龙须草纳米微晶的制备与表征

Preparation and Characterization of Cellulose Nanocrystals from Eulaliopsis binata

用亚氯酸钠和17.5%氢氧化钠对龙须草进行预处理,再以硫酸水解法制备龙须草纳米微晶,采用正交试验优化酸水解条件,并利用场发射扫描电镜、动态光散射、红外光谱、X射线衍射和热重分析对纳米微晶进行表征。研究表明,酸水解条件为硫酸浓度59%,温度45℃,时间2 h,纳米微晶长度、粒径和长径比分别为171.1 nm,17.2 nm和10.3;纳米微晶的纤维素存在纤维素Ⅰ和纤维素Ⅱ两种晶型,其结晶指数为78%;纳米微晶的热裂解起始温度和最大热重损失温度分别为178℃和224.4℃,700℃热降解的残余率为30.6%。

Following the pretreatment with sodium chlorite and 17.5% sodium hydroxide, the cellulose crystals was prepared by sulfuric acid hydrolysis from Eulaliopsis binata, the properties of nanocrystals were characterized by Field Emission Scanning Electron Microscopy（FE-SEM）, Dynamic Light Scattering（DLS）, Fourier Transform Infrared Spectroscopy（FTIR）, X-Ray Diffraction（XRD） and Thermogravimetric Analysis（TGA）. The results indicate that the optimal condition of orthogonal tests is sulfuric acid concentration of 59%, temperature of 45℃ and time of 2 h. the dimension of nanocrystals is length of 171.1 nm, diameter of 17.2 nm and aspect ratio of 10.3, its crystallinity index is 78%, and initial decomposition at 178℃, maximum weight loss at 224.4℃, and the solid residuals at 700℃ is 30.6%. Cellulose Ⅰ and cellulose Ⅱ coexist in the nanocrystals.