Aerogel is among the best solid thermal insulators. Aerogel is a silica gel formed by supercritical extraction which results in a porous open cell solid insulation with a thermal conductivity as low as $0.013W∕mK$. Aerogels have a wide range of uses such as insulation for windows, vehicles, refrigerators∕freezers, etc. Usage for aerogel can be extended for use where flexibility is needed, such as apparel, by embedding it into a polyester batting blanket. These aerogel blankets, although flexible, have little resistance to compression and experience a residual strain effect upon exposure to elevated pressures. It was suggested, by Aspen Aerogels Inc., that a prototype aerogel blanket would have increased resistance to compression and minimized residual strain upon exposure to elevated pressures. Samples of prototype and normal product-line aerogel insulating blankets were acquired. These materials were separately tested for thermal conductivity and compressive strain at incremental pressure stops up to $1.2MPa$. The compressive strain of the prototype aerogel blanket reached a level of $0.25mm∕mm$ whereas the product-line aerogel blanket compressed to $0.48mm∕mm$ at $1.2MPa$. Before compression, the thermal conductivity of the prototype aerogel blanket was slightly higher than the product-line aerogel blanket. During compression the thermal conductivity increased 46% for the product-line aerogel blanket whereas it increased only 13% for the prototype aerogel blanket at $1.2MPa$. The total thermal resistance decreased 64% for the product-line aerogel blanket at $1.2MPa$ and remained at that value upon decompression to atmospheric pressure. The total thermal resistance of the prototype aerogel blanket decreased 33% at $1.2MPa$ and returned to within 1% of its initial value upon decompression to atmospheric pressure. It was found that the prototype aerogel blanket has approximately twice as much resistance to hydrostatic compression to a pressure of $1.2MPa$ and also recovers to its original state upon decompression. The thermal resistance of the prototype aerogel blanket remained 37% higher than the product-line aerogel blanket at $1.2MPa$. This resistance to compression and the ability to recover to its original state upon decompression from elevated pressures makes the prototype aerogel blanket suitable for applications where high insulation, resistance to compression, and recovery after a compression cycle is needed.

1.
Lu
X.
et al.
, 1992, “
Thermal Conductivity of Monolithic Organic Aerogels
,”
Science
0036-8075,
255
(
5047
), pp.
971
972
.
2.
Hrubesh
,
L. W.
, and
Pekala
,
R. W.
, 1994, “
Thermal Properties of Organic and Inorganic Aerogels
,”
J. Mater. Res.
0884-2914,
9
(
3
), pp.
731
738
.
3.
Hrubesh
,
L. W.
, and
Poco
,
J. F.
, 1995, “
Thin Aerogel Films for Optical, Thermal, Acoustic and Electronic Applications
,”
J. Non-Cryst. Solids
0022-3093,
188
, pp.
46
53
.
4.
Zeng
,
S. Q.
,
Hunt
,
A. J.
, and
Grief
,
R.
, 1995, “
Mean Free Path and Apparent Thermal Conductivity of a Gas in a Porous Medium
,”
J. Heat Transfer
0022-1481,
117
, pp.
758
761
.
5.
Scheuerpflug
,
P.
,
Hauck
,
M.
, and
Fricke
,
J.
, 1992, “
Thermal Properties of Silica Aerogels Between 1.4 and 300K
,”
J. Non-Cryst. Solids
0022-3093,
145
, pp.
196
201
.
6.
Scheuerpflug
P.
, et al.
, 1991, “
Low-Temperature Thermal Transport in Silica Aerogels
,”
J. Phys. D
0022-3727,
24
, pp.
1395
1403
.
7.
Fricke
,
J.
et al.
, 1987, “
Thermal Loss Coefficients of Monolithic and Granular Aerogel Systems
,”
Sol. Energy Mater.
0165-1633,
16
, pp.
267
274
.
8.
Herrmann
,
G. H.
,
Bednarek
,
H.
,
Reichert
,
H.
,
Stephans
,
R.
, and
Strahle
,
R.
, 1995, “
Aerogels the Leading Edge in Thermal Insulation
,”
H & V Engineer
,
68
(
725
), pp.
8
11
.
9.
Fesmire
,
J. E.
, 2006, “
Aerogel Insulation Systems for Space Launch Applications
,”
Cryogenics
0011-2275,
46
(
2–3
), pp.
111
117
.
10.
Jensen
,
K. I.
,
Schultz
,
J. M.
, and
Kristiansen
,
F. H.
, 2004, “
Development of Windows Based on Highly Insulating Aerogel Glazings
,”
J. Non-Cryst. Solids
0022-3093,
350
, pp.
351
357
.
11.
Reim
,
M.
, et al.
, 2005, “
Silica Aerogel Granulate Material for Thermal Insulation and Daylighting
,”
Sol. Energy
0038-092X,
79
(
2
), pp.
131
139
.
12.
Abu Obaid
,
A.
,
Anderson
,
S.
,
Gillespie
, Jr.,
J. W.
,
Vaidyanathan
,
R.
, and
Studley
,
A.
, 2005, “
Investigation of Thermal and Acoustic Performance of Aerogel-Based Glass Fiber Composites
,”
Proceedings 50th International SAMPE Symposium and Exhibition
, Vol.
50
,
Long Beach
,
CA
.
13.
Gibson
,
P.
, and
Lee
,
C.
, 2004, “
Application of Nanofiber Technology to Nonwoven Thermal Insulation
,”
Proceedings of the 14th Annual International TANDEC Nonwovens Conference
,
Knoxville
,
TN
.
14.
Bardy
,
E.
,
Mollendorf
,
J.
, and
Pendergast
,
D.
, 2005, “
Thermal Conductivity and Compressive Strain of Foam Neoprene Insulation under Hydrostatic Pressure
,”
J. Phys. D
0022-3727,
38
(
20
), pp.
3832
3840
.
You do not currently have access to this content.