Abstract

Herein, the rheological properties of 2,2,6,6-tetramethylpiperidin-1-oxyl radical-oxidized cellulose nanofiber (TOCNF) suspensions individualized using high-intensity ultrasonication were investigated. The surface charge density of the nanofibers and sonication time were 0.659–1.24 mmol/g and 30–600 s, respectively. With increased surface charge density, the minimum time required for disintegration decreased due to the repulsive force between oxidized nanofibers. Additionally, increased sonication time enhanced the TOCNF nanofibrillation, thereby forming networks between the nanofibers. Further disintegrating TOCNF increased shear viscosity and yield stress of TOCNF suspensions. Based on the crowding factor theory, the relationship between the average fiber width and sonication time was found at various surface charge densities. Ultrasonication was considered as an energy saving and precisely controllable nanofibrillation method. This research shows the change of fiber shapes during the nanofibrillation process, and suggests an estimation of disintegration degree by the relationship between the rheological properties and TOCNF morphology.

Graphic abstract

中文翻译：

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受控的高强度超声分解细化纳米原纤化纤维素纳米纤维的流变学研究

摘要

在本文中，研究了使用高强度超声法分离的2,2,6,6-四甲基哌啶-1-氧基自由基氧化纤维素纳米纤维（TOCNF）悬浮液的流变特性。纳米纤维的表面电荷密度和超声处理时间分别为0.659-1.24 mmol / g和30-600 s。随着表面电荷密度的增加，由于氧化纳米纤维之间的排斥力，崩解所需的最短时间减少了。另外，增加的超声处理时间增强了TOCNF纳米原纤化，从而在纳米纤维之间形成网络。进一步崩解的TOCNF增加了TOCNF悬浮液的剪切粘度和屈服应力。基于拥挤因子理论，发现了各种表面电荷密度下平均纤维宽度与超声处理时间之间的关系。超声处理被认为是一种节能且可精确控制的纳米原纤化方法。这项研究表明了纳米纤化过程中纤维形状的变化，并通过流变性质和TOCNF形态之间的关系提出了崩解程度的估计。

图形摘要