离子液体为溶剂的纤维素侧链液晶的制备及应用研究

发布时间：2019-06-12 09:17

【摘要】：纤维素作为地球上储量最丰富的可再生资源,对其开发和应用越来越被重视。已经工业化的纤维素纤维有粘胶纤维和Lyocell纤维,但是其纺制过程中存在环境污染、能耗大等问题。离子液体,作为新型溶剂,对纤维素有很强的的溶解能力,纤维素/离子液体体系制备纤维素纤维有环保及溶剂易回收等优点,但是纤维素浓度增大会导致纤维素溶液体系粘度急剧增大,为了制备"高浓低粘"的纤维素溶液,纤维素液晶体系被提出。本研究设计并合成了新型纤维素侧链液晶基元,研究了形成侧链液晶的条件,制备了侧链型纤维素液晶,并研究其流变性和液晶性,并且利用干湿法纺丝制备了纤维素纤维,具体研究内容如下:利用浊度测试和红外研究了液晶基元在离子液体中的溶解度及相互作用力,研究表明,常温时,液晶基元在离子液体中的溶解度为5.78 wt%,液晶基元和离子液体之间只通过物理力结合而不发生化学反应。采用稳态和动态流变测试、偏光显微镜、差示扫描量热仪和小角X衍射仪来研究纤维素/液晶基元/离子液体体系的相行为和流变行为。结果表明,当纤维素的浓度是6 wt%时,形成纤维素液晶溶液所需液晶基元的临界浓度是2-4wt%,临界温度是40-80℃,形成的晶态结构是近晶相。COX-MERZ法则的偏离说明纤维素和液晶基元之间是氢键相互作用。利用扫描电子显微镜、电子单纤维强力仪来表征常规纤维素纺丝液及纤维素液晶纺丝液制备的纤维,结果显示,纤维素液晶溶液纺出的丝比纯纤维素溶液纺出的丝更细,机械强度提高了 34%。
[Abstract]:Cellulose, as the most abundant renewable resource on the earth, has been paid more and more attention to its development and application. The industrialized cellulose fiber has Viscose fiber and Lyocell fiber, but there are some problems in the spinning process, such as environmental pollution, high energy consumption and so on. Ionic liquid, as a new solvent, has a strong solubility to cellulose. Cellulose / ionic liquid system has the advantages of environmental protection and easy solvent recovery, but the increase of cellulose concentration will lead to a sharp increase in the viscosity of cellulose solution system. In order to prepare "high concentration and low viscosity" cellulose liquid crystal system, cellulose liquid crystal system has been proposed. In this study, a new type of cellulose side chain liquid crystal element was designed and synthesized, the conditions for the formation of side chain liquid crystal were studied, the side chain cellulose liquid crystal was prepared, and its rheology and liquid crystal properties were studied. The cellulose fiber was prepared by dry and wet spinning. The specific research contents are as follows: the solubility and interaction force of liquid crystal element in ionic liquid were studied by turbidity test and infrared spectroscopy. The results show that at room temperature, The solubility of liquid crystal elements in ionic liquids is 5.78 wt%,. There is no chemical reaction between liquid crystal elements and ionic liquids only by physical force. The phase behavior and Rheological behavior of cellulose / liquid crystal element / ionic liquid system were studied by steady and dynamic flow test, polarizing microscope, differential scanning Calorimeter and small angle X-ray diffractometer. The results show that when the concentration of cellulose is 6 wt%, the critical concentration of liquid crystal elements for the formation of cellulose liquid crystal solution is 2 鈮，

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