Oxygen plasma treatment to mitigate the shedding of fragmented fibres (microplastics) from polyester textiles

The release of fragmented fibres (FFs) during the manufacture and service life of textiles is one of the key sources of microplastic pollution. Polyester (polyethylene terephthalate (PET)) is the most widely used fibre with production volume of 63 million tonnes - represents 55% of all textile fibres and 80% of synthetic fibres. The impact of textile material and structural variables as well as chemical modification of textiles to mitigate the release of FFs has previously been reported. For the first time, the current research brings together disciplines of textile technology and tribology to understand the impact of inter-fibre friction on the release of FFs. The oxygen plasma, a sustainable alternative approach to chemical treatment methods, was employed to alter the surface morphology and consequently the frictional behaviour of fibre surfaces and eventually its impact on the release of FFs. Using commercially relevant methods, bespoke polyester fabric was manufactured and treated with low pressure oxygen plasma. The treated and untreated samples were characterised for surface roughness (fibre surface profilometry), coefficient of friction (nanotribometer), FFs shedding, shear properties and wettability. An increase in surface roughness of polyester fibres was observed after the treatment. The oxygen plasma treatment significantly increased the coefficient of friction, shear hysteresis, wettability and reduced the FFs shedding by 43 % in mass (accumulative of prewash and 5 accelerated washes) and 73 % in count (number) compared to untreated sample, without impacting the fabric handle and imparting hydrophilic property. Strong negative correlations between shed FFs and fabric coefficient of friction (r = −0.907 for FFs mass and r = −0.918 for FFs count) were observed. The outcomes of this study confirm that the fibre tribological properties can play a role to modulate the release of FFs from polyester textiles, using a sustainable method of plasma treatment technology.