Radiation assisted pre-oxidation of polyacrylonitrile fiber: Graphite formation and lower crystal size revealed by 2D WAXD at a synchrotron facility

Zhang, Wenli; Wang, Mouhua; Cheng, Li; Wang, Guozhong

doi:10.1016/j.polymdegradstab.2020.109264

Cited by 11 publications

(8 citation statements)

References 38 publications

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“…It can easily lift an object that exceeds 4,000 times its own weight ( Figure 1C ), can be twisted into yarns by a customized yarn-spinning device ( Movie 1), and also can be knitted with cotton yarns into a piece of composite fabric ( Figures 1D,E ). For a case, the results from both XRD (two broad peaks around 2θ = 24° and 2θ = 45°; Wang et al, 2015 ; Wu et al, 2017 ) and Raman spectroscopy (the characteristic bands of D band at 1,335 cm −1 and G band at 1,587 cm −1 ; Bukalov et al, 2018 ; Zhang et al, 2020 ) indicate that the carbonized silks are composed of amorphous carbon ( Figures 1F,G ). For another case, a negligible azimuthal intensity anisotropy of wide-angle x-ray two dimensional (2D) scattering patterns reveals an isotropic carbon arrangement in the CBSs ( Figure 1H ; Cho et al, 2017 ).…”

Section: Resultsmentioning

confidence: 99%

Animal Silk-Derived Amorphous Carbon Fibers for Electricity Generation and Solar Steam Evaporation

Ren

Ling

2021

Front. Chem.

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Animal silk-derived carbon materials are of interest to various applications, such as smart cloth and wearable sensors. However, it remains a challenge to massively transform silks into continuous carbon fibers. In this work, carbon fibers based on two kinds of animal silks, i.e., Bombyx mori (B. mori) silk and Antheraea pernyi (A. pernyi) silk, are prepared by using a large-scale-capable one-step heating process without any additives or activation process. These carbon fibers and yarns are electroconductive and mechanically robust. To expand the application of these carbonized silks, we further weaved them with cotton yarns to obtain composite fabrics with different textures and evaluated their performance for solar steam evaporation. Our results confirmed that the advantages of these composite fabrics in light absorption, large surface area, and hierarchical liquid transport channels allowed them to be used as a solar steam generation for desalination and sewage treatment. In addition, we reported that these conductive carbon fibers could be assembled into fluidic nanogenerators to generate electricity from the water flow. This work is expected to guide a large-scale preparation and use of animal silk-derived amorphous carbon fibers.

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Section: Resultsmentioning

confidence: 99%

Animal Silk-Derived Amorphous Carbon Fibers for Electricity Generation and Solar Steam Evaporation

Ren

Ling

2021

Front. Chem.

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“…[24,27] As a result, the amorphous region experienced transformation to the crystalline region under fixed tension. [17] However, after being maintained at 240 °C for 15 min, the diffraction peak intensity of both PAN fibers decreased, suggesting a decline in the crystallinity. This can be attributed to the obvious cyclization reaction (as seen in Figure 2) occurring at this temperature, causing the melting of the crystals in the crystal region.…”

Section: Crystal Structure Of Pan During the Pre-oxidation Processmentioning

confidence: 98%

“…The Hermans orientation of the PAN fibers increased significantly at this stage, indicating an increase in crystal orientation under fixed tension. [17] As a result, this crystal increasing stage can delay the maintenance time in order to maximize the degree of orientation of the crystal. Afterward, the temperature was raised to 240 °C and maintained for 15 min.…”

Section: Crystal Structure Of Pan During the Pre-oxidation Processmentioning

confidence: 99%

“…Under drawing and heating, some of the molecular chain crystals in the amorphous region crystallize, increasing crystal size and crystallinity. [15][16][17] As the pre-oxidation temperature increases, cyclization and oxidation reactions occur in the crystal region, causing the crystalline phase of PAN fiber to destroy gradually, resulting in reduced crystal orientation, crystal size, and crystallinity. [9,10] At the ultimate stage of pre-oxidation, the crystal structure of PAN almost disappears, and the orientation reaches its minimum.…”

Section: Introductionmentioning

confidence: 99%

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Research on Improving the Pre‐Oxidation Process of the Excellent Mechanical Strength Carbon Fiber

Cui,

Liu,

Song

et al. 2023

Macro Chemistry & Physics

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This study used Synchrotron Wide‐Angle X‐ray Diffraction (WAXD) and Synchrotron Small Angle X‐ray Scattering (SAXS) to carry out in‐situ study of the pre‐oxidation process of Polyacrylonitrile (PAN) fibers with two different preparation processes. Through analysis of 2D WAXD/SAXS data, This study divides the evolution of PAN fiber's crystal and microporous structures during pre‐oxidation into three and two stages, respectively. The evolution of PAN fiber's crystal structure during pre‐oxidation can be divided into three stages: 1) Initial stage: small‐sized crystals melt, crystal orientation decreases, and no cyclization reactions occur. 2) Intermediate stage: cyclization reactions happen in the amorphous region, leading to increased crystal size, crystal orientation, and crystallinity. 3) Final stage: cyclization reactions occur in the crystal region, resulting in reduced crystal size and orientation. The evolution of microporous structure can be divided into two stages: microporous shrinkage stage and microporous expansion stage. These features were analyzed using 2D WAXD/SAXS techniques. This study provides valuable references and guidance for the industrial production of PAN fibers by exploring the mechanism of the pre‐oxidation process in‐depth.This article is protected by copyright. All rights reserved

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“…Recently, Zhang et al investigated the microstructures of ox-PAN fibers derived from irradiated and unirradiated PAN, respectively, by WAXS; however, to the best of our knowledge, no such comparison has been made for the final CFs derived therefrom. [57] In CFs, the carbon mainly exists in form of a turbostratic modification similar to graphite, but with the graphene planes corrugated, curved, cross-linked, and with little long-range order. [56,[58][59][60] Moreover, the graphite-like crystallites in this structure are only a few nm in size.…”

Section: Wide-angle X-ray Scattering (Waxs) Analysis Of Cfs Derived From Tex-panmentioning

confidence: 99%

High‐Performance Carbon Fibers Prepared by Continuous Stabilization and Carbonization of Electron Beam‐Irradiated Textile Grade Polyacrylonitrile Fibers

König

Bauch

Herbert

et al. 2021

Macro Materials & Eng

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The manufacturing of high-performance carbon fibers (CFs) from low-cost textile grade poly(acrylonitrile) (PAN) homo-and copolymers using continuous electron beam (EB) irradiation, stabilization, and carbonization on a kilogram scale is reported. The resulting CFs have tensile strengths of up to 3.1 ± 0.6 GPa and Young's moduli of up to 212 ± 9 GPa, exceeding standard grade CFs such as Toray T300. Additionally, the Weibull strength and modulus, the microstructure, and the morphology of these CFs are determined.

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Radiation assisted pre-oxidation of polyacrylonitrile fiber: Graphite formation and lower crystal size revealed by 2D WAXD at a synchrotron facility

Cited by 11 publications

References 38 publications

Animal Silk-Derived Amorphous Carbon Fibers for Electricity Generation and Solar Steam Evaporation

Animal Silk-Derived Amorphous Carbon Fibers for Electricity Generation and Solar Steam Evaporation

Research on Improving the Pre‐Oxidation Process of the Excellent Mechanical Strength Carbon Fiber

High‐Performance Carbon Fibers Prepared by Continuous Stabilization and Carbonization of Electron Beam‐Irradiated Textile Grade Polyacrylonitrile Fibers

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