The effect of silica aerogel on thermal and sound absorption insulation properties of epoxy plate and glass fiber fabric epoxy composite

Silica aerogel (SA) is used as an additive in composite production to improve their thermal–mechanical properties, owing to their excellent properties such as high porosity, low density, and low thermal conductivity. All these unique properties make it attractive to be used for improving sound absorption and thermal insulation properties of composite materials. However, there are very limited studies on both improvement of sound and thermal insulation properties of glass fiber fabric epoxy composite by adding silica aerogel. With this aim, this study investigates the effect of incorporation of SA as a filler in glass fiber fabric epoxy composite (GFEC) and epoxy plate used in a wide variety of structural and engineering applications such as buildings, constructions, communication, aerospace and transportation, on sound absorption and thermal insulation. Results indicate that SA addition decreased the thermal conductivity coefficient from 0.55 to 0.48 W/mK for GFEC, and from 0.25 to 0.23 W/mK for epoxy plate, providing improvement on thermal insulation. Silica aerogel increased the maximum sound absorption coefficient (SAC) from 0.27 to 0.65, shifting the frequency from 4000 to 400 Hz for GFEC. The maximum SAC value increased from 0.28 to 0.41 at 800 Hz and decreased from 0.54 to 0.47 at 2000 Hz in SA incorporated-epoxy plate with 1 cm air gap thickness. The results reveal that SA has an improvement effect on low-frequency sound absorption for both GFEC and epoxy plate.