Polyester is a broad term for polymers containing the ester group. Specifically—polyethylene terephthalate is the common polymer widely used in clothing. The material also finds uses in bedding, shower curtains, conveyor belts, etc.
Polyester can be derived straight from crude oil and gas, or recycled plastics. In short, plastics are melted down and spun into long threads. With the help of compounds/petrochemicals (e.g. caustic acid), the fibers are processed and woven into sheets of fabric with properties that appeal to manufacturers and fashion designers; along with its low-cost of production.
The material is often blended with natural fibers such as cotton to increase wrinkle resistance, reduce shrinking and hold color better. Some polyesters are biodegradable, but most are not.
Polyester’s water footprint is massive and much of the greywater produced during the process contains toxins not properly treated before discharge. This further complicates its impact with the fact that most manufacturing operations are located in water-pollution hotspots—with 92% of global polyester fiber production occurring in Asia.
Besides these facts, polyester has been under scrutiny for its role in releasing microplastics (<5mm in length) into the environment. Compared with acrylic and nylon, a 2017 study showed that polyester sheds the greatest amount of microplastic fibers. Washing 6kg (13.2lbs) of material could shed 700,000 fibers. Extrapolate this to countless washes throughout a piece’s lifetime coupled with the large share of manmade fibers in the textile industry (as seen in the figure) and one can begin to imagine the constant flow of pollutants into systems that support all life on Earth.
Many studies exist demonstrating the potential harm that microplastics carry into marine and terrestrial life as well as ecosystems as a whole. Polyester is a versatile and useful material—however, it pays to keep a cognitive eye towards the impacts that the products we consume have at all stages of its lifecycle.
How do we combat synthetic textiles’ negative impacts on the planet?
Carney Almroth, Bethanie M et al. “Quantifying shedding of synthetic fibers from textiles; a source of microplastics released into the environment.” Environmental science and pollution research international vol. 25,2 (2018): 1191-1199. doi:10.1007/s11356-017-0528-7
Freitas, Alexandra et al. Water Footprint Assessment Of Polyester And Viscose And Comparison To Cotton. Water Footprint Network, 2017, https://waterfootprint.org/media/downloads/WFA_Polyester_and__Viscose_2017.pdf. Accessed 30 July 2020.
Muthu S.S., Rathinamoorthy R. (2021) Sustainability and Fashion. In: Bacterial Cellulose. Sustainable Textiles: Production, Processing, Manufacturing & Chemistry. Springer, Singapore. https://doi.org/10.1007/978-981-15-9581-3_1
Palacios-Mateo, C., van der Meer, Y. & Seide, G. Analysis of the polyester clothing value chain to identify key intervention points for sustainability. Environ Sci Eur 33, 2 (2021). https://doi.org/10.1186/s12302-020-00447-x