Influence of monomer and catalyst concentration on RF and carbon aerogel structure

Structure and density of organic RF (resorcinol formaldehyde) aerogels and pyrolized RF aerogels (carbon aerogels) can be modified upon variation of the resorcinol to catalyst (RC) ratio and by varying the mass ratio of the reactants resorcinol and formaldehyde in the sol. Here, series of RF and carbon aerogels have been produced with RC 200, 500 and 1500, each covering a wide density range. All samples were investigated using small angle X-ray scattering (SAXS), N-2 and CO2 adsorption. The creation of a huge amount of microporosity due to pyrolysis was observed and investigated by CO2 adsorption. SAXS scattering curves exhibit interesting structural changes. These investigation were accompanied by sound velocity measurements to obtain the elastic modulus. (C) 1998 Elsevier Science B.V. All rights reserved.