Polyurethane foam and preparation method thereof

The invention discloses polyurethane foam and a preparation method thereof.The polyurethane foam comprises soft polyurethane foam, a phosphorylated cellulose nanofiber layer and a titanium carbide layer are sequentially deposited on the surface of the soft polyurethane foam, and the surface of the soft polyurethane foam and phosphorylated cellulose nanofibers are combined through hydrogen bonds. The phosphorylated cellulose nanofibers and the titanium carbide are combined through hydrogen bonds. Compared with the conventional additive flame retardant, the layer-by-layer self-assembly technology adopted by the invention does not generate negative influence on the compression performance and mechanical property of the soft polyurethane foam, but can improve the strength and toughness of the material. Compared with a large amount of oxycarbide and hydrocyanic acid flue gas generated during combustion of conventional soft flame-retardant polyurethane foam, the titanium carbide layer prepared by the preparation me