建立低粘度的离子液体与质子型有机溶剂混合体系,考察纤维素在该体系中的溶解性。结果表明,3种有机溶剂二甲基亚砜(DMSO)、二甲基甲酰胺(DMF)、二甲基乙酰胺(DMAc)都有助于降低混合体系的粘度,当有机溶剂质量分数为20%时,混合体系粘度下降50%。纤维素在质量分数为20%的二甲基亚砜/1-乙基-3-甲基咪唑醋酸盐混合体系(DMSO/[Emim]Ac)中溶解性最佳,高聚合度(DP 1460)的松木纤维90℃下的溶解度从未添加DMSO 时的5.0 g/100 g提高到7.5 g/100 g,溶解时间减少；红外光谱证实,DMSO/[Emim]Ac混合体系为纤维素的非衍生化试剂,X衍射表明,松木纤维经过溶解再生后发生了从纤维素Ⅰ型到纤维素Ⅱ型的晶型转变。
A complex solvent with reduced viscosity was established by mixing ionic liquid and the protic organic solvents.The dissolving and solution property of cellulose in the complex solvent was studied.Results demon-strated that DMSO,DMF,and DMAc can effectively reduce the viscosity of the mixing system.The viscosity was fell by almost half when the mass fraction of 20% organic solvent.And the viscosity of the mixing system of the three organic solvents decreased 50%.But the optimum solubility of cellulose was gained in the mixing system with a mass ratio of DMSO/[Emim]Ac 20%.The solubility of the pine cellulose with a high polymeri-zation degree of 1460 increased from 5.0 g/100 g to 7.5 g/100 g when 20%(w/w)DMSO was added to [Emim]Ac at 90 ℃,dissolution time reduced.It was confirmed by the infrared spectra that cellulose can be uni-formly dissolved in the DMSO/[Emim]Ac mixture without derivation.X-ray diffraction spectra indicated that crystalline form of pine cellulose transformed completely from type Ⅰ to type Ⅱ after regeneration from etha-nol.
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