To meet the requirements of the regeneration process, the impurity content of textile pulp needs to be at the same level as that of commercial dissolving pulps. Increasing recycling that contributes to a toxin-free environment entails addressing potential risks in an integrated and effective way. This is important because impurities such as additives, colourants, and other finishing agents in cotton fabric may represent major technical problems in maintaining the continuity of chemical recycling, and may also transfer potentially hazardous chemicals present in the raw material. A potential benefit of chemically recycling cotton into man-made fibres, in contrast to mechanical recycling (common for cotton today), is that, besides obtaining quality similar to that of virgin regenerated fibres, impurities could be removed and other fibres separated in parallel.
One method to recycle cotton could be to regenerate the cotton cellulose into man-made cellulosic fibres via chemical recycling. Notably, the use phase of the garment can affect the fibres at a molecular level and reduce the degree of polymerization of the cellulose polymer, limiting the options for recycling. However, the fibre-to-fibre recycling route is still challenging for both synthetic and natural fibres, and to achieve feasible business models using reclaimed fibres as the raw material, it is crucial that the fibres be of virgin quality. Recycling textiles such as cotton into regenerated fibres has environmental benefits compared with incineration with energy recovery in the Nordic region, and the environmental performance of the secondary raw material is expected to be similar to that of other regenerated cellulosic fibres. This expected shortfall in cellulose-based fibres may be somewhat reduced by using post-production and post-consumer cotton as raw material in regenerated man-made cellulosics, such as viscose or lyocell. The results might lead to progress in overcoming quality challenges in cellulosic chemical recycling.Īs the global demand for textile fibres is expected to increase, based on the estimated global increase in population and increased standards of living, there will be an estimated cellulosic gap of five million metric tonnes of fibres globally by 2020. This study finds that reactive dyes and DMDHEU wrinkle-free finish affect the viscose dope quality and the regeneration performance. The alkaline/acid bleaching sequence was found to strip the reactive dye and DMDHEU wrinkle-free finish from the cotton fabric, so the resulting pulp could successfully be spun into viscose fibres, though the mechanical properties of these fibres were worse than those of commercial viscose fibres. The study investigates the spinning performance and mechanical properties (e.g., tenacity and elongation) of the regenerated viscose fibres.
Potentially, such a bleaching sequence could advantageously be integrated into the viscose process, reducing the costs and environmental impact of the product.
This study examines the impact on regenerated viscose fibre properties of a novel alkaline/acid bleaching sequence to strip reactive dyes and dimethyloldihydroxyethyleneureas (DMDHEU) wrinkle-free finish from cotton textiles. These challenges may disrupt the regeneration process steps and reduce the fibre quality.
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The chemical recycling of cellulosic fibres may represent a next-generation fibre–fibre recycling system for cotton textiles, though remaining challenges include how to accommodate fibre blends, dyes, wrinkle-free finishes, and other impurities from finishing.
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