LiCl/DMSO再生大豆秸秆纤维凝胶的制备及其性能研究

经乙二胺预处理后大豆秸秆先溶解于8%LiCl/DMSO木质纤维全溶体系,然后于乙醇中凝胶化制备多孔吸液木质纤维凝胶。研究发现:木质纤维原料脱木质素程度会影响凝胶的多孔结构、热稳定性及溶胀性能。随着脱木质素程度加强,木质纤维原料中纤维素、半纤维素和木质素之间解离程度加强,凝胶热稳定性提高,残炭量减少,可形成小孔径、高比表面积的致密多孔网络结构并影响其溶胀性能。当大豆秸秆经2 h脱木质素处理时,该秸秆原料所制备的凝胶热分解温度、残炭量、比表面积和平均孔径分别为230℃、15%、64.29 m~2/g和17.813 nm,在15℃下平衡溶胀率为2 126.79%,与未脱木质素的大豆秸秆制备的凝胶相比,热分解温度提高了30℃,残炭量降低了47.7%,比表面积增加11.02 m~2/g,平均孔径减小了2.468 nm,而平衡溶胀率降低了16.6%。

Preparation and Characterization of Lignocellulose Gel fromSoybean Stem/LiCl/DMSO Solution

The lignocellulose gels with mesopore structures were prepared via dissolving ethylenediamine (EDA) pretreated soybean stem in 8% LiCl/DMSO solvent system and gelation in ethanol.The results showed that the delignification could affect the pore strucutre, thermal stability and swelling ability of lignocellulose gels.As the delignification went on, the thermal stability as well as the liberation degrees of cellulose, hemicellulose and lignin increased, and the char yield decreased.Meanwhile, the denser fibril network structure with smaller mesopore and higher specific area were generated because of the separation of carbohydrates and lignin as well as the increasing crystallinity of lignocellulose.Then the swelling ability was also dramatically affected.For the gel prepared from soybean stem with 2 h of delignification, the thermal decomposition temperature was 230 ℃, the char yield was 15%, the specific area and mesopore size were 64.29 m2/g and 17.813 nm, respectively, and its equilibrium swelling ratio at 15 ℃ was 2 126.79%.Within contrast to the gel made form soybean stem without delignification, the thermal decomposition temperature and specific area increased by 30 ℃ and 11.02 m2/g, respectively.The char yield and mespore size decreased by 47.7% and 2.468 nm, while the equilibrium sewlling ratio reduced by 16.6%.