论文部分内容阅读
以正硅酸四乙酯为硅源，钛白粉为红外遮光剂，通过溶胶－凝胶及超临界干燥过程制备了钛白粉掺杂ＳｉＯ２ 气凝胶。用透射电镜、扫描电镜以及孔径分布仪对其结构进行了表征，并用动态热线法对其热学特性进行了测试。结果表明： 钛白粉能较均匀的分散在ＳｉＯ２ 气凝胶中；掺杂ＳｉＯ２ 气凝胶的孔洞大小分布在５～７０ｎｍ ，峰值在２０ｎｍ 附近，组成ＳｉＯ２ 网络的胶体颗粒为５～１０ｎｍ ；随着钛白粉掺杂量的增加，掺杂ＳｉＯ２ 气凝胶的孔径分布峰高变矮，同时出现孔径为几纳米的微孔；热学测试结果显示钛白粉掺杂量为２０ｗ ｔ％ 的ＳｉＯ２ 气凝胶在常压、８３１Ｋ 时的热导率为０．０３５ｗ ｍ － １Ｋ－ １。
Tetraethyl orthosilicate as silica source and titanium dioxide as infrared sunscreen agent were prepared by sol-gel and supercritical drying process. Its structure was characterized by transmission electron microscopy, scanning electron microscopy and pore size distribution analyzer, and its thermal properties were tested by dynamic hot-wire method. The results show that titanium dioxide can be more evenly dispersed in SiO2 aerogels. The pore size of doped aerogels is in the range of 5 ~ 70nm and the peak is near 20nm, and the colloidal particles of SiO2 network are 5 ~ 10nm. Titanium dioxide doping amount increased, pore size distribution of doped aerogels shorter height, at the same time the pore size of a few nano-pores; thermal test results show that titanium dioxide doping amount of 20w t% SiO2 airgel At atmospheric pressure, the thermal conductivity at 831K is 0.035w m - 1K - 1.