Thermal insulation and flame retardancy of attapulgite reinforced gelatin-based composite aerogel with enhanced strength properties

•Attapulgite (ATP) is functionalized by biological dopamine and has good biocompatibility with gelatin.•ATP can significantly improve the mechanical properties of gelatin-based aerogels.•The composite aerogels constructed by ATP embedded in the gelatin skeleton have better inhibit the thermal decompsoition of organic phase.•The composite aerogels exhibit excellent thermal insulation and flame retardant properties. The advanced thermal management material with high mechanical strength and low thermal conductivity have an extremely important position in thermal insulation. Herein, we successfully prepared a green sustainable and low-cost composite aerogel with attapulgite and gelatin as the main components, and then obtained by chemical crosslinking and freeze-drying. Dopamine was used to functionalize attapulgite to increase interface compatibility between inorganic phase and gelatin molecules. The results show that the as-prepared attapulgite/gelatin composite aerogel have lower bulk density (ρ = 0.036–0.062 g cm−3), compression modulus up to 3.92 MPa, lower thermal insulation (λ = 34.28–35.29 mW/m K) and an excellent fire resistance (total heat release rate (THR) to 5.4 J kg−1), which mainly attributed to the improvement of the physical properties of the composite aerogel and the construction of the micro/nano structure by the attapulgite with high aspect ratio and high specific surface area embedded in the gelatin skeleton.