柔性氧化硅气凝胶隔热复合材料的制备和性能

以正硅酸乙酯为原料,高硅氧纤维为增强体,采用氨水催化一步法制备了柔性的纤维增强氧化硅气凝胶隔热复合材料。当pH=7时,气凝胶的比表面积最大;水含量增大,比表面积降低;乙醇含量增大,比表面积增大,EtOH/TEOS(摩尔比)大于10以上,比表面积增加不明显,趋于稳定。以比表面积较大的气凝胶作为基体的柔性复合材料常温热导率为0.031 W/(m.K)纯高硅氧纤维毡为0.044 W/(m.K)]。该柔性隔热材料安装方便,特别适用于大面积、不规则形状的包覆隔热。

Preparation and Properties of Flexible SilicaAerogel Composites for Thermal Insulators

Flexible fiber reinforced silica aerogel composites for thermal insulators were prepared by ammonia-catalyzed one-step sol-gel process,using tetraethoxysilane as precursor,high silica fiber as reinforcement.The highest specific surface area(SSA) can be obtained in an aerogel derived from the sol with pH=7.The SSA decreases with increasing the water molar ratio,while it increases with increasing the ethanol molar ratio.When the molar ratio of ethanol/ tetraethoxysilane is higher than 10,the SSA only increases mildly with increasing the ethanol ratio.The thermal conductivity of the high silica fiber-reinforced high SSA aerogel composites is 0.031 W/(m·K)0.044 W/(m·K)for the high silica fiber matrix].The flexible aerogel composites are easy-to-install and are very suitable for insulations on large surfaces and complex shapes.