UV-Protected Polyurethane/f-Oil Fly Ash-CeO2 Coating: Effect of Pre-Mixing f-Oil Fly Ash-CeO2 with Monomers.

A series of UV-protected coatings were prepared using cerium-oxide-functionalized oil fly ash (f-OFA-CeO2) in waterborne polyurethane (WBPU) dispersions. Three monomers, namely, poly(tetramethyleneoxide glycol) (PTMG), polydimethylsiloxane-hydroxy terminated (PDMS) and 4,4-dicyclohexylmethane diisocyanate (H12MDI), were used to pre-mix with f-OFA-CeO2 separately, followed by the synthesis of WBPU/f-OFA-CeO2 dispersions. The f-OFA-CeO2 distribution and enrichment into any part (top/bottom/bulk) of the coating was strongly affected by the pre-mixing of f-OFA-CeO2. The f-OFA-CeO2 was densely distributed in the top, bottom and bulk when the f-OFA-CeO2 was pre-mixed with PDMS, H12MDI and PTMG, respectively. Only an f-OFA-CeO2-enriched top surface showed excellent UV protection. The lowest UV-degraded exposed coating was found when the top surface of the coating was f-OFA-CeO2-enriched.