A Study of the Physical and Mechanical Properties of Aerogels Obtained from Bacterial Cellulose.

Abstract

Aerogels with a density of 4.2-22.8 kg/m3 were obtained from bacterial cellulose synthesized under static and dynamic cultivation conditions on a molasses medium. The strength properties and porous structure of the aerogels strongly depended on their density. With an aerogel density of 22.8 kg/m3, the modulus of elasticity at 80% compression of the sample was 0.1 MPa. The decrease in the density of aerogels led to an increase in the pore sizes ranging from 20 to 1000 μm and a decrease in the modulus of elasticity. These characteristics were more pronounced in aerogels obtained from bacterial cellulose under static cultivation conditions. The aerogels had a low coefficient of thermal conductivity (0.0257 W m-1 °C-1), which is comparable to the thermal conductivity of air, and moderate thermal stability because the degradation processes of the aerogels began at 237 °C. The aerogels obtained from bacterial cellulose had high sound absorption coefficients in the frequency range of 200-5000 Hz, which makes it possible to use the aerogels as heat- and sound-insulating materials.