两种咪唑型离子液体对纤维素的溶解及纺丝性能的比较

Comparision of Dissolution and Spinning Performances of Cellulose Using Two Kinds of Imidazole-based Ionic Liquids as the Solvents

以1-乙基-3-甲基咪唑醋酸盐([EMIM] Ac)和1-丁基-3-甲基咪唑氯盐([BMIM] Cl)两种咪唑型离子液体为溶剂,研究比较了它们对纤维素的溶解性能及其溶液的纺丝加工性能。结果发现:两种离子液体均能在一定条件下溶解纤维素,但[EMIM] Ac较[BMIM] Cl对纤维素具有更低的溶解温度和更快的溶解速率。从流变分析还发现:纤维素/[EMIM] Ac溶液与纤维素/[BMIM] Cl溶液均为切力变稀流体,相同条件下纤维素/[EMIM] Ac溶液的黏度远低于纤维素/[BMIM] Cl溶液,使其可在相对低的温度下纺丝。此外,GPC分析结果表明:纤维素在用[EMIM] Ac溶解及纺丝过程中降解程度较小,而用[BMIM] Cl进行溶解纺丝时,降解作用则较明显。对纤维结构与力学性能的分析结果进一步表明:与相同喷头拉伸比下制得的[EMIM] Ac法再生纤维素纤维相比,[BMIM] Cl法再生纤维素纤维的聚集态结构相对较完善,结晶度与取向度更高些,从而使其力学性能也相对较好。

Two kinds of imidazole-based ionic liquids, 1-ethyl-3-methylimidazolium acetate （[EMIM]Ac） and l-butyl-3-methylimidazolium chloride （[BMIM]CI） were used as the solvents of cellulose. The dissolution of cellulose in these two ionic liquids and the rheological behavior and spinning performance of the resultant dopes were investigated. It was found that cellulose had lower dissolution temperature and faster dissolution rate in [EMIM]Ac than in [BMIM]Cl. Both of cellulose/[EMIM]Ac and cellulose/[BMIM]Cl solutions were the typical shear thinning fluids. And the viscosity of the former was lower than that of the later, which means the cellulose/[EMIM]Ac solution could be spun under a lower temperature. GPC results showed further that during the dissolution and spinning process of cellulose, the degradation of cellulose was greater in [BMIM]Cl than that in [EMIM]Ac. Moreover, it was found that the orientation, crystallinity, breaking tenacity and initial modulus of the cellulose fiber regenerated from [BMIM]Cl were higher than those from [EMIM]Ac.