Facile preparation of lightweight PE/PVDF/Fe3O4/CNTs nanocomposite foams with high conductivity for efficient electromagnetic interference shielding

Light-weight Polyethylene/Poly(vinylidene fluoride)/Fe3O4/Carbon nanotubes (PE/PVDF/Fe3O4/CNTs) nanocomposite foams with efficient electromagnetic interference (EMI) shielding performance were prepared using green processing methods of melt blending and supercritical CO2 foaming. The microwave- absorbing ability of the PE/PVDF/Fe3O4/CNTs nanocomposite foams were significantly improved. Moreover, due to the selective dispersion of Fe3O4 and CNTs in the PVDF and PE matrix, respectively, CNTs directionally arranged in the cell wall during the foaming, leading to a high electric conductivity to improve the electromagnetic interference shielding effectiveness (EMI SE) through dielectric loss and polarization loss. The produced PE/PVDF/Fe3O4-10CNTs foam with a density of 0.9 g/cm3 and a thickness of 2.6 mm, exhibited a higher electrical conductivity of 0.25 S/cm. The outstanding total EMI SE of 26 dB (the corresponding specific EMI SE was 110 dB cm2/g), measured across the Ku-band frequency region, was obtained. This forming strategy has potential industrial application and large-scale EMI shielding materials producing guidance.