University of Sfax, LMSE, Faculty of Science, BP 802, 3018 Sfax, Tunisia.
Univ. Grenoble Alpes, CNRS, Grenoble INP, LRP, F-38000 Grenoble, France.
Carbohydr Polym. 2022 Jun 15;286:119308. doi: 10.1016/j.carbpol.2022.119308. Epub 2022 Mar 4.
Twin-screw extrusion (TSE) is a recent strategy used to prepare nanocelluloses at high solid contents. However, various aspects of the mechanism of disintegration and the role of fiber pretreatment remain to be elucidated. Oxidized cellulose fibers with carboxyl contents between 300 and 700 μmol·g were extruded in the presence of polyvinyl alcohol (PVA) at a 80/20 (w/w) ratio, to produce high-consistency nanocellulose gels at 15 wt% solid content, ready for use in multiple applications. The influence of the origin of the pulps and the oxidation treatment on the efficiency of fiber disintegration was evaluated by porosity measurement. The rheological properties of the nanocellulose-PVA gels and the mechanical properties and transparency of the resulting nanopapers were studied as well. Combining TSE and rotor-stator dispersion or short sonication homogenization contributed to enhancing the fibrillation during extrusion, providing a method to increase the fraction of nanocellulose in a much less energy-consuming manner.
双螺杆挤出（TSE）是一种最近用于制备高固含量纳米纤维素的策略。然而，纤维预处理的解体机制和作用的各个方面仍有待阐明。用聚醋酸乙烯酯（PVA）在 80/20（w/w）的比例存在下将羧基含量在 300 和 700μmol·g 之间的氧化纤维素纤维进行挤出，以在 15wt%的固含量下生产高浓度纳米纤维素凝胶，可用于多种应用。通过孔隙率测量评估了纸浆来源和氧化处理对纤维解体效率的影响。还研究了纳米纤维素-PVA 凝胶的流变性能以及所得纳米纸的机械性能和透明度。TSE 与转子-定子分散或短超声匀化相结合有助于在挤出过程中增强纤维的纤维化，提供了一种以更节能的方式增加纳米纤维素分数的方法。
