Preparation of functionalized halloysite reinforced polyimide composite aerogels with excellent thermal insulation properties

Abstract Excellent thermal insulating aerogels have broad application prospects in pipeline transportation, aerospace, construction and other fields. However, defects in thermal stability and mechanical are the main factors limiting their use to special environments. In this work, a novel polyimide composite aerogel is successfully synthesized through 3-Aminopropyltriethoxysilane (APTES) functionalized clay halloysite nanotubes (FHal) as inorganic enhancement phase and uniformly embedded in polyimide (PI) aerogels. Functionalization can increase the interfacial compatibility between clay inorganic phase and polyimide acid. The results indicated that FHal with high aspect ratio interacts with PI to form a three-dimensional network structure. The FHal/PI composite aerogels had low shrinkage (21.9%–30.79%), low bulk densities (65.285–71.464 mg/cm3), low thermal conductivities (39.18–42.57 mW/(m·K)), high thermal stability (onset of decomposition above 520 °C) and excellent mechanical property (1.14 MPa, 2.62 times of pure PI aerogel). Therefore, FHal/PI composite aerogels can be used as a promising thermal management material for practical and complex insulation applications.