The chemical recycling of hemp fabric into high-tenacity man-made cellulose fibers was demonstrated. The fabric was laundered 25 and 50 times to mimic the wear cycles of post-consumer textile waste. Despite the launderings, the molar mass of the material was still too high for recycling via dry-jet-wet spinning. Thus, the fabrics were treated with an aqueous sulfuric acid solution to adjust the intrinsic viscosity to the targeted level of 400–500 ml/g. The acid hydrolyzed sample was dissolved in 1,5-diazabicyclo[4.3.0]non-5-enium acetate and man-made cellulose fibers were regenerated by dry-jet-wet spinning. The properties of hemp and regenerated fibers were determined by tensile testing, birefringence measurements, and X-ray diffraction. Regenerated fibers were spun into yarn and knitted into a fabric. The tensile properties of the yarn and the abrasion and pilling resistance of the fabric were determined. Regenerated fibers showed a higher modulus of toughness (55.9 MPa) compared with hemp fibers (28.7 MPa). The fineness and staple length uniformity of regenerated fibers resulted in a high yarn structure evenness, a yarn tenacity of 28.1 cN/tex, and an elongation at break of 7.5%. Due to the even fabric structure, the fabric from regenerated fibers showed higher abrasion resistance than the hemp fabric.

The hydrolysis kinetics of 7-methyl-1,5,7triazabicyclo[4.4.0]dec-5-enium acetate [mTBDH][OAc] was investigated in a comprehensive study by the utilization of the well-known Schlenk technique to achieve a better understanding of its stability for dry-jet wet spinning applications (e.g., Ioncell) and due to the course of operation for recovery methods like fractional distillation. Decomposition behavior as a function of temperature, time, acid−base stoichiometry, and water content was extensively analyzed and characterized by nuclear magnetic resonance spectroscopy (NMR), capillary electrophoresis (CE), and thermogravimetric analysis (TGA). Furthermore, kinetic models were formulated for the prediction of the stability and the results were compared with the closely related amidine-based analogues 1,5diazabicyclo[4.3.0]non-5-enium acetate [DBNH][OAc] and 1,8-diazabicyclo[5.4.0]undec-7-enium acetate [DBUH][OAc].

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