Effect of Particle Size on the Mechanical Properties of TiO₂-Epoxy Nanocomposites

This study investigated the effects of the packing density and particle size distribution of TiO₂ nanoparticles on the mechanical properties of TiO₂-epoxy nanocomposites (NCs). The uniform dispersion and good interfacial bonding of TiO₂ in the epoxy resin resulted in improved mechanical properties with the addition of nanoparticles. Reinforcement nano-TiO₂ particles dispersed in deionized water produced by three different ultrasonic dispersion methods were used; the ultrasonication effects were then compared. The nano-TiO₂ suspension was added at 0.5-5.0 wt.%, and the mechanical and thermal properties of TiO₂-epoxy NCs were compared using a universal testing machine, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC). The tensile strength of the NCs was improved by the dispersion strengthening effect of the TiO₂ nanoparticles, and focused sonication improved the tensile strength the most when nano-TiO₂ suspensions with a particle size of 100 nm or smaller were used. Thus, the reinforcing effect of TiO₂ nanoparticles on the epoxy resin was observed, and the nano-TiO₂ suspension produced by focused sonication showed a more distinct reinforcing effect.