Synchronously Repairing Core/Surface Defects of Carbon Fibers by In Situ Growth of ZIF-8 and Uniquely Matched High-Energy Irradiation

Abstract

Currently, the actual mechanical properties of carbon fibers (CF) differ significantly from the theoretical values. This is primarily attributed to significant limitations imposed by structural defects, greatly hindering the widespread application of CF. To solve this problem, we used in situ growth of zeolitic imidazolate framework-8 (ZIF-8) and γ rays to modulate the core−shell of CF in this study. For the surface structure of CF during the process of γ irradiation, the organic structure within ZIF-8 gradually degrades and forms a cross-linking structure with the surface defects of the CF. This process significantly enhances the binding strength between inorganic material from the postdecomposition of ZIF-8 and the carbon layer on the surface of CF, repairing the surface defects. For the internal structure of CF, γ irradiation can improve the orientation of the internal micropores of CF and increase the degree of internal graphitization of CF. In this paper, an in-depth analysis of CF before and after repair was conducted by using characterization techniques such as nanoindentation and ultrasmall angle X-ray scattering (USAXS). Compared to unmodified CF, its mechanical properties improved by approximately 19.99%, which exceeds that in approximately 95% of similar works in the field.