Optimized ultrasonic assisted dispersion of un-functionalized titanium dioxide (TiO) nanoparticles (0.5-20wt%) into epoxy resin is reported. The investigation shows that there is a direct relation among nanoparticles content, inter-particle spacing and cluster size of the particles on the glass transition temperature (T) and tensile properties of the prepared nanocomposites. A significant improvement in tensile strength and modulus with minimal detrimental effect on the toughness was observed for the prepared composites, where compared to pristine epoxy resins, about 26% and 18% improvement in tensile strength and strain-to-break %, respectively, was observed for 10wt% particles loading, whereas a maximum improvement of about 54% for tensile toughness was observed for 5wt% particles loaded resins. The investigations found that a strong particle-matrix interface results in the enhancement of the mechanical properties due to leading toughening mechanisms such as crack deflection, particle pull out and plastic deformation.

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Titania nanoparticle dispersion and its effect on thermal properties of epoxy-based nanocomposite were examined by producing it via ultrasonic vibration process. Atomic force microscope images of the epoxy/TiO2 nanocomposite revealed a good dispersion of nanoparticle up to an optimum level of loading (10 wt%), which results in its improved glass transition temperature and thermal stability. But, a higher particle loading in epoxy reflects decrease in the glass transition temperature and thermal stability of the nanocomposite, which may be attributed to the significant increase in clustering of the nanoparticles.

Dispersion of nanoparticles and its effect on the mechanical properties were investigated by fabricating nanocomposites via mechanical mixing (MM) and ultrasonic dual mode mixing (UDMM) methods. The mechanical mixing of ZrO 2 nanoparticles in epoxy resin was employed using glass rod stirring and the ultrasonic dual mode mixing was employed by ultrasonic vibration along with magnetic stirring to produce ZrO 2 -epoxy nanocomposite. Micrographs obtained using a field emission scanning electron microscope revealed an improved dispersion quality of ZrO 2 nanoparticles especially for the UDMM method. The improvement in dispersion was reflected in much improved tensile and fracture properties of the nanocomposite.