The Role of Isobutanol as a Precipitant of Cellulose Films Formed from N-Methylmorpholine N-Oxide Solutions: Phase State and Structural and Morphological Features

Makarov, Igor; Голова, Л. К.; Vinogradov, M. I.; Миронова, М. В.; Левин, И. С.; Бондаренко, Г. Н.; Shandryuk, G. A.; Архарова, Н. А.; Куличихин, В. Г.

doi:10.1134/s0965545x19050110

Cited by 8 publications

(16 citation statements)

References 13 publications

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“…As is seen in the photos, the film washed in IPA is turbid and only after holding such a film in water and drying it becomes transparent. Changes in the optical properties of the film can be associated with both structural and morphological features [19,[39][40][41] and the presence of a residual solvent [33]. The study of the chemical composition by elemental analysis showed that the nitrogen content in the film formed and washed in IPA is about 0.5%.…”

Section: Resultsmentioning

confidence: 99%

“…Apparently, it is the formation of liquid droplets by coagulation of a solution of cellulose in IPA and IBA is a source of major defects in the dried film. As mentioned above, this defect is mainly inherent in films obtained by coagulation of the solution in IBA [ 33 ]. As an example, a microphotograph of the transverse cleavage of such a film is shown in Figure 10 a.…”

Section: Resultsmentioning

confidence: 99%

“…Along with this work, the process of coagulation of a cellulose solution into isobutanol was studied in [33]. If we compare the rates of coagulation of the solution with isopropanol and isobutanol, the coagulation process is almost twice as slow for isobutanol.…”

Section: Low-temperature Coagulationmentioning

confidence: 99%

“…An IR spectroscopy study of the NMMO monohydrate-IBA system revealed that the alcohol is bound by hydrogen bonds with water, and so strongly that part of the water can be released from the NMMO and exist as a separate liquid phase or, possibly, a water-alcohol associate, which leads to an interaction between NMMO and alcohol through water [33]. If the cellulose solution is formed in an alcohol bath and then the fiber or film is washed with water, the NMMO and alcohol residues are completely washed out.…”

Section: Introductionmentioning

confidence: 99%

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A Role of Coagulant in Structure Formation of Fibers and Films Spun from Cellulose Solutions

et al. 2020

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Replacing the aqueous coagulation bath with an alcoholic one during spinning cellulose fibers (films) from solutions in N-methylmorpholine-N-oxide leads to a radical restructuring of the hydrogen bonds net of cellulose and, as a result, to a change in the structure and properties of the resulting material. By the method of optical interferometry, it was possible to identify the intrinsic features of the interaction of the solvent and isomeric alcohols and to construct phase diagrams of binary systems describing the crystalline equilibrium. Knowledge of the phase states of the system at different temperatures renders it possible to exclude the process of solvent crystallization and conduct the spinning in pseudo-homogeneous conditions. The structure and morphology of samples were studied using X-ray diffraction and scanning electron microscopy methods for a specific coagulant. When the solution under certain conditions is coagulated at contact with alcohol, the solvent may be in a glassy state, whereas, when at coagulation in water, an amorphous-crystalline structure is formed. The structural features of cellulose films obtained by coagulation of solutions with water and alcohols help to select potential engineering or functional materials (textile, packaging, membranes, etc.), in which their qualities will manifest to the best extent.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Low-temperature Coagulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Role of Coagulant in Structure Formation of Fibers and Films Spun from Cellulose Solutions

et al. 2020

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“…For cellulose solutions in NMMO, such transformations are described in detail for coagulation into aqueous solutions of NMMO [15][16][17] and alcohols [18][19][20]. Along with a change in the chemical composition of the baths, their temperature was also varied in [18,21], which made it possible to change the structure of the spun fibers. It is important to note that if the formed film (fiber) after coagulation into alcohol passes through a second bath with a different liquid, its structure and properties change [21,22].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Alcohol Precipitants on Structural and Morphological Features and Thermal Properties of Lyocell Fibers

Makarov

Голова

Vinogradov

et al. 2020

Fibers

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This research examines the possibilities of regulating the structure of cellulose precursor fibers spun from solutions in N-methylmorpholine-N-oxide when replacing aqueous coagulation baths with thermodynamically softer alcohol baths at different temperatures. The fibers were spun by the dry jet–wet method in isobutanol coagulation baths with a temperature of 25 °C and 70 °C. The study of the phase state of the solvent–coagulant system using viscometry and point cloud methods revealed the temperature-concentration regions of the single-phase and two-phase states of the system. Using elemental analysis, DSC (differential scanning calorimetry) and XRD (X-ray diffraction) methods, it was shown that just spun fibers, due to the presence of a residual amount of solvent and coagulant in them, regardless of the temperature of the precipitator, have an amorphous structure. Additional washing with water completely washed away the solvent and coagulant as well, however, the structure of cellulose changes slightly, turning into a defective amorphous-crystalline one. A relationship was found between the phase composition, structure, and properties of just spun fibers and precursors washed with water. Thus, the loss of structural ordering of both just spun and washed cellulose fibers leads to a decrease in strength characteristics and an increase in deformation. The thermal behavior of the fibers is determined by their phase composition. Fibers just spun into hot alcohol containing a coagulant and traces of solvent acquire thermal stability up to 330 °C. During the pyrolysis of the obtained precursors up to 1000 °C, the value of the carbon yield doubles. The amorphized structure of the obtained fibers allows us to consider it as a model when analyzing the transformation of the structure of precursors during thermolysis.

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Aerobic Oxidation of 5‐Hydroxymethylfurfural via Hydrogen Bonds Reconstruction with Ternary Deep Eutectic Solvents

Chu,

Lu,

Zhao

et al. 2023

ChemSusChem

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Hydrogen bonding effect exists widely in various chemical and biochemical systems, primarily stabilizing the molecular structure as a positive factor. However, the presence of intermolecular hydrogen bonds among biomass molecules results in a formidable challenge for the efficient utilization of biomass resources. Here in, a novel strategy of “hydrogen bonds reconstruction” was developed by a series of ternary deep eutectic solvent (DESs) as molecular scissors, which disrupting the initial intermolecular hydrogen bonds and reconstructing the new ones to increase the reactivity of the biomass‐based compound. The DESs played a crucial role in enhancing the reactivity of 5‐hydroxymethylfurfural (HMF) and promoting its oxidation through reconstructing the hydrogen bonds interactions. Furthermore, DESs was also found to activate the Anderson‐type catalyst Na5IMo6O24 (IMo6) through an electron‐transfer mechanism, which facilitated the generation of oxygen vacancies and significantly enhances its ability to activate molecular oxygen. With this novel catalytic system, oxidation of HMF exhibited remarkable efficiency as HMF was almost entirely converted into FFCA with an impressive yield of 98 % under the optimized conditions. This finding offers novel insights into the utilization of biomass resources and endows the solvent with new functions in the chemical reaction.

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The Role of Isobutanol as a Precipitant of Cellulose Films Formed from N-Methylmorpholine N-Oxide Solutions: Phase State and Structural and Morphological Features

Cited by 8 publications

References 13 publications

A Role of Coagulant in Structure Formation of Fibers and Films Spun from Cellulose Solutions

A Role of Coagulant in Structure Formation of Fibers and Films Spun from Cellulose Solutions

The Effect of Alcohol Precipitants on Structural and Morphological Features and Thermal Properties of Lyocell Fibers

Aerobic Oxidation of 5‐Hydroxymethylfurfural via Hydrogen Bonds Reconstruction with Ternary Deep Eutectic Solvents

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