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以正硅酸乙酯为硅源,采用酸碱两步催化法经过溶胶-凝胶和冷冻干燥制备出SiO2气凝胶基材,并在凝胶老化过程中添加三乙胺盐酸盐得到兼具中远红外吸收特性的硅基复合气凝胶。利用X射线衍射、扫描电子显微镜、氮吸附-脱附和傅里叶红外吸收光谱对气凝胶的结构和性能进行了表征。结果表明:胺盐在硅气凝胶网络结构中穿插结晶;基材的比表面积、最大孔容和平均孔径分别为524.5m2/g、1.2 cm3/g和9.2 nm,复合材料的比表面积、最大孔容和平均孔径分别为37.93~138.7 m2/g、0.08~0.28 cm3/g和7.1~8.8nm;基材和复合气凝胶的表观密度分别为0.25g/cm3和0.35~0.51g/cm3;复合气凝胶在中远红外窗口具有宽频吸收的特性,且随着三乙胺盐酸盐含量的增加,中红外相对吸收强度成比例增强。
SiO2 aerogels were prepared by sol-gel and freeze-drying using acid-base two-step catalysis with ethyl orthosilicate as the silicon source and adding triethylamine hydrochloride during the gel aging Silicon-based composite aerogels with far-infrared absorption characteristics. The structure and properties of the aerogels were characterized by X-ray diffraction, scanning electron microscopy, nitrogen adsorption-desorption and Fourier transform infrared spectroscopy. The results showed that the amine salt interpenetrated into the network structure of the silica airgel. The specific surface area, the maximum pore volume and the average pore diameter of the substrate were 524.5m2 / g, 1.2cm3 / g and 9.2nm, respectively. The specific surface area of the composites was the largest Pore volume and average pore diameter were 37.93 ~ 138.7 m2 / g, 0.08 ~ 0.28 cm3 / g and 7.1 ~ 8.8 nm, respectively. The apparent densities of substrate and composite airgel were 0.25 g / cm3 and 0.35 ~ 0.51 g / cm3, respectively . The composite airgel has broad-band absorption characteristics in the middle and far infrared windows, and the relative absorption intensity of mid-infrared increases proportionally with the increase of triethylamine hydrochloride content.