Browsing by Author "Sawada, Daisuke"

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    Chemical recycling of hemp waste textiles via the ionic liquid based dry-jet-wet spinning technology
    (Sage, 2022-12-18) Rissanen, Marja; Schlapp-Hackl, Inge; Sawada, Daisuke; Raiskio, Susanna; Ojha, Krishna; Smith, Edward; Sixta, Herbert
    The chemical recycling of hemp fabric into high-tenacity man-made cellulose fibres 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 hydrolysed sample was dissolved in 1,5-diazabicyclo[4.3.0]non-5-enium acetate and man-made cellulose fibres were regenerated by dry-jet-wet spinning. The properties of hemp and regenerated fibres were determined by tensile testing, birefringence measurements, and X-ray diffraction. Regenerated fibres 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 fibres showed a higher modulus of toughness (55.9 MPa) compared with hemp fibres (28.7 MPa). The fineness and staple length uniformity of regenerated fibres 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 fibres showed higher abrasion resistance than the hemp fabric.