Thermal superinsulating silica aerogels and xerogels reinforced with short cellulose fibers

International audienceSilica-based aerogels are highly porous nanostructured materials with thermal super-insulating properties (i.e. thermal conductivity below that of air, 0.025 W/(m.K), in ambient conditions). Aerogels are obtained via drying in supercritical conditions. To overcome the latter step, drying at ambient pressure and slightly elevated temperature is used, leading to xerogels with similar thermal properties but not monolithic. One way to keep macroscopic monolithicity is to reinforce xerogels with non-woven fibrous mats. We synthesized composite aerogels and xerogels with short cellulose fibers and demonstrated that a) mechanical properties of aerogels are strongly improved and b) it is possible to obtain monolithic xerogels with morphological and thermal properties similar to those of their supercritical-dried counterparts /G. Markevicius et al, Ambient-dried thermal superinsulating monolithic silica-based aerogels with short cellulosic fibers“Journal Materials Science, in press/. The proof of concept was demonstrated with model Tencel® fibers and extended to other natural fibers and paper waste