The electrical conductivity and EMI shielding properties of polyurethane foam/silicone rubber/carbon black/nanographite hybrid composites

Electrically conductive nanocomposites based on an open cell polyurethane foam were fabricated by dip-coating of the PU foam in a cross-linkable doping solution. The doping solution was prepared by mixing of room temperature vulcanizing silicone rubber, and a hybrid of conductive filler systems consisted of carbon black and graphite nanoplates in n-hexane as a solvent. The influence of conductive filler types and GN: CB ratio at a constant concentration, on the electrical conduction, dielectric properties in the frequency range of 10(degrees)-10(5) Hz, and electromagnetic wave interference shielding effectiveness (SE) in the X-band frequency (8.2-12.4 GHz) were studied. SEM images showed the formation of continuous conductive networks by both CB and GNP particles within silicon rubber. The impedance analysis results revealed highest electrical resistance of nanocomposite based on GNP while by incorporation of CB, the electrical conductivity of hybrid systems increased. The EMI SE results indicated reflection loss as the dominant shielding mechanism in all samples. Higher absorption loss in the hybrid nanocomposites in compared with GNP based composite was observed. POLYM. COMPOS., 39:3452-3460, 2018. (c) 2017 Society of Plastics Engineers