Monolithic carbon aerogels within foam framework for high-temperature thermal insulation and organics absorption

Carbon aerogels exhibit high porosity, good electrical conductivity , and low thermal conductivity , but their practical applications are greatly hindered by their tedious preparation and inherent structure brittleness . Herein, monolithic carbon aerogels (MCAs) with low density and large size are prepared via a facile sol-gel polymerization of phenolic resin within melamine foam (MF), followed by ambient pressure drying and co-carbonization. During ambient pressure drying process, the MF matrix can deliver supporting force to counteract against the solvent evaporation surface tension, thus inhibiting volume shrinkage and shape deformation. Upon co-carbonization process, the MF matrix and organic aerogel could pyrolyze and shrink cooperatively, which could effectively prevent the brittle fracture of monolith. Therefore, large-sized MCAs (up to 250 × 250 × 20 mm) with low densities of 0.12–0.22 g·cm −3 are obtained. The as-obtained MCAs possess high compressive strength (2.50 MPa), ultra-low thermal conductivity (0.051 W·m −1 ·K −1 at 25 °C and 0.111 W·m −1 ·K −1 at 800 °C), and high-volume organic absorption capability (77.3–88.0%, V/V). This facile and low-cost method for the fabrication of large-sized monolithic carbon aerogels with excellent properties could envision enormous potential for high-temperature thermal insulation and organics absorption.