A facile method to prepare cellulose whiskers–silica aerogel composites

Abstract

Highly porous and hydrophobic cellulose whiskers–silica aerogel composites were successfully fabricated by a novel co-precursor method based on sol–gel process under ambient pressure drying. Cellulose whiskers were dispersed in the initial sol and were finally inlaid in silica aerogel skeleton by physical combination, which retained the integrality of the aerogel matrix. With the increase of cellulose whiskers content from 0 to 15%, the volume shrinkage of alcogels during drying process decreased from 25.5 to 17.6%, while the porous nano-structure of aerogels were not significantly altered. The potential impact of cellulose whiskers on the thermal conductivity and thermal stability of the prepared composites was investigated. The new composite was intact and white, which exhibited typical properties of 0.137 g cm−3 density, 3.525 cm3 g−1 pore volume, and 139.6° contact angle, respectively. This work explained how the addition of an organic filler into the silica aerogels influenced their properties and provided a technique for silica aerogels to endure and remain monolithic under ambient pressure drying.