蒲绒活性炭负载Fe2O3的制备及其在软质聚氯乙烯中的阻燃应用

以蒲绒为原料、H₃PO₄为活化剂制备了蒲绒活性炭（AC），利用浸渍焙烧法，制备了AC负载Fe₂O₃（AC-Fe₂O₃）复合物，将AC及AC-Fe₂O₃应用于软质聚氯乙烯（PVC）的阻燃处理，制备了AC阻燃软质PVC（AC/PVC）复合材料和AC负载Fe₂O₃阻燃软质PVC（AC-Fe₂O₃/PVC）复合材料。采用热重分析法研究了AC/PVC和AC-Fe₂O₃/PVC阻燃复合材料的热分解行为，采用极限氧指数（LOI）、垂直燃烧（UL-94）、锥形量热（CONE）等方法测试了AC/PVC和AC-Fe₂O₃/PVC阻燃复合材料的阻燃性能。结果表明：添加阻燃剂所制备的PVC基复合材料均达到UL-94 V-0级，LOI值均有提高。相比纯PVC，AC/PVC和AC-Fe₂O₃/PVC复合材料的热释放速率峰值和烟释放总量均有明显降低。这主要是由于AC和Fe₂O₃在凝聚相发挥协同阻燃作用。一方面AC的加入起到了物理阻隔的作用；另一方面Fe₂O₃的加入促进了PVC的早期交联碳化反应，催化PVC在燃烧前期形成更加稳定的炭层，使残炭率提高，可以有效抑制PVC的燃烧。

Preparation of cattail activated carbon supported Fe2O3 and its flame retardant application in flexible polyvinyl chloride

The activated carbon (AC) was synthesized using cattail as a raw material and H₃PO₄ as an activator. Activated carbon supported Fe₂O₃ (AC-Fe₂O₃) composite was prepared by a dipping-roasting method. The obtained AC and AC-Fe₂O₃ were incorporated into the flexible polyvinyl chloride (PVC) to prepare AC/PVC and AC-Fe₂O₃/PVC, respectively. The thermal decomposition behavior of AC/PVC and AC-Fe₂O₃/PVC composites was investigated by thermal gravity analysis; the flame retardation of AC/PVC and AC-Fe₂O₃/PVC composites was studied by limiting oxygen index test (LOI), vertical burning test (UL-94) and cone calorimeter (CONE). The results show that AC/PVC and AC-Fe₂O₃/PVC composites can meet the requirement of V-0 grade in UL-94 test and LOI value is higher. Both the peak heat release rate and total smoke release for AC/PVC and AC-Fe₂O₃/PVC composites decrease significantly in comparison to neat PVC. The enhancement for AC/PVC and AC-Fe₂O₃/PVC composites in flame retardation mainly attributes to synergistic effect of AC and Fe₂O₃ in condensed phase. On one hand, it can be assigned to the physical barrier effect of the AC; on the other hand, during the earlier stage of combustion of PVC, Fe₂O₃ promotes the crosslinking carbonization reaction which can catalyze charring of PVC to form a more stable char layer, improving the char residual ratio and effectively suppressing combustion of PVC.