Ammonium polyphosphate (APP) with different polymerization degrees were modified by a novel phosphorus-containing organosilicon compound (PCOC), and the products obtained were coded as MAPP-30 and MAPP-1000. Then they were applied to prepare flame-retardant rigid polyurethane foam (RPUF), separately. The impact of the modified APP (MAPP) on the flame-retardant properties of RPUF was investigated by the limited oxygen index (LOI) test, horizontal burning test, and cone calorimeter test. The morphologies of the char residues were observed by SEM. Furthermore, the mechanical properties of RPUF composites were measured by compressive strength test. Results showed that no matter the degree of polymerization of MAPP is 30 or 1000, they both had greater charring ability and better flame-retardant properties than unmodified APP. The residual char yield of RPUF/MAPP-30 (37.3%) and RPUF/MAPP-1000 (36.5%) were both significantly higher than RPUF/APP-30 (22.8%) and RPUF/APP-1000 (24.9%). The peak heat release rate value of RPUF/MAPP-30 was 29.9% lower than that of RPUF/APP-30, and the drops of RPUF/MAPP-1000 was 50.9% comparing to RPUF/APP-1000. Moreover, the total heat release of RPUF/MAPP-1000 (9.7 MJ/m2) was much lower than that of RPUF/MAPP-30 (11.3 MJ/m2). In summary, MAPP-1000 got the best flame-retardant properties among all the RPUF composites. In addition, the results also showed that flame retardant performance and the mechanical properties dramatically decreased with the increased addition of MAPP-1000, and the RPUF composite had the best comprehensive performance with 20% content of MAPP-1000.

中文翻译：

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含有改性聚磷酸铵的硬质聚氨酯泡沫具有出色的炭化能力和更高的阻燃性

用新型含磷有机硅化合物（PCOC）对不同聚合度的多聚磷酸铵（APP）进行改性，所得产物分别编码为MAPP-30和MAPP-1000。然后将它们分别用于制备阻燃硬质聚氨酯泡沫（RPUF）。通过极限氧指数(LOI)试验、水平燃烧试验和锥形量热试验研究了改性APP(MAPP)对RPUF阻燃性能的影响。通过扫描电镜观察炭残留物的形态。此外，RPUF复合材料的力学性能通过抗压强度测试进行测量。结果表明，无论MAPP的聚合度为30还是1000，均比未改性的APP具有更强的炭化能力和更好的阻燃性能。RPUF/MAPP-30 (37.3%) 和 RPUF/MAPP-1000 (36.5%) 的残炭率均显着高于 RPUF/APP-30 (22.8%) 和 RPUF/APP-1000 (24.9%)。RPUF/MAPP-30的热释放率峰值比RPUF/APP-30低29.9%，RPUF/MAPP-1000比RPUF/APP-1000下降50.9%。此外，RPUF/MAPP-1000 的总放热量（9.7 MJ/m2）远低于 RPUF/MAPP-30（11.3 MJ/m2）。综上所述，在所有 RPUF 复合材料中，MAPP-1000 的阻燃性能最好。此外，结果还表明，随着MAPP-1000添加量的增加，阻燃性能和力学性能显着下降，其中MAPP-1000含量为20%的RPUF复合材料综合性能最佳。5%) 均显着高于 RPUF/APP-30 (22.8%) 和 RPUF/APP-1000 (24.9%)。RPUF/MAPP-30的热释放率峰值比RPUF/APP-30低29.9%，RPUF/MAPP-1000比RPUF/APP-1000下降50.9%。此外，RPUF/MAPP-1000 的总放热量（9.7 MJ/m2）远低于 RPUF/MAPP-30（11.3 MJ/m2）。综上所述，在所有 RPUF 复合材料中，MAPP-1000 的阻燃性能最好。此外，结果还表明，随着MAPP-1000添加量的增加，阻燃性能和力学性能显着下降，其中MAPP-1000含量为20%的RPUF复合材料综合性能最佳。5%) 均显着高于 RPUF/APP-30 (22.8%) 和 RPUF/APP-1000 (24.9%)。RPUF/MAPP-30的热释放率峰值比RPUF/APP-30低29.9%，RPUF/MAPP-1000比RPUF/APP-1000下降50.9%。此外，RPUF/MAPP-1000 的总放热量（9.7 MJ/m2）远低于 RPUF/MAPP-30（11.3 MJ/m2）。综上所述，在所有 RPUF 复合材料中，MAPP-1000 的阻燃性能最好。此外，结果还表明，随着MAPP-1000添加量的增加，阻燃性能和力学性能显着下降，其中MAPP-1000含量为20%的RPUF复合材料综合性能最佳。比RPUF/APP-30低9%，RPUF/MAPP-1000比RPUF/APP-1000下降50.9%。此外，RPUF/MAPP-1000 的总放热量（9.7 MJ/m2）远低于 RPUF/MAPP-30（11.3 MJ/m2）。综上所述，在所有 RPUF 复合材料中，MAPP-1000 的阻燃性能最好。此外，结果还表明，随着MAPP-1000添加量的增加，阻燃性能和力学性能显着下降，其中MAPP-1000含量为20%的RPUF复合材料综合性能最佳。比RPUF/APP-30低9%，RPUF/MAPP-1000比RPUF/APP-1000下降50.9%。此外，RPUF/MAPP-1000 的总放热量（9.7 MJ/m2）远低于 RPUF/MAPP-30（11.3 MJ/m2）。综上所述，在所有 RPUF 复合材料中，MAPP-1000 的阻燃性能最好。此外，结果还表明，随着MAPP-1000添加量的增加，阻燃性能和力学性能显着下降，其中MAPP-1000含量为20%的RPUF复合材料综合性能最佳。