摘要
本文以正硅酸乙酯(TEOS)为前驱体,通过酸碱两步溶胶-凝胶法,常压干燥制备疏水性SiO2气凝胶。研究了两种改性剂(三甲基氯硅烷、六甲基二硅氮烷)对二氧化硅气凝胶结构和性能的影响。对制备的气凝胶样品进行表面微观形态分析、热重差热分析、傅里叶红外分析以及比表面积分析。结果表明,通过改性制备的样品具有较好的性能,使用六甲基二硅氮烷改性得到的SiO2气凝胶密度为0.204g/cm3,接触角为128°,BET比表面积为973m2/g,平均孔径7.57nm;使用三甲基氯硅烷改性得到的SiO2气凝胶密度为0.115g/cm3,疏水性优良,接触角为158°,BET比表面积为1067m2/g,平均孔径13.40nm。综合考虑各种因素,采用TMCS进行改性制备得到的SiO2气凝胶综合性能更加优异。
Ambient pressure dried hydrophobic silica aerogels were fabricated by the two-step sol-gel method where tetraethylorthosilicate(TEOS)acted as precursor.The effect of two modifiers,trimethylchlorosilane(TMCS) and hexmethyldisilazae(HMDZ),on the microstructure and properties of the silica aerogels was investigated. Microstructure of as-prepared silica aerogels was analysed by scanning electron microscope(SEM);the thermal evolution was studied by Thermogravimetric and Differential scanning calorimeter(TG-DSC);the chemical components and hydrophobicity were identified by Fourier transform infrared spectra(FT-IR).Results show that the modified silica aerogels have relatively better characteristics.The density is 0.204g/cm3,contact angle is 128°,BET surface area is 973m2/g and average pore diameter is 7.57nm as with the HMDZ as the modifier.The silica aerogels modified with TMCS,however,give the density of 0.115g/cm3,contact angle of 158°,BET surface area of 1067m2/g and average pore diameter of 13.40nm,which are even superior to the former in overall performance through comprehensive consideration of various factors.
出处
《材料科学与工程学报》
CAS
CSCD
北大核心
2014年第2期178-182,共5页
Journal of Materials Science and Engineering
基金
国家"973"计划资助项目(2012CB719701)
中国科学技术大学火灾科学国家重点实验室开放课题资助项目(HZ2012-KF03)
关键词
二氧化硅气凝胶
表面改性
疏水性
常压干燥
silica aerogel
surface modification
hydrophobicity
ambient pressure drying
