The acrylation of a tetrafunctional epoxy resin was carried out through the reaction with acrylic acid in the presence of two different organoclays under ultrasonic irradiation. As reinforcing agents, two different kinds of commercial organoclays, namely Cloisite 15A and Cloisite 30B, were used individually in nanocomposite fabrication. The acrylation reaction of epoxy resin in addition to curing processes was monitored by Fourier transform infrared spectroscopy. The main advantage of the ultrasonic process was a significant reduction in reaction time as low as 8 min. Thermal and mechanical properties of the UV-cured samples were investigated by means of differential scanning calorimetry, dynamic mechanical thermal analysis and the film hardness. The clay dispersion was characterized through X-ray diffraction patterns coupling with the images of two microscopic techniques. The enhancements in nanocomposite glass transition temperature, thermal stability and mechanical properties may be attributed to proper dispersion of organoclay platelets as evidenced in transmission electron microscopy. However, the nanocomposite films reinforced with the Cloisite 30B exhibit more pronounced improvements in the final properties of the nanocomposite film.