水玻璃基低密度疏水二氧化硅气凝胶制备及性能研究

摘要

Taking water glass as silicon source,through two step acid-base sol-gel method and by one step substitution,low density hydrophobic SiO2 aerogel were prepared at room temperature under atmospheric pressure.The effects of pH,aging mode and the amount of TMCS on the gel time,SiO2 aemgel apparent density and porosity were discussed.The microstructure,specific surface area,pore size distribution,modification effect and hydmphobic properties of SiO2 aerogels were investigated by FE-SEM,BET,FT-IR and contact angle tester respectively.The results showed that the prepared SiO2 aerogel possessed classic three-dimensional nano network structure,the apparent density was 0.130 1 g/cm3,the porosity was 94.27％,the specific surface area was 599 m2/g,the average pore size was at 10～30 nm,and the contact angle was 142°.%以水玻璃为硅源,通过酸碱两步溶胶-凝胶法及一步置换改性,常温常压下制备了低密度疏水性二氧化硅气凝胶.探讨了pH、老化方式及三甲基氯硅烷(TMCS)用量对凝胶时间、二氧化硅气凝胶表观密度和孔隙率的影响.采用冷场发射扫描电镜(FESEM)、比表面积及孔径分析仪(BET)、傅里叶变换红外光谱仪(FT-IR)和接触角测试仪分别研究了二氧化硅气凝胶的微观形貌、比表面积及孔径分布、改性效果及疏水性能.结果表明,二氧化硅气凝胶具有三维纳米网络结构,表观密度为0.130 1 g/cm3、孔隙率高达94.27％、比表面积为599 m2/g、平均孔径为10～30 nm、接触角为142.