A novel cost-effective choline chloride/ionic liquid solvent for all-cellulose composite production

The potential of a blended cellulose solvent, consisting of a 1:1 mass ratio of choline chloride with the ionic liquid 1-ethyl-3-methylimadazolium acetate, was evaluated by using a film-casting technique. When comparing films produced with the neat ionic liquid to casting products from the mixed solvent, mechanical properties could largely be retained, while transparency was somewhat impaired. This is attributed to a fibrous microstructure and a higher degree of crystallinity caused by incomplete dissolution of the initial cellulose fibres. The presence of these residual fibres significantly reduced shrinkage during the film formation process. Functional group analyses, together with information on their crystallographic structure, proved that these film-like products should be classified as all-cellulose composites (ACCs). Statistical analyses of tensile properties justify further research on the mixed solvent system for cellulose processing.