CAS OpenIR
离子液体/羊毛纤维/凝固剂三元相图的构建及其应用研究
潘凤娇
Thesis Advisor聂毅, 蒋元力
2020-07-01
Degree Grantor中国科学院大学
Degree Name硕士
Degree Discipline化学工程
Keyword离子液体,羊毛纤维,三元相图,Cosmo-rs,复合纤维
Abstract

随着经济的迅速发展,人们对资源、能源的需求量日趋增大。天然高分子作为一种环境友好型的可再生资源,已经引起研究者们的广泛关注。角蛋白是储量丰富的天然高分子之一,羊毛纤维中含有95 wt.%的角蛋白,是天然角蛋白的重要来源,具有优异的机械性能和生物学特性。然而,由于羊毛纤维分子结构复杂,含有大量分子间及分子内氢键、二硫键等化学键,使其不溶或难溶于水和普通有机溶剂。离子液体作为一种新兴绿色溶剂,由于其结构可设计、性质可调控、不易挥发、热稳定性强、溶解性高等优异性能,在溶解羊毛纤维、纤维素、甲壳素等天然高分子方面表现出了独特的优势。但是,目前离子液体溶解羊毛纤维的研究,主要集中在其溶解性能方面,对羊毛角蛋白再生性能的研究相对较少。羊毛角蛋白再生过程涉及离子液体、羊毛纤维、凝固剂三元体系,三元相图是研究羊毛角蛋白再生过程热力学行为的有效工具。本研究通过浊度法构建离子液体/羊毛纤维/凝固剂体系浊点线性关系(LCP)曲线和三元相图,系统研究了凝固剂种类、再生温度和离子液体结构对羊毛角蛋白再生性能的影响规律。并利用真实溶剂似导体屏蔽模型(COSMO-RS)预测离子液体、氧化型谷胱甘肽(羊毛纤维模型)、凝固剂之间的相互作用关系。进一步以优选的离子液体1-乙基-3-甲基咪唑磷酸二乙基([Emim]Dep)溶解羊毛纤维/木桨纤维素制备复合纤维,研究羊毛纤维/木桨纤维素比例对复合纤维机械性能、热稳定性等性能的影响规律。创新成果如下: (1)构建了离子液体/羊毛纤维/凝固剂三元相图。利用浊度法结合Boom经验方程构建离子液体/羊毛纤维/凝固剂体系浊点线性关系(LCP)曲线,并外推出全浓度下离子液体/羊毛纤维/凝固剂三元相图。进一步系统研究了凝固剂种类、再生温度、离子液体结构对羊毛角蛋白再生能力的影响规律。以[Emim]Dep为溶剂溶解羊毛纤维,再生温度为25 ℃,获得不同凝固剂体系,羊毛角蛋白再生能力顺序为水 > 乙醇 > 异丙醇;以[Emim]Dep为溶剂溶解羊毛纤维,以水为凝固剂再生羊毛角蛋白,获得不同再生温度体系,水对羊毛角蛋白的再生能力随再生温度升高而降低;再生温度为25 ℃,以水为凝固剂再生羊毛角蛋白,获得不同离子液体体系,水对羊毛角蛋白再生能力顺序为[Emim]Dep > [DBNE]Dep > [DBNH]OAc。(2)再生条件对再生羊毛角蛋白性质的影响规律。以[Emim]Dep为溶剂溶解羊毛纤维,以水(25、40、60 ℃)、乙醇(25 ℃)和异丙醇(25 ℃)为凝固剂再生羊毛角蛋白。以水为凝固剂再生羊毛角蛋白结晶度和α-螺旋结构含量比乙醇和异丙醇为凝固剂更高,且随再生温度升高,以水为凝固剂再生羊毛角蛋白结晶度和α-螺旋结构含量逐渐降低。再生温度为25 ℃,以水为凝固剂再生羊毛角蛋白结晶度为22.5%,α-螺旋结构含量为84.1%。(3)离子液体[Emim]Dep、氧化型谷胱甘肽、凝固剂相互作用规律。利用COSMO-RS计算离子液体[Emim]Dep、氧化型谷胱甘肽和凝固剂(水、乙醇、异丙醇)在不同再生温度(25、40、60 ℃)下相互作用。其中离子液体[Emim]Dep、氧化型谷胱甘肽和水的相互作用大于离子液体[Emim]Dep、谷胱甘肽和乙醇或异丙醇,且随再生温度升高,离子液体[Emim]Dep、氧化型谷胱甘肽和水的相互作用逐渐降低。(4)羊毛纤维/木桨纤维素比例对羊毛纤维/木桨纤维素复合纤维性能的影响规律。以[Emim]Dep为溶剂溶解不同比例的羊毛纤维/木桨纤维素制备复合纤维,羊毛纤维/木桨纤维素比例为1 : 9时,复合纤维机械性能和热稳定性最高,其中断裂强度为523 MPa,热分解温度为295 ℃。;With the rapid development of economic, people’s demand for resources and energy is increasing. As an environment-friendly renewable resource, natural polymers have attracted extensive attention from researchers. Keratin is one of the natural polymers with abundant reserves, wool fiber consists 95 wt% of keratin, which is an important source of natural keratin and has excellent mechanical and biological properties. However, due to the numerous complex inter- and intra-molecular hydrogen bonds, disulfide bonds and other chemical solvents, wool fiber is insoluble in water and common organic solvents. As an emerging green solvent, ionic liquid (IL) show outstanding performance in dissolving natural polymers such as wool fibers, cellulose, chitin, etc. due to their tunable structure, non-volatile, thermal stability, as well as high solubility for biopolymer. According to the reports, the current researches on the dissolution of wool fibers by ILs are mainly focused on the solubility of wool fibers. The studies on the regeneration properties of wool keratin all still limited. There are three components involved in the regeneration process, and thus the thermodynamic behavior of polymer regeneration can be investigated by the ternary phase diagram. In this study, the linearized cloud point (LCP) correlation and ternary phase diagram of IL/wool fiber/coagulator system were constructed by the turbidity method. The effects of coagulator types, coagulation temperatures, and structures of ILs on the properties of wool keratin regeneration were investigated systematically. The interaction between IL, oxidized glutathione (wool fiber model, GSSG) and coagulator at different temperatures was predicted by the Conductor-like