Department of Forest Science, Federal University of Lavras, C.P. 3037, 37200-900 Lavras, MG, Brazil; Université Grenoble Alpes, CNRS, Grenoble INP (Institute of Engineering Univ. Grenoble Alpes), LGP2, 38000, Grenoble, France.
Department of Forest Science, Federal University of Lavras, C.P. 3037, 37200-900 Lavras, MG, Brazil.
Int J Biol Macromol. 2022 Jul 31;213:780-790. doi: 10.1016/j.ijbiomac.2022.06.012. Epub 2022 Jun 9.
This study aimed to evaluate the properties of cellulose nanofibers (CNFs) with different hemicellulose contents and cellulose II polymorphs. A link was found between these polysaccharides and the properties of CNFs. A decrease in crystallinity (from 69 to 63%) and changes in the crystalline structure of cellulose subjected to an alkaline environment were observed, promoting the partial conversion of cellulose I to cellulose II (from 2 to 42%) and preventing CNFs production at NaOH concentrations higher than 5%. Most treatments showed pseudoplastic fluid behavior, except for the 10% NaOH treatment over 2 h, which showed Newtonian fluid behavior. The quality index of the reference CNFs (TEMPO-oxidized) was the highest (80 ± 3), followed by that of the 5% NaOH-treated (68 ± 3 and 22% energy savings compared to the untreated sample), and the untreated (63 ± 3) samples; and the 10% NaOH treatments had quality indices of 51 ± 3 and 32 ± 1, respectively.
本研究旨在评估具有不同半纤维素含量和纤维素 II 多晶型的纤维素纳米纤维 (CNF) 的性能。发现这些多糖与 CNF 性能之间存在关联。在碱性环境下，纤维素的结晶度（从 69%降至 63%）和结晶结构发生变化，促进了纤维素 I 向纤维素 II 的部分转化（从 2%增至 42%），并阻止了在 NaOH 浓度高于 5%时 CNF 的生成。大多数处理均表现出假塑性流体行为，只有 10% NaOH 处理 2 小时以上表现出牛顿流体行为。参考 CNF（TEMPO 氧化）的质量指数最高（80±3），其次是 5% NaOH 处理（68±3，与未处理样品相比节能 22%）和未处理（63±3）样品；而 10% NaOH 处理的质量指数分别为 51±3 和 32±1。
