Previous studies of polymer nanographite composites shows, that piezoresistive sensitivity under external mechanical influence is strongly affected by carbon nanoparticle size, shape, and conditions of composite manufacture. In this work we studied ultrasonic milling of thermally exfoliated graphite in organic solvent using various power modes of ultrasonic homogenizer and sonification times. The particle sizes of achieved nanographites was determined using scanning electron microscope, as well as temperature dependence of electrical resistivity has been determined for each sample. Based on these results the optimal ultrasonification parameters has been determined, which hereafter will be used for fabrication of polyisoprene thermally exfoliated nanographite composites to use them as chemical and mechanical sensors. Also we compare the previous results of polyisoprene nanographite composite chemical and mechanical sensing properties, where as the fillers graphitized extra conductive carbon black and multi wall carbon nanotubes are used.