Viscoelasticity and Solution Stability of Cyanoethylcellulose with Different Molecular Weights in Aqueous Solution.

Qian Li,Jinping Zhou,Yujie Li,Yifan Chen,Yuehu Li,Zehua Jin

doi:10.3390/molecules26113201

Qian Li, Jinping Zhou + Show 4 more

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https://doi.org/10.3390/molecules26113201

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Abstract

Water-soluble cellulose ethers are widely used as stabilizers, thickeners, and viscosity modifiers in many industries. Understanding rheological behavior of the polymers is of great significance to the effective control of their applications. In this work, a series of cyanoethylcellulose (CEC) samples with different molecular weights were prepared with cellulose and acrylonitrile in NaOH/urea aqueous solution under the homogeneous reaction. The rheological properties of water-soluble CECs as a function of concentration and molecular weight were investigated using shear viscosity and dynamic rheological measurements. Viscoelastic behaviors have been successfully described by the Carreau model, the Ostwald-de-Waele equation, and the Cox–Merz rule. The entanglement concentrations were determined to be 0.6, 0.85, and 1.5 wt% for CEC-11, CEC-7, and CEC-3, respectively. All of the solutions exhibited viscous behavior rather than a clear sol-gel transition in all tested concentrations. The heterogeneous nature of CEC in an aqueous solution was determined from the Cox–Merz rule due to the coexistence of single chain complexes and aggregates. In addition, the CEC aqueous solutions showed good thermal and time stability, and the transition with temperature was reversible.

Highlights

In recent years, natural ecosystems have been damaged due to the overuse of a wide variety of plastic polymers
Nanocellulose obtained from natural polymers by breaking up the amorphous regions are used as reinforcement fillers for the preparation of nanocomposites
The shear viscosity–shear rate curves of the CEC-11 aqueous solution exhibited a linear relationship at low concentration (c < 0.8 wt%), suggesting a feature of Newtonian fluid

Summary

Introduction

Natural ecosystems have been damaged due to the overuse of a wide variety of plastic polymers. Natural polymers as alternatives to the traditional petroleum-based materials have attracted much attention. Cellulose is the most abundant, renewable, and biodegradable natural polymer on Earth [2,3]. Cellulose-based materials, including regenerated cellulose or cellulose derivatives, have been created in the application of packaging, food, cosmetics, and environmentally friendly biocomposites. Cellulose ethers (CEs), one of the most important cellulose derivatives, are produced by the reaction of cellulose with an etherification agent in the presence of aqueous NaOH. For more than 60 years, CEs have been widely used in biology, pharmaceutics, food, cosmetic, and paint industries [7,8].

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