Changes of polyacrylonitrile fiber fine structure during thermal stabilization

Fazlitdinova, A. G.; Tyumentsev, V. A.; Podkopayev, S. A.; Швейкин, Г. П.

doi:10.1007/s10853-010-4473-9

Cited by 44 publications

(32 citation statements)

References 19 publications

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“…The typical sharp peaks at 16.8° and 29.3° are belonged to (100) and (010) diffraction of the as‐received PAN, respectively, which is accepted by most of the researchers. While the dispersed peak at 25.8° is controversial, some researchers ascribed it to the diffraction of amorphous molecular chain . With the temperature increasing, the peaks at 25.8° and 29.3° disappear at 280 °C, and the peak at 16.8° disappear at 800 °C, that means the molecular chain structure was totally decomposed at 800 °C.…”

Section: Resultsmentioning

confidence: 99%

The conjugated plane formed in polyacrylonitrile during thermal stabilization

Shuai

Cao

2016

J of Applied Polymer Sci

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The formation process and mechanism of the pseudo‐graphite sheets of polyacrylonitrile (PAN) during thermal treatment in inert atmosphere were investigated by thermo‐gravimetry (TG) and X‐ray diffraction (XRD). According to the results, the conjugated plane originally formed during stabilization was proposed as the basic planar structure of the pseudo‐graphite sheets, and it was connected and stacked to form pseudo‐graphite microcrystal through chain scission reaction and non‐carbon atoms elimination reaction in 280–450 °C and 800–1300 °C respectively. The in situ measurements for time dependence of ultraviolet‐visible (UV‐vis) and Fourier transform infrared spectra (FTIR) were applied to study the conjugated plane of PAN during isothermal stabilization. It was found that with the higher temperature the conjugated plane forms more rapidly, and it has higher conjugated extent with the extending of heating time. The FTIR data showed that both cyclization and dehydrogenation are beneficial to the evolution of conjugated plane in the first 3 h, but only cyclization continues after 3 h at 250 °C. Further investigation indicated that stabilized PAN with large quantity and high conjugated extent of the conjugated plane would contribute to get large size of pseudo‐graphite microcrystal after carbonization, which is consistent with the former assumption. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43890.

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Section: Resultsmentioning

confidence: 99%

The conjugated plane formed in polyacrylonitrile during thermal stabilization

Shuai

Cao

2016

J of Applied Polymer Sci

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“…Thus, stabilisation is a kinetic reaction and driven by diffusion mechanisms. An increase in process temperature and longer dwell times enhance the reactions and the stabilisation degree, respectively . The stabilisation degree can further be enhanced by a preoxidation step before stabilisation of fibres which leads to higher carbon yields, a more distributed exothermic heat peak, a minor porosity and a higher crystallite orientation to fibre axis .…”

Section: Process‐structure‐relations and Their Technical Potentialsmentioning

confidence: 99%

Influence of processing parameters on the properties of carbon fibres – an overview

Jäger

Cherif

Kirsten

et al. 2016

Materialwissenschaft Werkst

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Several studies have shown the importance of carbon fibres (CF) for different high technology markets. In recent years, different fibre types with improved properties have been developed for those markets. Polyacrylonitrile (PAN) copolymers are the basic raw material (precursor) for these fibres in the predominant case. Improvements of the mechanical fibre properties have mainly been achieved by defect reduction during the manufacturing process. Thus, commercial carbon fibres with tensile strengths up to approx. 7000 MPa are currently available. It can be shown that the strengths can be further increased (in the direction of graphene properties) when the relationship between process conditions and defects due to manufacturing of the fibres is better understood. In this context, novel processes like electron beam crosslinking or UV‐activation have proven to be very promising. The article gives an overview about the current situation in the field of carbon fibres development and particularly shows recent shortcomings with respect to novel applications.

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“…The crystallinity of fiber was calculated from the area of the crystalline diffraction peaks and the amorphous zone using Hinrichen's method as the Eq. 4 [13].…”

Section: Characterizationmentioning

confidence: 99%

Structure and properties of partially cyclized polyacrylonitrile‐based carbon fiber—precursor fiber prepared by melt‐spun with ionic liquid as the medium of processing

Liu

Han

Chen

et al. 2015

Polymer Engineering & Sci

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Carbon fiber has many excellent properties. Currently, the precursor fiber of polyacrylonitrile (PAN)-based carbon fiber is made from solution by wet or dry spinning process that requires expensive solvents and costly solvent recovery. To solve this problem, we developed a meltspun process with ionic liquid as the medium of processing. The melt-spun precursor fiber exhibited partially cyclized structure. The structure and properties of the melt-spun PAN precursor fiber were analyzed by combination of scanning electron microscope, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, thermogravimetry, ultraviolet spectroscopy, flotation technique, sound velocity orientation test, linear density, and tensile strength tests. The results showed that the tensile strength of melt-spun PAN precursor fiber was fairly high reached up to 7.0 cN/dtex. The reason was the low imperfect morphology and a cyclized structure formed by in situ chemical reaction during meltspun process. Due to the existence of partially cyclized structure in the melt-spun PAN precursor fiber, exothermic process was mitigated and the heat evolved decreased during thermal stabilization stage in comparison with commercial precursor fibers produced by solution-spun, which could shorten the residence time of thermal stabilization and reduce the cost of final carbon fiber. POLYM. ENG. SCI., 55:2722-2728, 2015

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Changes of polyacrylonitrile fiber fine structure during thermal stabilization

Cited by 44 publications

References 19 publications

The conjugated plane formed in polyacrylonitrile during thermal stabilization

The conjugated plane formed in polyacrylonitrile during thermal stabilization

Influence of processing parameters on the properties of carbon fibres – an overview

Structure and properties of partially cyclized polyacrylonitrile‐based carbon fiber—precursor fiber prepared by melt‐spun with ionic liquid as the medium of processing

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