Functional monomers and polymers, 74. Physico‐chemical study on the chitosan‐iodine complexes

Abstract

Abstract The adsorption of iodine on chitosan was studied by physico‐chemical methods. The scanning electron micrograph measurements of chitosan‐iodine adducts showed that iodine molecules were adsorbed uniformly on the chitosan film when the film was treated with aqueous iodine‐potassium iodide solution. The thermogravimetric analysis of the adducts revealed that the loss in weight began at about 190°C, and that iodine molecules were thus well‐complexed with chitosan. It was also found that the IR spectra of the chitosan films showed the amide I and amide II bands shifted to lower frequencies due to the iodine adsorption. The X‐ray diffractometry of these adducts was further carried out, and it was found that the iodine adsorbed chitosan showed no crystalline pattern, different from that of the original chitosan which showed crystallinity in some extent. The chitosan recovered after desorbing iodine by immersion in aqueous sodium thiosulfate solution was amorphous.