Eco-Sustainable Finishing Treatment of Polyamide Fabrics to Reduce the Release of Microplastics During Washing Processes

The washing processes of synthetic clothes have been lately identified as a main source of microplastic pollution in marine environment. During a common washing process, synthetic fabrics undergo mechanical and chemical stresses that induce the detachment of microfibers from the main yarns. Such microfragments remain in the wastewater, eventually reaching marine ecosystems where they represent a serious threat for the flora and fauna. A possible solution that could mitigate such source of microplastic pollution is the application of functional finishing treatments able to protect fabrics during washings, reducing the amount of microfibres released. The present work proposes an innovative finishing treatment of polyamide fabrics by using pectin, a natural polysaccharide extracted from fruits. Pectin was chemically modified by reaction with glycidyl methacrylate (GMA), whose vinylic groups were exploited to graft pectin on the surface of the polyamide fabric, creating a coating on the fibres. The effectiveness of the surface treatment was assessed by using the following characterization techniques: scanning electron microscopy (SEM), solid-state nuclear magnetic resonance spectroscopy (NMR) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Furthermore, washing tests of untreated and treated fabrics were carried out to assess the release of microplastics. The washing effluents were filtered and the filters were analysed by SEM to evaluate the amount of microfibres released. The obtained results showed that the application of the pectin-based coating, could reach a reduction of more than 80% of the number of microplastics released by untreated polyamide fabrics during a domestic washing process.