Open-cage POSS modified bismaleimide aerogels with excellent thermal properties and low dielectric constant properties via ambient pressure drying

Aerogels with lightweight, high-temperature resistance, and low thermal conductivity are emerged as a research hotspot in advanced materials. However, their commonly employ drying techniques such as supercritical CO₂ drying and freeze-drying, which significantly increase production costs. This work developed a novel strategy for rapid preparation of aerogel composites via ambient pressure drying by employing autonomous synthesis three types of vinyl-functionalized open-cage polyhedral oligomeric silsesquioxane(POSS) to modify bismaleimide (BMI). The incorporation of heat-resistant POSS contributes to enhanced porosity and maintained excellent thermal stability to ensure excellent thermal insulation performance and low dielectric properties. The results demonstrate that the tetravinyl open-cage POSS (OP₂-POSS) can endow the aerogel with ultralow dielectric constant and dielectric loss of 1.29 and 3.94 × 10⁻⁴ at 1 kHz, respectively, remarkable thermal stability with char yield exceeding 50 % at 800 °C under nitrogen, and low thermal conductivity possessing 0.021 W m⁻¹ k⁻¹. This aerogel holds great promise for applications in high-frequency communication and aerospace fields.