Construction of polyimide composite aerogels via multi-coordination structure of polymer-metal for improving heat-induced shrinkage, thermal insulation, mechanical and dielectric properties

Abstract

The fabrication of polyimide (PI) composite aerogels can promote and optimize the characteristics and performance efficiency. But in fact, interface effect and assembly technique are the key problems in preparing PI composite aerogels. To settle this critical issue, a series of PI composite aerogels were designed via forming multi-coordination structure between PI molecular chain and Cu(II) metal ions. Multi-coordination structure connects the two-phase systems closely to obtain the improved comprehensive performances. The resulting PI composite aerogels still have high specific surface and mesoporous structure. The addition of Cu(II) improves the thermal and mechanical properties of the PI composite aerogels with an over 581 °C initial decomposition temperature, tensile strength of up to 9.48 MPa and modulus of up to 232.4 Mpa，along with compression Young’s modulus increased by 173% (up to 28.7 MPa) and stress at 10% strain improved by 150% (up to 1.70 Mpa). In the meantime, the brilliantly controllable dielectric property (with the dielectric constant down to 1.60 and the dielectric loss reaching 0.0171 at 10 MHz) and thermal insulation property (with the thermal conductivity down to 31.9 mWm−1K−1) of PI composite aerogels make them can be used as low dielectric and thermal protection materials. The small heat-induced shrinkage between 100 and 250 °C allows the PI composite aerogels to operate in persistent extreme conditions. Besides, this work can provide a new strategy for preparing PI composite aerogels.