Yuan, G, Li, B, Li, X et al. (5 more authors) (2019) Effect of Liquid Crystalline Texture of Mesophase Pitches on the Structure and Property of Large-Diameter Carbon Fibers. ACS Omega, 4 (1). pp. 1095-1102. ISSN 2470-1343
Abstract
Two types of carbon fibers with a large diameter of ∼22 μm, derived from unstirred and vigorously stirred mesophase pitch melts with different liquid crystalline mesophase textures, were prepared by melt-spinning, stabilization, carbonization, and graphitization treatments. The morphology, microstructure, and physical properties of the carbon fibers derived from the two kinds of mesophase precursors after various processes were characterized in detail. The results show that the optical texture (i.e., size and orientation) of the liquid crystalline mesophase in the molten pitch is obviously modified by thermomechanical stirring treatment, which has a significant effect on the texture of as-spun pitch fibers, and finally dominates the microstructure and physical properties of the resulting carbon and graphite fibers. These large-diameter fibers expectedly maintain their morphological and structural integrity and effectively avoid shrinkage cracking during subsequent high-temperature heat treatment processes, in contrast to those derived from the unstirred pitch. This is due to the smaller crystallite sizes and lower orientation of graphene layers in the former. The tensile strength and axial electrical resistivity of the 3000 °C-graphitized large fibers derived from the unstirred pitch are about 1.8 GPa and 1.18 μΩ m, respectively. In contrast, upon melt stirring treatment of the pitch before spinning, the resulting large-diameter graphite fibers possess the corresponding values of 1.3 GPa and 1.86 μΩ m. Despite the acceptable decrease of mechanical properties and axial electrical and thermal conduction performance, the latter possesses relatively high mechanical stability (i.e., low strength deviation) and ideal morphological and structural integrity, which is beneficial for the wide applications in composites.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | Copyright © 2019 American Chemical Society. ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. (https://pubs.acs.org/page/policy/authorchoice_termsofuse.html) |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 15 Feb 2019 09:53 |
Last Modified: | 15 Feb 2019 09:53 |
Status: | Published |
Publisher: | American Chemical Society |
Identification Number: | 10.1021/acsomega.8b03189 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:142567 |