Viscoelastic behaviour and modelling of nano and micro TiO2 powderepoxy resin composites

Epoxy resin composites reinforced with different weight fractions of TiO2 micro-particles 0.2 mu m in size (1%, 5%, 10%, 15% wt) and of TiO2 nano-particles 21nm in size (0.5%, 1%, 3% wt) were manufactured. The quasi-static mechanical properties of both nano-composites and micro-composites were investigated and compared through tensile testing. The experimental results were predicted and the degree of matrix-particle adhesion and particle dispersion were evaluated, by the Property Prediction Model (PPM) developed by the first author. The composites were also subjected to creep-recovery tests as well as to relaxation tests in order to investigate their viscoelastic behaviour. The experiments were carried out at different filler-weight fractions and loading conditions. Non-linear viscoelastic behaviour was observed in all cases and appropriate models were applied in order to describe, and/or predict the viscoelastic behaviour of all materials tested. A fair agreement between experimental results and theoretical predictions was observed for both viscoelastic and static results. (C) 2016 Portuguese Society of Materials (SPM). Published by Elsevier Espana, S.L.U.. All rights reserved.