疏水性二氧化硅气凝胶的制备及其性能研究

Preparation and Properties of Hydrophobic Silica Aerogels

以正硅酸四乙酯(TEOS)和甲基三甲氧基硅烷(MTMS)作为共前体,采用溶胶-凝胶法,经过正己烷溶液置换、20%六甲基二硅氮烷(TMDS)的乙醇溶液疏水改性后,通过常压干燥法制备出了具有良好疏水性和有机物吸附性能的二氧化硅气凝胶。当TEOS、MTMS、乙醇、水的摩尔比为1∶3∶5∶70时,制备的二氧化硅气凝胶样品密度为0.182 g/cm~3,与水的接触角为153.5°,对3种不同化学试剂(正己烷、乙醇、二氯甲烷)的吸附能力高达5.2~9.8 g/g。

With tetraethyl orthosilicate(TEOS) and methyl trimethoxysilane(MTMS) as co precursors,silica aerogel with good hydrophobicity and organic adsorption properties are prepared by the normal pressure drying method using the sol gel method,after n-hexane solution replacement and 20% bis(trimethylsilyl)amine(TMDS) ethanol solution hydrophobic modification.When the molar ratio of TEOS,MTMS,ethanol and water is 1∶3∶5∶70,the density of silica aerogel samples is 0.182 g/cm~3,the contact angle with water is 153.5°.The adsorption capacity of the samples to organic solvents is determined by using three different chemical reagents(n-hexane,ethanol,dichloromethane) up to 5.2~9.8 g/g.