Abstract: HNTs/SiO2 composite aerogels with excellent mechanical properties and thermal insulation performance were prepared via supercritical CO2 drying,employing tetraethoxysilane (TEOS) as silicon source and halloysite nanotubes (HNTs) modified by isooctyltriethoxy silane as reinforcing phase.Surface states of HNTs after modification,the morphology,pore structure,mechanical properties,and thermal conductivity of composite aerogels were investigated by FTIR,SEM,surface area and porosity analyzer,universal testing machine and thermal conductivity measurement.Our results reveal that the modified HNTs are uniformly dispersed into the silica gel matrix,and make good combinations with SiO2 nanoparticles.HNTs/SiO2 composite aerogels exhibit a three-dimensional network structure,when the content of HNTs is 15wt;,the average pore size of aerogels is 10.47 nm;with the increase of HNTs content,the mechanical properties of composite aerogels are improved,and the thermal conductivity also increase continuously.When the HNTs content is 15wt;,the compressive strength of HNTs/SiO2 composite aerogel is 0.85 MPa,and the thermal conductivity is 0.024 W/mK.

Key words: HNTs/SiO2 composite aerogels with excellent mechanical properties and thermal insulation performance were prepared via supercritical CO2 drying,employing tetraethoxysilane (TEOS) as silicon source and halloysite nanotubes (HNTs) modified by isooctyltriethoxy silane as reinforcing phase.Surface states of HNTs after modification,the morphology,pore structure,mechanical properties,and thermal conductivity of composite aerogels were investigated by FTIR,SEM,surface area and porosity analyzer,universal testing machine and thermal conductivity measurement.Our results reveal that the modified HNTs are uniformly dispersed into the silica gel matrix,and make good combinations with SiO2 nanoparticles.HNTs/SiO2 composite aerogels exhibit a three-dimensional network structure,when the content of HNTs is 15wt;,the average pore size of aerogels is 10.47 nm;with the increase of HNTs content,the mechanical properties of composite aerogels are improved,and the thermal conductivity also increase continuously.When the HNTs content is 15wt;,the compressive strength of HNTs/SiO2 composite aerogel is 0.85 MPa,and the thermal conductivity is 0.024 W/mK.