Abstract
We present the vibrational spectra of polyacrylonitrile-based carbon fibers collected using inelastic neutron scattering. We ascertain the behavior of a broad range of vibrational spectra that are optically silent, and demonstrate a direct connection between these modes and thermomechanical properties of the fibers. We show directionally dependent coupling of hydrogen in the carbon fiber matrix, which is directly linked to mechanical properties. Further, we show hydrogen preferentially couples to the midband of the vibrational spectrum, and that there are higher overall mode populations in the traditional Raman D-G intervalley region, suggesting involvement of these modes in tensile strength reduction and transport properties.
Original language | English |
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Article number | 013609 |
Journal | Physical Review Materials |
Volume | 6 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2022 |
Funding
A portion of this research used resources at the Spallation Neutron Source, a Department of Energy Office of Science User Facility operated by the Oak Ridge National Laboratory. This research was funded by the US Department of Energy. Z.E.B. and J.L.N. conducted experiments and analysis, A.M. contributed to experiment planning and data interpretation, and Y.Q.C. and L.D. supported the experiment and data interpretation. Z.E.B. and J.L.N. wrote the manuscript with input from all authors. J.L.N. supervised the project.