文摘
Polyimide aerogels for low density thermal insulation materials were produced by 4,4′-diaminodiphenyl ether and 3,3′,4,4′-biphenyltetracarboxylic dianhydride, cross-linked with 1,3,5-triaminophenoxybenzene. The densities of obtained polyimide aerogels are between 0.081 and 0.141 g cm–3, and the specific surface areas are between 288 and 322 m2 g–1. The thermal conductivities were measured by a Hot Disk thermal constant analyzer. The value of the measured thermal conductivity under carbon dioxide atmosphere is lower than that under nitrogen atmosphere. Under pressure of 5 Pa at −130 °C, the thermal conductivity is the lowest, which is 8.42 mW (m K)−1. The polyimide aerogels have lower conductivity [30.80 mW (m K)−1], compared to the value for other organic foams (polyurethane foam, phenolic foam, and polystyrene foam) with similar apparent densities under ambient pressure at 25 °C. The results indicate that polyimide aerogel is an ideal insulation material for aerospace and other applications.