High Stiffness Cellulose Fibers from Low Molecular Weight Microcrystalline Cellulose Solutions Using DMSO as Co-Solvent with Ionic Liquid

There is a need to develop high-performance cellulose fibers as sustainable replacements for glass fibers, and as alternative precursors for carbon filaments. Traditional fiber spinning uses toxic solvents, but in this study, by using dimethyl sulfoxide (DMSO) as a co-solvent with an ionic liquid, a novel high-performance fiber with exceptional mechanical properties is produced. This involves a one-step dissolution, and cost-effective route to convert high concentrations of low molecular weight microcrystalline cellulose into high stiffness cellulose fibers. As the cellulose concentration increases from 20.8 to 23.6 wt%, strong optically anisotropic patterns appear for cellulose solutions, and the clearing temperature (T _c) increases from ≈100 °C to above 105 °C. Highly aligned, stiff cellulose fibers are dry-jet wet spun from 20.8 and 23.6 wt% cellulose/1-ethyl-3-methylimidazolium diethyl phosphate/DMSO solutions, with a Young's modulus of up to ≈41 GPa. The significant alignment of cellulose chains along the fiber axis is confirmed by scanning electron microscopy, wide-angle X-ray diffraction, and powder X-ray diffraction. This process presents a new route to convert high concentrations of low molecular weight cellulose into high stiffness fibers, while significantly reducing the processing time and cost.