Best Before : A selective service life analysis of denim fabrics with a focus on washing and drying degradation to optimize their recycling efficiency

Abstract: Resource scarcity and increasing environmental pressure have raised the stakes for rethinking material efficiency and textile recycling potential. As current practices fail to feed a closed loop recycling system, this research aims to contribute to the improvement of prevailing practices regarding denim as one of the most popular apparel materials worldwide while focusing on the issue of increasing amounts of discarded post-consumer textiles. The superordinate objective to define the optimum point for denim recycling to retain the value of the cotton fibre as long as possible in a closed loop system, thereby elevating the recycling efficiency, can be considered a key driver for the present research. The following data acquisition is constructed and executed along a mixed method research, in which a qualitative approach based on expert interviews informs and builds up on the quantitative counter part of laboratory use simulation testing on two different denim fabrics and vice versa, leading to an embedded research design. A subjective assessment of potential alterations of the denim fabrics’ visual and tactile characteristics, caused by the use simulation, provides quantitative data through an employed expert panel, which is enhanced by objectively recorded results from the conducted tear strength test and comparative weight investigation to inform changes regarding the physical properties. The applied research methods provide parameters to monitor the decomposition and weakening of the overall fabric structure throughout the experiment. The analysis of the data allowed to assign the number of washing and drying cycles, that a denim garment has undergone, to a corresponding degree of degradation. The presented findings are a valuable resource for developing and innovating current open-end recycling options. The maintenance of the raw material value throughout various reprocessing cycles can counteract the elevated natural fibre scarcity. The insights on the material and process level build a fundament for the successful operationalisation and management of sustainable recycling practices. Further research in this field can pave the way towards value retaining circularity.