柔性交联型聚酰亚胺气凝胶的制备及性能

Polyimide aerogels were synthesized by sol-gel reaction, followed by supercritical drying. The effects of sol solid content and cross-linking agent ratio on performance of polyimide aerogels were investigated. The results showed that both the shrinkage and density of polyimide aerogels increased with increasing sol solid content and cross-linking agent ratio. With the increased sol solid content, the suitable thermal conductivity(0.026-0.033 W•m^-1•K^-1) declined at first and then increased, and the modulus and strength of polyimide aerogels was improved obviously. Introducing the cross-linking agent into molecular structure improved the toughness of polyimide aerogels, and the maximum value of break strain was 21.7%. The polyimide aerogels also showed high temperature stability. The good properties made them an ideal insulation for light weight and flexible thermal protection of advanced weapons and space vehicles.