For all the talk of sustainable fashion, the truth hiding in most of our wardrobes is awkward: the average t-shirt is a chemistry problem. Mix cotton with polyester — as the vast majority of modern clothing does — and you create a fabric that almost no recycler can handle. The two fibres get in each other's way, and the garment ends up in landfill or, at best, shredded into something less useful than it started as.
That long-standing roadblock may have just shifted. Researchers at Dutch chemistry company Avantium and the University of Amsterdam have developed a chemical process that cleanly separates cotton from polyester in blended textiles, recovering both in a form that can be used to make new materials. Their work, published in Nature Communications and highlighted this week in a global review of the year's most significant scientific breakthroughs, could be the missing piece in genuinely circular clothing recycling.
Why blended fabrics have defeated recyclers
The world now produces around 132 million tonnes of textile fibre a year — more than double the figure from 25 years ago — yet only about 8% of fibres in the clothing supply chain come from recycled sources. The single biggest reason is blends. Pure cotton can be mechanically shredded and respun. Pure polyester can be chemically broken down and remade. But put the two together and existing technologies stall: cotton fibres clog polyester recycling streams, and polyester contaminates cotton ones.
Since most clothing — your jeans, your school uniforms, the hotel sheets, the office shirts — is some flavour of poly-cotton, that limitation has effectively kept circular fashion stuck at the prototype stage.
What the new process actually does
The Avantium–UvA team's approach is, in plain English, a controlled bath. Mixed-fabric waste is steeped in highly concentrated hydrochloric acid (around 43% by weight) at room temperature. The acid dissolves the cotton — which is essentially cellulose, a long chain of sugar molecules — breaking it down into glucose, a simple sugar. The polyester, which doesn't react with the acid in the same way, is left behind as a solid that can be filtered out and recycled separately.
So far the process has hit a 75% recovery rate for cotton (as glucose) and 78% for polyester building blocks. The cotton-derived glucose isn't waste either: it can be fed into industrial processes to make new bio-based plastics, resins and solvents — including, conveniently, Avantium's own next-generation plant-based polymers.
The work has been honed at Avantium's Dawn Technology pilot plant in Delfzijl, in the north of the Netherlands, where PhD students from Amsterdam's Industrial Sustainable Chemistry group have been on secondment. In April the project picked up an innovation award for its potential to scale.
How close is it to your high street?
Honestly? Closer than the usual lab announcement, but not yet on your receipt. A demonstration plant — the step between pilot and full commercial operation — is being built this year. Avantium is targeting commercial-scale operations of around 100,000 tonnes a year by the end of the decade. That is a meaningful volume, but it is still a fraction of global textile waste, and the economics will depend on a willing supply chain.
Regulation may help that along. Since January 2025, the Netherlands has required fashion brands to pay for the processing of the textile waste they create — a policy known as Extended Producer Responsibility. Similar rules are advancing in several US states and across the EU. Suddenly, paying a recycler to convert old garments into virgin-quality feedstock looks less like a PR exercise and more like the cheaper option.
What it could mean for shoppers
For anyone who has ever stood over a clothes bin wondering whether their worn-out hoodie is doing any good at all, the honest answer until now has been: probably not much. If technologies like this one reach commercial scale, that calculation changes. Mixed-fabric clothing could be fed back into the system rather than buried, and brands would have a credible route to making new garments from old ones — not as a marketing flourish, but as standard practice.
It is not a silver bullet. We will still, collectively, need to buy less and keep clothes longer. But for the first time in a long time, the chemistry is on the side of the wardrobe.
