莱赛尔纤维生产过程中的副反应及副产物

Side Reactions and By-Products in the Production of Lyocell Fiber

用N-甲基吗啉-N-氧化物(NMMO)作为溶剂溶解纤维素来制备莱赛尔纤维,理想情况下,该生产过程应该是一个物理过程,不会导致纤维素或溶剂发生化学变化。然而,在纤维素/NMMO/水中存在一些副反应并产生一系列副产物,这会导致一系列不利因素,如纤维素降解、成品纤维白度降低、纤维断裂强度等性能下降、NMMO分解、稳定剂的消耗增加,甚至发生热失控反应。介绍了莱赛尔纤维生产过程中副反应的类别及反应机制,将NMMO分解反应划分为均裂反应(自由基)和异裂反应(非自由基)两个方向,并对产生的副产物进行了分析。

Lyocell fibers are prepared by dissolving cellulose with N-methylmorpholin-N-oxide(NMMO)as a solvent.Ideally,the production process should be a physical process that does not cause chemical changes in cellulose or solvent.However,there are some side reactions in cellulose/NMMO/water and produce a series of by-products,which can lead to a series of adverse factors,such as cellulose degradation,temporary or permanent discoloration of the resulting fibers,decreased fiber breaking strength and other properties,NMMO decomposition,increased stabilizer consumption,and even thermal runaway reactions.The types and mechanisms of side reactions in the production of Lyocell fiber were introduced.The NMMO decomposition reaction was divided into two directions:homolyticreaction(radical)and heterolytic reaction(non-radical),and the by-products were analyzed.