Ultralight and Low Thermal Conductivity Polyimide–Polyhedral Oligomeric Silsesquioxanes Aerogels

The research on rapid growing, organic, and ultralight cross-linking polyimide aerogels is receiving significant interest. In this work, poly(aminophenyl) silsesquioxanes (PAPSQ) are introduced as a cross-linker into the polymide (PI) aerogel. A comparative aerogel is prepared, using 1,3,5-triaminophenoxybenzene (TAB) as a cross-linker. The aerogels are characterized in terms of their micro- and nanostructures, density, shrinkage, thermal conductivity and insulation, and mechanical properties. It is found that the PI-PAPSQ aerogel have lower density, smaller shrinkage, lower thermal conductivity, higher thermal stability and insulation, and higher compression strength than the PI-TAB aerogel. The 1.1 wt% PI-PAPSQ shows the lowest aerogel density (0.010 g cm⁻³) and the 2.2 wt% PI-PAPSQ has a lower thermal conductivity (22.90 mW (m K)⁻¹ than air. A model of the PI-TAB and PI-PAPSQ cross-linking networks are proposed to explain the excellent performance of the PI-PAPSQ aerogel.