Mechanical Properties of Graphene Oxide Doped Woven Carbon Fibers/Epoxy Composites in Tension

Here, the mechanical properties of single layer graphene oxide (GO) doped woven carbon fibers (CFs)/epoxy (EP) system with two preparation methods are investigated by uniaxial longitudinal static tensile experiments and metallographic images analysis. Mechanical characterizations indicate the optimal GO-doped fabrics of woven CFs/EP (CFs-GO/EP) specimen demonstrates 12.5, 15.7, and 16.2% increase respectively in tensile strength (433.4 MPa), elastic modulus (11.8 GPa) and elongated strain at break (4.3%) compared to the undoped system. And the GO-doped matrix of woven CFs/EP (CFs/GO-EP) specimen shows similar mechanical behavior to CFs-GO/EP specimens with better mechanical properties. The highest tensile strength is 495.2 MPa at 0.2 wt % GO, 14.3% higher than the optimal CFs-GO/EP specimen at 0.1 wt % GO. The maximum elastic modulus and elongated strain at break are 11.9 GPa and 4.5%. With metallographic images, the dominant tensile damage is interface decohesion (fiber-matrix debonding and matrix fracture). We find that without any previous treatment, the GO sheets strongly attached to the CF fabric surface and minimized grooves, voids and defects, improving the interface rough between fibers and matrix, and the interfacial adhesion, which is responsible for the intrinsic improved interlaminar properties and leads to superior mechanical properties. The surface of CFs/GO-EP specimen has much more granular nanofillers between the interfacial region surrounding the fiber surface. The present work provides significant guidelines and in-depth understanding for the effective use of GO in strain engineering applications and as protective coating.