氯化铁体系绿色高效催化制备纳米纤维素

 采用氯化铁（FeCl₃）催化水解法制备纳米纤维素（CNC），考查了反应温度、反应时间、FeCl₃用量、超声时间等因素对CNC得率的影响。结果表明，反应温度110℃，反应时间60 min，FeCl₃质量分数10%，超声时间180 min 时，CNC 得率最高，达22%。采用傅里叶红外光谱仪（FTIR）、透射电镜（TEM）、X 射线衍射仪（XRD）、Zeta 电位测定仪等对CNC 的结构、形貌、谱学性质和晶体性能、分散在液相介质中带电颗粒的有效电荷进行了表征，结果表明，电镜观察CNC 为棒状，直径20~50 nm，长200~300 nm；XRD 分析表明，CNC 属于纤维素Ⅰ，结晶度达到76.2%，较纸浆纤维显著提高；Zeta 电位测定结果显示，CNC 在水溶液中具有良好的分散稳定性。该催化制备体系具有绿色环保、反应条件温和、容易控制、操作简单等优点，单根纳米纤维呈棒状，纤维之间相互交织成网状，有利于其在复合材料中的应用。

Environmentally-friendly and Efficient Preparation of Cellulose Nanocrystals by FeCl3-catalyzed Hydrolysis of Cellulose

Cellulose nanocrystals (CNC) were prepared by FeCl₃-catalyzed hydrolysis of cellulose. The effects of temperature, reaction time, the content of FeCl₃ and ultrasonic time on the yield of CNC were analyzed. The results show that at the temperature of 110℃, with reaction time of 60 min, 10% FeCl₃, and ultrasonic time of 180 min, the yield of CNC reached 22%. The structural, morphological, spectroscopic and crystal properties of CNC and the charges of charged particles dispersed in the liquid phase were investigated using fourier transformation infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Zetasizer. The TEM image shows that CNC are rod-like with the diameter of 20-50 nm, the length of 200-300 nm. XRD spectra shows that CNC are celluloseⅠ with crystallinity of 76.2%. Zeta potential text shows that CNC are well dispersed in water. This catalyst system is environmentally friendly, with mild reaction conditions and simple operations. The obtained CNC have a network structure, which benefits their application in composites.