Characterization of lignocellulose aerogels fabricated using a LiCl/DMSO solution
Characterization of lignocellulose aerogels fabricated using a LiCl/DMSO solution
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使用 LiCl/DMSO 溶液制备木质纤维素气凝胶的表征
DOI：
10.1016/j.indcrop.2019.01.057
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发表时间：
2019-05-01
影响因子：
5.9
通讯作者：
Wang, Zhiguo
中科院分区：
文献类型：
--
作者：
Liu, Zhulan;Wu, Jinxiu;Wang, Zhiguo
木质纤维素气凝胶是一种新型可再生材料。大多数情况下，纤维素、半纤维素或木质素必须先从木质纤维素中繁琐地分离出来，然后再单独制备气凝胶。本文以木质纤维素/LiCl/DMSO溶液为原料，直接制备了木质纤维素介孔气凝胶。采用乙二胺（EDA）对不同脱木素程度的大豆茎秆进行预处理，再用LiCl/DMSO溶剂溶解，然后依次进行浸渍、溶剂置换和冷冻干燥。采用流变学和压缩试验来测量醇凝胶的机械强度。采用扫描电子显微镜（SEM）、BET、热重分析（TGA）和重量分析等手段对气凝胶的形貌、孔隙率、热稳定性和溶胀性能进行了表征。未脱木质素的木质纤维素气凝胶具有最大的溶胀能力，但孔隙率、机械强度和热稳定性略低。随着脱木素程度的适当增加，木质素的脱除，纤维素和半纤维素发生一定程度的解离，纤维的机械强度和热稳定性提高，纤维网络结构更加致密，孔径（D-pore）减小，比表面积（S-BET）增大。而进一步的脱木素会显著降低气凝胶的S-BET比表面积和孔结构的均匀性。通过调节脱木素程度，可以在一定程度上控制气凝胶的性能。
Lignocellulose aerogel has attracted great attentions in advanced renewable material research. Mostly, cellulose, hemicellulose or lignin should be separated tediously from the lignocellulose first then to fabricate the aerogel individually. Herein, lignocellulose mesoporous aerogels were prepared directly from lignocellulose/LiCl/DMSO solution. The soybean stem with different range of delignification were pretreated by ethylenediamine (EDA), then dissolved in LiCl/DMSO solvent followed by coagulating, solvent replacing and freeze drying sequentially. Rheology and compression tests were employed to measure the mechanical strength of the alcogel. Scanning electron microscopy (SEM), Brunauer-emmett-teller (BET), Thermo-gravimetric (TGA) and the gravimetric analysis were taken to characterize the morphology, porosity, thermal stability and swelling ability of the aerogels. Comparing these samples, the lignocellulose aerogel without delignification had the greatest swelling ability but a little lower porosity, mechanical strength and thermal stability. And as the delignification increased in a proper extent, which induce the lignin removal, the cellulose and hemicellulose dissociated certainly, the mechanical strength and thermal stability improved, a denser fibril network structure with lower pore diameter (D-pore) and a higher S-BET formed. While, exacerbate delignification could reduce the S-BET and the uniformity of the pores in the aerogels remarkably. The performance of the aerogels could be controlled to some extent, by adjusting the degree of the delignification.