Poly (m-phenylene isophthalamide)/graphene composite aerogels with enhanced compressive shape stability for thermal insulation

Abstract

To develop graphene-based composite aerogels with improved compressive shape stability that suitable for high-temperature applications, poly (m-phenylene isophthalamide, PMIA) with excellent heat resistance and flame retardancy was used as the supporting material. The effects of PMIA content on aerogel morphology, structure, mechanical and thermal properties were discussed. Unlike other polymers, PMIA in the composite aerogels appeared as separate or stacked particles instead of interconnected framework or uniform coatings. Higher PMIA content tended to result in denser aerogels with smaller pores and thinner graphene sheet walls. The densified structure with plenty of PMIA particles incorporated was found to make the aerogel more rigid and less flexible. Their compressive strength therefore was greatly enhanced. Besides, it was also observed that the thermal conductivity of the prepared aerogels increased with the increase of PMIA content. Nevertheless, their thermal conductivity was still <0.045 W m−1 K−1, indicative of considerable thermal insulation ability. Given that, the prepared composite aerogels with enhanced compressive shape stability may have a broad application prospect in thermal insulation.