The change in mechanical and interfacial properties of GF and CF reinforced epoxy composites after aging in NaCl solution

In seawater environment, the interfacial control between fiber and matrix can be very important to transfer high strength of each of fiber and matrix effectively. If seawater can penetrate into the interface, the area can be weak and deteriorated. In this work, the change of mechanical, interfacial and micromechanical properties were observed after NaCl and aging treatment for glass and carbon fiber. The changes in mechanical properties of fiber were investigated using single-fiber tensile test. Interfacial properties between fiber and epoxy resin were evaluated with nondestructive acoustic emission (AE) and micromechanical fatigue test. Relative interfacial properties were evaluated from the difference in fatigue properties. The decrease of mechanical and interfacial properties was observed as well as the reduction of glass fiber diameter with aging treatment in NaCl solution. On the other hand, carbon fiber diameter was not changed and mechanical and interfacial properties were also maintained.