Graphene Nanoplatelet/Multi-Walled Carbon Nanotube/Polycarbonate Hybrid Nanocomposites for Electrostatic Dissipative Applications: Preparation and Properties

Graphene nanoplatelet (GNP)/multi-walled carbon nanotube (MWCNT)/polycarbonate (PC) hybrid nanocomposites were prepared via a melt mixing process using a twin screw extruder. The content of GNPs was in the range of 0-2.0 pph of resin (part per hundred resin) whereas the dosage of MWCNTs was kept constant at 0.5 wt%. X-ray diffraction (XRD) showed that GNPs slightly intercalated in the PC matrix since the peak of GNPs at 2 theta = 26.4 degrees clearly remained and its intensity increased as the amount of GNPs increased. Transmission electron microscopy (TEM) revealed poor dispersion and intercalation of GNPs in the PC matrix. The nanocomposite containing 0.5 wt% MWCNTs had a measured tribo-charge voltage outside the electrostatic dissipative (ESD) specification. When 0.2-2.0 pph of resin of GNPs were added in MWCNT/PC nanocomposites, the ESD properties were improved and mostly within the specification range. However, the tribo-charge voltage did not show any trend with increased GNP content. The glass transition temperature (T-g) and heat capacity jump at the glass transition stages of the nanocomposites insignificantly changed as the content of GNPs increased. The decomposition temperature (T-d) slightly increased at low GNP loadings and then began to decrease with increasing GNP contents from 0.6-2.0 pph of resin. The decrease of T-d at high GNP content might result from poor dispersion of GNPs in the PC matrix causing hot spot defects. The melt flow index (MFI) of GNP/MWCNT/PC nanocomposites tended to decrease as the content of GNPs increased due to the formation of a nanoplatelet network which obstructed the motion of polymer chains. This work opens up the possibility of using GNP/MWCNT/PC nanocomposites in ESD applications. However, suitable surface modification of GNPs is required to improve the dispersion and intercalation of GNPs in the PC matrix.