Aerogels of polysaccharides with chelating functions can be useful as supports in many applications because of their hosting properties. This work demonstrates a facile method for the preparation of aerogels of chitosan derivative “ureido‐chitin”, containing ureido functional groups. The nanofibrillar networks of “ureido‐chitin” were produced by the nucleophilic addition of amine groups of chitosan with isocyanic acid prepared in situ. The presence of ureido functional groups was confirmed by FTIR, solid‐state CP‐MAS ¹³C and ¹⁵N NMR analyses. 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, with the chitin polymers oriented in a highly ordered crystalline structure. The nanofibrillar networks showed no solubility under either aqueous acidic or alkaline conditions. Bio‐based hosting materials of this kind with two different hosting functional groups, ureido and amine, can potentially be utilized for a wide range of applications in aqueous medium, including filters, catalysis and biomedicine.

中文翻译：

---

轻松制备包含尿素和胺作为螯合官能团的“尿素-甲壳素”纳米原纤维网络

具有螯合功能的多糖气凝胶由于具有宿主特性，因此可以在许多应用中用作载体。这项工作展示了一种简便的方法，用于制备含有脲基官能团的壳聚糖衍生物“脲基-几丁质”的气凝胶。“脲基-几丁质”的纳米原纤维网络是通过将壳聚糖的胺基与原位制备的异氰酸亲核加成而制得的。FTIR，固态CP‐MAS ¹³ C和¹⁵证实了脲基官能团的存在N NMR分析。没有观察到分子链的交联。脲基官能团的最大程度估计为约66％。通过粉末XRD表征，证实聚合物链是自组装的，几丁质聚合物以高度有序的晶体结构定向。纳米原纤维网络在水性酸性或碱性条件下均不显示溶解性。这种具有两种不同的宿主官能团（脲基和胺）的生物基宿主材料可以潜在地用于水性介质中的广泛应用，包括过滤器，催化和生物医学。