Kenneth R. Brown

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Graphene reinforced carbon fibers

Fig. 3 TEM images and Raman spectra of the PAN/graphene composite CFs. (A) TEM images of the added graphene obtained from shear exfoliation. (B) HRTEM image of the graphene, with inset showing the corresponding FFT pattern. (C) TEM image of PAN/graphene (0.075 wt %) precursor fiber, with inset showing the FFT pattern of the selected area (red square). (D and E) TEM images of the carbonized PAN/graphene fiber (0.075 wt % graphene) at different magnifications. (F) Raman spectra of the carbonized PAN/graphene fibers with different concentrations of graphene. a.u., arbitrary unit. (G) The possible flow-induced graphene alignment mechanism of the PAN/graphene dope (33).

Publication

Science Advances 24 Apr 2020:
Vol. 6, no. 17, eaaz4191
DOI: 10.1126/sciadv.aaz4191

Authors

Zan Gao, Jiadeng Zhu, Siavash Rajabpour, Kaushik Joshi, Małgorzata Kowalik, Brendan Croom, Yosyp Schwab, Liwen Zhang, Clifton Bumgardner, Kenneth R. Brown, Diana Burden, James William Klett, Adri C.T. van Duin, Leonid V. Zhigilei, and Xiaodong Li

Abstract

The superlative strength-to-weight ratio of carbon fibers (CFs) can substantially reduce vehicle weight and improve energy efficiency. However, most CFs are derived from costly polyacrylonitrile (PAN), which limits their widespread adoption in the automotive industry. Extensive efforts to produce CFs from low cost, alternative precursor materials have failed to yield a commercially viable product. Here, we revisit PAN to study its conversion chemistry and microstructure evolution, which might provide clues for the design of low-cost CFs. We demonstrate that a small amount of graphene can minimize porosity/defects and reinforce PAN-based CFs. Our experimental results show that 0.075 weight % graphene-reinforced PAN/graphene composite CFs exhibits 225% increase in strength and 184% enhancement in Young’s modulus compared to PAN CFs. Atomistic ReaxFF and large-scale molecular dynamics simulations jointly elucidate the ability of graphene to modify the microstructure by promoting favorable edge chemistry and polymer chain alignment.