Preparation and Aging of Polyurethane Foams Filled with Silica Aerogels

Polyurethane foam (PUF)/silica aerogel composites were successfully prepared as a heat insulating material by the supercritical carbon dioxide drying of PUFs 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 degrees 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.