In this work, rigid polyurethane foams (RPUF) were flame retarded by adding 8 wt % expandable graphite (EG) and EG/Phenylphosphonic-aniline salt (FR1) flame retardant compounds. The adding amount of EG/FR1 compound is 8 wt % as well, and different ratios (8:1 and 12:1) of EG to FR1 were designed. Detailed characterizations of the density, cellular structure, and thermal conductivity of RPUF were carried out. An increase in thermal conductivity was observed as the FR1 content increased. The thermogravimetric analysis (TGA) indicated that EG and FR1 accelerated the degradation of the foam but increased the char residue. The results from the fire tests showed that RPU3 improved the fire resistance of the RPUF on a higher grade than RPU1. In detail, RPU3 increased the limited oxygen index (LOI) value from 19.2% to 29.8% and reached V-0 rating on the vertical burning test. Results from the cone calorimeter test showed that the RPU3 effectively reduced peak of heat released rate (pHRR) in comparison to PU and RPU1 reference samples. A combined synergistic flame-retardant mechanism by the barrier effect of EG in condense phase and radical capture mechanism of FR1 in gas phase was proposed. Moreover, the compression performance of the foams increased by the combined addition of EG and FR1 at the same 12:1 ratio in the RPUF. A good interfacial adhesion between FR1 and PU matrix besides an increasing density of the foam, could be the responsible for this result.

在这项工作中，通过添加8 wt％的可膨胀石墨（EG）和EG /苯基膦酸苯胺盐（FR1）阻燃剂化合物来阻燃硬质聚氨酯泡沫（RPUF）。EG / FR1化合物的添加量也为8重量％，并且设计了EG与FR1的不同比例（8∶1和12∶1）。对RPUF的密度，孔结构和导热率进行了详细的表征。随着FR1含量的增加，观察到热导率的增加。热重分析（TGA）表明，EG和FR1加速了泡沫的降解，但增加了残炭。防火测试的结果表明，RPU3在比RPU1更高的等级上提高了RPUF的耐火性。详细地说，RPU3将极限氧指数（LOI）值从19.2％增加到29。8％，在垂直燃烧测试中达到V-0等级。锥形量热仪测试的结果表明，与PU和RPU1参考样品相比，RPU3有效降低了放热率（pHRR）的峰值。提出了EG在凝聚相中的阻隔作用与FR1在气相中的自由基捕获机理相结合的协同阻燃机理。此外，通过以相同的12：1比例在RPUF中组合加入EG和FR1，可以提高泡沫的压缩性能。FR1和PU基质之间的良好界面粘合力，除了泡沫密度的增加外，可能是造成这种结果的原因。提出了EG在凝聚相中的阻隔作用与FR1在气相中的自由基捕获机理相结合的协同阻燃机理。此外，通过以相同的12：1比例在RPUF中组合加入EG和FR1，可以提高泡沫的压缩性能。FR1和PU基质之间的良好界面粘合力，除了泡沫密度的增加外，可能是造成这种结果的原因。提出了EG在凝聚相中的阻隔作用与FR1在气相中的自由基捕获机理相结合的协同阻燃机理。此外，通过以相同的12：1比例在RPUF中组合加入EG和FR1，可以提高泡沫的压缩性能。FR1和PU基质之间的良好界面粘合力，除了泡沫密度的增加外，可能是造成这种结果的原因。