Analysis on the effect of nanographite obtained by an ultrasound technique in polypropylene compounds

In this work, the effect of inclusion of nanographite particles in a polypropylene (PP) matrix is studied. Nanographite particles were obtained through ultrasound exfoliation from graphite upon using a water-based hydrophobically modified alkali-swellable emulsion (HASE) associative polymer as a surfactant. Results indicate that exfoliation renders particle size distribution ranging from 3 to 3000 nanometers. Nanographite was blended with PP through two extrusion processes: twin screw and single screw, the latter includes the coupling to a static-mixer head, to generate extensional flows. Concurrently, ultrasonic waves are applied to the molten flow through ultrasonic transducers attached to the mixing head, which induces high particle dispersion and good particle distribution in the polymer matrix. It was found that at HASE concentration of 5% by weight and sonication time of 14 days (period of the exfoliation process), optimum tensile properties of the compound were achieved. Also, with respect to the P...