The report integrates global market relevance, material properties, environmental and human health considerations, recyclability constraints and circular economy design principles. Cotton, man-made cellulosic fibres (MMCFs) and polyester (PES) are analysed as key fibre systems due to their dominant market share, contrasting performance profiles and distinct end-of-life challenges. Special attention is given to fibre blends as a critical design and system-level barrier to closed-loop recycling.

A harmonised analytical framework is defined, covering fibre composition, morphology, mechanical performance and recyclate quality. This framework supports both baseline material characterisation and comparative assessment before and after ageing, use-phase and recycling processes. A preliminary case study on mechanical recycling of denim garments is included to validate the applicability of the proposed methodology and to demonstrate how material selection decisions translate into experimental outcomes.

Rather than delivering fully optimised recycling solutions, this report defines what materials and garment archetypes are prioritised, why they are relevant, and how their circular performance will be assessed. The results provide a robust foundation for subsequent WP4 activities, including extended experimental validation, circular loop development and AI/ML-driven decision-support tools.