection methods.However,pure organic coatings or coatings with single filler are easy to lose their protective properties for metals in advance due to local damage.Adding the filler loaded with corrosion inhibitor into the coating can effectively prolong and improve the service life and reliability of the coating products.Polypyrrole(PPy)has been widely used in the field of metal corrosion protection due to its environmental friendliness,low cost,easy synthesis and corrosion inhibition mechanism.This article aims to improve the long-term protection of the coating against metals by preparing polypyrrole-based composite fillers loaded with corrosion inhibitors and applying them to the epoxy resin coating of Q235 steel to provide the epoxy resin coating with active protection against metals.When the coating is damaged,the corrosion inhibitor in the coating filler can be released and inhibit the corrosion reaction of the metal in time.The specific studies are as follows:(1)Preparation of benzotriazole/phytic acid-polypyrrole(BTA/PA-PPy)and application in epoxy resin coating.The phytic acid-polypyrrole(PA-PPy)particles were prepared using ammonium persulphate as the oxidant and phytic acid(PA)as the dopant.After loading with the corrosion inhibitor benzotriazole(BTA),the morphology,structure and corrosion inhibitor release process of the materials were characterized and analyzed,and their effects on the properties of epoxy resin coatings were investigated.The results showed that PA-PPy had good dispersion stability and the amount of BTA loaded was 8.5 wt%,driven by the concentration gradient,the BTA in BTA/PA-PPy could be effectively released after 4 h.1 wt%BTA/PA-PPy filler can disperse well in the epoxy coating,due to the synergistic effect between the passivation effect of PPy and the corrosion inhibition function of BTA,the composite coating with a thickness of 100±5 μm shows good corrosion protection performance for Q23 5 steel in the durability test for up to 60 days,and has a certain active corrosion protection function.(2)Preparation of benzotriazole/polypyrrole/MIL-88(Fe)and application in different environments.PPy/MIL-88(Fe)particles were prepared using an iron-based organic backbone MIL-88(Fe)as oxidant and hard template.After loading with BTA,the morphology,structure and corrosion inhibitor release process of the materials were characterized and analyzed,and the corrosion inhibition functions that could be performed under different application environments were investigated.The results show that the PPy/MIL-88(Fe)particles have uniform particle size and good dispersibility,and the loading amount of BTA reaches 17.8 wt%.The release of BTA from BTA/PPy/MIL-88(Fe)was pH-responsive,with the highest release rate and the amount released in alkaline environments.The electrochemical experiments of the composites in the solution system,scratched coating and intact coating respectively show that BTA/PPy/MIL-88(Fe)can effectively inhibit the corrosion of Q235 steel.The composite coating with filler content of 0.5 wt%and thickness of 50±2 μm shows good corrosion durability and certain active corrosion resistance.BTA/PPy/MIL-88(Fe)composite filler can organically combine the passivation of PPy with the inhibitory effect of MIL-88(Fe)and BTA dual corrosion inhibitors to improve the corrosion protection performance of epoxy coatings. |
PDF Full Text Request