纯物理法制备高长径比纤维素纳米纤维的研究

Preparation of cellulose nanofibers with high aspect ratio by pure physical method

为了制备具有高长径比、直径均一的纤维素纳米纤维,采用N-甲基吗啉-N-氧化物(NMMO)水溶液溶胀和超声波处理相结合的纯物理方法,研究了溶胀和超声波处理条件对纤维素裂纤效果的影响,得到制备纤维素纳米纤维的最佳工艺条件:NMMO水溶液质量分数为76%,溶胀温度为100℃,溶胀时间为4 h,超声时间为1 h。扫描电镜和透射电镜测试表明,所制得的纤维素纳米纤维为纤丝状,平均直径约30 nm,长度为几微米左右。X-射线衍射分析表明,所得纤维素纳米纤维为纤维素Ⅰ型结晶结构,结晶度较原料棉浆粕降低。

Cellulose nanofibers（CNFs） with high aspect ratio and uniform particle size are prepared by physical swelling-ultrasonic fibrillate method. The optimal processing conditions are as follows： 76% of the concentration of Nmethylmorpholine-N-oxide（NMMO） aqueous solution,100℃ of swelling temperature,4 hours of swelling time and 1hour of ultrasonic time. The morphology of CNFs is studied by scanning electron microscopy（SEM） and transmission electron microscopy（TEM）. The results show that the average diameter of CNFs is about 30 nm and the length is in the range of several microns. X-ray diffraction analysis shows that the obtained CNFs remain its original cellulose I crystal structure. Their crystallinity is lower than that of raw cotton pulp.