Composite of an RF-Aerogel with an Aramid-honeycomb
Polycondensation within the aqueous solution of resorcinol and formaldehyde leads to the formation of polymeric particles which build a 3D network in the solvent. These thermoset resin gels can be dried either supercritically with carbondioxide or subcritically by just evaporation of the solvent solution. They are very light with densities in the range of 60 to 250 kg/m3, have an extremely low thermal conductivity down to 0.01 W/km, are fire resistant, and thermally decompose without fume and hazardous smoke or toxic volatiles. These thermoset resins, often called RF-aerogels, can be manufactured with a huge variety of mechanical properties. They can be brittle with fracture strength in the range of a few MPa or flexible, corky or even rubberlike superflexible with just a of kPa strength, but deformable by more than 50% without breaking. One just has to adopt the chemistry and processing.
Thermoset aerogels are especially suitable for filling the holes in honeycombs made for example from aramid. Then one can obtain a composite being light, very stiff, thermally isolating and with a good sound adsorption capacity. Such composites could be an interesting alternative to styrofoams. They also could be a core material for metal plated sandwiches, where they exhibit additional functions for lightweight constructions in cars, airplanes and trains. The combination of these aerogels with inorganic granulates offers another new composite material with a combination of both properties.