Epoxy/TiO2 composite materials and their mechanical properties

Abstract

The physicomechanical properties and thermal stability of epoxy nanocomposites with TiO2 (anatase — 75 %, rutile — 25 %) nanoparticles were studied. The TiO2/epoxy polymer (TiO2/EP) nanocomposite films were obtained by curing a pre-sonicated mixture of diane-epoxy resin ED-20, 4,4'-diaminodiphenylmethane and TiO2 nanoparticles using stepwise technique: 90 ºС for 3 hours, then 160 ºС for 3 hours. Tensile tests were carried out according to American Society for Testing and Materials ASTM D882–10. The average size of TiO2 nanoparticles and microstructure of the obtained nanocomposites were studied by scanning electron microscopy. It was found that addition of the TiO2 nanoparticles at a concentration above 3 wt.% leads to a decrease in tensile strength at break, apparently due to secondary aggregation processes of nanoparticles. During curing, the average diameter of TiO2 nanoparticles increases from 40 nm to 60 nm. An increase in the elastic modulus, a slight increase in the glass transition temperature, and a decrease in the elongation at break of epoxy nanocomposites at a concentration of TiO2 nanoparticles > 1 wt.% indicate an increase in the rigidity of the epoxy matrix. The nanocomposites obtained were shown to be stable at concentrations of TiO2 nanoparticles up to 5 wt.% and up to 300 ºС in vacuum.