低温碱尿素法制备纤维素纤维的研究进展

Research progress in cellulose fiber preparation with alkali/urea aqueous solution at low temperature

纤维素是最有可能大规模替代石油的资源,但是纤维素的特殊结构导致其难以溶解在普通溶剂中,也不能熔融纺丝,极大地限制了这类强极性高分子的工业发展,因此纤维素纤维的高效绿色制备新方法成为国际研究热点。在我国已发明的低温碱尿素水溶液直接溶解纤维素新方法的基础上,对这一新技术进行了纺丝工程研究,分别包括间歇式、连续式以及连续式原位化学改性。结果证明将双螺杆应用于纤维素的溶解,利用双螺杆挤出机的强剪切力可以明显提高纤维素的溶解效率,提高纤维素的溶解度,提高溶液均匀性并延长纺丝液凝胶时间,从而实现纤维素纺丝液的高浓度连续稳定纺丝。

Cellulose is a resource which is most likely to replace the petroleum, but cellulose can neither dissolve in common solvent nor be melt-spun due to its special structure, which seriously limits the industrial development of these nor be strong polar polymers. Therefore, green high-efficiency preparation methods of cellulose fiber have become hot spots of research all over the world. Based on the new dissolving technology of cellulose in alkali/urea aqueous solution at low temperature, the spinning engineering experiments of cellulose have been investigated systemically in our country, including batch process, continuous process and continuous in-situ chemical modification process. The results showed that the strong shear stress of twin screw extruder can obviously increase the dissolving efficiency and solubility of cellulose, enhance the evenness of the solution, as well as prolong the gelating time of solution, and as such the continuous and stable spinning of cellulose dopes with high concentration is achieved.