为提高聚氨酯可控膨胀材料的耐火性能与力学性能，通过分子设计，在聚脲合成中引入降活胺扩链剂和低活性异氰酸酯组分调控聚脲涂层（ PUA）的反应速度及力学性能，并与新型淀粉基磷酸酯蜜胺盐阻燃剂（SPM）复配，在聚氨酯可控膨胀材料（PUF）表面制备了降活型防火聚脲涂层，通过极限氧指数、垂直燃烧法以及抗压抗折测试等手段研究了降活型防火聚脲涂层改性聚氨酯可控膨胀材料的耐火性能及力学性能。结果表明：改性可控膨胀材料 PU/PUA10S可通过 UL-94测试，达到 V-0等级，锥形量热测试显示其具有良好的耐火效果。与纯聚氨酯可控膨胀材料相比， PU/PUA10S的力学性能得到了明显提升，其抗压强度从 3. 4 MPa提高到 5. 0 MPa，抗折强度从 2. 5 MPa提高到3. 4 MPa，可作为抢修抢建、应急防护等领域的表面增强耐火防护材料。

Low-activity amine chain extenders and low-activity isocyanate componentswere introduced to regulate the reaction rate and mechanical properties of polyurea coatings（PUA）. Combined with a novel starch-based phosphate melamine salt flame retardant（SPM）a deactivated flame retardant polyurea coating was prepared on the surface of the polyurethane-，based expansion materials（PUF）. The flame retardancy and mechanical properties of the modified-PUF materials were investigated through characterization methods such as extreme oxygenindex，vertical combustion method，and compressive and flexural tests. The research resultsindicated that the modified PU/PUA10S successfully passed the UL-94 test，reached the V-0，and had a good flame retardant effect. Compared with the initial PUF，the mechanical properties of PU/PUA10S were significantly improved，with compressive strength increasing from 3. 4 MPato 5. 0 MPa and flexural strength increasing from 2. 5 MPa to 3. 4 MPa. In this study，a surface-enhanced flame retardant protective material in situ was prepared，which could be applied in fields such as emergency repair/construction and emergency protection.