Co-polyimide aerogel using aromatic monomers and aliphatic monomers as mixing diamines

A novel co-polyimide aerogel using aromatic monomers (4,4′-diaminodiphenyl ether, ODA) and aliphatic monomers (1,3-Diaminopropa) as mixing diamines has been prepared via the sol–gel technique. The effects on the properties (density, shrinkage, surface area, and average pore size) of co-polyimide aerogel have been investigated by changing the molar ratios of mixing diamines. The density of co-polyimide aerogel reaches as low as 0.0448 g cm⁻³, because of replacing part of ODA (M = 269.5) in the backbone with 1,3-diaminopropa (molecular M = 76.1).The thermal conductivities reach as low as ~0.031 W m⁻¹ K⁻¹ (25 °C), BET surface areas are 331 m² g⁻¹ and the compressive modulus range from 1.253 to 3.273 MPa. The facile preparation route and low thermal conductivity indicate that co-polyimide aerogels may be ideal candidates for aerospace and thermal insulations.