硅橡胶泡沫（SRF）作为一种新型高分子泡沫材料，因同时兼具硅橡胶和泡沫的特性而被广泛应用在国防军工、航空航天、交通运输、电子工业、农业、动力电池。由于SRF材料有机硅侧链存在大量的碳氢基团，发泡后内部产生孔洞结构具有较高的空气流通性，增加了比表面积，在高温或遇火条件下会发生燃烧分解，导致阻燃性能差。为此，本文将改性LDHs与可膨胀石墨（EG）阻燃剂添加到SRF材料研究其阻燃性能。

采用共沉淀法制备水滑石（LDHs），并对其进行改性，制备含不同添加量稀土Ce³⁺的LDHs、硅凝胶包覆含不同添加量稀土Ce³⁺LDHs。利用XRD、SEM-EDS、FT-IR、TG等对制备的阻燃剂的结构、微观形貌进行表征测试。通过LOI仪、垂直燃烧测试仪、万能拉力试验机、锥形量热仪、热重红外分析仪等考察改性LDHs与EG复配的添加对所制备的SRF材料燃烧性能以及力学性能的影响。

成功制备了LDHs、含不同添加量稀土Ce³⁺的LDHs、硅凝胶包覆含不同添加量稀土Ce³⁺的LDHs。含稀土Ce³⁺LDHs的加入，可明显提高SRF材料的极限氧指数（LOI），力学性能也有所提升。添加0.3 mol Ce³⁺改性LDHs（LDHs-2）且含量为3wt%时，SRF材料的阻燃性能较好，样品的LOI值达到31.2%。随着硅凝胶包覆LDHs-2（SiLDHs-2）添加量的增加，SRF材料的LOI逐渐增大。添加量为5wt%SiLDHs-2具有较好的阻燃性能，添加量为1wt% SiLDHs-2表现出较好的抑烟性能。随着复配体系中EG添加量的增加，SRF材料的LOI值呈增加趋势，但力学性能有所降低；含3.3 wt%SiLDHs-2/6.7wt%EG SRF材料的LOI值、热释放率峰值、总热释放量均比纯SRF材料分别降低了43.21%、66.60%、52.76%；含6.7 wt%SiLDHs-2/3.3wt%EG SRF材料的产烟率峰值相比原样降低了71.43%，具有良好的抑烟性能，说明SiLDHs-2与EG具有协效阻燃抑烟作用。含LDHs-2、SiLDHs-2以及EG/SiLDHs-2复配阻燃剂的加入，初期均促进了SRF材料的热解，后期有效的延缓了SRF材料主链的破坏，残炭率均有提高，其中含SiLDHs-2的SRF材料热稳定性较好，其残炭率相比原样降低了14.98%。这说明EG/SiLDHs-2的加入，显著提高了SRF材料的阻燃性能以及热稳定性能。

Silicone rubber foam (SRF), as a new type of polymer foam material, is widely used in national defense and military industry, aerospace, transportation, electronics industry, agriculture, and power batteries because of the characteristics of both silicone rubber and foam. Due to the large number of hydrocarbon groups in the silicone side chain of the SRF material, the internal pore structure after foaming has high air circulation and increases the specific surface area. It will burn and decompose under high temperature or fire conditions, resulting in flame retardancy. Poor performance. For this reason, this article adds modified LDHs and expandable graphite (EG) flame retardant to the SRF material to study its flame retardant properties.

The hydrotalcite (LDHs) was prepared by co-precipitation method and modified to prepare LDHs containing different amounts of rare earth Ce³⁺, and silica gel coated with different amounts of rare earth Ce³⁺LDHs. XRD, SEM-EDS, FT-IR, TG, etc. were used to characterize and test the structure and microscopic morphology of the prepared flame retardant. The influence of the addition of modified LDHs and EG on the combustion performance and mechanical properties of the prepared SRF material was investigated by LOI instrument, vertical combustion tester, universal tensile testing machine, cone calorimeter, thermogravimetric infrared analyzer, etc.

LDHs, LDHs containing different amounts of rare earth Ce³⁺, and silicone gel coated LDHs containing different amounts of Ce³⁺ have been successfully prepared. The addition of Ce³⁺LDHs containing rare earths can significantly increase the limiting oxygen index (LOI) of SRF materials, and the mechanical properties are also improved. When 0.3 mol Ce³⁺ modified LDHs (LDHs-2) is added and the content is 3wt%, the flame retardant performance of the SRF material is better, and the LOI value of the sample reaches 31.2%. As the amount of silicone gel coated LDHs-2 (SiLDHs-2) increases, the LOI of SRF materials gradually increases. The addition of 5wt% SiLDHs-2 has better flame retardant properties, and the addition of 1wt% SiLDHs-2 shows better smoke suppression properties. With the increase in the amount of EG added in the compound system, the LOI value of the SRF material shows an increasing trend, but the mechanical properties are reduced; the LOI value, peak heat release rate, and total heat release of the SRF material containing 3.3 wt% SiLDHs-2/6.7 wt% EG are reduced by 43.21%, 66.60%, and 52.76%, respectively, compared with the pure SRF material; The peak smoke production rate of the SRF material containing 6.7 wt% SiLDHs-2/3.3 wt% EG is reduced by 71.43% compared with the original, and has good smoke suppression performance, indicating that SiLDHs-2 and EG have synergistic flame retardant and smoke suppression effects. The addition of LDHs-2, SiLDHs-2 and EG/SiLDHs-2 compound flame retardants advances the initial decomposition temperature of SRF materials, effectively delays the destruction of the main chain of SRF materials in the later stage, and improves the carbon residual rate of samples. Among them, the SRF material containing SiLDHs-2 has better thermal stability, and its carbon residue rate is reduced by 14.98% compared to the original. This shows that the addition of EG/SiLDHs-2 significantly improves the flame retardancy and thermal stability of SRF materials.

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