Hydrophobic silica aerogel powder and hollow glass microspheres (HGM) were used as fillers for an epoxy adhesive to improve its thermal insulator properties. At 50 wt% of HGM content, the thermal conductivity of the HGM/epoxy composite decreased from 0.182 W/m·K to 0.104 W/m·K. The aerogel/epoxy composite, on the contrary, showed a slight increase in its thermal conductivity, most probably due to the filling of aerogel pores with the epoxy adhesive. Furthermore, it was shown that adhesion values of epoxy composites increase with the addition of aerogel and decrease when HGM was used as the filler material. Realistic numerical finite element method simulations revealed an increase in thermal isolation properties for both HGM/epoxy and aerogel/epoxy composites.
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