Thermally insulating polyimide composite aerogel with flexibility and dimensional stability by flexible chain segments and dual-crosslinked network

Polyimide (PI) aerogels demonstrate significant potential in cutting-edge applications such as aerospace thermal protection and flexible sensors. However, their limited elasticity and flexibility, coupled with the common issue of volume shrinkage during preparation, hinder their ability to meet the stringent material requirements of flexible devices. In this study, the rigid diamine (PPDA) was partially replaced by the aromatic flexible diamine (BAPP) to copolymerize with (BPDA), forming a polyamic acid (PAA) precursor. Subsequently, NH 2 -SiO 2 nanoparticles were introduced to construct an organic–inorganic dual-crosslinked network, successfully yielding PI/SiO 2 composite aerogels. The resulting material exhibits high elasticity, good flexibility, and superior thermal insulation properties. The incorporation of BAPP significantly enhances the elasticity and flexibility of the material. After 50 radial compression cycles, the aerogel retains over 90% of its compressive strength. The incorporation of NH 2 -SiO 2 effectively suppressed drying shrinkage and reduced material density, endowing the aerogel with a low thermal conductivity (0.0285 W·m −1 ·K −1 ), high thermal stability (T 5% , 547 °C), and significant thermal insulation performance across a wide temperature range (− 40 to 300 °C). This study proposes a synergistic design strategy. It combines rigid–flexible copolymer chains with NH 2 -SiO 2 . The strategy effectively balances the flexural elasticity, thermal insulation properties, and structural stability of the aerogel. It demonstrates significant application potential in advanced thermal insulation fields. Graphical abstract