Chemical Recycling Opens a New Path for Circular PEX Pipes

Announced in February 2023, a Borealis, Neste, and Uponor pilot shows how chemical recycling could give PEX waste a second life

6 Feb 2026

Chemical recycling is emerging as a possible solution to one of the construction sector’s more persistent waste problems: how to reuse cross-linked polyethylene, or PEX, once it reaches the end of its life.

PEX is widely used in plumbing and heating systems because of its durability and flexibility. Those same qualities, created through cross-linking during production, make it difficult to recycle mechanically. As a result, most PEX waste has historically been incinerated or sent to landfill, despite growing policy and industry pressure to reduce plastic waste and promote circular production.

In February 2023, Borealis, Neste and Uponor announced a joint proof of concept aimed at changing that outcome. The companies said they had demonstrated that chemical recycling could convert PEX waste into a feedstock suitable for producing new polyethylene pipes.

Unlike mechanical recycling, which relies on melting and reshaping plastic, chemical recycling breaks polymers down into their basic components. These can then be refined and reused to produce new material with properties comparable to virgin polyethylene, according to the companies involved.

Borealis said its work focused on confirming that chemically recycled feedstock can meet the strict performance and safety standards required for construction and infrastructure uses. Pipes used for drinking water and heating systems are expected to perform reliably for decades, leaving limited tolerance for changes in material quality.

Uponor, a major manufacturer of PEX pipes, said products made using the recycled material performed in line with conventional pipes. This would allow installers and end users to use existing designs and installation practices without modification.

Neste’s role has been to process recycled inputs into a consistent raw material for polymer production. The company has said that while the technical feasibility has been shown, large-scale industrial deployment is still under development.

The approach faces hurdles. Chemical recycling is energy intensive and requires significant investment, and its environmental benefits depend on process efficiency and access to low-carbon energy. Costs also remain higher than for conventional plastic production.

Even so, the collaboration marks an early step towards reintroducing PEX waste into the value chain. It suggests that materials long considered unrecyclable could play a role in more circular models for durable plastics, if the process can be scaled economically.