“Blue glue”: A new precursor of carbon aerogels

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 °C min−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 (0.15–0.31 g cm−3), monolithic, carbon gels could be successfully derived from these materials, having high BET surface areas (900–1300 m2 g−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.

Carbon aerogels two times cheaper than their counterparts made from resorcinol–formaldehyde were prepared for the first time from “blue glue” (urea-branched phenol–resorcinol–formaldehyde adhesive resin). pH adjustment followed by supercritical drying in methanol and pyrolysis at two different heating rates led to carbon aerogels having attractive porous structures: total porosity, 85–93%; BET surface area, 900–1300 m2 g−1; mesopore fraction, 60–80%, depending on the preparation conditions.Figure optionsDownload as PowerPoint slideHighlights
► The first carbon aerogels derived from blue glue are presented.
► Different preparation conditions (pH and heating rates) were used.
► Carbon aerogels presented very high surface areas and mesopore fractions.
► These carbon aerogels are two times cheaper than those derived from resorcinol.