A comparative study on effects of natural and synthesised nano-clays on the fire and mechanical properties of epoxy composites

In this research, two nano-clays, halloysite nano-tube (HNT) and layered double hydroxide (LDH), were employed to compare fire and mechanical properties of epoxy composites based on ammonium polyphosphate (APP) and each of the two nano-clays. The results showed that the combination of APP and nano-clay achieved a significant reduction (approx. 87%) in peak heat release rate of epoxy resin. The comparative analysis also demonstrated that the total heat release of the composite including HNT was approx. 18% lower than that of the LDH based composite. Moreover, HNT generated higher tensile properties in the composite. Overall, the HNT (similar to 1.5 USD/kg) is a more cost-effective nano-clay than LDH (similar to 180 USD/kg) to effectively improve the fire resistance and maintain the mechanical properties of epoxy composites.