Abstract Although the removal of lignin and hemicelluloses from cellulose pulp to produce fully bleached cellulose nanofibrils (B-CNF) is the most common practice, the presence of residual lignin and hemicelluloses in raw materials for the production of lignin containing cellulose nanofibrils (LCNFs) holds several advantages. In this work, we investigated the effect of residual lignin in Eucalyptus globulus cellulose fibers on the properties of the resulting LCNFs. The stability of the colloidal suspensions was assessed by zeta-potential values and charge density analyses. Morphology of the CNFs was studied using scanning electron microscopy and atomic force microscopy. Fibril diameter and diameter distributions for CNFs with different levels of residual lignin showed a decrease on fiber diameter as the lignin content increases. Differences in the chemical composition of the CNFs was evidenced as indicated in the Fourier-transform infrared spectroscopy spectra, particularly in fingerprint region. Thermal behavior of the CNFs was not altered by the presence of lignin, as indicated by thermogravimetric analysis. Finally, the rheological behavior of the samples was evaluated observing a gel-like behavior as well as an increase of the viscosity in LCNFs with higher lignin contents.

中文翻译：

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残留木质素对纤维素纳米纤丝悬浮液流变学性能的影响

摘要 虽然从纤维素纸浆中去除木质素和半纤维素以生产完全漂白的纤维素纳米纤丝 (B-CNF) 是最常见的做法，但在生产含木质素的纤维素纳米纤丝 (LCNFs) 的原材料中存在残留的木质素和半纤维素几个优点。在这项工作中，我们研究了蓝桉纤维素纤维中残留的木质素对所得 LCNF 性能的影响。胶体悬浮液的稳定性通过 zeta 电位值和电荷密度分析进行评估。使用扫描电子显微镜和原子力显微镜研究了 CNF 的形态。随着木质素含量的增加，具有不同残留木质素水平的 CNF 的原纤维直径和直径分布显示纤维直径减小。如傅立叶变换红外光谱所示，CNF 的化学成分存在差异，特别是在指纹区域。如热重分析所示，CNF 的热行为不会因木质素的存在而改变。最后，评估样品的流变行为，观察凝胶状行为以及具有较高木质素含量的 LCNF 的粘度增加。