Regenerated cellulose by the Lyocell process, a brief review of the process and properties

Zhang, Shaokai; Chen, Chunxia; Duan, Chao; Hu, Hui‐Chao; Li, Hailong; Li, Jianguo; Liu, Yishan; Ma, Xiaojuan; Stavik, Jaroslav; Ni, Yonghao

doi:10.15376/biores.13.2.zhang

Cited by 123 publications

(71 citation statements)

References 46 publications

(85 reference statements)

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“…Microphotographs of the surface and transverse cleavage of fibers coagulated in alcohol at various temperatures and washed with water and dried are presented in Figure 7. Lyocell fibers, unlike viscose fibers, have a cross-sectional shape close to a circle [48]. When precipitated into alcohol, the cross-sectional surface of the obtained fibers has a similar shape, with a furrowed texture on the surface of the fiber.…”

Section: Structure and Morphology Of The Solvent And Precursorsmentioning

confidence: 96%

“…The average fiber diameter is 14-20 microns. Lyocell fibers, unlike viscose fibers, have a cross-sectional shape close to a circle [48]. When precipitated into alcohol, the cross-sectional surface of the obtained fibers has a similar shape, Fibers 2020, 8, 43 with a furrowed texture on the surface of the fiber.…”

Section: Structure and Morphology Of The Solvent And Precursorsmentioning

confidence: 97%

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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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Section: Structure and Morphology Of The Solvent And Precursorsmentioning

confidence: 96%

Section: Structure and Morphology Of The Solvent And Precursorsmentioning

confidence: 97%

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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“…To overcome the problems related to the extensive use of CS 2 , it has been developed the so called second cellulose processing that is based on the dissolution of cellulose in aqueous systems using solvation-mediators. For example, in cupro process cellulose fibers produce via a spinning process using a copper-based complexing agent such as tetraaminecopper dihydroxide (Burchard et al 1994;Zhang et al 2018). Another class of aqueous cellulose solvents is based on alkaline systems in which cellulose should be activated in a pretreatment step.…”

Section: Solution-spinningmentioning

confidence: 99%

Cellulose-based fiber spinning processes using ionic liquids

et al. 2022

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Cellulose, a natural, renewable, and environment friendly biopolymer, has been considered as a sustainable feedstock in the near future. However, only 0.3% of cellulose is today processed since it is not soluble in conventional solvents due to the strong hydrogen bonding network and highly ordered structure. Hence, the search of effective and eco-friendly solvents for cellulose dissolution has been a key pillar for decades. In the recent years, ionic liquids (ILs) have been proposed as green solvents for cellulose and have been applied for the production of cellulose-based fibers. This review aims to focus the attention toward fiber spinning methods of cellulose based on ILs, as well as recent progress in cellulose dissolution using ILs. Moreover, the development of cellulosic fibers blended with other biopolymers, and cellulose composites are presented. Finally, different applications of cellulose fibers and composites are summarized and discussed.

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“…It is typically cited as being the worlds most abundant polymer [1], and for this reason it is an interesting candidate for packaging and clothing applications in particular. In this context, several efforts have been made to dissolve cellulose into single chains in order to either form more elastic films (for packaging applications) or to be able to weave fabrics with specific properties, such as in the lyocell process [2]. Cellulose is a glucose β (1→4) polymer, where each glucose unit is rotated 180 • along the screw axis as illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

Computational Study of the Dissolution of Cellulose into Single Chains: the Role of the Solvent and Agitation

Bering¹,

Torstensen²,

Lervik³

et al. 2021

Preprint

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We investigate the dissolution mechanism of cellulose using molecular dynamics simulations in both water and a mixture solvent consisting of water with Na + , OH - and urea. As a first computational study of its kind, we apply periodic external forces that mimic agitation of the suspension. Without the agitation, the bundles do not dissolve, neither in water nor solvent. In the solvent mixture the bundle swells up with significant amounts of urea entering the bundle, as well as more water than in the bundles subjected to pure water. We also find that the mixture solution stabilizes cellulose sheets, while in water these immediately collapse into bundles. Under agitation the bundles dissolve more easily in the solvent mixture than in water, where sheets of cellulose remain that are bound together through hydrophobic interactions. Our findings highlight the importance of urea in the solvent, as well as the hydrophobic interactions, and are consistent with experimental results.

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Regenerated cellulose by the Lyocell process, a brief review of the process and properties

Cited by 123 publications

References 46 publications

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

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

Cellulose-based fiber spinning processes using ionic liquids

Computational Study of the Dissolution of Cellulose into Single Chains: the Role of the Solvent and Agitation

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