Low density, resorcinol-formaldehyde aerogels

Abstract

The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer "Clusters". The covalent crosslinking of these "clusters" produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density.ltoreq.100 mg/cc; cell size .ltoreq.0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100.circle.. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron. TABLE I ______________________________________ Theo- [Form- retical Actual Formu- % alde- [Resor- density Density lation Solids hyde] cinol] Na.sub.2 CO.sub.3 (g/cc) (g/cc) ______________________________________ A 5.0% 0.29M 0.58M 0.0029M 0.050 0.079 B 5.0% 0.29M 0.58M 0.0019M 0.050 0.073 C 5.0% 0.29M 0.58M 0.0015M 0.050 0.070 D 4.0% 0.24M 0.47M 0.0012M 0.040 0.054 E 3.5% 0.21M 0.41M 0.0010M 0.035 0.044 F 2.0% 0.12M 0.24M 0.0006M 0.020 0.030 ______________________________________

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