Citric Acid Catalyzed Organic Aerogels

Kurzfassung

Organic aerogels based on resorcinol (R) and formaldehyde (F) using citric acid (CA) as a catalyst are synthesized via a sol-gel process and ambient pressure drying at a temperature of 80°C. The influence of the ratio resorcinol to catalyst (R/C) as well as variations of the mole fraction of water at constant ratio of R to F (R/F) on gelation time and the morphology of the monolithic aerogel samples is studied. The molar ratio of resorcinol to formaldehyde is kept at 1:1.3. The molar ratio of resorcinol to catalyst (R/C) is varied between 15 and 1429 and the molar ratio of resorcinol to water (R/W) is between 0.01 and 0.05. The process limits of the RF aerogels are established and the aerogels are characterized with respect to density, particle size and specific surface area