Qiu Jiahao, Guo Xingzhong, Lei Wei, Ding Ronghua, Zhang Yun, Yang Hui
State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311200, China.
Nanomaterials (Basel). 2023 Feb 3;13(3):613. doi: 10.3390/nano13030613.
Cellulose aerogels are the latest generation of aerogels and have also received extensive attention due to their renewable and biocompatible properties. Herein, cellulose aerogel was facilely prepared by using NaOH/urea solution as solvent, raising the temperature to control gelation and drying wet gel sequentially. With NaOH/urea solution as solvent, the cellulose concentration has an important impact on the micromorphology of cellulose aerogels, while the aging time rarely affects the micromorphology. The appropriate solvent and drying method allow the formation of different cellulose crystalline structures. Different from the Cellulose Ⅰ crystalline structure of raw cellulose powder, the cellulose phase of as-prepared cellulose aerogels belongs to the Cellulose Ⅱ crystalline structure, and to some extent the pyrolysis temperature is also lower than that of raw cellulose powder. The resultant cellulose aerogel prepared by using NaOH/urea solution as solvent and freeze-drying has a uniform macroporous structure with a macropore size of 1~3 µm.
纤维素气凝胶是新一代气凝胶，因其可再生和生物相容性特性也受到了广泛关注。在此，以氢氧化钠/尿素溶液为溶剂，通过升温控制凝胶化并依次干燥湿凝胶，简便地制备了纤维素气凝胶。以氢氧化钠/尿素溶液为溶剂时，纤维素浓度对纤维素气凝胶的微观形态有重要影响，而老化时间对微观形态影响较小。合适的溶剂和干燥方法能够形成不同的纤维素晶体结构。与原料纤维素粉末的纤维素Ⅰ晶体结构不同，所制备的纤维素气凝胶的纤维素相属于纤维素Ⅱ晶体结构，并且在一定程度上其热解温度也低于原料纤维素粉末。以氢氧化钠/尿素溶液为溶剂并采用冷冻干燥法制备的纤维素气凝胶具有均匀的大孔结构，大孔尺寸为1~3 µm。
