纤维素氨基甲酸酯的绿色合成、溶解及其新型纤维的制备

Nowadays, with the decreasing of oil resources and worsening environmental pollution, the research and development of the natural polymers have been one of the superior areas of polymer science. As the most abundant renewable resources on the earth, cellulose will be one of the main chemical raw materials. In our country, the viscose process is still occupied the leading position in the regenerated cellulose fiber and cellophane industries, although this process generates several environmentally hazardous byproducts, which include carbon disulfide, hydrogen sulfide and heavy metals. Therefore, the development of non-polluting solvent and novel process is the key to the development of cellulose industry.CarbaCell process is a novel technology to produce cellulose fibers and films. In comparison with the viscose process, CarbaCell process has the advantage of a better ecological compatibility such as the use of the innocuous urea, relatively stable of cellulose carbamates, and most of the conventional equipment of a viscose plant can be used without any problems. The starting point of this process is the transformation of cellulose with urea into cellulose carbamate. There were many rigorous conditions in the conventional synthetic methods of cellulose carbamates, which had major limitations for the potential technical applications. Therefore, industrial cellulose carbamate production sites have not yet been established. In this project, we plan to provide an efficient and environmentally friendly method for the rapid synthesis of cellulose carbamate assisted by microwave irradiation, and the reaction mechanism will be clarified. Secondly, the dissolution, solution stability and sol-gel transition behavior of cellulose carbamate in NaOH aqueous solution will be studied, and the spinning solution is suitable for industrial applications will be prepared. Thirdly, high-strength novel regenerated cellulose fiber will be prepared through laboratory and pilot scale wet-spinning devices, the structure and properties of cellulose carbamate and its new fiber will be characterized, and the relationship between structure and properties of the material will be clarified. Therefore, the project will have great scientific significance and prospects of applications to Cellulose Industries, and it is well accorded with the target of our country and has an great importance for a sustainable development.

纤维素是自然界最丰富的可再生资源，由于其独特的反应功能和分子特性将成为未来主要的化工原料。目前，我国仍采用黏胶法生产人造丝和玻璃纸，生产过程大量使用二硫化碳而造成严重环境污染并损害人体健康。因此，开发清洁、高效的溶剂体系和加工方法已成为纤维素工业发展的关键。本项目拟通过微波加热方法在无溶剂污染、无催化剂条件下快速合成纤维素氨基甲酸酯，阐明其反应机制；研究纤维素氨基甲酸酯在NaOH溶液中的溶解、溶液稳定性及其溶液-凝胶化转变行为，制备出适合工业应用的纺丝溶液；通过实验室和中试纺丝装置制备高强度新型纤维素纤维；对纤维素氨基甲酸酯及其新型纤维的结构和物性进行表征，确定材料结构与物性之间的相互关系。本项目将建立绿色合成纤维素氨基甲酸酯的新方法，通过高分子物理和化学手段解决纤维素溶解和溶液稳定性的难题，制备出新型高强度纤维素纤维，这将对我国黏胶工业的改造和进一步发展具有非常重要的现实意义。

纤维素难以溶解和熔融加工，开发清洁、高效的溶剂体系和加工方法一直是纤维素研究中的重要科学问题。本项目围绕纤维素的溶解、纺丝以及构建新型功能材料方面开展工作，所取得的主要进展和成果包括：.一、纤维素氨基甲酸酯（CC）的合成、溶解及其纺丝新技术.1）通过常规加热在低尿素用量下合成CC，阐明其反应机理以及反应条件对产物的影响，证明反应产物水洗前后均能很好地溶解于NaOH/ZnO水溶液；2）系统研究了CC在NaOH/ZnO水溶液中的溶解和溶液稳定性，证明7-9 wt% NaOH溶液中加入0.4-2.0 wt%的ZnO可显著提高CC的溶解性和溶液稳定性；3）通过中试纺丝由CC-NaOH/ZnO溶液制备新型纤维素纤维，阐明纺丝过程和牵伸比对纤维形貌、结构与性能的影响；4）在工业化试验线上，采用工业原料论证了CC合成、低温溶解以及湿法纺丝的可行性，并制备出性能优良的新型纤维素纤维。.二、新型纤维素功能材料的构建.1）通过流延法由CC-NaOH/ZnO溶液制备再生纤维素微孔膜，阐明凝固条件对膜孔径、力学性能和水通量的影响；2）通过一步凝固再生由CC-NaOH/ZnO溶液制备具有优良紫外吸收和抑菌性的新型纤维素/ZnO纳米复合膜；3）通过溶胶-凝胶法由CC-NaOH/ZnO溶液制备表面包覆ZnO纳米颗粒的纤维素/ZnO纳米复合微球和纤维，复合材料具有很好的光催化活性；4）通过一步原位还原，由纤维素铜氨溶液制备具有特殊导电特性的再生纤维素/Cu纳米复合膜；5）利用纤维素铜氨溶液的“卷绳效应”，制备具有连续周期螺旋结构的再生纤维素纤维，并以此为模板制备多种无机物螺旋纤维；6）利用铜氨纤维的非均一结构，通过高温灼烧铜氨复合纤维制备多种无机中空微米纤维，并阐明中空结构的形成过程和机理。.本项目为纤维素的溶解、纺丝以及构建功能材料提供了新的途径。尤其，氨基甲酸酯法制备纤维素纤维的新技术，解决了一系列从基础理论到工业化生产的科学与技术问题，将推进我国黏胶工业的改造升级，符合国家可持续发展战略，具有学术价值和应用前景。

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