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...
Composite silica aerogels were prepared using sodium silicate and ceramics fibers. The thermal conductivities of these composites were investigated to determine how effective they would be as thermal insulation. As temperature increased to 400oC, the thermal conductivity of these composites only increased from 0.0266 to 0.0572 W/(m·K). This indicates that these composites which have good structural and mechanical properties would be good thermal insulators during thermal processes....
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....
Biobased foams derived from lignins and tanins were produced by mechanical frothing and curing. The obtained foams did not crack after drying. The foams were found to be good thermal insulators with thermal conductivities ranging from 0.035 to 0.055 Wm-1K-1....
The authors prepared silica aerogel/polyurethane composites by two different methods for the comparison of the two methods. The objective was to study the thermal insulation and hydrophobic properties of the composites to evaluate their potential for use as fabric membranes. It was found that the composites are better thermal insulators than polyurethane alone, and that they also have improved hydrophobic properties. It was also determined that the thermal conductivities ...
