Ultrasonic dispersion of inorganic nanoparticles in epoxy resin

The incorporation of nanoscale fillers into a polymer can lead to a considerable improvement of mechanical properties, i.e. stiffness and toughness of a material can be enhanced simultaneously by the insertion of nanofillers. Thereby, the crucial difference between conventional microscale fillers and nanofillers is the high specific surface of the latter. In order that this surface can interact with the matrix material a good dispersion, i.e. a good separation and a homogeneous distribution of the nanoparticles into the polymer, is required. In the present study ultrasonic waves generated by an ultrasonic horn were used to disperse titanium dioxide nanoparticles into epoxy resin. The process parameters, e.g. the ultrasonic amplitude, the dispersion time and the material's volume, were varied systematically with the aim of achieving an optimum dispersion process. A dispersion model for bead mills was adapted to the ultrasonic process and compared to a second dispersion model in order to find an adequate mathematical expression to correlate the ultrasonic process parameters to the particle sizes in the material and to allow predictions for further experiments.