Synthesis and Characterization of Resorcinol-Formaldehyde (RF) and Carbon Aerogel Microbeads by Dropping Method

Abstract

Resorcinol formaldehyde (RF) aerogel microbeads have been shown to improve the quality of metal castings when mixed with the casting sand. Reports for the production of RF aerogel microbeads mostly involve emulsion gelation methods, which have the disadvantage of a complicated upscaling of the synthesis. Hence, the aim of this work is to investigate the synthesis conditions of RF aerogel microbeads with a dropping method. Xanthan gum (XG) was added to a RF sol to increase its viscosity. A XG containing base-catalyzed pre-gelled sol was then dropped into hydrochloric acid to induce rapid gelation of the droplets. After ambient drying the gels were fully characterized concerning their size, bulk and skeletal densities, porosities, surface area, pore size distribution, IR spectra and microstructure. The here described reaction parameters can in future be transferred to a mechanical JetCutter for easy upscaling of the process.