Experimental and Prediction Study of Displacement-Rate Effects on Flexural Behaviour in Nano and Micro TiO₂...

Epoxy resin composites with different weight fractions of TiO₂ microparticles (1%, 5%, 10%, 15%, 20%) and of TiO₂ nanoparticles (0.5%, 1%, 2%, 3%) were prepared. The particle size of the nanoparticles was averaged around 21 nm while the particle size of the micro TiO₂ particles was averaged around 0.2 μm. The morphology of the manufactured particulate composites was studied by means of scanning electron microscopy (SEM). The mechanical properties of both nanocomposites (21 nm) and microcomposites (0.2 μm) were investigated and compared through flexural testing. Furthermore, the effect of displacement-rate on the viscoelastic behavior of composite materials was investigated. The flexural tests were carried out at different filler weight fractions and different displacement-rates (0.5, 5, 10, 50 mm/min). The influence of TiO₂ micro- and nanoparticles on the mechanical response of the manufactured composites was studied. For micro TiO₂ composites, a maximum increase in flexural modulus on the order of 23% was achieved, while, in the nanocomposites, plastification of the epoxy matrix due to the presence of TiO₂ nanoparticles was observed. Both behaviors were predicted by the Property Prediction Model (PPM), and a fair agreement between experimental results and theoretical predictions was observed.