SiO2 aerogel multiscale reinforced by glass fibers and SiC nanowhiskers for thermal insulation

Abstract

SiO2 aerogel attracts much interest as thermal insulation material due to ultra-low density and excellent thermal performance at room temperature. However, the poor mechanical property and a mass of heat transfer by radiation in high temperature limit application of aerogels. Herein, a novel aerogel composites multiscale reinforced by glass fibers with SiC nanowhiskers (SiCnw) (AFW) was prepared. SiCnw were evenly distributed in glass fibers felts by freezing-drying method to form a uniform multiscale felts. The SiCnw inside felts provided more contact point with aerogel to increase the interfacial adhesion force so that compressive stress of AFW with 4% volume fraction SiCnw was increased to 0.29MPa. SiCnw blocked infrared radiation to decrease the heat transfer. Therefore, Even though SiCnw raised thermal conductivity of aerogels at room temperature, thermal conductivity at 500℃ of AFW with was only 0.040 W/(m·K). In another word SiCnw reduced the sensitivity of thermal conductivity to temperature. AFW shows potential in the field of medium and high temperature insulation.