A robust heat-insulating organic–inorganic hybrid aerogel with a green preparation strategy inspired by diatoms

Abstract

Organic–inorganic composite aerogels represent a novel class of materials that effectively combine the advantages of both organic and inorganic components. Polybenzoxazine (PBz) has emerged as a promising organic alternative due to its structural rigidity, thermal stability, and cost-effectiveness. However, achieving efficient compatibility between PBz and inorganic components remains a significant challenge. In this study, inspired by the structure of diatoms, tannic acid (TA) was introduced as a compatibilizer to stabilize the dispersion of inorganic silica precursors within a PBz solution and improve their compatibility. A uniform structure with minimal phase separation was achieved through a two-step catalytic copolymerization method at room temperature. Benefiting from the inherent rigidity of PBz and superior thermal stability of polysiloxane, the resulting polybenzoxazine/silicon hybridized aerogel (BSA) exhibits a low thermal conductivity of 0.0487 W m⁻¹ K⁻¹, a high compressive strength exceeding 20.0 MPa, and outstanding thermal degradation stability (T_d5 of 389.75 °C). This biomimetic and environmentally sustainable approach holds significant potential for advancing the development of next-generation thermal insulation materials.