The end of rPET illusions
For years, the push towards recycled polyester, primarily derived from PET bottles (about 99 per cent), has been the poster child for the fashion industry’s sustainability shift. But what if this approach is more illusion than solution? Fibre2Fashion speaks to Dr. Gray Li, the materials scientist behind Celys, to talk about the real problems in today’s recycling narrative and why compostability and chemical textile-to-textile recycling must define the next generation of synthetics.
What is the problem with the industry’s obsession with recycled polyester?
The issue is simple: most of what is called ‘sustainable’ polyester is not solving the core problem. rPET today is almost entirely made from recycled PET bottles, not old garments. That is not circularity. That is supply diversion. And it is about to hit a wall.
Firstly, PET bottles are part of a food-grade recycling system that regulators increasingly want to keep closed. The more the textile industry depends on that feedstock, the more unsustainable it becomes. Secondly, mechanical recycling—the dominant process—downcycles fibre quality. You cannot keep recycling it indefinitely. So, you end up with lower-grade output, and not new, high-performance textiles as desired.
And third, even ‘recycled’ synthetics still behave like conventional polyester: they persist in landfills, shed microplastics, and require high heat and energy to process. If that is sustainability, we need to redefine the word.
So, what should we be aiming for instead?
We need to flip the conversation. Currently, everyone is obsessed with recyclability, but very few discuss where products actually end up. The global reality is that the vast majority of garments do not get recycled—they end up in landfills, incineration, or worse, are released into the environment.
That is why we designed Celys to be ‘compostable first, recyclable second’. Compostability is the most honest solution for today’s global waste infrastructure. Celys biodegrades 95.27 per cent within 179 days under industrial composting conditions (ASTM D6400), leaving no microplastics behind. If it ends up in a landfill or the environment—which is still the most likely outcome for most apparel—it does not stay there for centuries.
But beyond that, we have also engineered Celys for future textile-to-textile chemical recycling. It can be depolymerised and re-synthesised into virgin-quality fibre. That is the true circularity we should be aiming for, not just reusing someone else’s drink bottle.
But the infrastructure for chemical recycling is not fully there yet, is it?
Not yet—and we are upfront about that. Most investment has gone into mechanical recycling, which is why it is scaled. But mechanical recycling is not a long-term solution for synthetics. Chemical recycling is the only route that preserves performance and fibre quality.
Celys is built for that future, but it also delivers real sustainability benefits now. It dyes at lower temperatures (around 100°C), uses 20–25 per cent less energy during processing, and works with current manufacturing setups. So, brands do not have to wait for some distant infrastructure revolution. They can make progress today.
What about quality? Does compostability come with trade-offs in performance?
Not with Celys. We engineered it to deliver what brands and consumers expect, without compromise.
- It is softer than PET, with a cotton-like hand feel ideal for next-to-skin applications.
- It absorbs 4× more moisture than standard polyester and wicks it away quickly, thanks to its inherent hydrophilicity, keeping the wearer cooler and drier.
- And its durability has been tuned to reduce pilling without impacting longevity.
So, no, compostability does not mean you have to give up performance. In our view, it is the next evolution of performance.
Beyond Celys, what other initiatives is Intimiti Australia undertaking to promote sustainability in the textile industry?
Yes, we are not stopping at the fibre. We recently launched the Intimiti Sustainability Academy (ISA)—a knowledge-sharing and collaboration platform for brands, mills, and innovators committed to genuine sustainability. Because this is not something any single player can solve in isolation. We need to build a more transparent, technically sound, and honest path forward together.
What key message would you like to leave with the industry about Celys and the future of sustainability?
That recycled is not always sustainable. That ‘recyclable’ does not mean circular. And that if we want to solve the problem of textile waste, we need to start at the end, not the beginning.
Celys is not just a fibre. It is a platform built for the real world we live in—and the circular future we are trying to develop.
