Synergistic effects of graphene nanoplatelets on X-band electromagnetic interference shielding, thermal expansion and thermal stability of poly (ether-ketone) based nanocomposites

In this work, the electromagnetic interference shielding effectiveness (EMI-SE) of the poly(ether-ketone) (PEK)-graphene nanoplatelets (GNP) nanocomposites fabricated by planetary ball mill followed by hot pressing were investigated in X-band (8.2-12.4 GHz). A percolation threshold of about 0.4 vol% GNP was obtained. The electrical conductivity was increased to about 0.02 S/cm with an EMI-SE of similar to 33 dB for 1 mm thick 5 vol% GNP filled PEK nanocomposite. This higher value is corresponding to more than 99.95% blocking of the EMI. The EMI-SE increases with increasing thickness of the nanocomposite. The thermal stability and the char yield of the nanocomposites reinforced with 5 vol% GNP were found to increase to 570 degrees C and to 61.6%, respectively. The dimensional stability of the nanocomposites was also increased compared to neat PEK.