Abstract
The cross-section of carbon fibers (CFs) possessed radial heterostructure, which restricted its mechanical properties. In this paper, heating and γ-irradiation were integrated during PAN fibers stabilization process to improve the radial structure of CFs. The synergy between irradiation and heating during stabilization caused the decrease of ID/IG, increase of crystal size, and reduction of pore fractal dimension in whole CFs. Through Raman spectra along fibers cross-section, a radial heterogeneity was found during the whole carbonization process. The combination of γ-irradiation and heating reduced the ID/IG of core part more significantly compared to the skin part of CFs, which weakened radial heterogeneity of CFs. At the same time, it significantly enhanced the tensile strength of CFs. Subsequently, a hierarchy model with three zones containing outer-surface, sub-surface and core parts was presented to explain the evolution of tensile strength for CFs. The γ-irradiation during stabilization enhanced the structure of each part in CFs by generating more cross-linked structures.
Published Version
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