Screening Model for Real Solvents (COSMO-RS). In addition, the optimized IL of 1-ethyl-3-methylimidazole diethyl phosphate ([Emim]Dep) was used to dissolve wool fiber/wood pulp cellulose to prepare composite fiber, and the influence of wool fiber/wood pulp cellulose ratio on the mechanical properties and thermal stability of composite fibers were systematically studied. The innovation results are as follows:(1) The construction of the IL/wool fiber/coagulator ternary phase diagram.The LCP correlation of IL/wool fiber/coagulator can be generated from the experimental cloud point combined with the Boom empirical equation. And the phase diagram of the whole mass fraction of IL/wool fiber/coagulator was extrapolated by the LCP correlation. The effects of coagulator types, coagulation temperatures, and structures of ILs on the properties of wool keratin regeneration capacity were investigated systematically by LCP correlation and ternary phase diagram.The regenerated wool keratin was obtained using [Emim]Dep as the solvent with the coagulation temperature of 25 ℃. In different coagulator systems, the order of wool keratin regeneration capacity is water > ethanol > iso-propanol. The regenerated wool keratin was obtained using [Emim]Dep as the solvent, and water as the coagulator. In different coagulation temperature systems, as the coagulation temperature increased, the regeneration capacity of wool keratin gradually decreased. The regenerated wool keratin was obtained using water as the coagulator with the coagulation temperature of 25 ℃. In different IL structure systems, the order of wool keratin regeneration capacity is [Emim]Dep > [DBNE]Dep > [DBNH]OAc. (2) The effects of regeneration conditions on the properties of regenerated wool keratin.The regenerated wool keratin was obtained using [Emim]Dep as the solvent, and water (25, 40, 60 ℃), ethanol (25 ℃) and iso-propanol (25 ℃) as the coagulator. The crystallinity and α-helix structure content of regenerated wool keratin with water are higher than that of ethanol and iso-propanol, and as the coagulation temperature increased, the crystallinity and α-helix structure content of regenerated wool keratin gradually decreased. The crystallinity and α-helix structure content of regenerated wool keratin using water as coagulator with the coagulation temperature of 25 ℃ are 22.5% and 84.1%, respectively. (3) The interaction of [Emim]Dep, GSSG and coagulator.COSMO-RS was used to predict the interaction of [Emim]Dep, GSSG and coagulator (water, ethanol and iso-propanol) with the coagulation temperature of 25, 40, 60 ℃. Among them, the interaction of [Emim]Dep, GSSG and water is greater than that of ethanol and iso-propanol, and as the coagulation temperature increases, the interaction of [Emim]Dep, GSSG and water gradually decreases.(4) The effects of wool fiber/wood pulp cellulose radio on the performance of wool fiber/wood pulp cellulose composite fiber.The composite fiber was prepared using [Emim]Dep as the solvent with different wool fiber/wood pulp cellulose radio. When the wool fiber/wood pulp cellulose radio is 1:9, the mechanical properties and thermal stability of composite fiber are the best, i.e., 523 MPa and 295 ℃, respectively. 

Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/49714
Collection中国科学院过程工程研究所
Recommended Citation
GB/T 7714
潘凤娇. 离子液体/羊毛纤维/凝固剂三元相图的构建及其应用研究[D]. 中国科学院大学,2020.
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