Silica aerogel/aramid pulp composites with improved mechanical and thermal properties

For maintaining the integrality and improving the mechanical strength of fiber/silica aerogel composites without compromising thermal insulation properties, aramid pulp reinforced silica aerogel composites were prepared under ambient pressure drying by adding aramid pulps into silica sol directly. The microstructures indicated the ample fibrillated fibers of aramid pulps were inlaid in silica aerogel matrix which retained the integrality and nice interface adhesion, instead of separating the aerogel matrix into small fragments. As the aramid pulp content increased, the compressive strength was enhanced obviously up to about 1.2 MPa and the low thermal conductivity of 0.0232–0.0278 W·m− 1·K− 1 approximated linear growth. TG-DTA analysis indicated that the thermal stability of the as-prepared composites was about 260 °C which primarily depended on the thermal stability of pure silica aerogels. Thus it concluded that excellent silica aerogel composites with intact microstructures, improved mechanical strength and tailored thermal properties can be prepared by using aramid pulps as reinforcements.