A variety of tannin-formaldehyde aerogels were produced in order to examine the effects of pH and dilution during their manufacture. The authors produced a phase diagram that could describe them. Extensive physical property characterization was performed on the sample aerogels, including porosity, thermal conductivity, volume shrinkage, BET surface area and microscopic texture. Conditions under which the highest surface area and pore volumes were produced were identified. The TPS instrument was ...
The authors present a method of fiber-reinforced aerogel composites by impregnation of four layers of aligned glass fibers into silica sol layer-by-layer. The effect of different fiber alignments, as well as the effect of fiber lamination on the mechanical strength of the silica aerogel composites was investigated. In addition to this, the thermal conductivity of each composite was determined. The objective of this work was to investigate whether it is ...
This paper proposes conducting carbon aerogels, composed of graphene and multi-walled carbon nanotubes, as an option for a thermoelectric material. The researchers found that this combination of materials increased the electrical conductivity and the Seebeck coefficient due to bridging effects, and decreased the thermal conductivity through high porosity and a uniquely structured 3-D skeleton. Atomic force microscopy and X-ray diffraction were used to quantify the physical structure of the aerogels. ...
In this article the effectiveness of silica aerogels as a transparent heat insulation material (TIM) is studied. They are a good candidate for this application as the amount of energy that they absorb and emit is adjustable. The effects of different treatments (hydrothermal and firing) on the thermal properties of the silica gels was studied, in addition to research on the most favorable conditions for use of this material as ...
This article investigates how the thermal conductivity of a resorcinol-formaldehyde aerogels varies with increasing resorcinol (R) to water (W) ratios. The thermal conductivity was measured using a transient plane source (TPS) method. As the R:W increases so does the thermal conductivity, this is because there is more conductive solids present to transfer more energy....
