Improved heat insulation and mechanical properties of silica aerogel/glass fiber composite by impregnating silica gel

In this paper, a kind of silica gel was applied to improve the mechanical properties of silica aerogel/glass fiber composite without compromising its thermal conductivity. The composite was prepared by acid-base catalyzed tetraethylorthosilicate sol-gel followed by supercritical CO₂ drying, in which the silica gel was impregnated. The effects of the silica gel on the thermal conductivity and strength of the composite were investigated. The results indicated that the composite possessed not only ultra-low thermal conductivity of 0.0179 W·(m·K)⁻¹, but also excellent mechanical strain and low bulk density of 0.246 g/cm³, and was dust-free. It was demonstrated that the impregnated silica gel filled in the gap between the glass fibers and anchored the silica aerogel on the glass fiber tightly via the –Si-O-Si- network, which not only prevented the heat transfer but also trapped and protected the silica aerogel from collapsing. This new approach shed light on solving the big issue of the silica aerogel in practical application due to its brittle and dust-drop.