Degradation of braided composites in hot water

Fiber-reinforced plastics are used for various applications in water environments on account of their good mechanical properties and waterproof behavior. Braided composites have excellent mechanical properties, because the reinforcing fibers are oriented continuously throughout the composite. It is expected that the degradation characteristics of braided composites would be different from those of other types of composite. In this paper, immersion tests and tensile tests on immersed specimens were carried out to investigate the degradation of braided composites in hot water from the viewpoint of change in weight and mechanical properties. It is shown that the degradation of braided composites is closely connected with the properties of the fiber/matrix interface. Degradation of the interface around a fiber bundle decreased the mechanical properties of braided composites. However, degradation of the interface inside a fiber bundle had little influence on the mechanical properties.