Fibre and Particle Engineering Research Unit, University of Oulu, P.O. Box 4300, 90014 Oulu, Finland.
Carbohydr Polym. 2018 Oct 15;198:34-40. doi: 10.1016/j.carbpol.2018.06.051. Epub 2018 Jun 13.
In this study, a deep eutectic solvent (DES [based on triethylmethylammonium chloride (TEMA) and imidazole]) was used as a reaction medium for cationization of cellulose fibers with trimethylglycine (betaine) hydrochloride in the presence of p-Toluenesulfonyl (tosyl) chloride. Cellulose betaine ester with a cationic charge up to 1.95 mmol/g was obtained at mild reaction conditions (four hours at 80 °C). The reaction was further demonstrated in the fabrication of cationic cellulose nanofibers (CCNFs) by a mild mechanical disintegration of cationized cellulose. In addition to CCNFs, cationic wood nanofibers (CWNFs) were produced directly from groundwood pulp (GWP) with a high lignin content (27 w%). Individualized CCNFs and CWNFs had a fiber diameter of 4.7 ± 2.0 and 3.6 ± 1.3 nm, respectively, whereas some larger fiber aggregates (diameter below 200 nm) were also observed, especially in the case of CWNFs.
在这项研究中，使用了深共晶溶剂（DES [基于三乙基甲基氯化铵（TEMA）和咪唑]）作为反应介质，在对甲苯磺酰氯（tosyl）氯的存在下，用三甲基甘氨酸（甜菜碱）盐酸盐对纤维素纤维进行季铵化。在温和的反应条件下（80°C 下反应四小时），获得了带有高达 1.95 mmol/g 正电荷的纤维素甜菜碱酯。该反应进一步通过温和的机械离解季铵化纤维素来制备阳离子纤维素纳米纤维（CCNFs）。除了 CCNFs 之外，还可以直接从木质素含量高（27 wt%）的磨木浆（GWP）中制备阳离子木纳米纤维（CWNFs）。单个的 CCNFs 和 CWNFs 的纤维直径分别为 4.7 ± 2.0 和 3.6 ± 1.3 nm，而在 CWNFs 的情况下，还观察到一些较大的纤维聚集体（直径低于 200 nm）。
