Abstract:A three-dimensional porous Nata aerogel material with remarkable toughness and a density of 30 mg/cm3 was prepared by freeze-drying with Nata hydrogel as the raw material. The morphological structure, supra-molecular structure, crystal structure, and thermal properties of the prepared Nata aerogel were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, and thermo-gravimetric analysis. The XRD pattern revealed that the supramolecular structure of cellulose in the Nata aerogels was cellulose I, and Nata aerogels showed a higher relative crystallinity and larger grain size than Nata and microcrystalline cellulose (MCC). FTIR spectra indicated that no new functional groups were generated, and the calculated infrared crystallinity index was greater than those of Nata and MCC, which was consistent with the XRD result. Peak separation and fitting were performed for FTIR characteristic peaks. The peaks sizes of 3100–3600 cm-1 were fitted for the changes in intra- and inter-molecular hydrogen bonds, which showed that the strength of intramolecular hydrogen bonds for O (2) H... O (6) was decreased, the strength of O (3) H... O (5) was increased, and the strength of intermolecular hydrogen bonds for O (6) H ... O (3 ') was increased. The peaks in the range of 660–760 cm-1 were fitted for the content of cellulose Iα, showing a result of 92.18%. Scanning electron microscopy indicated the presence of a large number of pores in the aerogels. Thermo-gravimetric analysis revealed a thermal decomposition temperature of 322.07?C, indicating that the thermal stability of Nata aerogels is better than those of Nata and MCC.
