The effect of rubber micro-particles and silica nano-particles on the tensile fatigue behaviour of a glass-fibre epoxy composite

Fibre-reinforced polymer (FRP) matrix composites are widely used in airframe structural components. Although composites offer good and useful structural properties, they are brittle. Indeed, the commonly employed thermosetting epoxy matrices typically have a poor resistance to crack initiation and growth. Therefore, efforts have been made to improve the mechanical properties of the epoxy polymeric matrix, and thereby the properties of FRPs, through the incorporation of second-phase particles in the resin matrix [1–8]. The addition of micrometre-sized rubber particles [1–3] and, more recently, nano-sized silica (SiO2) particles [4–8], into an epoxy polymer have been shown to improve the fracture energy of bulk epoxies by up to 10–15 times, without significantly impairing their other desirable engineering properties [5]. FRPs based upon such particlereinforced matrices have also shown a remarkable improvement in their interlaminar fracture energy [6, 8]. If this enhanced toughness was accompanied by improved fatigue behaviour, then these materials would be highly attractive for structural applications. The present letter addresses the tensile fatigue behaviour of a glass-fibrereinforced-plastic (GFRP) with various particulate-toughened epoxy matrices, and describes some very novel and exciting results.