甲基三甲氧基硅烷对块状SiO_2气凝胶性能和结构的影响  

STRUCTURE AND PROPERTIES OF MONOLITHIC SILICA AEROGELS BY METHYLTRIMETHOXYSILANE

作　　者：吴国友[1] 余煜玺[1,2] 程璇[1,2] 张颖[1,2] 

机构地区：[1]厦门大学材料学院材料科学与工程系 [2]福建省特种先进材料重点实验室,福建厦门361005

出　　处：《硅酸盐学报》2009年第7期1206-1211,共6页Journal of The Chinese Ceramic Society

基　　金：特种先进材料福建省重点实验室(2006L2003)资助项目

摘　　要：以正硅酸乙酯(tetraethoxysilane,TEOS)为硅源,甲基三甲氧基硅烷(methyltrimethoxysilane,MTMS)为改性剂,无水乙醇(ethanol,EtOH)为溶剂,通过溶胶–凝胶法制备了SiO2湿凝胶,并经过超临界干燥得到了SiO2气凝胶。利用N2吸脱附测试、红外光谱、热重–差热分析、扫描电镜、高分辨透射电镜、接触角测试等手段对气凝胶的基本性能、表面基团、热稳定性、微观形貌结构进行了研究。结果表明:以TEOS,MTMS,EtOH,H2O的摩尔比为1:0.3:15:4制得的改性气凝胶为轻质疏水块状固体材料,密度为0.1g/cm3,比表面积为1070m2/g,孔隙率为95.5%。经MTMS改性后SiO2气凝胶的比表面积、孔体积和孔隙率更大,密度更低,其疏水耐温性从250℃提高到500℃以上。The monolithic hydrophobic silica aerogels were synthesized via supercritical drying of wet gels that were obtained using the sol-gel co-precursor method with tetraethoxysilane （TEOS） as a precursor, methyltrimethoxysilane （MTMS） as modifiers and ethanol （EtOH） as a solvent. The physical properties, surface functional groups, thermal stability, microstructure and morphology of silica aerogels were studied by nitrogen adsorption/desorption tests, Fourier transform infrared spectroscopy, thermogravimetric and differential thermal analysis, scanning electron microscopy, high resolution transmission electron microscopy and contact angle measurement. The silica aerogels, prepared with a mole ratio of TEOS, MTMS, EtOH, H2O constant at 1：0.3：15：4, is a mesoporous hydrophobic materials with a specific surface area of 1070 m^2/g, a density of 0.1 g/cm^3 and a porosity of 95.5%. The silica aerogels with MTMS as co-precursor has a greater specific surface area, pore volume and porosity but lower density than those of aerogels without surface modification, and the hydrophobicity is up to 500℃.

关 键 词：二氧化硅气凝胶 共前驱体法 甲基三甲氧基硅烷 疏水性 

分 类 号：O482.3[理学—固体物理]