硬质聚氨酯泡沫（PU）是一种主链含有大量氨基甲酸酯基（—NHCOO—）重复结构单元的有机高分子材料，遇火极易被点燃。为改善其燃烧性能，研究以m-SiO₂为硅源，植酸（PA）为酸源，4-氨基吡啶（4-AP）为氮源，同时选用过渡金属离子Zn²⁺为催化成炭剂，采用逐层改性的方式制备生物基改性P-N-Si系阻燃剂m-SKAPA-Zn。按照质量分数5%、10%、15%的比例添加到PU中，制备阻燃PU复合材料。结果表明：随着m-SKAPA-Zn添加量的增加，阻燃性能整体呈上升趋势，添加质量分数15% m-SKAPA-Zn的PU材料，极限氧指数（LOI）提高至22.6%，UL-94测试可达V-1级，烟密度等级降低37.5%。m-SKAPA-Zn表现出较好的阻燃性和抑烟效果。

Rigid polyurethane foam (PU) is an organic polymer material with a large number of repeating structural unit carbamate groups (—NHCOO—) in the main chain, which is very easy to be ignited by fire. In order to improve its combustion performance, in this study, m-SiO₂ was used as the silicon source, phytic acid (PA) was used as the acid source, 4-aminopyridine (4-AP) was used as the nitrogen source, the transition metal ion Zn²⁺ was selected as the catalytic carbon forming agent, and the biobased modified P-N-Si flame retardant m-SKAPA-Zn was prepared by a layer-by-layer modification. m-SKAPA-Zn was respectively added into the PU at the mass fraction of 5%, 10% and 15% to prepare flame retardant PU composites. The results showed that the flame retardant properties increased with the increase of m-SKAPA-Zn addition, the LOI of PU material with 15% m-SKAPA-Zn increased to 22.6%, the UL-94 test could reach the V-1 rating, and the smoke density level was reduced by 37.5%. m-SKAPA-Zn showed better flame retardancy and smoke inhibition effect.