离子液体中纤维素的溶解及再生特性

Structural characteristics of cellulose after dissolution and regeneration from the ionic liquid [bmim]Cl

探讨了不同来源纤维素在离子液体1-丁基-3-甲基咪唑氯代盐([bmim]Cl)中的溶解性能,并采用红外光谱、X-射线衍射及热重分析等手段对木浆纤维素在离子液体[bmim]Cl中溶解和再生前后的结构变化进行了分析。结果表明,未经活化的纤维素可直接溶解于离子液体[bmim]Cl而不发生其它衍生化反应,原纤维素聚合度越低,溶解越容易。再生纤维素分子量较原纤维素有所降低,结晶状态由纤维素Ⅰ转变为纤维素Ⅱ,再生后纤维素热分解温度降低,热稳定性略有下降。

For many decades, considerable efforts have been devoted to the development of new solvents for cellulose which are non-toxic and and do not cause derivatization of the solute. In recent years, it has been found that some types of ionic liquids are capable of dissolving cellulose. The structural differences between wood pulp and cellulose regenerated from the ionic liquid 1-butyl-3-methylimidazolium chloride （[bmim]Cl） have been investigated using Fourier transform infrared （FT-IR） spectroscopy, X-ray diffraction and thermogravimetry （TG） measurements. The results show that the crystalline form of wood pulp cellulose transforms completely from cellulose Ⅰ to cellulose Ⅱ after regeneration from [bmim] Cl solution and that the regenerated cellulose exhibits a lower onset temperature of thermal decomposition. It is concluded that the ionic liquid [bmim]Cl is a good recyclable cellulose solvent with considerable potential for application in the cellulose industry.