FINIX workwear study - Identification of the Cellulose Material Changes in the course of the Chemical Recycling of Workwear

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Volume Title

School of Science | Master's thesis

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Date

2024-11-18

Department

Major/Subject

Materials Physics and Quantum Technology

Mcode

Degree programme

Master's Programme in Engineering Physics

Language

en

Pages

53

Series

Abstract

Recycling of textiles has become one of the priorities as we move towards a sustainable circular economic industry. Similar to all other textiles, the industry identified the importance of recycling workwear. Workwear is being used in various fields of different applications and is known for its longevity and durability. In this study, the focus was on the production of man-made cellulosic fibres from pre- and post-consumer (50 times washed) cotton workwear fabrics. The fabric has a nitrogen-phosphorus-based flame-retardant finish and is dyed navy blue with vat dyes. The following three recycling strategies have been pursued to produce fibres (1) directly, (2) by removing the flame-retardant reagent and (3) by removing both the flame-retardant reagent and the dye. In all cases, an acidic treatment was required to adjust the substrate properties to the requirement of the dry jet-wet spinning method. By the exploitation of the differences in dissolution of the natural (cellulose) and synthetic (flame-retardant) polymer a separation via filtration was possible. Finally, via a common procedure (dithionite and hydrogen peroxide treatments), the colour was removed. In case of strategy (1) and (2) fibres of high strength have been produced and analysed. But for strategy (3) the material properties changed and a production of fibres was not possible. Hence, further research and experimentation are required to successfully produce fibres without flame-retardant and colour.

Description

Supervisor

Hummel, Michael

Thesis advisor

Schlapp-Hackl, Inge

Keywords

Ionic liquid, intrinsic viscosity, dry jet-wet spinning, Ioncell®, fibre spinning, draw ratio, filter treatment, dithionite and peroxide treatment, flame-retardant removal, vat dye removal

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Permanent link to this item

https://urn.fi/URN:NBN:fi:aalto-202412238096

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[dipl] Perustieteiden korkeakoulu / SCI