Unique gelation and rheological properties of the cellulose/CO2-based reversible ionic liquid/DMSO solutions

Zhang, Lihua; Shi, Wentao; Wang, Junqin; Jin, Longming; Hu, Gang; Zheng, Qiang; Xie, Haibo; Chen, Peng

doi:10.1016/j.carbpol.2019.115024

Cited by 17 publications

(11 citation statements)

References 56 publications

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“…44 The freshly prepared cellulose solution was transparent and the dark-field POM image indicated complete dissolution of cellulose in the solution (Figure S1). When the cellulose solution was stocked at room temperature (25 °C) or a high temperature (50 °C) for 2 weeks, no precipitation or gelation 49 was observed (Figure S1). These results indicated that the modified procedure not only ensured the complete dissolution of cellulose but also enhanced the stability of the obtained cellulose solution.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Structure and Properties of Regenerated Cellulose Fibers Based on Dissolution of Cellulose in a CO₂ Switchable Solvent

Liu

et al. 2021

ACS Sustainable Chem. Eng.

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Development of an effective, nontoxic, and easy-to-process novel cellulose dissolution system for the preparation of regenerated cellulose fibers is of great importance and necessity for a greener and more sustainable future, with which the traditional viscose process with serious pollution can be gradually substituted. Herein, we demonstrated the successful utilization of a CO2 switchable solvent, a novel cellulose derivative dissolution system resembling viscose but without releasing toxic gases such as CS2 and H2S, for the preparation of regenerated cellulose fibers. The corncob cellulose raw material can be readily dissolved completely after the capture of CO2 in dimethyl sulfoxide (DMSO) with 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU), resulting in cellulose spinning dope with high stability. Results showed that regenerated cellulose fibers with smoother surface morphology, a higher degree of crystallinity, and satisfactory mechanical properties were obtained under mild conditions with relatively slower double diffusion. Moreover, drawing treatment further increased the degree of crystallinity and orientation and the mechanical properties. All fibers had a dense structure, circular cross sections, no fibrillation, and high thermal stability. The regenerated cellulose fibers had degrees of crystallinity and orientation and tensile strength of 75.3%, 0.82, and 1.05 cN/dtex and 68.4%, 0.82, and 1.00 cN/dtex, respectively, in water and 30 vol % DMSO coagulation baths with a drawing ratio of 2.0 and 1.5, respectively. This work illustrated that the CO2 switchable solvent, which could be considered as “green viscose”, is a good candidate with great potential for the preparation of regenerated cellulose fibers with high performance and various functionalities in the future.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Structure and Properties of Regenerated Cellulose Fibers Based on Dissolution of Cellulose in a CO₂ Switchable Solvent

Liu

et al. 2021

ACS Sustainable Chem. Eng.

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“…Similarly, the G” of PAPS in response to pH was in perfect agreement with the G’ ( Figure 6 B). In addition, we found that the G” at pH 1–6 and pH 13–14 was always higher than the G’ over the range of scanning frequencies, thus creating liquid-like behavior, while the G’ at pH 7–12 was always higher than the G”, thus leading to solid-like behavior ( Figure S4 ) [ 40 , 46 ]. This feature was also visualized in Figure 6 C, where there were two intersections of G” and G’ between pH 6–7 and pH 13–14, causing the samples to show different characteristics at different pH levels ( Figure 6 D).…”

Section: Resultsmentioning

confidence: 99%

High-Efficiency Extraction of Pantoea alhagi Exopolysaccharides Driven by pH-Related Changes in the Envelope Structure

