Use of bio-waste for silica aerogel composites

Silica aerogel, with its exceptionally low thermal conductivity, needs wider applications despite current limitations. Meanwhile, bio-sourced materials are gaining traction because of their large availability, with comparable or superior properties to non-renewable options. Additonnaly, their low carbon footprints are crucial for reducing emissions linked to the building sector. Therefore, combining silica aerogel with bio-sourced materials is a promising way to address both environmental and performance goals. In the present study, composites made of silica aerogel and bio-based materials issued from waste (e.g. loose cellulose fibers and sawdust) are investigated, aiming for thermal insulation as the main application. The impact of each component is studied on properties related to thermal insulation - thermal conductivity, mechanical strength, moisture behavior, and mold development. Using empirical methodology, fine-tuned compositions are developed to get the best properties. Thermal conductivity down to 20 mW m ⁻¹.K ⁻¹ is achieved, with compression strength fulfilling the standard for thermal insulation materials.