Interaction between an acidic extractant and an octadecylamino group introduced into a grafted polymer chain

Asai, Shiho; Watanabe, Kazuo; Sugo, Takanobu*; Saito, Kyoichi*

Poly-glycidyl methacrylate (GMA) was appended onto a porous membrane of a hollow-fiber form. Octadecylamine was added to the epoxy group of the polymer brush at a maximum molar conversion of the epoxy group into the octadecylamino group of 59%. Bis(2,4,4,-trimethylpentyl)phosphinic acid (Cyanex 272), was impregnated on the octadecylamino group by immersion of the octadecylamine-added porous membrane. The phosphinic acid moiety of Cyanex 272 was attracted by the amino part of the octadecylamino group of the polymer brush to swell the entire volume of the porous membrane. The impregnated Cyanex 272 was repositioned on the charged polymer brush in response to the properties of surrounding liquids. The hydrophobic interaction enables the hydrophobic moiety of Cyanex 272 to associate with the octadecyl part of the octadecylamino group of the polymer brush to capture zinc ions. The binding efficiency of the Cyanex 272-impregnated polymer brush for zinc ion was as high as 93%.