▎ 摘　　要

NOVELTY - Preparation of electromagnetic shielding composite material involves (s1) mixing carbon filler, graphene-loaded ferroferric oxide composite particles, compatibilizer and foaming base material, extruding into a sheet to obtain a single-layer magnetic-electric bifunctional polyurethane composite material, repeating the loading step for at least two times, (s2) combining at least two single-layer magnetic-electric bifunctional polyurethane composite material prepared by the loading step, and obtaining multilayer magnetic-electric bifunctional polyurethane composite material, (s3) punching the multilayer magnetic-electric bifunctional polyurethane composite material to obtain punched composite material, and (s4) foaming the punched composite material to obtain carbon nanotube/reduced graphene oxide loaded ferroferric oxide/polyurethane composite foam, and spraying a layer of high conductive material on one side of the composite foam. USE - Preparation of electromagnetic shielding composite material used in preparation of electronic communication device, aerospace equipment, medical care equipment (all claimed), military, civil and precision equipment. ADVANTAGE - The method enables to prepare electromagnetic shielding composite material with low reflection magnetic-electric double function gradient structure, which shortens foaming agent dipping time in foaming process, increases impedance matching of material and electromagnetic wave, and increases multiple reflection and scattering of electromagnetic wave in the material, expands the propagation path of the electromagnetic wave and enhances the attenuation of the wave to endow the material with low reflection characteristic. DETAILED DESCRIPTION - Preparation of electromagnetic shielding composite material involves (s1) mixing carbon filler, graphene-loaded ferroferric oxide composite particles, compatibilizer and foaming base material, extruding into a sheet to obtain a single-layer magnetic-electric bifunctional polyurethane composite material, repeating the loading step for at least two times, adjusting the content of carbon filler in single-layer magnetic-electric bifunctional polyurethane composite material to make it different from the content used by the previous loading step, obtaining at least two single-layer magnetic-electric bifunctional polyurethane composite material with different carbon filler loading amount, (s2) combining at least two single-layer magnetic-electric bifunctional polyurethane composite material prepared by the loading step, and obtaining multilayer magnetic-electric bifunctional polyurethane composite material, (s3) punching the multilayer magnetic-electric bifunctional polyurethane composite material to obtain punched composite material, and (s4) foaming the punched composite material to obtain carbon nanotube/reduced graphene oxide loaded ferroferric oxide/polyurethane composite foam, and spraying a layer of high conductive material on one side of the composite foam.