Multi-stage foam sound-absorbing black body material and preparation method thereof

A preparation method for a multi-stage foam sound-absorbing black body material, comprising the steps of:

• immersing a polymer foam into a graphene oxide dispersion, with graphene oxide of the graphene oxide dispersion filling into an interior of the polymer foam,
• drying the polymer foam filled with graphene oxide to obtain a dried foam;
• adding the dried foam in a foaming agent solution for foaming, and
• drying after foaming to obtain the multi-stage foam sound-absorbing black body material;
• wherein the multi-stage foam sound-absorbing black body material comprises a polymer foam skeleton having a pore size of 10 μm or more and a continuous graphene resonant cavity attached thereto, wherein a cavity wall of the graphene resonant cavity is graphene having a thickness of 100 nm or less;
• and wherein the polymer foam skeleton forms a primary foam structure, and the graphene resonant cavity forms a secondary foam structure.