Facile Preparation of Nanofibrillar Networks of “Ureido-Chitin” Containing Ureido and Amine as Chelating Functional Groups

Abstract

Aerogels of polysaccharide with chelating functions can be useful as supports in many applications because of their hosting property. We demonstrate a facile method for the preparation of aerogels of chitosan derivative, “ureido‐chitin” containing ureido functional group. The nanofibrillar networks of “ureido‐chitin” were produced by the nucleophilic addition of amine groups of chitosan with in situ prepared isocyanic acid. The presence of ureido functional groups was confirmed by FT‐IR, solid state CP‐MAS 13C and 15N NMR. No crosslinking of molecular chains was observed. The maximum degree of ureido functional groups was estimated to be about 66%. Characterization by powder XRD confirmed that the polymer chains self‐assembled in a way how the chitin polymers orient themselves in a highly ordered crystalline structure. The nanofibrillar networks showed no solubility under aqueous acidic and alkaline conditions. Bio‐based hosting materials of this kind with two different hosting functional groups: ureido and amine can be potentially utilized for wide applications in aqueous medium including filters, catalysis and biomedicine.