“Blue glue”: A new precursor of carbon aerogels

Abstract

New carbon aerogels have been prepared from urea-branched phenol–resorcinol–formaldehyde resin. Such material, called “blue glue” and used as cold-set adhesive for wood, has been modified in order to obtain highly porous organic gels. The latter were prepared at different pH (5, 7 and 9), dried with supercritical methanol, and carbonised at two different heating rates (2.5 and 5°Cmin−1). FTIR analysis confirmed the expected chemical structure of the gel, and GC–MS analysis of the solvent condensed after supercritical drying suggested a slight chemical degradation of the gels during the drying process. However, low-density (0.15–0.31gcm−3), monolithic, carbon gels could be successfully derived from these materials, having high BET surface areas (900–1300m2g−1) and high mesopore fractions (60–80%). These ranges of values originate from the conditions tested for preparing the materials. Such carbon aerogels are two times cheaper than their traditional resorcinol–formaldehyde-based counterparts and present similar, if not more developed, porous structures.