Sun

Wang

et al. 2022

Molecules

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Increasing numbers of exopolysaccharides and their properties have been explored. However, the difficulty of extracting high-viscosity exopolysaccharides has hindered their further industrialization. In this research, we explored a strategy based on encapsulated structure control under different pH to efficiently extract Pantoea alhagi exopolysaccharides (PAPS). Results showed that at pH levels of 6, 12, and 13, the extraction efficiency of PAPS was elevated, and the yield did not decrease. The rheological properties of the pH−12-treated PAPS were better than those of PAPS treated at pH 7, while the pH−6-treated PAPS decreased. The effects of pH−12-treated PAPS on soil macroaggregates and soil’s water evaporation rate were similar to those of PAPS treated at pH 7. In addition, we observed that treatment at pH 12 produced a significantly reduced encapsulated structure compared with treatment at pH 7. The proportion of unsaturated fatty acids after treatment at pH 12 was higher than after treatment at pH 7, which may result in reduced encapsulated structure in pH−12 conditions. These results enrich the understanding of the effect that alters pH conditions on the encapsulated structure to improve the extraction efficiency of exopolysaccharides and provide a theoretical basis for the extraction of exopolysaccharides with extreme viscosity.

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“…The results in Figure c revealed that the elasticity modulus deviated from the scaling law in the terminal region and developed a plateau at low frequencies. This result indicated that a crosslinked structure was formed during the high-temperature isothermal treatment. − Hence, was this crosslinking process physical or chemical in nature? Was it reversible or irreversible?…”

Section: Resultsmentioning

confidence: 99%

Competition between Chain Extension and Crosslinking in Polyamide 1012 during High-Temperature Thermal Treatments as Revealed by Successive Self-Nucleation and Annealing Fractionation

Wang

et al. 2021

Macromolecules

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Successive self-nucleation and annealing (SSA) is an efficient way to thermally fractionate semicrystalline polymers. SSA thermal fractions have distinct melting points corresponding to different lamellar thicknesses. SSA was employed to investigate the in-situ evolution of lamellar thicknesses of polyamide 1012 (PA1012) during high-temperature thermal treatments. A competition between chain growth and crosslinking occurred during the thermal treatments as detected (as a function of time) by SSA, rheology, and dissolution behavior. Based on a master curve of "time−temperature superposition" at a reference temperature, the mechanism for lamellar thickness evolution was divided into three stages: initially, chemical crosslinking predominated. As the number of end groups rapidly increased, linear chain growth and crosslinking occurred simultaneously. Eventually, linear chain growth was increased by chain end-group reactions. The structural changes provoked by the thermal treatments enhanced the mechanical and heat resistance properties of PA1012. This work provides guidance for the design for high-performance polyamide materials.

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Unique gelation and rheological properties of the cellulose/CO2-based reversible ionic liquid/DMSO solutions

Cited by 17 publications

References 56 publications

Structure and Properties of Regenerated Cellulose Fibers Based on Dissolution of Cellulose in a CO₂ Switchable Solvent

Structure and Properties of Regenerated Cellulose Fibers Based on Dissolution of Cellulose in a CO₂ Switchable Solvent

High-Efficiency Extraction of Pantoea alhagi Exopolysaccharides Driven by pH-Related Changes in the Envelope Structure

Competition between Chain Extension and Crosslinking in Polyamide 1012 during High-Temperature Thermal Treatments as Revealed by Successive Self-Nucleation and Annealing Fractionation

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Unique gelation and rheological properties of the cellulose/CO2-based reversible ionic liquid/DMSO solutions

Cited by 17 publications

References 56 publications

Structure and Properties of Regenerated Cellulose Fibers Based on Dissolution of Cellulose in a CO2 Switchable Solvent

Structure and Properties of Regenerated Cellulose Fibers Based on Dissolution of Cellulose in a CO2 Switchable Solvent

High-Efficiency Extraction of Pantoea alhagi Exopolysaccharides Driven by pH-Related Changes in the Envelope Structure

Competition between Chain Extension and Crosslinking in Polyamide 1012 during High-Temperature Thermal Treatments as Revealed by Successive Self-Nucleation and Annealing Fractionation

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Structure and Properties of Regenerated Cellulose Fibers Based on Dissolution of Cellulose in a CO₂ Switchable Solvent

Structure and Properties of Regenerated Cellulose Fibers Based on Dissolution of Cellulose in a CO₂ Switchable Solvent