Studying the Viscoelastic Properties of an Epoxy Resin Strengthened with Silicon Dioxide Nanoparticles by Instrumented Microindentation

The viscoelastic properties of surface layers of a Primer-204 epoxy resin modified by silicon dioxide nanoparticles with weight fractions of 0.24, 0.41, 0.65, and 2% were investigated. Material specimens were indented using a Hysitron TI 950 Triboindenter nanomechanical test system. The load and the loading and holding times had a significant effect on the values of hardness and reduced the elastic modulus obtained by indentation. The material exhibited viscosity at the microscopic level. With filler content growing from 0.24 to 2 wt.%, the reduced elastic modulus and hardness of surface layers of the material increased, but the creep decreased. It is shown that the rheonomic properties of the Primer-204 epoxy resin modified by silicon dioxide nanoparticles should be taken into account.