Effect of Bath Concentration on Coagulation Kinetics at the Early Stage during Wet Spinning of PAN Copolymer Nascent Fibers

Zhou, Pengpeng; Lü, Chunxiang; Shi, Jiyou; Li, Kaixi; He, Fei; Zhang, Shouchun; Li, Yonghong

doi:10.1080/00222348.2010.503133

Cited by 16 publications

(13 citation statements)

References 22 publications

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“…1a) because of the phase-separation during the coagulation, which was an essential step of the wetspinning and signicantly affected the microstructure of the ber. [29][30][31] When the PAN/DMSO jet le the spinneret to enter into the coagulation bath (DMSO/water), the DMSO (solvent) diffused out of the ber, while the water (nonsolvent) diffused into it due to the concentration difference between the ber and the coagulation bath. The composition of the single-phase PAN/ DMSO solution thereby changed gradually until the spinodal curve was crossed, and then the system entered the unstable two-phase region (as shown in Scheme 1b (le), the composition variation path from A to B).…”

Section: Resultsmentioning

confidence: 99%

“…An interpenetrating 3D meso-/macroporous network was observed in the PF (Fig. 1a) because of the phase-separation during the coagulation, which was an essential step of the wetspinning and significantly affected the microstructure of fiber [29][30][31] . When the PAN/DMSO jet left the spinneret to enter into the coagulation bath (DMSO/water), the DMSO (solvent) diffused out of the fiber, while the water (nonsolvent) diffused into it due to the concentration difference between the fiber and the coagulation bath.…”

Section: The Microstructure Of Porous Carbon Fiber Samplesmentioning

confidence: 99%

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Nitrogen- and oxygen-enriched 3D hierarchical porous carbon fibers: synthesis and superior supercapacity

et al. 2015

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Supplementary InformaƟon (ESI) available: SEM and TEM images, the porous structure parameters, XRD patterns, electrochemical capacitive performances using a two-electrode and a three-electrode cell.. See Nitrogen-and oxygen-enriched hierarchical porous carbon fiber was fabricated by the phase-separable wet-spinning and the subsequent chemical activation of polyacrylonitrile (PAN) precursor. The wet-spinning could readily offer an interpenetrating 3D meso-/macro-porous network owing to the phase-separation of PAN in the coagulation bath (DMSO/ H2O), caused by the different solubility of PAN in DMSO and H2O, and the different content of PAN in fiber and the coagulation bath. The later chemical activation introduced abundant small-sized nanopores within the meso-/macroporous network skeleton. The obtained hierarchical porous carbon fiber exhibited high specific surface area of 2176.6 m 2 g -1 , large pore volume of 1.272 cm 3 g -1 , and was highly doped by heteroatoms of nitrogen and oxygen. When it was used as supercapacitor electrodes, high performance of reversible specific capacitances of 329 F g -1 at 0.1 A g -1 and 223 F g -1 at 20 A g -1 as well as the capacitance retention of 97.6% after 2000 cycles were achieved in a two-electrode cell.

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Section: Resultsmentioning

confidence: 99%

Section: The Microstructure Of Porous Carbon Fiber Samplesmentioning

confidence: 99%

Nitrogen- and oxygen-enriched 3D hierarchical porous carbon fibers: synthesis and superior supercapacity

et al. 2015

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“…The key parameters of the coagulation step are the composition [86,87], temperature [88], and time [89] of the coagulation bath. A higher concentration of the solvent in the lowtemperature coagulation bath at around 19 • C was preferable because of the improved morphologies, such as the increased circular cross-section and reduced diameter (Figure 10), improved molecular orientation, and advanced mechanical performances [90], while there was an optimum solvent concentration of around 70% where the coagulation temperature was maintained at 50 • C. The crystallinity was maximized, while the defects of the crosssection and surface were the least at the optimum concentration of 70% [86].…”

