多壁碳纳米管(MWCNTs)凭借优异的物理化学性能,可被用作补强填料来改善复合材料的性能。目前对MWCNTs改善室温硫化(RTV)硅橡胶材料耐烧蚀性能的机理还没有较深入的研究。为了研究MWCNTs对RTV硅橡胶耐烧蚀性能的影响,采用溶液共混法制备了不同配方的MWCNTs/RTV硅橡胶复合材料。通过氧乙炔烧蚀试验,结合扫描电子显微镜(SEM)研究其烧蚀特性,分析碳化层的微观形貌,从碳化层结构、孔隙率、热解气体沉积等方面方面揭示了碳纳米管改善RTV硅橡胶复合材料耐烧蚀性能的内在机理。结果表明:MWCNTs对RTV硅橡胶耐烧蚀性能有增强作用,在添加量为1份时线烧蚀率最低为0.133 mm/s,碳化烧蚀率最低为0.186 mm/s,比未添加MWCNTs的材料分别降低21.5%、12.8%。通过SEM分析碳化层微观形貌发现,碳化层表面一侧形成较厚的致密层,背面一侧孔隙率较大,在碳化层中观测到相互交错联结的MWCNTs,其表面有较多热解产物沉积。MWCNTs的添加增加了碳化层结构强度,促进了致密层的形成,有效提高了RTV硅橡胶的耐烧蚀性能。

In order with excellent physicochemical properties, multi-walled carbon nanotubes (MWCNTs) can be used as reinforcing fillers to improve the properties of composite materials. The mechanism of MWCNTs to improve the ablative corrosion resistance of room temperature vulcanized (RTV) silicone rubber materials has not been studied in depth. To investigate the effect of MWCNTs on the ablation resistance of RTV silicone rubber, different formulations of MWCNTs/RTV silicone rubber composites were prepared by solution blending method. The ablation characteristics were studied by oxyacetylene ablation test combined with scanning electron microscopy (SEM), and the microscopic morphology of the carbonized layer was analyzed to reveal the intrinsic mechanism of carbon nanotubes to improve the ablation resistance of RTV silicone rubber composites in terms of carbonized layer structure, porosity, and pyrolysis gas deposition. The results show that MWCNTs have enhanced the ablation resistance of silicone rubber, with the lowest wire ablation rate of 0.133 mm/s and the lowest carbonized ablation rate of 0.186 mm/s at the addition of 1 part, which are 21.5% and 12.8% lower than those of the materials without MWCNTs. The addition of MWCNTs increased the structural strength of the carbonized layer, promoted the formation of dense layer, and effectively improved the ablation resistance of silicone rubber.