CTAB-SDS复配体系制备SiO_(2)气凝胶及其性能研究

Preparation and Properties of SiO_(2) Aerogels by CTAB-SDS Compound System

以碱性硅溶胶为前驱体,去离子水为唯一溶剂,通过酸-碱两步催化和常压干燥工艺,仅用一天时间制备出了SiO_(2)气凝胶。在制备过程中,将十六烷基三甲基溴化铵(CTAB)和十二烷基硫酸钠(SDS)进行复配,减小了蒸发干燥时水的毛细管张力,减小了其对气凝胶结构的破坏。结果表明,当SDS与CTAB的摩尔比为0.5时,经450℃热处理得到的SiO_(2)气凝胶具有最小的密度209 mg/cm^(3)、最低的室温热导率0.036 W/(m‧K)和最高的比表面积409 m^(2)/g。本文提出的制备方法降低了生产成本,简化了生产工艺,缩短了制备时间,有利于SiO_(2)气凝胶的大批量工业化生产和使用。

In this paper,using alkaline silica sol as precursor and the deionized water as the only solvent,SiO_(2) aerogel was prepared in only one day by the two-step acid-base catalyzed approach and ambient pressure drying.In the preparation process,the cetyltrimethylammonium bromide(CTAB)and the sodium dodecyl sulfate SDS were added to reduce the surface tension of water during the drying process,and reducing the shrinkage and cracking of the samples.When the molar ratio of SDS to CTAB was 0.5,the obtained silica aerogel showed the minimum density of 209 mg/cm^(3).The lowest thermal conductivity of 0.036 W/(m‧K)and the highest specific surface area of 409 m^(2)/g after heat treatment at 450℃.The preparation method proposed in this work reduces the production cost,simplifies the production process and shortens the preparation time,which is conducive to the large-scale industrial production and application of SiO_(2) aerogel.