Section: Coagulationmentioning

confidence: 99%

“…Coagulation is fundamentally attributed to the exchange of the outflow solvent and the influent nonsolvent, and the inhomogeneity of the solvent concentration distribution results in dense skin and loose cores [ 83 , 84 , 85 ]. The key parameters of the coagulation step are the composition [ 86 , 87 ], temperature [ 88 ], and time [ 89 ] of the coagulation bath. A higher concentration of the solvent in the low-temperature coagulation bath at around 19 °C was preferable because of the improved morphologies, such as the increased circular cross-section and reduced diameter ( Figure 10 ), improved molecular orientation, and advanced mechanical performances [ 90 ], while there was an optimum solvent concentration of around 70% where the coagulation temperature was maintained at 50 °C.…”

Section: Spinning Processmentioning

confidence: 99%

Designing Materials and Processes for Strong Polyacrylonitrile Precursor Fibers

2021

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Although polyacrylonitrile (PAN)-based carbon fibers have been successfully commercialized owing to their excellent material properties, their actual mechanical performance is still much lower than the theoretical values. Meanwhile, there is a growing demand for the use of superior carbon fibers. As such, many studies have been conducted to improve the mechanical performance of carbon fibers. Among the various approaches, designing a strong precursor fiber with a well-developed microstructure and morphology can constitute the most effective strategy to achieve superior performance. In this review, the efforts used to modulate materials, processing, and additives to deliver strong precursor fibers were thoroughly investigated. Our work demonstrates that the design of materials and processes is a fruitful pathway for the enhancement of the mechanical performance of carbon fibers.

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“…Among all kinds of fibres, PAN fibres have a higher melting point and a greater carbon yield and are considered as the perfect precursors for producing high-property carbon fibres. [5][6][7] In general, the manufacturing process of PANbased carbon fibres contains two important steps: (1) manufacturing excellent PAN precursors and (2) pre-oxidation and carbonization of the precursors. 8,9 During the conversion process of the PAN precursors to carbon fibres, the physical and chemical structures of the precursors undergo a great change, which facilitates important changes in the mechanical properties of the fibres.…”

Section: Introductionmentioning

confidence: 99%

Research on the multi-scale microstructure of polyacrylonitrile precursors prepared by a dry-jet wet spinning process

Chen

Wang

Gao

et al. 2018

High Performance Polymers

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An understanding of the properties of polyacrylonitrile (PAN) precursors is an essential precondition for manufacturing high-performance carbon fibres, and the structure of the precursors has a direct and profound effect on the performance of carbon fibres. In this study, PAN precursors, formed in a multistage coagulation bath, were spun by a dry-jet wet spinning process, and the multi-scale microstructure and morphology of the precursors were investigated by separating the fibrils from the precursors. Scanning electron microscopy and high-resolution transmission electron microscopy were employed to examine the surface morphology, cross-sectional morphology and microstructure of the precursors. X-ray diffraction was used to characterize the crystal structure. The micropore sizes of the precursors were determined with nitrogen adsorption experiments; the adsorption increased after ultrasonic etching and decreased with an increase in the treated concentration. All the results demonstrated that the PAN precursors had a multi-scale microstructure, the precursors consisted of fibrils with diameters of 80–200 nm and the fibrils consisted of some microfibrils with diameters of 20–40 nm, including the periodic tissues with thicknesses of 16–30 nm perpendicular to the fibre axis.

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Effect of Bath Concentration on Coagulation Kinetics at the Early Stage during Wet Spinning of PAN Copolymer Nascent Fibers

Cited by 16 publications

References 22 publications

Nitrogen- and oxygen-enriched 3D hierarchical porous carbon fibers: synthesis and superior supercapacity

Nitrogen- and oxygen-enriched 3D hierarchical porous carbon fibers: synthesis and superior supercapacity

Designing Materials and Processes for Strong Polyacrylonitrile Precursor Fibers

Research on the multi-scale microstructure of polyacrylonitrile precursors prepared by a dry-jet wet spinning process

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