Abstract
The purpose of this paper is to investigate the esterification of the surface hydroxyl groups of hydrated alumina powder (main constituent being boehmite) with normal chain alcohols, for hydrophobing of anodic oxide film on aluminum. Esterification was carried out by the reflux method. The surface hydroxyl groups of the hydrated alumina powder was esterifled with alcohols as -OH→-OR (R: alkyl group), and the amount of alkoxy group calculated from the data of ultimate analysis was about 4-5×10-4mol/g. The esterified powders showed hydrophobic properties. They floated on water, and this effect was remarkable in the case of treatment with a mixed solution of 1-dodecanol and dodecane, where the treated powder never sedimented in water. The surface hydrophilicity of the powder wasdecreased to about 1/3 of that of the original powder.
