▎ 摘　　要

NOVELTY - Preparing rigid polyurethane foam coated with surface coated with flame retardant aerogel coating comprises immersing rigid polyurethane foam in polymer/clay dispersion liquid, taking out and placing in an ethanol/liquid nitrogen bath for freezing, then performing vacuum freeze-drying, repeating the immersion-freeze-vacuum freeze-drying operation to obtain the hard polyurethane foam with surface coated with flame-retardant aerogel coating. In the polymer/clay dispersion liquid, the polymer is at least one of alginate, melamine salt, polyimide, and graphene oxide. The clay is bentonite clay or montmorillonite; the dispersion is deionized water. USE - The method is useful for preparing rigid polyurethane foam coated with surface coated with flame retardant aerogel coating. ADVANTAGE - The rigid polyurethane foam has excellent physical mechanical performance and flame retardant and fire-resistant performance.