摘要
以廉价的工业水玻璃为凝胶前躯体,柠檬酸为凝胶促进剂,使用溶胶-凝胶与CO2超临界干燥工艺制备了块状的SiO2气凝胶,并探讨了酸性和碱性条件对所制备SiO2气凝胶结构与性能的影响.实验结果表明:水玻璃在酸性条件(pH≈4)和碱性条件(pH≈10)下均可以制备出完整、无开裂的二氧化硅气凝胶块体样品,酸性和碱性环境对水凝胶和最终SiO2气凝胶结构和性能的影响较大.酸性条件下获得的水凝胶呈透明块体,而碱性条件下所得水凝胶为白色不透明体.与碱性条件下制备的SiO2气凝胶相比,酸性条件下所得气凝胶具有更高的比表面积、较大的密度以及尺寸较小的胶体粒子.
The silica aerogel monoliths were prepared by sol-gel method and supercritical drying technique,using water-glass as the precursor and citric acid as the catalyst.The effects of acidic and alkaline condition on the microstructure and properties of silica aerogel monoliths were discussed in detail.The results show that the wet gel monoliths can be prepared in acidic（pH≈4） and alkaline（pH≈10） conditions which have significant effect on the properties of silica aerogels.The wet gel monoliths prepared in acidic condition are transparent,while the wet gel monoliths obtained in alkaline condition have a milky appearance.The silica aerogel monoliths prepared in acidic condition possess higher specific surface area,larger density and smaller-size colloidal nano particles compared with those obtained in alkaline condition.
出处
《材料科学与工艺》
EI
CAS
CSCD
北大核心
2013年第2期77-82,共6页
Materials Science and Technology
基金
国家高技术研究发展计划资助项目(No.2009AA032503)
国家自然科学基金青年基金资助项目(No.51002145)
国家重点基础研究发展规划资助项目(No.2010CB735810)
关键词
SIO2气凝胶
酸性条件
碱性条件
比表面积
SiO2 aerogel
acidic condition
alkaline condition
specific surface area
