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Polyurethane foam (PUF)/silica aerogel composites were successfully prepared as a heat insulating material by the supercritical carbon dioxide drying of PUTs filled with silica aerogels. PUF/silica aerogel composites were flexible and their thermal conductivities were as low as for the silica aerogel. The durability of PUF/silica aerogel composites was improved by using hydrophobic silica aerogel. PUF/hydrophobic silica aerogel composites were aged at 70°C and 95% RH. PUF/hydrophilic silica aerogel composite easily adsorbed water. Simultaneously, the volume shrank and the thermal conductivity of the composite drastically increased. On the other hand, PUF/hydrophobic silica aerogel composite was stable even at high temperature and in humidity conditions. After 10 weeks, the thermal conductivity of the composite hardly increased. [ABSTRACT FROM AUTHOR]

Silica aerogels/acrylic resin composites were prepared to develop a heat insulating material. Silica aerogels are synthesized from TMOS and its oligomer. Silica aerogels from TMOS have uniform particle and pore sizes. Although those from the oligomer have a distributed particle and pore sizes, it was found that the silica aerogel with low thermal conductivity can be obtained from the oligomer by optimizing the reaction conditions. The mixture of the silica aerogel and an acrylic resin has a high viscosity and the composite film cannot be obtained. Additionally, the surface modification of silica aerogel was carried out. A composite film was prepared from a mixture of surface modified silica aerogel and acrylic resin. The addition of the surface modified silica aerogel reduces the thermal conductivity by about 44 per cent. [ABSTRACT FROM AUTHOR]