Electrical Resistivity of Polycarbonate/Multiwalled Carbon Nanotube Composites Under Varying Injection Molding Conditions

Abstract

Multiwalled carbon nanotube (MWCNT)- filled polycarbonate composites were prepared by a corotating intermeshing twin-screw extruder. The surface resistivities of compression- and injection-molded specimens were quite different, the difference ranging from 10 3 to 10 7 Ω/sq at varying MWCNT concentrations. The surface resistivity of the injection-molded specimen at 2 wt % loading varied up to 10 5 Ω/sq in the specimen thickness direction and up 10 4 Ω/sq in the polymer flow direction with respect to the gate. The difference in surface resistivity with the positions of injection-molded specimen was confirmed with the morphology, which showed the difference in MWCNT number density (numbers/surface area). There was no significant effect on surface resistivity with injection pressure, holding pressure, and molding temperature. The specimens prepared at the injection speed of 13 mm/s showed surface resistivities 10 3-10 4 Ω/sq depending on the positions, which was comparable with the compression-molded specimens, which had a surface resistivity of 10 3 Ω/sq.