Structure of Polyacrylonitrile Fibers Produced from N-Methylmorpholine-N-Oxide Solutions

Makarov, Igor; Голова, Л. К.; Vinogradov, M. I.; Левин, И. С.; Sorokin, S. E.

doi:10.1007/s10692-019-10020-9

Cited by 7 publications

(8 citation statements)

References 17 publications

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“…As can be seen from Figure 7 , for the obtained cellulose films, the main reflexes (marked in Figure 7 ) are in the typical cellulose allomorph II position (2θ~12.1°, ~20.1°, and ~21.5°) (planes 1–10, 110, and 020) [ 11 , 36 ]. For PAN, the diffraction patterns show reflections in the regions 2θ = 16.9°, 2θ = 29.4°, and a broad reflection in the region 25.7° [ 28 ], marked with a red dotted line. Interestingly, the introduction of PAN into cellulose in an amount of up to 5 wt.% does not lead to a significant change in the form of diffraction patterns; only reflection characteristics of cellulose are observed on them [ 30 ].…”

Section: Resultsmentioning

confidence: 99%

“…In previous works, the preparation of polyacrylonitrile (PAN) solutions [ 27 , 28 ] and joint cellulose-PAN solutions in NMMO, as well as the composite fibers [ 29 ], was demonstrated. The introduction of up to 5 wt.% of PAN into the cellulose matrix did not significantly affect the rheological behavior of the mixed solutions but allowed for changing the mechanical and thermal properties of fibers [ 30 , 31 ].…”

Section: Introductionmentioning

confidence: 99%

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Membranes Based on Cellulose and Copolymers of Acrylonitrile Prepared from Joint Solutions

Makarov,

Shambilova,

Vinogradov

et al. 2023

Membranes

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Cellulose and copolymers of acrylonitrile (PAN) are characterized by their chemical resistance to several conventional solvents. Therefore, these polymers are often used to obtain membranes for the recovery of such solvents. In this work, for the first time, composite membranes formed from highly concentrated mixed solutions based on cellulose and PAN are considered (the total content of polymers is 18 wt.%). For mixed solutions, the morphology and rheological behavior were evaluated. It is shown that the resulting solutions are two-phase, and their morphology depends on the components’ ratio and the system’s history. The non-monotonous change in the viscosity with the PAN content indicates a specific interaction of cellulose and PAN in N-methylmorpholine-N-oxide solutions. The rheological behavior of mixed solutions allows for their processing in conditions identical to those of cellulose solutions. The introduction of PAN into the cellulose matrix promotes a decrease in the structural order in the system, affecting the membranes’ transport properties. For composite membranes, it was found that with an increase in the content of the PAN phase, the retention of Remazol and Orange decreases, while the observed values are several times higher than those for cellulose membranes. The permeability of ethanol increases with increasing terpolymer content.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Membranes Based on Cellulose and Copolymers of Acrylonitrile Prepared from Joint Solutions

Makarov,

Shambilova,

Vinogradov

et al. 2023

Membranes

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“…Thus, based on the brief review, to obtain high-strength fibers it is necessary to work with a high molecular weight polymer [ 22 ], and it is advisable to spin the fibers from highly concentrated solutions. Namely, this combination of polymer and solution characteristics makes it possible to exclude defects caused by both coagulation processes [ 23 , 24 , 25 ] and uneven shrinkage [ 19 ], leading to the formation of fibers with a non-circular cross-section and a corresponding deterioration in mechanical properties [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

High Molecular Weight AB-Polybenzimidazole and Its Solutions in a Complex Organic Solvent: Dissolution Kinetics and Rheology

et al. 2022

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AB-polybenzimidazole (ABPBI) dissolution kinetics in an eco-friendly complex acid-free solvent based on dimethyl sulfoxide (DMSO), methanol and KOH, and the rheological behavior of their solutions are investigated. The optimal component ratio of solvent providing the complete ABPBI dissolution is determined. Methanol containing dissolved KOH contributes to the creation of a single-phase superbasic medium, which accelerates and improves the polymer solubility in a mixture with DMSO, significantly reducing the viscoelasticity of the resulting solution. The optimum methanol content is up to 60 wt.% related to DMSO. The polymer dissolution rate increases by 5 times in this composition. It found the polymer concentration of 9% is close to the dissolution limit due to the strong solution structuring, which is probably associated with an increase in the amount of water released during the KOH-methanol-DMSO interactions. As a result, the conditions for obtaining high concentrated solutions in a complex, mainly organic solvent for fiber spinning are developed. The viscoelastic properties of solutions are measured in the concentration range of 1–9% at temperatures of 20–50 °C. The flow activation energy for 7 and 9% solutions decreases by 1.5 and 2.3 times, respectively, as the content of methanol in the complex solvent increases from 10 to 60%.

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“…In order to further meet the demand for the high performance of carbon fiber, many contributions have been done in the modification of spinning solution, which include doping high-performance materials in spinning liquid or choose a new solvent. In this case, chemical and structural transformations occur already at the stage of fiber production [ 1 , 2 , 3 , 4 ]. However, thermal stabilization is another key process of the preparation for polyacrylonitrile (PAN)-based carbon fibers, in which PAN linear molecular chains are transformed into a heat-resistant ladder structure through chemical reactions.…”

Section: Introductionmentioning

confidence: 99%

Formation and Evolution of sp2 Hybrid Conjugate Structure of Polyacrylonitrile Precursor during Stabilization

Dong

You

et al. 2021

Materials

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The generated sp2 hybrid conjugate structure of a C atom, which resulted from the chemical reaction affected by temperature and time, is an effective six-membered ring planar structure of the final carbon fiber. This kind of hybrid conjugate structure determined the formation of the final structure and mechanical properties of carbon fiber. In this paper, the formation and evolution of sp2 hybrid conjugated structures of PAN precursor during thermal stabilization were investigated by Raman, UV-vis and 13C-NMR methods. The results indicated that with the increase of stabilization temperature, the degree of the sp2 hybrid conjugated structure of stabilized PAN fiber increases “linearly”, while the content of the sp2 hybrid carbon atoms increases with “S-type”. The final sp2 hybrid conjugated ring structure is mainly composed of single-ring, double-ring, triple-ring, and double-bond structures. Compared with the time factor, the temperature effect plays a decisive role in the formation of the sp2 hybrid conjugate structure.

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Structure of Polyacrylonitrile Fibers Produced from N-Methylmorpholine-N-Oxide Solutions

Cited by 7 publications

References 17 publications

Membranes Based on Cellulose and Copolymers of Acrylonitrile Prepared from Joint Solutions

Membranes Based on Cellulose and Copolymers of Acrylonitrile Prepared from Joint Solutions

High Molecular Weight AB-Polybenzimidazole and Its Solutions in a Complex Organic Solvent: Dissolution Kinetics and Rheology

Formation and Evolution of sp2 Hybrid Conjugate Structure of Polyacrylonitrile Precursor during Stabilization

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