R. Petricevic et al., STRUCTURE OF CARBON AEROGELS NEAR THE GELATION LIMIT OF THE RESORCINOL-FORMALDEHYDE PRECURSOR, Journal of non-crystalline solids, 225(1), 1998, pp. 41-45
Resorcinol-formaldehyde (RF) gels with a very high molar ratio of reso
rcinol/catalyst (R/C), e.g., 1500 and a low relative molar mass conten
t of resorcinol + formaldehyde (RF-ratio) of about 30% can be ambient
pressure dried with minimal shrinkage. The resulting RF-aerogels exhib
it average cluster and pore sizes > 50 nm. Upon pyrolysis the RF-aerog
els are transformed into carbon aerogels exhibiting the same morpholog
y of the gel network but in addition showing a high amount of micropor
osity (< 2 nm). Below an RF-ratio of thirty mass percent the average p
article and pore size increase to several hundred nanometers. The macr
o- and microscopic properties of these aerogels were investigated by s
canning electron microscopy, permeability measurements, small angle X-
ray scattering and CO, sorption. (C) 1998 Elsevier Science B.V. All ri
ghts reserved.