The incorporation of flame retardants (FRs) is often applied to reduce the fire risk of flexible polyurethane foam (FPUF), however, the addition of FRs usually brings mechanical loss, and the emigration of FRs during service life results in a decrease in flame retardancy. In this work, a hyperbranched FR (HPNP) containing nitrogen and phosphorous was synthesized via transesterification between dimethyl methyl phosphonate (DMMP) and triethanolamine. The distribution of HNPN in FPUF was simulated by the Materials Studio software. The flammability was characterized by the open flame test, horizontal combustion test, limiting oxygen index (LOI) and cone calorimeter test. The FPUF sample containing only 4 wt% HPNP self-extinguished immediately after the removal of the ignitor. For the FPUF containing 8 wt% HPNP sample, the LOI was increased to 26.3% from 17.9%. The total heat release and total smoke production were reduced by 65% and 75%, respectively compared to that of the control FPUF sample. More importantly, the radical trapping action in the gas phase and the charring promotion in the condensed phase were simulated and verified based on the experimental data. Furthermore, the interfacial energy calculation and molecular dynamics simulation suggested that the improved compatibility of FPUF/HPNP resulted in the superior durability of HPNP in FPUF. In addition, the FPUF samples containing HPNP also showed enhanced mechanical properties. It was expected the hyperbranched HPNP would be an ideal additive to produce flame retardant FPUF with excellent comprehensive performance.

阻燃剂（FRs）的掺入通常用于降低软质聚氨酯泡沫（FPUF）的火灾风险，然而，FRs的添加通常会带来机械损失，并且FRs在使用寿命期间的迁移导致阻燃性降低. 在这项工作中，通过甲基膦酸二甲酯 (DMMP) 和三乙醇胺之间的酯交换反应合成了一种含有氮和磷的超支化 阻燃剂(HPNP)。FPUF 中 HNPN 的分布由 Materials Studio 软件模拟。可燃性通过明火试验、水平燃烧试验、极限氧指数（LOI）和锥形量热仪试验表征。仅包含 4 wt% HPNP 的 FPUF 样品在移除点火器后立即自熄。对于含有 8 wt% HPNP 样品的 FPUF，LOI 增加到 26.3% 从 17.9%。与对照 FPUF 样品相比，总热释放量和总烟气产生量分别减少了 65% 和 75%。更重要的是，根据实验数据模拟验证了气相中的自由基捕集作用和凝聚相中的炭化促进作用。此外，界面能计算和分子动力学模拟表明，FPUF/HPNP 相容性的提高导致 HPNP 在 FPUF 中具有优异的耐久性。此外，含有 HPNP 的 FPUF 样品还表现出增强的机械性能。超支化HPNP有望成为生产综合性能优异的阻燃FPUF的理想添加剂。