Mechanical and viscoelastic properties of SiO 2 /epoxy nanocomposites post-cured at different temperatures

Abstract

Response: In this investigation, an experimental study has been carried to determine the effects of post-curing temperature (Tc) on the mechanical and viscoelastic properties of SiO₂/epoxy nanocomposites. The nanocomposites were prepared through ultrasonic mixing with a dispersion of 2, 4, 6, and 8 wt.% SiO₂ nanoparticles and post cured at 75, 100, 125, and 150 °‌‌C. The viscoelastic properties were determined using dynamic mechanical analysis tests. The glass transition temperature (Tg) increased with an increase in Tc for pristine epoxy and nanocomposites; however, the increase in the value of Tg for pristine epoxy is less than nanocomposites. The results show that the Tc below the Tg of pristine epoxy improves the tensile properties; however, for Tc above Tg have a detrimental effect on the properties of nanocomposites. With the increase in Tc above Tg, the fracture toughness and fracture energy decrease for nanocomposites.