荷梗纤维素纳米晶须的制备及其表征分析

Preparation and Characterization of Nanocrystalline Whiskers of Lotus-stem Cellulose

摘要:

采用单因素与Box-Behnken响应面实验相结合的方法，以荷梗纤维素纳米晶须的得率为指标，优化晶须的制备工艺，并对其形貌结构和理化特性进行表征。最佳制备工艺条件为料液比5:100（g/mL）、水解时间3.50 h、水解温度49 ℃，此条件下晶须的得率为65.61%。扫描和透射电镜结果表明硫酸水解将纤维素转化为短棒状的均匀纳米结构；X射线衍射和红外数据显示成功制备了荷梗纤维素纳米晶须，并保持了纤维素基本的化学结构，属于纤维素I型；粒径分析和PDI值显示随水解程度的增加，制备的晶须的粒径越小。经Zeta电位分析，制备的晶须悬浮液中纳米颗粒的表面状态和稳定性较好，因其Zeta电位绝对值> 35 mV；热分析表明晶须最佳热分解温度为243 ℃，热稳定性较好。综上，该文成功利用农业废弃物荷梗制备了纤维素纳米晶须，其具备良好的理化性质，相较于其他来源的晶须粒径更小，稳定性更佳。该制备工艺常用且高效，且证明可用于稳定Pickering乳液，从而提高莲藕副产物资源利用，促进行业减损增值及可持续发展。

Abstract:

Using the yield as an indicator, the preparation of nanowhiskers of lotus-stem cellulose was optimized by single-factor experiments combined with Box-Behnken response surface design. Moreover, the morphology, structure, and physical and chemical characteristics of the whiskers were comprehensively characterized. The optimal preparation conditions were as follows: solid-to-liquid ratio of 5:100 (g/mL), hydrolysis time of 3.50 h, and hydrolysis temperature of 49 ℃. Under these conditions, the yield of the cellulose nanowhiskers was 65.61%. Scanning and transmission electron microscopy observations revealed that cellulose was hydrolyzed by sulfuric acid and converted into a uniform, short, rod-like nanostructure. X-ray diffraction and infrared analysis indicated that lotus-stem cellulose nanowhiskers were successfully prepared and the product still maintained the basic chemical structure of cellulose, with the cellulose I structure. The particle size and polydispersity index (PDI) suggest that as the degree of hydrolysis increases, the particle size of the whiskers decreases. The absolute zeta potential of the whisker suspension was greater than 35 mV, which indicates a good surface structure and stability of the nanoparticles in the suspension. Thermal analysis demonstrated that the optimal thermal decomposition temperature of the whiskers is 243 ℃, indicating good thermal stability. In conclusion, cellulose nanowhiskers were successfully prepared from lotus stem, an agricultural waste, and the products exhibited good physical and chemical properties. Compared with nanowhiskers produced from other sources, nanowhiskers of lotus-stem cellulose have a smaller particle size and better stability. The process for preparing lotus -stem-cellulose nanowhiskers is simple and efficient, and it has been proven that the product can be used to stabilize Pickering emulsions. The technique enables enhanced utilization of by-products from lotus-root production and facilitates loss reduction, value addition, and sustainable development of the industry.