Structure of thermally stabilized PAN fibers

Mathur, R.B.; Bahl, Om P.; Mittal, Jagjiwan; Nagpal, K. C.

doi:10.1016/0008-6223(91)90189-p

Cited by 59 publications

(27 citation statements)

References 14 publications

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“…The peak that appeared around 330°C shows that VGCF's existence promoted the reactions of aromatization and intermolecular crosslinking and helped the molecular chain undergo realignment, reorientation, and reinforcement to a formation of a highly ordered and compact structure which had been found to be helpful for the later carbonization in many studies. 17,18 The evidence for these explanations could be found in the IR and Raman spectra as follows: Figure 5 shows the changes of the IR spectra measured for the 1/0, 9/1, and 3/1 composites with the indicated heat-treatment stages. The main changes are similar, indicating the change of PAN's structure.…”

Section: Resultsmentioning

confidence: 96%

Oxidative stabilization of PAN/VGCF composite

Zhu

Koganemaru

et al. 2003

J of Applied Polymer Sci

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An oxidative stabilization process to prepare carbon films was carried out for a new kind of precursor using the composite of polyacrylonitrile (PAN) and vaporgrown carbon fiber (VGCF) by a process of gelation/crystallization from dilute solutions. It was found that the new precursor has special features in the stabilization process different from those of the homopolymer in regard to thermal and morphological aspects. In the stabilization process under heat treatment at 180 -350°C in an oxidative atmosphere, it was inferred that, although the introduction of VGCF hinders the initiation and propagation step of the cyclization and dehydrogenation reactions, the precursor helps the oxidation and the additional aromatization and intermolecular crosslinking reactions in the stabilization process, thus promoting the formation of the later carbon product in film's shape with good performance. From characteristic works by wide-angle X-ray diffraction (WAXD), FTIR, Raman, and DSC, the changes of the precursors in structure, morphology, and mechanical property in terms of different heat-treat temperatures and tensions were studied. Through a series of experimental results, the effect of the VGCF's introduction on those changes was discussed.

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Section: Resultsmentioning

confidence: 96%

Oxidative stabilization of PAN/VGCF composite

Zhu

Koganemaru

et al. 2003

J of Applied Polymer Sci

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“…This peak is more distinct with stabilized fibers for 180 min, which showed a very small peak at 2θ of ~17˚ and disappearance of the peak at 2θ of ~29.3˚. Mathur et al reported that a broad peak at 2θ = 25.5˚ appeared with prolonged stabilization, associated with the (002) planes of the pre-graphitic structure [17]. Therefore, it is evident in Figure 6(g) that an original PAN structure changed by stabilization.…”

Section: Thermal Behavior Of Stabilized Pan Fibersmentioning

confidence: 88%

Structural Evolution of Polyacrylonitrile Fibers in Stabilization and Carbonization

Lee¹,

Kim²,

Ku³

et al. 2012

ACES

201

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The effect of structural evolution polyacrylonitrile (PAN) on mechanical properties was investigated in stabilization and carbonization. PAN spun fibers were stabilized in a convection oven with a constant tension for various times at 250˚C. Fourier Transform Infrared spectroscopy (FTIR) and gel fraction results suggested that intra and intermolecular stabilization reactions occurred simultaneously. X-ray diffractograms revealed a disruption of crystalline structure and an appearance of pre-graphitic structure of PAN fibers due to stabilization. These structural changes by stabilization resulted in the significant decrease of tensile properties of fibers. In Raman spectra with heat treated fibers from 400˚C up to 1200˚C, the intensity ratio of the D to G bands (I D /I G ) decreased as heat treatment temperature increased, indicating an increase of basal plane of graphitic layer of heat treated fibers. Tensile strength of heat treated fibers at 1200˚C was found to be as high as 2.2 GPa.

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“…From the XRD study of stabilized fibers, the pitch fibers showed a peak at a specific 2θ (approximately 26°), which is different from PAN fibers (approximately 16°) [22,23], and the intensity of the peaks also varied depending on the stabilization conditions. This explains why the synthetic mechanism and structural change of the pitch fibers are slightly different from those of the PAN fiber after heat treatment.…”

Section: Thermal Characteristicsmentioning

confidence: 96%

“…The stabilization of pitch fibers is a process where the fiber structure progresses gradually into another structure [22]. The http://carbonlett.org gradually improved the coherence of the carbonized fibers.…”

Section: Stabilization Levelmentioning

confidence: 99%

Stabilization of pitch-based carbon fibers accompanying electron beam irradiation and their mechanical properties

Park¹,

Ko²,

Jung³

et al. 2015

Carbon letters

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Carbon fibers are prepared by stabilizing pitch fibers accompanying electron beam (E-beam) irradiation. The carbon fibers pretreated by E-beam irradiation achieve a higher stabilization index than the carbon fibers that are only heat-stabilized. In addition, the carbon fibers subjected to E-beam irradiation in the stabilization step exhibit a comparable tensile strength to that of general purpose carbon fibers. The carbon fibers pretreated with an absorbed dose of 3000 kGy have a tensile strength of 0.54 GPa for a similar fiber diameter. Elemental, Fourier-transform infrared spectroscopy, and thermogravimetric analyses indicate that Ebeam irradiation is an efficient oxidation and dehydrogenation treatment for pitch fibers by showing that the intensity of the aliphatic C-H stretching and aromatic CH 2 bending (out-ofplane) bands significantly decrease and carbonyl and carboxylic groups form.

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Structure of thermally stabilized PAN fibers

Cited by 59 publications

References 14 publications

Oxidative stabilization of PAN/VGCF composite

Oxidative stabilization of PAN/VGCF composite

Structural Evolution of Polyacrylonitrile Fibers in Stabilization and Carbonization

Stabilization of pitch-based carbon fibers accompanying electron beam irradiation and their mechanical properties

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