Synthesis of high porosity, monolithic alumina aerogels
Synthesis of high porosity, monolithic alumina aerogels
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DOI：
10.1016/s0022-3093(01)00432-x
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发表时间：
2001-06-01
影响因子：
3.5
通讯作者：
Hrubesh, LW
中科院分区：
文献类型：
--
作者：
Poco, JF;Satcher, JH;Hrubesh, LW
许多非二氧化硅气凝胶在整体形式中是显著地脆弱和易碎的。特别是，密度小于50 kg/m3的单块气凝胶很少具有任何显著的强度。特别难以制备坚固且水分稳定的纯氧化铝气凝胶的未破裂整料。在本文中，我们讨论了合成异常强大的，稳定的，单片，高孔隙率（> 98%的多孔）氧化铝气凝胶，使用两步溶胶-凝胶过程。氧化铝气凝胶具有多晶形态，其导致增强的物理性质。对于密度为37 kg/m3的氧化铝气凝胶，比表面积为376 m2/g，弹性模量为550 kPa，在30 ℃、400 ℃和800 ℃下的热导率分别为29、98和298 mW/mK。除比表面积外，所测得的氧化铝气凝胶的所有物理性能均上级同等密度的二氧化硅气凝胶。(C)2001 Elsevier Science B. V.保留所有权利。
Many non-silica aerogels are notably weak and fragile in monolithic form. In particular, few monolithic aerogels with densities less than 50 kg/m(3) have any significant strength. It is especially difficult to prepare uncracked monoliths of pure alumina aerogels that are robust and moisture stable. In this paper, we discuss the synthesis of unusually strong, stable, monolithic, high porosity (> 98% porous) alumina aerogels, using a two-step sol-gel process. The alumina aerogels have a polycrystalline morphology that results in enhanced physical properties. For an alumina aerogel with a density of 37 kg/m(3), the specific surface area is 376 m(2)/g, the elastic modulus is 550 kPa, and the thermal conductivities at 30 degreesC, 400 degreesC and 800 degreesC, are 29, 98 and 298 mW/mK, respectively. All of the measured physical properties of the alumina aerogels except the specific surface area are superior to those for silica aerogels for equivalent densities. (C) 2001 Elsevier Science B.V. All rights reserved.