SiO2气凝胶纤维隔热复合材料的常压制备及性能表征

SiO₂气凝胶的力学性能较差,隔热性能较强,为了使其成为良好的隔热材料,本文提出一种SiO₂气凝胶纤维隔热复合材料的制备方法。以正硅酸乙酯(TEOS)为前驱体,玻璃纤维和陶瓷纤维为增强体,硅烷偶联剂KH550和KH570为纤维处理剂,在常压条件下制备SiO₂气凝胶纤维隔热复合材料,并对材料性能进行表征。结果表明:前驱体中十六烷基三甲基溴化铵(CTAB)含量越高,复合材料中SiO₂气凝胶导热系数越低,低至0.028 W/(m·K);使用硅烷偶联剂KH550时,基体和纤维之间结合的紧密程度更高;纤维的加入使SiO₂气凝胶的力学性能达到很高水平;当前驱体中TEOS与CTAB摩尔比为1∶0.022时,经KH550处理的玻璃纤维/SiO₂气凝胶复合材料导热系数为0.054 W/(m·K),力学性能良好,隔热性能最优。

Atmospheric Pressure Preparation and Property Characterization of SiO2 Aerogel Fiber Thermal Insulation Composites

SiO₂ aerogel has poor mechanical properties and strong thermal insulation properties. In order to make SiO₂ aerogel a good thermal insulation material, a preparation method of SiO₂ aerogel fiber thermal insulation composites was proposed. SiO₂ aerogel fiber insulation composites were prepared under atmospheric pressure condition by ethyl orthosilicate (TEOS) as precursor, glass fiber and ceramic fiber as reinforcers, and silane coupling agents KH550 and KH570 as fiber treatment agents, and the material properties were characterized. The results show that the higher the content of hexadecyl trimenthyl ammonium (CTAB) in precursor is, the lower the thermal conductivity of SiO₂ aerogel in composite is, which can be as low as 0.028 W/(m·K). When using silane coupling agent KH550, the interface bonding strength between matrix and fiber is higher. The mechanical properties of SiO₂ aerogel reach a high level with the addition of fiber. When the molar ratio of TEOS to CTAB is 1∶0.022, the thermal conductivity of glass fiber/SiO₂ aerogel composites treated with KH550 is 0.054 W/(m·K), the mechanical properties are good, and the thermal insulation property is optimal.