Silica aerogels have extremely low thermal conductivities, potentially making them effective thermal insulators. In this study, the thermal conductivities of various samples were explored using the Transient Plane Source (TPS) Method. Samples of the silica aerogels were approximately 1.3 cm thick and between 4.1-4.3 cm in diameter, and were tested at different temperatures. Results showed that as the temperature of the samples increased from 25-50 °C, thermal conductivity increased exponentially. As ...
Ambient pressure dried hydrophobic silica aerogel monoliths were prepared via simultaneous solvent exchange and surface modification in order to minimize volume shrinkage and density. At room temperature, the obtained silica aerogels had a low density of 0.096 g/cm³, a high surface area and hydrophobicity, and a low thermal conductivity of 0.0217 W/m·K. The effect of heating on these properties was also determined. After the aerogel had been heated to 300°...
Ultralow density silica aerogels were formulated by sol-gel process using tetramethyl orthosilicate as the precursor. A supercritical drying step was performed using acetonitrile solvent extraction. These aerogels were found to have a high specific surface area (~812m2/g) and they were found to be excellent thermal insulators with thermal conductivities ranging from 0.024 to 0.043 W/m K at temperatures up to 400oC....
Aerogels are ultra-light, insulative, porous materials that have a wide variety of applications. The aim of this study was to synthesize resorcinol/formaldehyde (RF) cross-linked silica aerogels in one pot by acid catalysis. A thermal constant analyzer measured the thermal conductivity of the RF/SiO2 aerogels using the transient plane source (TPS) method. Results showed that although the RF/SiO2 aerogels had a lower density, their thermal conductivities resembled those ...
In this study, ultralow density silica aerogels were synthesized and their thermal conductivities were tested to determine how supercritical drying affected the samples. A thermal analyzer measured the thermal conductivity of the silica aerogels using the transient plane source (TPS) method which determined that the thermal conductivity of silica aerogels increased with temperature....