Abstract

The kinetics of the dissolution and swelling of different cellulose fibers in the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]) was studied by varying solvent power and temperature. Natural fiber, flax, and man-made fibers, Cordenka and Lyocell-type (Ioncell) were used with one Ioncell fiber containing lignin and hemicelluloses. Through the addition of water, the solvent power was modified from very good (neat ionic liquid), to moderate (with 5 wt% water) and weak (15 wt% water). The temperature was varied to correlate the fiber dissolution rate with the solvent viscosity. All fibers were characterized by chemical composition, crystallinity, molecular weight distribution and dynamic vapor sorption. It was demonstrated that while the rate of fiber dissolution in neat ionic liquid depends on fiber accessibility and solvent viscosity, the water-induced decreased solvent power dominates the general fiber behavior. Flax appeared to be the most “sensitive” to the solvent power due to its hierarchical structure. The fastest dissolution or swelling was recorded for Ioncell and the slowest for Cordenka.

Graphic abstract

中文翻译：

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天然和人造纤维素纤维在溶剂功率调谐离子液体中的溶胀和溶解动力学

摘要

通过改变溶剂功率和温度，研究了不同纤维素纤维在离子液体乙酸1-乙基-3-甲基咪唑鎓盐（[EMIM] [OAc]）中的溶解和溶胀动力学。天然纤维，亚麻纤维和人造纤维Cordenka和Lyocell型（Ioncell）与一种含有木质素和半纤维素的Ioncell纤维一起使用。通过添加水，溶剂能力从非常好（纯离子液体）变为中等（用5 wt％的水）和弱（15 wt％的水）。改变温度以使纤维溶解速率与溶剂粘度相关。所有纤维的特征在于化学组成，结晶度，分子量分布和动态蒸气吸附。结果表明，虽然纤维在纯离子液体中的溶解速度取决于纤维的可及性和溶剂粘度，由水引起的降低的溶剂能力主导了整个纤维的行为。亚麻由于其分层结构而显得对溶剂能力最“敏感”。离子电池的溶解或溶胀最快，而Cordenka的则最慢。

图形摘要