Preparing hydrophobic silica aerogels with superior thermal insulation and fire safety by introducing sepiolite

This study develops sepiolite-based hydrophobic silica aerogel composites (SEP/SAs) to enhance thermal insulation and fire safety. The incorporation of sepiolite preserves the mesoporous structure of silica aerogels, resulting in composites with high porosity (93.1–96.1 %), low density (0.10–0.22 g/cm³), and low thermal conductivity (21–26 mW/(m∙K)). The SEP/SAs also exhibit strong hydrophobicity (contact angle > 120°) and significantly improved thermal stability, with increases of 206°C in onset temperature and 198°C in exothermic peak temperature. In addition, the composites show reduced calorific values (–50.8 %), heat release rates (–48.6 %), and CO/CO 2 emissions, alongside extended ignition times, indicating enhanced fire safety. This cost-effective approach to enhancing aerogel performance has promising applications in thermal insulation and fire protection, particularly for construction and industrial use.