Convenient preparation of monolithic aerogel-like organosilica material through solid decomposition

Unlike aerogel preparation processes usually adopted, where a wet gel is first prepared and then solvent eliminated by supercritical extraction or ambient pressure evaporation, which often involves repeated time-consuming solvent exchange steps, the present process gives aerogel-like organosilica material through simple solid sublimation. In this process, a readily decomposable solid powder, ammonium carbonate (AC), is wetted with a resinous polymer solution of polymethylsilsesquioxane (PMSQ) and moulded into a desired shape. After PMSQ solution transforms to gel under catalysis by dibutyltin dilaurate, the sample is elevated to a higher temperature for the solvent to evaporate and AC to decompose. The obtained porous product has porosity up to 98.2% and bulk density of 0.035 g cm−3 and nitrogen adsorption-desorption measurement gives BET surface area of 103 m2 g−1, when 20 wt% PMSQ is used. FTIR spectra confirm the crosslinking of PMSQ after heating. Scanning electron microscopy (SEM) image shows that the obtained product is highly porous and aerogel-like. The porous product shows excellent oil collecting capability of 11 g g−1 porous solid in an oil-collecting test made by vacuum oil on water. This method is straightforward and convenient to use for highly porous aerogel-like material preparation.