Interfacial Microstructure and Properties of Carbon Fiber Composites Modified with Graphene Oxide

TLDR

The performance of carbon fiber‑reinforced composites depends largely on the fiber–matrix interface. The study aims to improve interfacial properties of carbon fiber/epoxy composites by directly incorporating graphene oxide sheets into the fiber sizing. The authors introduced GO sheets into the sizing, characterized the modified interface with AFM and SEM, and assessed interfacial and tensile properties using microbond, short‑beam shear, and ASTM‑standard tensile tests. GO‑modified composites showed markedly higher interfacial shear strength, interlaminar shear strength, and tensile properties—especially at 5 wt % GO—demonstrating a viable method to enhance carbon fiber composites for aerospace and automotive use.

Abstract

The performance of carbon fiber-reinforced composites is dependent to a great extent on the properties of fiber–matrix interface. To improve the interfacial properties in carbon fiber/epoxy composites, we directly introduced graphene oxide (GO) sheets dispersed in the fiber sizing onto the surface of individual carbon fibers. The applied graphite oxide, which could be exfoliated to single-layer GO sheets, was verified by atomic force microscope (AFM). The surface topography of modified carbon fibers and the distribution of GO sheets in the interfacial region of carbon fibers were detected by scanning electron microscopy (SEM). The interfacial properties between carbon fiber and matrix were investigated by microbond test and three-point short beam shear test. The tensile properties of unidirectional (UD) composites were investigated in accordance with ASTM standards. The results of the tests reveal an improved interfacial and tensile properties in GO-modified carbon fiber composites. Furthermore, significant enhancement of interfacial shear strength (IFSS), interlaminar shear strength (ILSS), and tensile properties was achieved in the composites when only 5 wt % of GO sheets introduced in the fiber sizing. This means that an alternative method for improving the interfacial and tensile properties of carbon fiber composites by controlling the fiber–matrix interface was developed. Such multiscale reinforced composites show great potential with their improved mechanical performance to be likely applied in the aerospace and automotive industries.