Tuning the microstructure of cellulosic porous materials: foams, cryogels and aerogels

The massive use of plastic materials derived from fossil fuels and their consequent environmental accumulation have driven the search for more sustainable alternatives. Among them, biopolymer-based materials such as cellulose stand out, as they are not only abundant and renewable but also readily available from lignocellulosic waste, promoting a circular economy. This study analyses porous structures derived from vine shoots’ waste biomass, specifically foams and aerogels obtained via freeze-drying and supercritical CO ₂ drying. Parameters such as density (15-70 mg/cm ³ ), shrinkage (15-75%), microstructure (wide range of pore sizes up to 3 µm, surface area up to 67 m ² /g), mechanical strength (up to 37 N/cm ² ), and thermal conductivity (29-36 mW/mK) were evaluated to determine the most optimal ones in terms of performance and cost-effectiveness. Finally, the efficiency of polylactic acid (PLA) as a reinforcement was examined to improve the hydrophobicity and sorption capacity (between 5-20 g water/g in sorption capacity measurements) and mechanical strength (up to 6-fold) of the materials, making them more competitive in various applications.