Two kinds of polyimide(PI) aerogels,PIA-1( BPDA/4-APBI/ OAPS) and PIA-2( BPDA/3-APBI/
OAPS) have been successfully prepared via the supercritical carbon dioxide drying process of the PI gels derived
from 3,3’,4,4’ -biphenylene tetracarboxylic dianhydride(BPDA),2-(4-aminophenyl) -5-aminobenzimidazole(4-
APBI) or 2-(3-aminophenyl) -5-aminobenzimidazole(3-APBI) and octa( aminophenyl) silsesquioxane( OAPS).
The obtained PI aerogels exhibited micromorphology of a strain of beads with the pore size distribution peaks of 22 nm
for PIA-1 and 14 nm for PIA-2. The densities of the PI aerogels are 0. 105 g/ cm3 for PIA-1 and 0. 080 g/ cm3 for
PIA-2; and the Branuaer-Emmet-Teller (BET) surface areas of the aerogels are 693 m2 / g and 302 m2 / g, respectively.
In addition, the PI aerogels exhibited good flexibility and thermal resistance with the Tg higher than 350℃ and
initial thermal decomposition temperatures over 530℃.