Relationship between pore size and the gas pressure dependence of the gaseous thermal conductivity
Relationship between pore size and the gas pressure dependence of the gaseous thermal conductivity
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DOI：
10.1016/j.colsurfa.2007.01.020
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发表时间：
2007-06-01
影响因子：
5.2
通讯作者：
Ebert, H.-P
中科院分区：
文献类型：
--
作者：
Reichenauer, G.;Heinemann, U.;Ebert, H.-P
在多孔材料中，例如泡沫或压制粉末板，通过气相的热导率在环境温度下对总热导率具有显著或甚至主导的贡献。开放多孔材料的热导率随气压的变化是孔径的函数。在低于1 bar的压力范围内，热导率的测量提供了孔径大于100 nm的非破坏性探头。如果热导率设置也允许在较高的压力下测量，孔径范围可以扩展到甚至更小的value.Experimental数据为各种不同的多孔材料，如开放的多孔泡沫，颗粒状多孔和无孔材料和气凝胶，多孔固体与可调的平均孔径在介孔或大孔范围内，提出。从热导率测量确定的孔隙特性进行了比较，从氮吸附和小角X射线散射data.The潜力和限制，这种方法在提取的平均孔径和孔径分布的形态数据进行了讨论。(c)2007 Elsevier B.V.保留所有权利。
In porous materials, such as foams or pressed powder boards, the thermal conductivity via the gas phase represents at ambient temperatures a significant or even dominant contribution to the total thermal conductivity. The variation of the thermal conductivity of an open porous material with gas pressure is a function of the pore size. In the pressure range below 1 bar, measurement of thermal conductivity offers a non-destructive probe of pore sizes larger than 100 nm. If the thermal conductivity setup also allows for measurements at higher pressures, the pore size range can be extended to even smaller values.Experimental data for a variety of different porous materials such as open porous foams, granular porous and nonporous materials and aerogels, porous solids with an adjustable mean pore size in the meso- or macro-pore range, are presented. The pore characteristics determined from thermal conductivity measurements are compared to morphological data derived from nitrogen sorption and small angle X-ray scattering data.The potential and limits of this method in terms of the extraction of an average pore size and a pore size distribution are discussed. (c) 2007 Elsevier B.V. All rights reserved.