摘要
以工业水玻璃为硅源,分别用三甲基氯硅烷[(CH3)3SiCl,TMCS]六甲基二硅醚[(CH3)3Si-O-Si(CH3)3,HMDSO]和乙醇(CH3CH2OH,EtOH)/TMCS/庚烷(C7H16)溶液对SiO2水凝胶进行溶剂交换和表面改性处理。通过TMCS与水凝胶中孔隙水和表面-OH基团之间的反应,使对水凝胶的溶剂交换和表面改性在一步同时完成,在常压干燥条件下合成了SiO2气凝胶。利用电子显微镜和Brunauer-Emmett-Teller法对气凝胶的微观结构和形貌进行了研究。结果表明:用EtOH/TMCS/C7H16和TMCS/HMDSO溶液均可获得具有海绵状结构的纳米介孔SiO2气凝胶;而用EtOH/TMCS/C7H16溶液对水凝胶进行改性处理更有利于获得均匀的大块气凝胶。所得SiO2气凝胶比表面积约为559-685m2/g,密度为0.128-0.141g/cm3。Fourier转换红外光谱分析表明:凝胶表面-OH基团已被改性为-O-SiCH3,表面呈现出明显的疏水性。
Using industrial water glass as silica sources, SiO2 aerogels were synthesized via ambient pressure drying technique. The solvent exchange and surface modification of SiO2 hydrogels were performed simultaneously in one step through reaction of （CH3）3SiCl （TMCS） with pore water and surface hydroxyl （--OH）, by using TMCS/（CH3）3 Si-O-Si（CH3）3 （HMDSO） or ethanol （EtOH）/TMCS/heptane as surface modification solutions respectively. The microstructure and morphology of SiO2 aerogels were studied by electron microscopy and Brunauer - Emmett - Teller analysis. The results indicate that nano-mesoporous SiO2 aerogel with a sponge structure can be obtained by using TMCS/HMDSO or EtOH/TMCS/heptane as the surface modification solution, whereas treating SiO2 hydrogel with EtOH/TMCS/heptane solution is more favorable for obtaining monolithic SiO2 aerogel. The specific surface areas and density of the synthesized SiO2aerogels are 559 to 685 m^2/g and 0. 128 to 0. 141 g/cm^3 respectively. Fourier transform infrared spectroscopy analyses indicate that the SiO2 aerogel surface hydroxyl （--OH） is modified into --O--SiCH3, and thus obvious hydrophobicity is presented at the surface.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2005年第8期963-967,974,共6页
Journal of The Chinese Ceramic Society
基金
辽宁省教育厅(2020701096)资助项目。
关键词
二氧化硅气凝胶
常压下燥
纳米介孔
表面改性
silica aerogel
ambient pressure drying
nano mesoporous
surface modification
