Determination of mesopore size of aerogels from thermal conductivity measurements

被引:220
作者
Lee, OJ
Lee, KH
Yim, TJ
Kim, SY
Yoo, KP
机构
[1] Pohang Univ Sci & Technol, Dept Chem Engn, Elect & Comp Engn Div, Nam Ku, Pohang 790784, Kyungbuk, South Korea
[2] Sogang Univ, Dept Chem Engn, Seoul, South Korea
关键词
D O I
10.1016/S0022-3093(01)01041-9
中图分类号
TQ174 [陶瓷工业]; TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
A novel method to determine the average mesopore size of aerogels was developed. This method is based on the findings that the heat transfer through the gas phase in porous materials is strongly affected by the size of mesopores. Polyisocyanurate acrogels were synthesized and the thermal conductivity of these materials was investigated from vacuum to ambient pressure using the transient hot-wire method. Thermal conductivity of porous materials can be recognized as the sum of gaseous, solid, radiative, and convective thermal conductivity. Extraction of gas phase thermal conductivity from total thermal conductivity was performed by considering different heat transfer mechanisms. Gas phase thermal conductivity increases with pressure in 'S' shape due to collisions of gas molecules with pore walls. Average mesopore size could be obtained by fitting gas phase thermal conductivity data with existing equations. Investigation of polyisocyanurate aerogels by SEM revealed that this method gives a reasonable estimate for the average mesopore size. It is expected that pore structure of fragile mesoporous materials can be analyzed by further refinements of this novel method. (C) 2002 Elsevier Science B.V. All rights reserved.
引用
收藏
页码:287 / 292
页数:6
相关论文
共 14 条
[1]  
[Anonymous], SPRINGER P PHYS
[2]   Polyurethane-based organic aerogels' thermal performance [J].
Biesmans, G ;
Randall, D ;
Francais, E ;
Perrut, M .
JOURNAL OF NON-CRYSTALLINE SOLIDS, 1998, 225 (01) :36-40
[3]  
Brinker C.J., 1990, SOL GEL SCI, P303
[4]  
DeCarvalho G, 1996, J APPL POLYM SCI, V62, P2281
[5]  
Fricke J., 1986, SPRINGER P PHYSICS, V6, P94
[6]  
GRAZZINI G, 1988, INT J HEAT MASS TRAN, V39, P2009
[7]   THERMAL-PROPERTIES OF ORGANIC AND INORGANIC AEROGELS [J].
HRUBESH, LW ;
PEKALA, RW .
JOURNAL OF MATERIALS RESEARCH, 1994, 9 (03) :731-738
[8]  
Kaganer MG, 1969, Thermal Insulation in Cryogenic Engineering
[9]   Coherent expanded aerogels and jellies. [J].
Kistler, SS .
NATURE, 1931, 127 :741-741
[10]  
LOEB LB, 1934, KINETIC THEORY GASES, P31