纳米纤维素超微结构的表征与分析

Characterization and Analysis of Ultrastructure of Nano-cellulose Crystal

采用场发射环境扫描电镜(FEGE-SEM)、场发射透射电镜(FETEM)和原子力显微镜(AFM)等仪器对硫酸水解法制备的纳米纤维素(NCC)进行超微结构的表征与分析。结果表明:NCC在水分散体系中可形成非常稳定的胶状溶液。由FEGE-SEM观察到微晶纤维素(MCC)呈不规则形状,直径约为15μm。通过硫酸水解制得形状较规整的短棒状NCC,直径范围在2～50nm之间。FETEM观察结果与AFM成像基本一致,FETEM观察大多数NCC直径约2～24nm,长度为50～450nm。AFM观察样品尺寸与FETEM观察相比所测得的样品尺寸偏大,这与其质地较软有关。X射线衍射(XRD)图谱表明NCC属于纤维素Ⅰ型,与MCC相比,结晶度由72.25%增大到77.29%。

The uhrastructure characterization and analysis of nano-cellulose crystal （NCC） preparing from sulfuric acid hydrolysis were investigated using field emission gun environment scanning electron microscopes （FEGE-SEM） , field emission transmission electron microscopy （ FETEM ） and atomic force microscopy （AFM）. The results showed that NCC dispersed in water can form a very stable suspension. It can be observed that microcrystalline cellulose （MCC） has irregular shape with diameter about 15 μm using FEGE-SEM. Regular short rod-like NCC can be obtained by sulfuric acid hydrolysis. The diameter of NCC was in the range of 2-50 nm. The results of AFM were in agreement with FETEM. Images of FETEM clearly reveals that the diameter of NCC was about 2-24 nm, with the length of 50-450 nm. The size of NCC observed from AFM was a little bigger than that of FETEM, it can be contributed to the soft texture of cellulose. The X-ray diffraction （XRD） pattern shows that the NCC has the cellulose Ⅰ crystal form. The crystallinity of NCC increased from 72.25 % to 77.29 %.