Drying of aerogel-bonded sands

Abstract

The drying of foundry sands bonded by polymeric aerogels is of essential importance for their industrial application and of general interest in the context of drying theories for porous media, since in these new materials the interstices between the sand grains are partially filled with an open porous nanostructured material, the aerogel. We describe measurements on the drying of various foundry sands with different amounts of aerogelic binder made from resorcinol and formaldehyde in which we also varied the drying temperature. The results suggest that the nanostructured aerogel dictates completely the drying behaviour. Sand type and sand grain size are of minor relevance. A simple qualitative picture is developed describing the observations.