FATIGUE PERFORMANCE OF CLAY-EPOXY NANOCOMPOSITES

Abstract

This paper presents an investigation of the possibility of improving the fatigue properties of an epoxy resin through dispersion of modified layered silicates within the polymer matrix. Montmorillonite-epoxy nancocomposites were successfully synthesized with a commercially available 1-Methylimidazole curing agent. The morphology of these materials was investigated by XRD and TEM. The findings demonstrated a pattern of clay morphology typically found in nanocomposite systems. Four point loading measurements showed an increase in modulus for 2.5 wt% and 10 wt% clay contents when compared to the unfilled epoxy, whereas the moduli showed a decrease for 5 wt% and 7.5 wt% clay contents. This behavior is typical for most particulate-filled systems. Fracture surfaces were examined using an E-SEM. The failure mechanism of the nanocomposites varied from that of the unfilled epoxy. Below a critical strain amplitude, the fatigue life of the filled epoxy improved significantly compared to that of the unfilled epoxy. In conclusions, the addition of silicates changes the fatigue failure mechanism and improves significantly the fatigue life.