Constructing conductive network using 1D and 2D conductive fillers in porous poly(aryl ether nitrile) for EMI shielding

Abstract

Electromagnetic interference shielding materials with high shielding effectiveness, light weight, and good heat resistance are desperately needed in areas of aerospace, aircraft, and automobiles. Herein, lightweight porous composites foams with satisfactory electromagnetic interference shielding effectiveness (EMI SE) and mechanical strength was prepared using 1D, 2D conductive fillers and poly(aryl ether nitrile) (PEN) by adapting non-solvent induced phase separation (NIP). It is found that the introduction of 1D and 2D conductive fillers could interweave to form conductive network more easily than the presence of 2D conductive filler alone. The EMI SE of 25.8 dB could be reached for composite foam with 5 wt% of graphene and 3 wt% of carbon nano tubes (PEN/5G3C) and the EMI shielding is dominated by absorption attenuation, with PEN/5G3C shows absorption ratio near 90% in the X-band range, which is believed to be attributed to the multiple internal reflection and absorption inside the conductive foam. Moreover, the network of fillers could strongly interact with the polymer matrix and enhance the tensile strength of the porous foams. The tensile strength of PEN/5G3C reached 4.14 MPa, which is 218% higher than that of neat PEN foam. Due to the high thermal resistance (Tg of 256.4 °C), low density (< 0.2 g/cm3) and satisfactory EMI SE, the composite foam based on PEN show great potential as the next-generation high-performance EMI shielding materials.