SYNTHESIS AND PROPERTIES OF HYBRID AEROGEL MATERIALS BASED ON LIGNOSULFONATE AND SILICA USING SUPERCRITICAL DRYING

Abstract

In this study, the sol-gel method was used for the synthesis of hydrogels based on liquid glass and sodium lignosulfonate. Isopropyl alcohol was used to subsitute water in the hydrogel structure, preventing linear shrinkage and maintaining the water content in the range of 1-4.8%. Subsequently, these hydrogels were subjected to supercritical drying at 40°C and a pressure of 12 MPa in a 250 mL device together with a supercritical CO2 consumption of 100 Nl/h, resulting in a hybrid aerogel with a specific surface area reaching 483 m2/g. The resulting aerogels have a micro-mesoporous structure with average pore sizes of 3-50 nm and a total pore volume ranging from 0.27 to 2.19 cm3/g. These hybrid aerogel materials have a noticeably low density (i.e., as low as 0.055 g/cm3).