College of Science, Gansu Agricultural University, Lanzhou, China.
School of Human Ecology, The University of Texas at Austin, Austin, TX, USA.
J Sci Food Agric. 2020 Sep;100(12):4390-4399. doi: 10.1002/jsfa.10476. Epub 2020 Jun 22.
There is a need to help farmers and industries develop value-added composite and nanocomposite materials from agricultural residuals. Cellulose nanofibers (CNFs) were made using a TEMPO oxidation method and celluloses were prepared by acid-base method and extracting method, which were all from corn stalk, an agricultural residual. The prepared celluloses were dissolved separately in dimethylacetamide/LiCl solvent and CNFs were added at 0.0%, 0.5%, 1.5% and 3.0% to form all-cellulose nanocomposites, and then cast into films. Morphology, structure and properties of the nanocomposite films were characterized using atomic force microscopy, field emission scanning electron microscopy, thermogravimetric analysis, X-ray diffraction and mechanical testing.
The all-cellulose nanocomposite films with different cellulose matrices exhibited good optical transparency and layer structure. The all-cellulose nanocomposite films with cellulose prepared by the extracting method (Composite E) exhibited a higher crystallinity, better thermal stability and higher mechanical strength compared to the all-cellulose nanocomposite films with cellulose prepared by the acid-base method (Composite A).
The crystal structure of the all-cellulose nanocomposite films indicated the coexistence of cellulose I and cellulose II. However, in contrast to Composite A, the diffraction intensity of cellulose I in Composite E was higher than that of cellulose II. This was another reason that the mechanical properties of Composite E were superior to those of Composite A. In addition, the mechanical properties of the all-cellulose nanocomposite films were significantly different when the addition of CNFs reached 3.0% by weight, as indicated by a multiple-range comparison. © 2020 Society of Chemical Industry.
需要帮助农民和工业界从农业残余物中开发增值的复合材料和纳米复合材料。使用 TEMPO 氧化法制备纤维素纳米纤维（CNF），并通过酸碱法和提取法制备纤维素，均来自农业残余物玉米秸秆。将制备的纤维素分别溶解在二甲基乙酰胺/氯化锂溶剂中，并将 CNF 添加到 0.0%、0.5%、1.5%和 3.0%以形成全纤维素纳米复合材料，然后浇铸成膜。使用原子力显微镜、场发射扫描电子显微镜、热重分析、X 射线衍射和力学测试对纳米复合材料膜的形态、结构和性能进行了表征。
不同纤维素基质的全纤维素纳米复合材料膜具有良好的光学透明度和层状结构。与通过酸碱法制备的纤维素（复合材料 A）相比，通过提取法制备的纤维素（复合材料 E）的全纤维素纳米复合材料膜具有更高的结晶度、更好的热稳定性和更高的机械强度。
全纤维素纳米复合材料膜的晶体结构表明纤维素 I 和纤维素 II 共存。然而，与复合材料 A 不同，复合材料 E 中纤维素 I 的衍射强度高于纤维素 II。这是复合材料 E 的机械性能优于复合材料 A 的另一个原因。此外，当 CNF 的添加量达到 3.0%（重量）时，全纤维素纳米复合材料膜的力学性能有显著差异，这通过多重范围比较得到了证实。© 2020 化学工业协会。
