▎ 摘　　要

NOVELTY - Method for preparing a polymer foam, involves mixing a thermoplastic polymer with a microwave absorber to obtain a body to be foamed, where the amount of the microwave absorber is 0-5 wt.% of the thermoplastic polymer, and when the thermoplastic polymer is a thermoplastic polymer with a dielectric loss to be less than 0.1, the amount of the microwave absorber is not 0, performing saturated adsorption of the to-be-foamed body in a gas foaming agent to obtain a pre-foamed body, and soaking the pre-foam in a microwave absorbing liquid for microwave heating and foaming to obtain the polymer foam, where the dielectric loss of the microwave absorbing liquid is greater than 0.1, and the initial temperature of the microwave absorbing liquid is 5-30℃. USE - The method is used for preparing polymer foam for special ship, automobile part, aerospace, food packaging, and sports apparatus. ADVANTAGE - The polymer foam has uniform size with the edge of the foam hole, foam cell density of 7.63-107cells/cm3, foaming ratio of 1.83-31.82, cell size of 6.32-38.28 µm, and uniformity of the polymer foam hole. The method shortens saturation adsorption time, and improves production efficiency.