The effect of drying method on the porosity of regenerated cellulose fibres

This study investigates the role of drying method and dissolving solvent has on the properties of regenerated cellulose fibres, leading to the preparation of porous cellulose fibres. The fibres are produced by wet spinning using 1-butyl-3-methylimidazolium acetate (BmimAc) as the solvent, and then dried using freeze drying or supercritical drying resulting in highly porous fibres. The properties of these fibres are compared to the traditional air-dried regenerated cellulose fibre. It was found that freeze drying produced fibres with micron pores on the surface and nanopores within the core, whereas supercritical-dried fibres had a smooth surface and a nanoporous core. The addition of DMSO to the spinning dope for supercritical dried fibres reduced the fibre diameter under identical draw conditions and increased the surface area to 260 m2/g.