乳液法制备微米级硅气凝胶小球及其表征

Preparation and Characterization of Microscaled Silica Areogel Balls by Emulsion Method

  • 摘要: 以硅溶胶为前驱物,在以吐温85和司班80为乳化剂、正丁醇为乳化助剂、正庚烷为分散介质的油相和二氧化硅醇溶胶为水相的乳液体系中,应用乳液成球技术制备μm级硅凝胶小球,然后通过常压干燥技术制备μm级硅气凝胶小球。用光学显微镜、SEM、TG-DTA及BET技术等对其进行表征。结果表明:所得μm级硅气凝胶小球表观粒径约为130 μm,密度约为360 kg·m-3,比表面积为382.5 m2·g-1,平均孔径约为17 nm,孔隙率达83.6%。μm级硅气凝胶小球是由大小约为10 nm的二氧化硅纳米微粒构成的轻质纳米多孔结构材料。

     

    Abstract: Using silica sols as precursors, silica alcogel balls were prepared in the W/O emulsion composed of oil phase of Span80 and Tween85 as surfactants, n-butanol as cosurfactant,n-heptane as disperse medium, and aqueous phase of silica alcosols. In order to produce microscaled silica areogel balls, the silica alcogel balls were dried at ambient pressure. The resultant aerogel microballs were characterized by optical microscopy, SEM, TG-DTA and BET technique. The results show that the prepared silica aerogel microsballs which consist of silica nanoparticles of 10 nm are a novel kind of nanoporous structural materials with the porosity of 83.6%. They have a narrow pore size distribution in the range of 2-32 nm with an average value of 17 nm. The apparent density and specific surface area of microsballs are about 360 kg·m-3 and 382.5 m2·g-1,respectively. 

     

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