Abstract Ammonium polyphosphate (APP) is well known to have a synergistic action with phosphorus-based flame retardants in enhancing the flame retardant performance of matrix polymers, but the effect of APP and phosphorous-containing hydrotalcite on synergistic effect and degradation mechanism of polypropylene (PP) has not been thoroughly studied. In the present work, a synergistic flame retardant containing P3O105− intercalated Mg/Al hydrotalcite modified by rare-earth coupling agent (W-LDH-P) and APP were prepared and used as compounded flame retardant (W-LDH-P/APP) for PP matrix. The W-LDH-P/APP and PP composites(PP/W-LDH-P/APP) possess a limiting oxygen index (LOI) value of 27.8% and achieves the V-0 standard of the flame retardant plastic. Additionally, the heat release rate (HRR), total heat release (THR) and total smoke release (TSR) for the PP/W-LDH-P/APP composites were decreased by 44.0%, 21% and 75% compared with PP/W-LDH-P. These results demonstrate that APP dramatically enhances the flame retardancy of the PP. The synergistic effect and degradation mechanism of APP and W-LDH-P are confirmed by SEM and TGA analysis. These analyses reveal that the APP and W-LDH-P promoted the formation of a more continuous and compact char layer during the burning process for PP matrix.

中文翻译：

---

聚磷酸铵对含磷水滑石协同聚丙烯阻燃机理的影响

摘要 众所周知，多磷酸铵（APP）与磷系阻燃剂在增强基体聚合物阻燃性能方面具有协同作用，但APP与含磷水滑石对聚丙烯（PP）的协同作用和降解机理的影响较小。 ) 还没有被彻底研究过。在目前的工作中，制备了一种含有经稀土偶联剂（W-LDH-P）和APP改性的P3O105−插层Mg/Al水滑石的协同阻燃剂，并将其用作复合阻燃剂（W-LDH-P/APP）对于 PP 矩阵。W-LDH-P/APP和PP复合材料(PP/W-LDH-P/APP)的极限氧指数(LOI)值为27.8%，达到阻燃塑料的V-0标准。此外，热释放率（HRR），与PP/W-LDH-P相比，PP/W-LDH-P/APP复合材料的总热释放量（THR）和总发烟量（TSR）分别降低了44.0%、21%和75%。这些结果表明，APP 显着提高了 PP 的阻燃性。SEM和TGA分析证实了APP和W-LDH-P的协同作用和降解机制。这些分析表明，APP 和 W-LDH-P 在 PP 基体的燃烧过程中促进了更连续和致密的炭层的形成。