Nanostructured cellulose acetate filaments produced by supercritical antisolvent precipitation

The supercritical antisolvent precipitation technique was used to precipitate cellulose acetate in form of nanostructured filaments. Two different solvents were used: acetone, chosen because it is a typical laboratory solvent, and a mixture acetic acid + water, that is industrially used in the cellulose acetylation process. The influence of the operating parameters, such as concentration of the liquid solution, pressure and temperature, on the structure of cellulose acetate filaments was studied. Several centimeter long structures, formed by nanoelements ranging from about 50 to 250 nm, were obtained. Some experiments were replicated on a pilot plant to demonstrate the scalability of the process.