磷酸酯类离子液体对纤维素溶解性能的研究

Study on Dissolution of Cellulose in Two Phosphate-based Ionic Liquids

采用一步法合成了两种磷酸酯类离子液体:1,3-二甲基咪唑磷酸二甲酯盐([MMIM]DMP)和1-乙基-3-甲基咪唑磷酸二乙酯盐([EMIM]DEP),并比较了它们对纤维素的溶解性能。结果表明,两种离子液体均能在一定条件下溶解纤维素,而[EMIM]DEP表现出较优的溶解能力,再生得到纤维素膜;随着溶解温度的升高,溶解时间缩短。采用红外光谱(FT-IR)、热重失重(TGA)分析、X射线衍射(XRD)、扫描电镜(SEM)等对再生前后的纤维素进行了表征。结果表明,未经活化的纤维素可直接溶于离子液体中而不发生其它衍生化反应;溶解再生后的纤维素晶型发生变化;经[EMIM]DEP溶解再生后纤维素热稳定性和聚合度下降较小,再生纤维素膜结构致密均一。

Two phosphate-based ionic liquids, [MMIM]DMP and [EMIM]DEP ionic liquids were synthesized by one step method. Dissolution of cellulose in ionic liquid [MMIM]DMP and [-EMIM]DEP was compared. It showed that both of them can dissolve cellulose under certain conditions and [EMIM]DEP displayed the better solubility. With the dissolution temperature increased, the dissolution time was greatly reduced. The both original cellulose and rege- nerated cellulose were characterized by Fourier transform infrared spectroscopy（FT-IR）, thermogravimetry（TG） , X- ray diffraction（XRD） measurements and scanning electron microscopy（SEM）. Results showed that the novel system was a good non-derivatizing cellulose solution. The crystal of regenerated cellulose changed, the thermostability and the degree of the polymerization of regenerated cellulose from [EMIM]DEP decreased slightly. The surfaces of regen- erated films displayed uniformity, indicating a dense texture.