Comprehensive assessment of fragmented fiber shedding from recycled cotton textiles part i structural changes in woven fabrics and mass loss quantification during laundering

This study evaluates fiber release from recycled cotton fabrics during washing. Understanding the behavior of recycled cotton textiles is becoming increasingly important, as their use is expected to grow under current EU legislation. The research, therefore, aims not only to assess the suitability of yarns made from various types of cotton waste but also to expand existing knowledge about cellulose particle emissions from mechanically recycled natural fibers through quantitative and qualitative analysis. Another goal is to characterize microcontaminants released during repeated washing cycles. This article presents the first of three parts focusing on quantitative emission analysis, the development of an image-based methodology, and a comprehensive evaluation of woven samples. The cumulative weight loss of released fibers stabilized at 1–1.5 mg·g⁻¹ after five cycles, consistent with modeled expectations. SEM and EDS analyses confirmed that the released material consists of cellulose dust, fibrillated fragments, and detached particles typical of degradation caused by mechanical recycling and repeated washing stress. Measurement accuracy was improved using Monte Carlo simulations (10,000 iterations), which showed that instrumental uncertainty contributes 5.7–8.4% of total relative uncertainty. The findings indicate that recycled cotton is a notable source of biodegradable microcontaminants, with quantities strongly linked to input material quality. These results provide a solid basis for further evaluation of the environmental impacts of recycled textiles in the circular economy.