硅系气凝胶是目前研究理论最为完善、合成技术最为成熟的气凝胶材料。本工作分别以四乙氧基硅烷(TEOS)、甲基三甲氧基硅烷(MTMS)、MTMS与二甲基二甲氧基硅烷(DMDMS)混合硅源、乙烯基甲基二甲氧基硅烷(VMDMS)为前驱体, 制备了不同种类的硅系气凝胶。所制得的硅系气凝胶具有较高的比表面积, 并呈现出纳米多孔的网络结构。本研究详细探讨了前驱体结构对气凝胶的力学及热学性能的影响。结果表明, 硅系气凝胶的骨架结构交联度越低, 弹性性能越好; 同时, 引入有机碳氢链会进一步提升气凝胶的弹性性能。所制备的硅系气凝胶兼具良好的保温隔热性能, 常温热导率在0.032~0.041 W/(m·K)范围内, 热重损失随着骨架结构内有机组分的增多而增大。这些优良的力学及热学性能使硅系气凝胶在保温隔热、储能等领域均具有广阔的应用前景。

In all kinds of aerogels, silicon-based aerogel possesses the most comprehensive mechanism of Sol-Gel process and maturest synthesis process. In this work, different types of silicon-based aerogels were prepared via different silicon precursors including tetraethoxysilane (TEOS), methyltrimethoxysilane (MTMS), vinylmethyldimethoxysilane (VMDMS) and the mixed precursor of MTMS and dimethyldimethoxysilane (DMDMS). All samples display high specific surface area and porous microstructure. Effect of the precursor structure on the mechanical and thermal properties of final samples was deeply investigated. The results show that elastic property of silicon-based aerogels depends greatly on the crosslinking degree of their skeleton. The lower the crosslinking degree of the sample is, the better the elastic property is. Furthermore, the elastic property can be further improved by introducing hydrocarbon chains into the skeleton. Thermal conductivity of the obtained aerogels is between 0.032 and 0.041 W/(m·K) at room temperature. Their weight loss increases with the increase of the organic component in the skeleton. Superior mechanical and thermal properties enable silicon-based aerogels to be promising candidates for thermal insulation and energy storage.