Helium and hydrogen selective carbon hollow fiber membranes: The effect of pyrolysis isothermal time

Favvas, Evangelos P.; Heliopoulos, Nikolaos S.; Papageorgiou, Sergios K.; Mitropoulos, A.Ch.; Kapantaidakis, G.; Kanellopoulos, N.K.

doi:10.1016/j.seppur.2014.12.048

Cited by 76 publications

(44 citation statements)

References 66 publications

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“…7 shows the cross-section of carbon fibers before and after isothermal oxidation. The cross-sectional observations revealed hollow cores in the longitudinal direction after isothermal oxidation, similar to the shape of hollow fibers [19,20]. According to the model proposed by Barnet and Norr [21], the crystallinity weakens towards the center of PANbased carbon fibers.…”

Section: Surface Morphologysupporting

confidence: 64%

Microstructural changes of polyacrylonitrile-based carbon fibers (T300 and T700) due to isothermal oxidation (1): focusing on morphological changes using scanning electron microscopy

Oh¹,

Lee²,

Kang³

et al. 2016

Carbon letters

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Polyacrylonitrile (PAN)-based carbon fibers have high specific strength, elastic modulus, thermal resistance, and thermal conductivity. Due to these properties, they have been increasingly widely used in various spheres including leisure, aviation, aerospace, military, and energy applications. However, if exposed to air at high temperatures, they are oxidized, thus weakening the properties of carbon fibers and carbon composite materials. As such, it is important to understand the oxidation reactions of carbon fibers, which are often used as a reinforcement for composite materials. PAN-based carbon fibers T300 and T700 were isothermally oxidized in air, and microstructural changes caused by oxidation reactions were examined. The results showed a decrease in the rate of oxidation with increasing burn-off for both T300 and T700 fibers. The rate of oxidation of T300 fibers was two times faster than that of T700 fibers. The diameter of T700 fibers decreased linearly with increasing burn-off. The diameter of T300 also decreased with increasing burn-off but at slower rates over time. Cross-sectional observations after oxidation reactions revealed hollow cores in the longitudinal direction for both T300 and T700 fibers. The formation of hollow cores after oxidation can be traced to differences in the fabrication process such as the starting material and final heat treatment temperature.

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Section: Surface Morphologysupporting

confidence: 64%

Microstructural changes of polyacrylonitrile-based carbon fibers (T300 and T700) due to isothermal oxidation (1): focusing on morphological changes using scanning electron microscopy

Oh¹,

Lee²,

Kang³

et al. 2016

Carbon letters

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“…Favvas and groups have pyrolyzed P84 copolyimide to investigate the effect of thermal soak time of their membranes. The results revealed that by applying lengthier thermal soak time, the carbon structure becomes denser and this also occurred on the surface of the membrane . In this study, the different thermal soak times did not influence the final structure of the membrane much.…”

Section: Resultsmentioning

confidence: 53%

“…The previous study by Favvas et al . demonstrated that the pore volume of the carbon membrane prepared under He atmosphere is more porous than those prepared under Ar and N 2 at the same temperature . The carbon membranes obtained from Ar and N 2 gas atmosphere produce an only slight difference in gas permeance results due to the small difference between their molecular sizes; Ar: 3.40 Å, N 2 : 3.64 Å.…”

Section: Resultsmentioning

confidence: 96%

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Exploiting pyrolysis protocols on BTDA‐TDI/MDI (P84) polyimide/nanocrystalline cellulose carbon membrane for gas separations

Sazali

Salleh

Ismail

et al. 2018

J of Applied Polymer Sci

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Tubular carbon membranes were fabricated by the blending of BTDA‐TDI/MDI (P84) polyimide with nanocrystalline cellulose in a controlled pyrolysis process, specifically the pyrolysis environment (He, Ar, and N2) and the thermal soak time (30–120 min). The carbon membrane layer on a tubular support is converted to carbon matrix at 800 °C with a heating rate of 3 °C min−1. The effects of these controlled pyrolysis conditions on the gas permeation properties have been investigated. The results revealed that the pyrolysis under Ar gas environment at 120 min of thermal soak time have the best gas permeation performance with the highest CO2/CH4 selectivity of 68.2 ± 3.3 and CO2 permeance of 213.6 ± 2.2 GPU. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46901.

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“…In addition to the impact of the membrane precursors on carbon nanostructures, it is revealed that the final pyrolysis temperature has a significant influence on the structure and separation performance of nano‐materials . Shao et al prepared carbon membranes for gas separation with a decomposition temperature up to 500 °C .…”

Section: Introductionmentioning

confidence: 99%

Preparation, characterization, and application of vertically aligned CNT sheets through template assisted pyrolysis of PBI‐Kapton

Azami

Omidkhah

2016

Can J Chem Eng

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This article investigates the synthesis of vertically aligned carbon nanotube (CNT) sheets through the pyrolysis of polybenzimidazole (PBI)‐Kapton inside the pores of anodized aluminium oxide (AAO). The nanocomposites of CNT/Alumina obtained were characterized by several techniques. It was found that the resulting carbon structures presented higher crystallinity compared with graphite. All of the CNT sheets had high antibacterial activity that was proportional to degree of CNT crystallinity. Moreover, the desalination of salty water using CNT sheets was performed. The results demonstrated that the vertically aligned CNT sheets could be used as an effective adsorbent for salty water desalination due to their very high adsorption capacity without CNT leakage into water.

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Helium and hydrogen selective carbon hollow fiber membranes: The effect of pyrolysis isothermal time

Cited by 76 publications

References 66 publications

Microstructural changes of polyacrylonitrile-based carbon fibers (T300 and T700) due to isothermal oxidation (1): focusing on morphological changes using scanning electron microscopy

Microstructural changes of polyacrylonitrile-based carbon fibers (T300 and T700) due to isothermal oxidation (1): focusing on morphological changes using scanning electron microscopy

Exploiting pyrolysis protocols on BTDA‐TDI/MDI (P84) polyimide/nanocrystalline cellulose carbon membrane for gas separations

Preparation, characterization, and application of vertically aligned CNT sheets through template assisted pyrolysis of PBI‐Kapton

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