Ultralight-Weight Cellulose Aerogels from NBnMO-Stabilized Lyocell Dopes

Abstract

Cellulose aerogels are intriguing new materials produced by supercritical drying of regenerated cellulose obtained by solvent exchange of solid Lyocell moldings. From N-methylmorpholine-N-oxide solutions with cellulose contents between 1 and 12%, dimensionally stable cellulose bodies are produced, in which the solution structure of the cellulose is largely preserved and transferred into the solid state. The specific density and surface of the obtained aerogels range from 0.05 to 0.26 g/cm3 and from 172 to 284 m2/g, respectively, depending on the cellulose content of the Lyocell dopes and regeneration procedure. A reliable extraction and drying procedure using supercritical carbon dioxide, the advantageous use of NBnMO as stabilizer for the Lyocell dopes, and selected physical properties of the materials is communicated.