We investigated the gelation and microstructure of cellulose nanocrystals (CNCs) in nonionic hydroxyethyl cellulose (HEC) solutions. Cellulose nanocrystals (CNCs) with a particle length of 90 nm and width of 8 nm currently produced by acid hydrolysis of wood pulp were used in this study. The microstructures of CNCs/polymer suspensions were investigated by performing linear small amplitude oscillatory shear (SAOS) and nonlinear large amplitude oscillatory shear (LAOS), in addition to constructing CNCs phase diagrams and measuring steady-state shear viscosities. Significant viscosity increases at low shear rates coupled with high shear thinning behaviors were observed in CNCs in HEC solutions above the overlapping concentration of HEC. The physical strength of CNCs/HEC solution gels increased with the increase in CNCs concentration and resembled the weakly crosslinked gels according to the scaling of linear dynamic mechanical experiments. According to LAOS analysis, CNCs/HEC mixtures showed type III behavior with intercycle stress softening, while the samples showed stress stiffening in single cycles.

Graphical abstract

中文翻译：

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探索水性纤维素纳米晶体 (CNC)-羟乙基纤维素 (HEC) 混合物的凝胶化

我们研究了非离子羟乙基纤维素 (HEC) 溶液中纤维素纳米晶体 (CNC) 的凝胶化和微观结构。本研究使用目前通过木浆酸水解产生的颗粒长度为 90 nm 和宽度为 8 nm 的纤维素纳米晶体 (CNC)。除了构建 CNCs 相图和测量稳态剪切粘度外，还通过执行线性小振幅振荡剪切 (SAOS) 和非线性大振幅振荡剪切 (LAOS) 来研究 CNCs/聚合物悬浮液的微观结构。在高于 HEC 重叠浓度的 HEC 溶液中，在 CNC 中观察到在低剪切速率下粘度显着增加以及高剪切稀化行为。CNCs/HEC溶液凝胶的物理强度随着CNCs浓度的增加而增加，并且根据线性动态力学实验的缩放类似于弱交联的凝胶。根据 LAOS 分析，CNCs/HEC 混合物表现出 III 型行为，具有循环间应力软化，而样品在单个循环中表现出应力硬化。

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