超临界干燥制备疏水型二氧化硅气凝胶

文章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，采用三甲基氯硅烷作为表面改性剂，对醇凝胶进行化学表面修饰，超临界干燥，制备了疏水性二氧化硅气凝胶粉末。运用红外光谱、BET、扫描电镜、XRD对其结构、形貌及化学组成进行了分析。结果表明：该样品是表面连有疏水基团-CH3的疏水性SiO2气凝胶，呈连续网络结构的球状纳米粒子，孔径分布主要集中在2～4nm，是热稳定性较高的非晶、多孔、轻质介孔材料。

Synthesis and Characteristic of Hydrophobic Silica Aerogels

A new method to produce hydrophobic silica aerogels was introduced in the paper. SiO2 alcogels, prepared from tetraethoxysilane （TEOS） via sol-gel process, were synthesized into hydrophohic silica aerogels by the surface chemical modification of dimethyldichlorosilane（TMCS） followed by supercritical drying of CO2. Test methods, such as FTIR, SEM, BET and XRD were used to analyze the structure, surface morphology, and chemical composition of the resulting samples in the experiments. The results showed： the samples were hydrophobic silica aerogels with hydrophobic group （CH3） linked to their surface, they were continuous network of spheroidic particles whose pore diameters mainly range from 2 to 4 nm, and they were non-crystallized, porous, light nanometer materials.