Lightweight and flexible silicone rubber foam with dopamine grafted multi-walled carbon nanotubes and silver nanoparticles using supercritical foaming technology: Its preparation and electromagnetic interference shielding performance

•Grafting dopamine forms chemical activation points on the multi-walled carbon nanotubes (MWCNTs).•The introduction of silver nanoparticles on MWCNTs improves conductivity.•The prepared foam has uniform cells and a density (0.3 g/cm3) at 15 parts of modified MWCNTs.•The electrical conductivity achieved as high as 5.69 S/m with a dopamine concentration of 2 g/L.•Lightweight and flexible silicone foam displays an EMI SE of 36 dB at thickness of 5 mm.•This type of composite foam has an absorption-based shielding mechanism.