Comparison of anti-corrosion properties of polyurethane based composite coatings with low infrared emissivity

Four polyurethane resins, pure polyurethane (PU), epoxy modified polyurethane (EPU), fluorinated polyurethane (FPU) and epoxy modified fluorinated polyurethane (EFPU), with similar polyurethane backbone structure but different grafting group were used as organic adhesive for preparing low infrared emissivity coatings with an extremely low emissivity near 0.10 at 8-14 μm, respectively. By using these four resins, the effect of different resin matrics on the corrosion protection of the low infrared emissivity coatings was investigated in detail by using neutral salt spray test, SEM and FTIR. It was found that the emissivity of the coatings with different resin matrics changes significantly in corrosion media. And the results indicated that the coating using EFPU as organic adhesive exhibited excellent corrosion resistance property which was mainly attributed to the presence of epoxy group and atomic fluorine in binder simultaneously.

Research highlights▶ Influences of different resins on the anti-corrosion properties of low infrared emissivity coatings are proposed and researched which have not been discussed before. ▶ The anti-corrosion mechanisms of the coatings with different resins are analyzed in detail. ▶ The conclusion that the introduction of epoxy group and atomic fluorine can highly improve the corrosion resistant properties of the low infrared emissivity is obtained which establishes a foundation of later researches.