Enhancements of thermal insulation and mechanical property of silica aerogel monoliths by mixing graphene oxide

Abstract

In order to improve the thermal insulation and mechanical property of silica (SiO2) aerogels, the graphene oxide (GO), as nanofillers, was added into SiO2 matrix to prepare the SiO2/GO composite aerogel monoliths on the basis of sol-gel technology and submitted to supercritical drying. The results showed that the monoliths were maintained and GO was well-distributed in the aerogel, due to the interfacial interaction between GO nanosheets and SiO2 matrix. The thermal insulation property of composite aerogels was improved in contrast with that of pure aerogel. The experimental results suggested that the thermal conductivity was lowered from 0.0089 W/mK to 0.0072 W/mK. A possible mechanism was analyzed to explain this result in virtue of GO loadings. The mechanical strength of aerogels was enhanced. It was found that with the loading of GO from 0.0 wt% to 5.0 wt%, the compressive modulus was enhanced from 0.238 MPa to 0.394 MPa, which was a significant improvement for low-solid-content silica aerogels. Moreover, the composite aerogels exhibited some toughness compared to the fragility of pure aerogel.