Yu Wang, Wang Chaoyun, Yi Yongjian, Wang Hongying, Zeng Liangbin, Li Mao, Yang Yuanru, Tan Zhijian
Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, Changsha 410205, China.
ACS Omega. 2020 Mar 5;5(10):5580-5588. doi: 10.1021/acsomega.0c00506. eCollection 2020 Mar 17.
Deep eutectic solvents (DESs), featured as promising green solvents, were applied to examine their effectiveness in pretreating raw ramie fibers (RFs) for cellulose nanofibril (CNF) production. The pretreatment performance of three DESs, i.e., choline chloride-urea (CU), choline chloride-oxalic acid dihydrate (CO), and choline chloride-glycerol (CG), was evaluated based on chemical composition analysis and structural and morphological changes. CO attained the most dramatic morphological changes of RFs, followed by CG and CU. Its high structural disruption of RFs during the pretreatment process, shown in the results from scanning electron microscopy and atomic force microscopy, could be due to an outstanding ability to remove amorphous cellulose and noncellulosic components from raw RFs, confirmed by the results of chemical composition analysis, Fourier transform infrared spectroscopy, and X-ray diffractometry. Overall, this study provided an innovative and effective pretreatment process for fractionating raw cellulosic fibers, so as to promote the subsequent preparation of CNFs.
深共熔溶剂（DESs）作为一种很有前景的绿色溶剂，被用于研究其在预处理苎麻原纤维（RFs）以生产纤维素纳米纤丝（CNF）方面的有效性。基于化学成分分析以及结构和形态变化，对三种深共熔溶剂，即氯化胆碱-尿素（CU）、氯化胆碱-二水合草酸（CO）和氯化胆碱-甘油（CG）的预处理性能进行了评估。CO使RFs的形态变化最为显著，其次是CG和CU。扫描电子显微镜和原子力显微镜的结果表明，在预处理过程中它对RFs的结构破坏很大，这可能是由于其具有卓越的从苎麻原纤维中去除无定形纤维素和非纤维素成分的能力，化学成分分析、傅里叶变换红外光谱和X射线衍射分析的结果证实了这一点。总体而言，本研究为分离天然纤维素纤维提供了一种创新且有效的预处理工艺，从而促进后续CNFs的制备。
