Preparation and dynamic moisture adsorption of fiber felt/silica aerogel composites with ultra-low moisture adsorption rate

Understanding the effects of preparation parameters on thermal insulation materials is important for reducing building energy consumption. In this study, fiber felt/silica aerogel composites with ultra-low moisture adsorption rate were prepared by the sol–gel and atmospheric drying technology. The effects of relative humidity and preparation parameters (e.g., silica sol ratios, volume ratios of the sol to fiber felt, aging duration, and modification duration) on the performance (thermal conductivity and moisture adsorption rates) of silica aerogel composites were explored. Furthermore, an isothermal adsorption model of silica aerogel composites for water vapor was established. The results showed in the environment with high relative humidity of 90 %, the moisture adsorption rate and thermal conductivity of the composites were approximately 1 % and 0.02 W·m−1·K−1, respectively. However, the moisture adsorption rate and thermal conductivity of the fiber felt were up to 20 % and 0.1687 W·m−1·K−1, respectively. With the change in the sol ratio, the moisture adsorption rate of the composites varied between 0.7 % and 0.8 % after reaching the adsorption equilibrium. The isothermal adsorption process was described by the D–A isothermal adsorption equation with the correlation of more than 0.99. The prepared fiber felt/silica aerogel composites with ultra-low moisture adsorption rate can be widely used for building insulation, especially in humid areas. This study provides the theoretical data reference for applying new aerogel composites insulation materials in high-humidity environments.