Mechanism of dissolution of cellulose in non-aqueous dissolving systems. Review

Голова, Л. К.; Куличихин, В. Г.; Papkov, S. P.

doi:10.1016/0032-3950(86)90354-0

Cited by 15 publications

(9 citation statements)

References 26 publications

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confidence: 99%

“…The extremely tempting conversion to technologies with direct dissolution of cellulose could allow reducing consumption of chemicals by ten times in comparison to consumption in viscose and cuprammonium processes, facilitating recycling, and decreasing and improving the cleanness of harmful industrial discharges. Attempts to reach these goals have been examined in many publications [1][2][3][4][5][6][7][8][9][10].Many substances have been tested as solvents of cellulose:caustic soda solution, which causes significant swelling of cellulose and dissolves it, but only at a maximum degree of polymerization (DP) of 150-200; such a DP is totally insufficient for manufacturing fibres; zinc chloride solution of 65% concentration, which allows obtaining sufficiently concentrated solutions of cellulose; this process could not be developed due to its rapid breakdown;St. Petersburg State University of Technology and Design.…”

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Lyocell fibres based on direct dissolution of cellulose in N-methylmorpholine N-oxide: Development and prospects

Perepelkin

2007

Fibre Chem

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The scientific principles of direct dissolution of cellulose in the NMMOwater system demonstrate the major possibility of obtaining concentrated spinning solutions and spinning hydrated cellulose fibres from them. The specific features of the properties of NMMO (high boiling point and insufficient thermal stability) that dissolves the NMMOwater system (narrow concentration range, optimum for dissolution of cellulose) makes it necessary to recycle the washing water by evaporating it, which causes high power consumption for this process. It is expedient to examine the possibilities of membrane technologies, including electrodialysis, for solving problems of recycling the solvent and cutting power consumption. However, this path only allows partially concentrating used washing water, since there is the danger of crystallization of NMMO di-and monohydrate. Spinning through an air gap from highly viscous solutions with long relaxation times at high spinneret draw ratios results in highly oriented fibres with high tensile rigidity (high deformation modulus). Fabrication of fibres whose properties correspond to ordinary viscose fibres will perhaps require going away from highly viscous solutions to a lower concentration and spinning by the ordinary wet method, but the volume of solvent used increases significantly, recycling it is more difficult, and power consumption increases. For the same reason of high orientation, the fibres exhibit important fibrillation when wet, and a peach skin effect is formed in the finished textiles. To reduce fibrillation, special treatments of the fabrics must be used, biofinishing, for example. During use of the articles, fibrillation can reappear, in laundering, for example. The technology for fabricating fibres of the Lyocell type requires solving many problems. Developing research on selecting alternative solvents and dissolving systems for direct dissolution of cellulose to obtain concentrated spinning solutions is simultaneously useful.An important part of the scientific and engineering legacy of A. I. Meos is dedicated to cellulose and cellulose fibres. In his lectures to students on man-made fibre technology, he spoke of the dream of researchers of finding a direct solvent of cellulose practically suitable for creating technology for fabrication of hydrated cellulose fibres. This dream came true, but only after he was no longer with us.Direct dissolution of cellulose to obtain concentrated solutions and spin fibres and films from them has been the object of research to develop the corresponding technologies for many years. The extremely tempting conversion to technologies with direct dissolution of cellulose could allow reducing consumption of chemicals by ten times in comparison to consumption in viscose and cuprammonium processes, facilitating recycling, and decreasing and improving the cleanness of harmful industrial discharges. Attempts to reach these goals have been examined in many publications [1][2][3][4][5][6][7][8][9][10].Many substances have been tested as solvents of ce...

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Lyocell fibres based on direct dissolution of cellulose in N-methylmorpholine N-oxide: Development and prospects

Perepelkin

2007

Fibre Chem

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“…Using the direct solvent NMMO with water content of about 8% makes it possible to obtain Lyocell fibers from concentrated cellulose solutions (up to 18%) [ 18 ]. The use of NMMO with a low water content is associated with high melting points of NMMO and obtaining solutions [ 19 ]. This imposes restrictions on the possible ways of processing solutions into fibers.…”

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confidence: 99%

The Thermal Behavior of Lyocell Fibers Containing Bis(trimethylsilyl)acetylene

et al. 2021

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This study focuses on the preparation of carbon fiber precursors from solutions of cellulose in N‑methylmorpholine‑N‑oxide with the addition of bis(trimethylsilyl)acetylene, studying their structural features and evaluating thermal behavior. The introduction of a silicon‑containing additive into cellulose leads to an increase in the carbon yield during carbonization of composite precursors. The type of the observed peaks on the differential scanning calorimetry (DSC) curves cardinally changes from endo peaks intrinsic for cellulose fibers to the combination of endo and exo peaks for composite fibers. For the first time, coefficient of thermal expansion (CTE) values were obtained for Lyocell fibers and composite fibers with bis(trimethylsilyl)acetylene (BTMSA). The study of the dependence of linear dimensions of the heat treatment fibers on temperature made it possible to determine the relation between thermal expansion coefficients of carbonized fibers and thermogravimetric curves, as well as to reveal the relationship between fiber shrinkage and BTMSA bis(trimethylsilyl)acetylene content. Carbon fibers from composite precursors are obtained at a processing temperature of 1200 °C. A study of the structure of carbon fibers by X‑ray diffraction, Raman spectroscopy, and transmission electron microscopy made it possible to determine the amorphous structure of the fibers obtained.

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“…NMMO exists in several thermodynamically equilibrium crystal-hydrate forms, and, with decreasing water content, their dissolving ability increases, but simultaneously the melting point of crystal-hydrates increases [ 10 ]. Dissolution of cellulose starts with monohydrate (water content 13.3% and T m ~80 °C).…”

Section: Introductionmentioning

confidence: 99%

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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Mechanism of dissolution of cellulose in non-aqueous dissolving systems. Review

Cited by 15 publications

References 26 publications

Lyocell fibres based on direct dissolution of cellulose in N-methylmorpholine N-oxide: Development and prospects

Lyocell fibres based on direct dissolution of cellulose in N-methylmorpholine N-oxide: Development and prospects

The Thermal Behavior of Lyocell Fibers Containing Bis(trimethylsilyl)acetylene

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

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