以Nata为原料，通过冷冻干燥制备了密度为30 mg/cm-3的具有三维多孔结构和良好韧性的Nata气凝胶，并使用X射线衍射（XRD），傅立叶红外光谱（FT-IR），扫描电镜（SEM），热重分析法(TGA)对其形貌结构，超分子结构、晶体结构及热性质进行表征。XRD谱图表明Nata气凝胶中纤维素超分子结晶形态为纤维素I，具有比Nata和微晶纤维素更高的相对结晶度和更大晶粒尺寸；FTIR光谱表明，没有新的官能团产生，计算出红外结晶指数比微晶纤维素大，结果与XRD一致；对FTIR光谱特征峰进行分峰拟合，3100-3600cm-1分峰拟合分子间氢键和分子内氢键变化，气凝胶中纤维素分子内氢键O(2) H. . . O(6)强度减弱，O(3) H. . . O(5)强度增大，分子间氢键O(6) H. . . O(3')强度增加；660-760 cm-1进行分峰拟合，纤维素Iα含量为92.18%；SEM显示该气凝胶中存在大量的孔隙；TGA显示：热分解温度为322.07 ℃，热稳定性优于Nata和MCC。

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.

国家自然科学基金资助（31270617）；高分子材料工程国家重点实验室开放课题基金资助（KF201301）