▎ 摘　　要

NOVELTY - Multi-stage foam sound absorbing black material comprises a polymer foam framework and continuous graphene resonant cavity attached on the framework. The aperture of the polymer foam framework is more than 10 um. The cavity wall of the graphene resonant cavity is graphene with thickness less than 100 nm. USE - Used as multi-stage foam sound absorbing black material. ADVANTAGE - The material: is economical; has excellent sound absorbing performance in wide frequency range, simple method and potential for a wide range of industrial applications; achieves rapid attenuation of sound waves; and combines with the friction loss of the porous structure of the polymer foam for sound waves. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the sound absorbing black foam material by immersing the polymer foam in a dispersion of graphene oxide, and placing the obtained foam in a foaming agent solution for foaming.