Density Changes of Acrylic Fibers by Thermal Stabilization

Takaku, Akira; Terui, Shun; Taga, Futoshi; Okui, Norimasa; Shimizu, Jiro

doi:10.2115/fiber.38.9_t398

Cited by 5 publications

(2 citation statements)

References 3 publications

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“…The results presented in Fig. 2 show that increasing oxygen attachement to the polymer backbone chains during the thermal stabilization stage results in an increase in the density of the stabilized precursor fiber, in agreement with the published literature [57]. The results also show a density increase between 9.7 and 15.3%, with respect to the density of the untreated sample, with increasing stabilization time (Table 1).…”

Section: Resultssupporting

confidence: 88%

“…It is interesting to note that the thermal stabilization may result in an increase in the molecular weight of up to about 11% and a reduction of molecular volume up to about 17% [57]. There is also a close relationship between the values of linear density in terms of tex for the bundle of 50 filaments and the stabilization time of the stabilized fibers as shown in Fig.…”

Section: Resultsmentioning

confidence: 88%

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An investigation on structure characterization of thermally stabilized polyacrylonitrile precursor fibers pretreated with guanidine carbonate prior to carbonization

Karacan

Erdogan

2011

Polymer Engineering & Sci

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Thermal stabilization of polyacrylonitrile (PAN) precursor fiber was performed with a pretreatment of an aqueous guanidine carbonate solution and its structure was thoroughly characterized using a combination of infrared spectroscopy (IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), density, elemental analysis, and X-ray diffraction measurements. The use of guanidine carbonate pretreatment of polyacrylonitrile precursor fiber was found to be very useful for the acceleration of thermal stabilization of polyacrylonitrile precursor fiber prior to the carbonization stage. The results obtained from density, thermal analysis (TGA and DSC), infrared-spectroscopy and X-ray diffraction methods suggested an accelerated thermally stable aromatic ladder structure formation resulting in much reduced thermal stabilization time. X-ray observations showed the transformation of the original structure from a highly ordered phase to a totally disordered amorphous phase which seemed to be a direct consequence of the crosslinked and cyclized structure present in the stabilized fibers. The results obtained from the infrared spectra of thermally stabilized samples showed a rapid and simultaneous cyclization and dehydrogenation reactions aided by the oxygen uptake in the form of oxygen containing functional groups. Guanidine carbonate pretreated and thermally stabilized PAN precursor fibers showed a carbon yield of 52.5% at 11008C obtained from TGA measurements. The use of guanidine carbonate pretreatment is expected to significantly increase the productivity of carbon fiber manufacturing at a substantially reduced cost by significantly reducing the time necessary for thermal stabilization of polyacryonitrile fiber. POLYM. ENG. SCI., 52:937-952, 2012. 943 FIG. 13. Elemental composition of unstabilized and thermally stabilized polyacrylonitrile fibers pretreated with 15% guanidine carbonate solution and stabilized at 2408C as a function of stabilization time. (&) carbon (%); (*) nitrogen (%); (l) oxygen (%); (!) hydrogen (%).

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Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 88%

An investigation on structure characterization of thermally stabilized polyacrylonitrile precursor fibers pretreated with guanidine carbonate prior to carbonization

Karacan

Erdogan

2011

Polymer Engineering & Sci

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Tensile properties of carbon fibers from acrylic fibers stabilized under isothermal conditions

Takaku

Hashimoto

Miyoshi

1985

J of Applied Polymer Sci

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SynopsisA series of carbon fibers were prepared from the acrylic fibers thermally stabilized in air under various temperature-time conditions, and the relation between the extent of stabilization and the tensile properties of carbon fibers was investigated. The density of stabilized fibers was adopted as a measure of the extent of stabilization. The tensile modulus of carbon fibers changed dependently on stabilization temperature. However, the variation of the tensile modulus of carbon fibers with the density of stabilized fibers was small if stabilization temperature was constant. In the relation between the tensile strength of carbon fibers and the density of stabilized fibers, a feature depending on stabilization temperature was not evident, and the tensile strength of carbon fibers showed a maximum in the density range from about 1.34 to 1.39 g/cm3 of stabilized fibers.

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The effect of ethylenediamine pretreatment on the molecular structure of thermally stabilized polyacrylonitrile fibers before carbonization

Karacan

Erdogan

2011

Polymer Engineering & Sci

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Aqueous ethylenediamine (EDA) pretreatment followed by thermal stabilization of polyacrylonitrile (PAN) fibers in an oxygen rich air environment was carried out prior to the carbonization stage. The results show that the EDA pretreatment is very effective and efficient in promoting the cyclization of nitrile groups by shortening the time necessary for the development of thermally stable structure needed to withstand the high carbonization temperatures. A direct relationship between the values of density and the oxygen content is found which is believed to be due to the positive role played by the oxygen containing functional groups in the formation of ladder frame structures. Analysis of the equatorial X-ray diffraction traces shows the transformation of the original structure from a highly ordered phase to a totally disordered amorphous phase as indicated by the loss of the degree of order of the original PAN fiber. X-ray, Differential Scanning Calorimetry (DSC), and infrared conversion indices show the rapid conversion from the original open structure to highly cyclized and crosslinked polymer structure. Utilization of EDA pretreatment prior to the thermal stabilization is expected to significantly reduce the cost of the final carbon fiber manufacturing by reducing the time necessary for the thermal stabilization stage. POLYM. ENG. SCI.,

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Density Changes of Acrylic Fibers by Thermal Stabilization

Cited by 5 publications

References 3 publications

An investigation on structure characterization of thermally stabilized polyacrylonitrile precursor fibers pretreated with guanidine carbonate prior to carbonization

An investigation on structure characterization of thermally stabilized polyacrylonitrile precursor fibers pretreated with guanidine carbonate prior to carbonization

Tensile properties of carbon fibers from acrylic fibers stabilized under isothermal conditions

The effect of ethylenediamine pretreatment on the molecular structure of thermally stabilized polyacrylonitrile fibers before carbonization

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