Rheological properties of cotton pulp cellulose dissolved in 1‐butyl‐3‐methylimidazolium chloride solutions

Abstract

Rheological properties of cotton pulp dissolved in 1‐butyl‐3‐methylimidazolium chloride ([Bmim]Cl) solutions were characterized using an advanced rheometer. The complex viscosity, dynamic modulus, and shear viscosity at different temperature were studied. In the steady shear measurements, all the solutions show a shear‐thinning behavior at high shear rates. The complex viscosity as a function of frequency was fitted by extended Carreau–Yasuda model. In all cotton pulp/[Bmim]Cl solutions, the complex dynamic viscosity (η*) and steady shear viscosity (ηa) followed the Cox–Merz rule only at lower frequency. The effects of tested temperature on viscosity and viscoelastic behavior of the solutions were also investigated. The value of activation energy for the dissolution of cotton pulp in ionic liquids was 65.28 kJ/mol at the concentration of 10 wt% and was comparable with the ones for the dissolution of cellulose in NMMO. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers

Biobased Protic Ionic Liquids as Sustainable Solvents for Wool Keratin/Cellulose Simultaneous Dissolution: Solution Properties and Composited Membrane Preparation

“…C0W100 behaves as a Newtonian fluid, and shear-thinning behavior becomes more obvious when cellulose increases. This non-Newtonian behavior is mainly because of the alignment of the cellulose/wool keratin chains in the direction of the shear field and the reduction of entanglement number when the shear rate is increased . Viscosity–temperature dependence of C20W80 solution is also observed, as shown in Figure b, indicating that the apparent viscosity decreases with the increase of temperature, which is consistent with classical polymer solutions .…”

“…Viscosity–temperature dependence of C20W80 solution is also observed, as shown in Figure b, indicating that the apparent viscosity decreases with the increase of temperature, which is consistent with classical polymer solutions . Increasing the temperature will facilitate the thermal movement of the macromolecular of wool keratin and cellulose, thereby increasing the intramolecular distance, which is more conducive to the disentanglement between molecular chains . As the entanglement points decrease, the chain segments are more likely to be oriented, thus resulting in a decreased viscosity.…”

“…This non-Newtonian behavior is mainly because of the alignment of the cellulose/wool keratin chains in the direction of the shear field and the reduction of entanglement number when the shear rate is increased. 68 Viscosity−temperature dependence of C20W80 solution is also observed, as shown in Figure 3b, indicating that the apparent viscosity decreases with the increase of temperature, which is consistent with classical polymer solutions. 69 Increasing the temperature will facilitate the thermal movement of the macromolecular of wool keratin and cellulose, thereby increasing the intramolecular distance, which is more conducive to the disentanglement between molecular chains.…”

Insight into the Cosolvent Effect of Cellulose Dissolution in Imidazolium-Based Ionic Liquid Systems

“…Room-temperature ionic liquids (ILs) are considered to be powerful “green” solvents as they have negligible vapor pressure and high thermal stability and are nonflammable. − It was reported in 2002 for the first time that cellulose can be directly dissolved in imidazolium-based ILs without any pretreatment, and the dissolved cellulose can be easily regenerated by precipitation upon addition of water or other common solvents . Since then, many kinds of ILs have been reported to act as cellulose solvents. − Although significant progress has been made in this field, some problems, such as slow dissolution rate, high dissolution temperature, and high viscosity of the dissolution systems, have yet to be resolved. Thus, advances toward improved processes for the dissolution of cellulose are still necessary.…”

Two-Dimensional FTIR as a Tool to Study the Chemical Interactions within Cellulose-Ionic Liquid Solutions

“…Cellulose/ionic liquid solution rheology properties are dependent on cellulose concentration and degree of polymerization together with the frequency and shear rate [5,6]. Typically studies have revealed cellulose solutions to be shearing thinning and dependent on temperature [5,[7][8][9]. However, cosolvents or water content can also influence cellulose solution rheology behaviours [10,11].…”