Development of epoxy/flyash composites containing halloysite nanotubes: Mechanical, morphological, and thermal degradation kinetics

This research article investigates the development of a composite material by the inclusion of halloysite nanotubes (HNTs) into an epoxy/flyash matrix using a solution blending technique. The HNTs were added at different loadings and were effectively dispersed throughout the epoxy/flyash matrix. The thermal properties and degradation kinetics of the epoxy/flyash composites were studied with a thermogravimetric analyzer (TGA) at different heating speeds (10, 15, 20, and 25 °C/min). TGA measurements showed a considerable improvement in the thermal stability of the composites. Incorporating 3 phr of HNTs into epoxy/flyash composites increased thermal stability by 13 °C, 16 °C, and 18 °C, with weight losses of 5 %, 10 %, and 50 %, respectively, as compared to composites without HNTs. The thermal degradation activation energy (E) was calculated using the model-free Kissinger Akahir-Sunose (KAS) and Flynn-Wall-Ozawa (FWO), and it was revealed that epoxy/flyash composites containing 3 phr HNTs have the highest E, 77.52 and 79.89 kJ/mol, respectively. The SEM micrographs of 3 phr HNTs show uniform dispersion of HNTs onto epoxy/flyash composites, resulting in a tensile strength increase from 37.2 MPa to 43.6 MPa and modulus increase from 1238.4 MPa to 1463.6 MPa. The obtained results show that the addition of flyash and nanofiller (HNTs) to the epoxy matrix greatly increases the mechanical and thermal properties.