Abstract

The rheological properties of aqueous suspensions of spherical and needle-shaped nanocellulose particles in the range of 25–70°C are compared. Nanocellulose samples are obtained by the acid hydrolysis of cotton cellulose fibers in H₂SO₄ (61–65%) at 25–45°C. The shape of nanocellulose particles affects the yield strength and non-Newtonian character of the suspension flow. In the shear stress region above 100 Pa, a decrease in effective viscosity occurs, depending on the shape of the particles and the temperature of the suspension. In the region of the shear rate close to the yield strength, the activation energy of the viscous flow of suspensions of spherical particles is 12 kJ/mol; needle-shaped particles, 18 kJ/mol. Features of the rheological behavior are due to the fact that spherical particles are involved mainly in rotational-translational motion, while the needle-like particles are oriented in the direction of flow.

中文翻译：

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纳米纤维素水悬浮液的流变行为

摘要

比较了球形和针状纳米纤维素颗粒在25–70°C范围内的水悬浮液的流变特性。纳米纤维素样品是通过将棉纤维素纤维在H ₂ SO _4中进行酸水解而获得的（61–65％）在25–45°C下。纳米纤维素颗粒的形状影响悬浮液的屈服强度和非牛顿特性。在高于100 Pa的剪切应力区域中，有效粘度会降低，具体取决于颗粒的形状和悬浮液的温度。在接近屈服强度的剪切速率范围内，球形颗粒悬浮液的粘性流的活化能为12 kJ / mol。针状颗粒，18 kJ / mol。流变行为的特征归因于以下事实：球形颗粒主要参与旋转和平移运动，而针状颗粒则沿流动方向取向。