疏水性二氧化硅气凝胶的合成及表征

Synthesis and Characteristic of Hydrophobic Silica Aerogels

本文以正硅酸乙酯为原料,经溶胶-凝胶过程制备二氧化硅醇凝胶,再利用二甲基二氯硅烷对醇凝胶进行化学表面修饰,最后用超临界干燥方法制备了疏水性二氧化硅气凝胶。运用红外光谱、BET、扫描电镜、X射线衍射等测试方法对制得样品的结构、形貌及化学组成进行了分析。结果表明该样品是表面存在疏水基团-CH3的疏水性SiO2气凝胶,是呈连续网络结构的球状纳米粒子,孔径分布主要集中在2～10nm,是热稳定性较高的非晶、多孔、轻质介孔材料。

In this paper, a new method to produce hydrophobic sihca aerogels was introduced. SiO2 alcogels were prepared by tetraethoxysilane （TEOS） via Sol-gel precess,then the surface was chemically modified by dimethyldichlorosilane （DMCS）, and finally dried by supercritical carbon dioxide method. Test methods, such as FT-IR, SEM, BET and XRD were adopted to analyze the structure, surface morphology,and chemical composition of the samples in the experiments. The results showed that the samples are hydrophobic silica aerogels linked with hydrophobic group （-CH3） on their surface. The hydrophobic silica aerogels were continuous network of spheroidic particles, which the pore diameters mainly ranged from 2 to 10 nm. The samples are non-crystal, porous, light materials with high thermal stability.