A US university has argued the case for biosynthetic fibres, which, it says, could eliminate the growing apparel-linked microplastics problem.
Melik Demirel, chair of Biomimetic Materials at research university Penn State, said polyester and other synthetic fibres like nylon are still around and are a major contributor to the microplastics load in the environment.
“These materials, during production, processing and after use, break down into and release microfibers that can now be found in everything and everyone.”
Unlike natural fibres like wool, cotton and silk, current synthetic fibres are petroleum-based products and are mostly not biodegradable. While natural fibres can be recycled and biodegrade, mixed fibres that contain natural and synthetic fibres are difficult or costly to recycle.
A study led by researchers at the University of Barcelona in November found natural and regenerated cellulose such as cotton and viscose are the main textile microfibres found in south European marine floors. They analysed the amount of these coloured fibres, which vary between 3-8mm in length but less than 0.1mm in diameter, which come mainly from home and industrial washing machines.
Suggestions to tackle the problem have included washing clothing at lower temperatures and moving to natural fibres over synthetic ones as well as wider investments into plastic-eating bacteria.
But Demirel says these options do not solve the problem of the tonnes of synthetic fibres currently used in clothing around the world.
Biosynthetic fibres are both recyclable and biodegradable and could directly substitute for the synthetic fibres. They could also be blended with natural fibres to provide the durability of synthetic fibres but allow the blends to be recycled.
Derived from natural proteins, biosynthetic fibres also can be manipulated to have desirable characteristics. Demirel, who developed a biosynthetic fibre composed of proteins found in squid ring teeth, suggests that by altering the number of tandem repeats in the sequencing of the proteins, the polymers can be altered to meet a variety of properties.
For example, material manufactured from biosynthetic squid ring-teeth proteins, called Squitex, is self-healing. Broken fibers or sections will reattach with water and a little pressure and enhance the mechanical properties of recycled cotton as a blend. Also, because the fibers are organic, they are completely biodegradable as well.