Results indicated that the Ce-CS-Mt particles enhanced the corrosion protection property of WPU coating. abet – stock.adobe.com. (symbol image)
30. Jan 2020 | Coatings Technologies
Water resistance and corrosion protection properties of water-borne polyurethane coating
Researchers have investigated the water resistance and corrosion protection properties of water-borne polyurethane (WPU) coating enhanced by montmorillonite modified with Ce3+.
In the study, water-borne coatings containing modified montmorillonites were investigated to enhance water resistance and corrosion protection on steel substrates.
It has been considered to use Ce3+ for substituting Na+ because directly adding Na-montmorillonite (Na-Mt) into coating would cause weak water resistance of coating due to its water absorption and swelling properties. Further, in order to increase the loading capacity of montmorillonite to Ce3+, it was pretreated by chitosan (CS) and was modified by Ce3+. Subsequently, Na-Mt and two modified montmorillonites (Ce-Mt, Ce-CS-Mt) were added to the water-borne polyurethane (WPU) matrix. The modification results of montmorillonite samples were examined by XRD and SEM/EDS.
Significant improvement for the water resistance
The results showed that Ce3+ was successfully loaded to the montmorillonite. Chitosan pretreatment increased Ce content in montmorillonite particles and improved their dispersion stability in the WPU matrix. In comparison, coating containing the Ce-CS-Mt particles exhibited the lowest water absorption, which indicated that adding Ce-CS-Mt particles had a significant improvement for the water resistance of WPU coating.
Results of salt spray test revealed that no obvious corrosion products were found on the composite WPU coating after 768 h of exposure to salt spray. These results indicated that the Ce-CS-Mt particles also enhanced the corrosion protection property of WPU coating.
The study has been published in Progress in Organic Coatings, Volume 136.
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