Ultralight and Low Thermal Conductivity Polyimide–Polyhedral Oligomeric Silsesquioxanes Aerogels

Abstract 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.