【摘要】 以水玻璃和醋酸为原料,加入适量的表面活性剂作为分散剂,采用溶胶凝胶法结合传统高温干燥、乙醇和CO2超临界流体技术制备 了纳米多孔SiO2超细粉体。通过透射电镜、BET(BurnauerEmmettTeller)法、X射线衍射、红外光谱和热重/差热分析等手段对样品进行 了表征。结果表明:干燥工艺对产物的粒径、分散程度、热稳定性和比表面积有较大的影响,通过CO2超临界流体技术制备的SiO2超细粉体分 散性好,比表面积高,颗粒均匀呈球状,粒径为10nm左右。更多还原

【Abstract】 Porous nano-silica powders were prepared from water glass by solgel method compared with conventional high-temperature dying routes, ethanol supercritical fluid and carbon dioxide supercritical fluid drying technique. The samples were characterized by transmission electron microscope, BET(BrunauerEmmettTeller) method, X-ray differaction, infrared and thermograrimetric/differential thermal analysis. The results show that the drying process has many influences on the particles size, dispersibility, thermal stability, and specific surface area of samples. The nano-silica powders with optimal dispersibility, higher specific surface area and well-proportioned spherical grains with average diameter of about 10 nm can be obtained by carbon dioxide supercritical drying technique.更多还原