硅橡胶改性氢氧化镁及其阻燃EVA复合材料的性能

Properties of magnesium hydroxide modified by silicone rubber and its flame retardant EVA composites

  • 摘要: 由于氢氧化镁(Magnesium Hydroxide, MH)较低的阻燃效率,其阻燃乙烯-醋酸乙烯酯共聚物(Ethylene-Vinyl Acetate Copolymer, EVA)复合材料的阻燃性能与力学性能之间相互制约显著,影响工程应用。本文采用硅橡胶(Silicone Rubber, SR)对MH进行包覆改性(SR-MH)并用于EVA的阻燃改性(EVA/SR-MH),对EVA/SR-MH复合材料的氧指数、力学性能及体积电阻率进行了研究。研究结果表明SR-MH的水接触角高达119.5°,表面极性得到有效改善;阻燃剂添加量为40wt.%时,EVA/SR-MH复合材料的极限氧指数(Limiting Oxygen Index, LOI)提升了85%、热释放速率峰值(Peak Heat Release Rate, pHRR)降低了29%、抗拉强度提升了103%、断裂伸长率提升了41%、体积电阻率提升了362%,复合材料的综合性能得到显著提升。

     

    Abstract: Due to the low flame retardant efficiency of Magnesium Hydroxide (MH), a significant interaction exists between flame retardants and Ethylene Vinyl Acetate Copolymer (EVA) composites regarding their flame retardant and mechanical properties during flame retardant modification. This trade-off effect restricts the widespread application of such composites in engineering. In this paper, silicone rubber (SR) was employed for the modification of MH coating (SR-MH) and further utilized for enhancing the flame retardancy of EVA (EVA/SR-MH). The oxygen index, mechanical properties, and volume resistivity of the EVA/SR-MH composite were systematically investigated. The results indicate that the water contact angle of SR-MH reaches 119.5°, demonstrating a significant enhancement in surface polarity. When the flame retardant content is 40wt.%, the Limiting Oxygen Index (LOI) of the EVA/SR-MH composite increases by 85%, the peak heat release rate (pHRR) decreases by 29%, the tensile strength improves by 103%, the elongation at break increases by 41%, and the volume resistivity rises by 362%. These findings confirm that the comprehensive properties of the composite are markedly enhanced.

     

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