Chemical recycling helps close the loop

Mechanical recycling breaks down a material but does not alter its chemical structure – chemical recycling does.

Borealis Chemical recycling

This refers to a diverse set of technologies which use chemical processes to turn plastic waste into feedstocks from which new products can be made. These include depolymerisation, pyrolysis, and hydrothermal treatment, each technology suited to different waste streams. For example, pyrolysis mostly targets mixed waste streams of polyethylene (PE) and polypropylene (PP), breaking them down into a range of shorter-chain hydrocarbons by heating them in the absence of oxygen (‘cracking’). The hydrocarbon product can be made into a range of new petrochemical products and materials that have the same quality as products made from conventional feedstock.

Chemical recycling shows that plastics that would otherwise be challenging or uneconomic to recycle can still be recycled. It also has the advantage of not degrading the properties of the plastic in the way that mechanical recycling does. This results in very high-quality plastic that can be used for sensitive applications, as well as allowing them to be recycled multiple times.

Mechanical and chemical recycling are complementary technologies, with different advantages and drawbacks. While mechanical recycling is an already established recycling method, especially for mono-streams, chemical recycling closes the gap by addressing hard-to-recycle waste streams, and produces materials that are safe for contact-sensitive applications. In 2022, total chemical recycling capacities for all plastics amounted to just 100,000 tonnes – although this is expected to increase to 1.2 million tonnes by 2025.

Plastics of the future will have many past lives