UV‐shielding by a polyurethane/f‐Oil fly ash‐CeO2 protective coating

Abstract

AbstractA waste material called oil fly ash (OFA) was acid‐functionalized, yielding f‐OFA‐COOH, which was then reacted with cerium oxide (CeO2) to make CeO2‐functionalized OFA, or f‐OFA‐CeO2. Pristine OFA and f‐OFA‐CeO2 were used to make waterborne polyurethane (WBPU) dispersions, referred to as WBPU/OFA and WBPU/f‐OFA‐CeO2, respectively, with defined OFA and f‐OFA‐CeO2 content. All the dispersions were applied to mild steel as organic coatings to evaluate their protective properties, such as their hydrophobicity, adhesive strength and UV‐shielding resistance. These protective properties varied based on the OFA and f‐OFA‐CeO2 content. The highest water contact angle, minimum water swelling and maximum adhesive strength were found using WBPU/f‐OFA‐CeO2‐20 coating (using 2.00 wt% f‐OFA‐CeO2), which also showed the maximum ultraviolet (UV) absorption via UV–vis spectroscopy analysis. This UV shielding result also matched field test results, as that coating was found to exhibit the lowest UV degradation near a marine atmosphere, as shown by X‐ray photoelectron spectroscopy (XPS) analysis. The least affected hydrophobicity was also recorded for the sample with the WBPU/f‐OFA‐CeO2‐20 coating.