NMMO工艺纤维素膜结晶结构

Study on the Crystalline Structure of Cellulose Membranes Prepared by NMMO Method

以纤维素为原料,N-甲基吗啉-N-氧化物(NMMO)为溶剂,采用相转化法制备非对称纤维素膜.利用X-射线衍射法对该工艺纤维素膜的结晶结构进行分析,讨论了铸膜液浓度、凝固浴温度及添加剂对膜结晶度的影响.结果表明:纤维素Ⅰ在NMMO.H2O中溶解并固化成膜后,得到的是纤维素Ⅱ,而不能形成纤维素Ⅰ;提高铸膜液中纤维素浓度、凝固浴温度及抗氧化剂(没食子酸丙酯)用量都可使该工艺纤维素膜的结晶度增大,添加少量的NH4Cl致使纤维素膜的结晶度有所下降.

With N - methylmorpholine - N - oxide （NMMO） as solvents, asymmetric cellulose membranes were prepared by using phase-inversion method. The crystalline structure of the cellulose membranes was determined by means of the X-ray diffraction method. And the influence of concentration of casting solution, temperature of coagulation bath and addictives on the crystalline structure were also discussed. The results showed that the crystalline modification of cellulose membrane made by NMMO process is cellulose Ⅱ. With increasing of concentration of casting solution, temperature of coagulation bath and dosage of GPE, the crystallinity of membrane increases. However, the addition of NH4Cl reduces the crystallinity degree of the membrane.