Abstract

TEMPO cellulose nanofibril (TEMPO-CNF) suspensions in the viscoelastic regime are often used as rheological modifiers and additives to prepare composites and hydrogels. Therefore, understanding their rheology is important, including the role of morphology and surface charge. The viscosity of TEMPO-CNF suspensions decreases with higher homogenization pressure or number of homogenization passes, and higher surface charges. To compare the effects of morphology and surface charge more robustly, a rheological “flow index” parameter is developed. Zero-shear viscosity η₀ is first determined from the Cross model, and the flow index k is defined through the scaling relation \(\hbox{log}_{10}(\eta_{0})=k\cdot c-\hbox{log}_{10}(\eta_{{\rm water}}),c \) being concentration and η_water the viscosity of pure water. The flow index decreases with higher homogenization energy and higher surface charge. The flow index condenses many viscosity points into a single parameter, establishing a clear and concise one-to-one relationship between TEMPO-CNF rheology and fibril characteristics, which can be used for quality control and/or benchmarking.

Graphic abstract

中文翻译：

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TEMPO-CNF粘弹性体系的悬浮液：利用流变参数捕获形态和表面电荷的影响

摘要

粘弹性体系中的TEMPO纤维素纳米原纤维（TEMPO-CNF）悬浮液通常用作流变改性剂和添加剂，以制备复合材料和水凝胶。因此，了解其流变学很重要，包括形态学和表面电荷的作用。TEMPO-CNF悬浮液的粘度随较高的均质压力或均质通过次数以及较高的表面电荷而降低。为了更稳健地比较形态和表面电荷的影响，开发了流变“流动指数”参数。零剪切粘度η ₀，首先从交叉模型确定，并且流动指数ķ通过标度关系定义\（\ hbox中{日志} _ {10}（\ eta_ {0}）= K \ CDOT C- \ hbox {log} _ {10}（\ eta _ {{\ rm water}}），c \）浓度为η_水，纯水的粘度为η。流动指数随着较高的均质能和较高的表面电荷而降低。流动指数将许多粘度点浓缩为一个参数，从而在TEMPO-CNF流变性和原纤维特性之间建立了清晰简洁的一对一关系，可用于质量控制和/或基准测试。

图形摘要