Injection-Molded Parts of Polypropylene/Multi-Wall Carbon Nanotubes Composites With an Electrically Conductive Tridimensional Network

Polypropylene-based composites filled with multi-wall carbon nanotubes (MWCNTs), ranging from 1 to 6 wt%, were obtained by injection molding from a previous masterbatch compounded by twin-screw extrusion (TSE). Resultant electrical percolation phenomenon was related to the ultrathin structure of the carbonbased fillers and the high dispersion achieved in the thermoplastic matrix. In particular, conductivity experiments showed a threshold value of 3 wt% (1.3 vol%) of MWCNTs for percolation to occur. Electrical percolation was achieved as a result of the formation of an interconnected three-dimensional structure compromising a top average inter-nanotube distance of about 493 nm among isolated nanotubes in polypropylene. The current work is hoped to bear significance toward understanding of the electrical performance for industrial ultrathin carbon black-based polyolefin composites. (C) 2014 Society of Plastics Engineers