Low-temperature carbonization of polyacrylonitrile/graphene carbon fibers: A combined ReaxFF molecular dynamics and experimental study

Graphene inclusion in a polymer matrix is a promising route to significantly enhance the mechanical properties of low-grade carbon fibers (CFs). Using ReaxFF molecular dynamics simulation, the atomistic mechanism leading to this enhancement is investigated. We demonstrate that the graphene edges alo...

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Bibliographic Details
Published in:Carbon (New York) 2021-04, Vol.174, p.345-356
Main Authors: Rajabpour, Siavash, Mao, Qian, Gao, Zan, Khajeh Talkhoncheh, Mahdi, Zhu, Jiadeng, Schwab, Yosyp, Kowalik, Malgorzata, Li, Xiaodong, van Duin, Adri C.T.
Format: Article
Language:English
Subjects:
Carbon
Carbon fiber
Carbon fiber reinforced plastics
Carbon fibers
Carbonization
Functional groups
Graphene
Graphite
Graphitic structure
Low temperature
Mechanical properties
Modulus of elasticity
Molecular dynamics
Nanocomposite
Polyacrylonitrile
ReaxFF molecular dynamics
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Summary:Graphene inclusion in a polymer matrix is a promising route to significantly enhance the mechanical properties of low-grade carbon fibers (CFs). Using ReaxFF molecular dynamics simulation, the atomistic mechanism leading to this enhancement is investigated. We demonstrate that the graphene edges along with the nitrogen and oxygen functional groups play a catalytic role and act as seeds to expedite alignment of the all-carbon rings, which are starting sites for the growth of graphitic structures. To examine the role of this proposed mechanism that enhances the graphitic structure of PAN/graphene CFs, we discuss the experimental results wherein the PAN/graphene CFs carbonized at 1250 °C demonstrate 91% (from 632 to 1207 MPa) increase in strength and 101% (from 88 to 177 GPa) enhancement in Young’s modulus compared to PAN-based CFs carbonized at 1500 °C. These enhanced mechanical properties of low-grade carbon fibers achieved via graphene inclusion at decreased carbonization temperature provide a means to realize both energy savings and cost reduction. [Display omitted] The graphene edges play a catalytic role and act as seeds in expedite graphitic structure growth, while the graphene surface carbon atoms are relatively inactive due to their conjugated sp2 electronic configuration.
ISSN:0008-6223
1873-3891
DOI:10.1016/j.carbon.2020.12.038