Global economy will triple by 2060 and this will drive the use of plastics. According to a OECD study “Global Plastics Outlook 2060” (2022), plastics use reached 460 Million tonnes (Mt) in 2019, and projections based on population growth trends and higher incomes in emerging economies will lead to 1231 Mt in 2060. Consequence of this is the generation of 353 million tons of plastic waste, that are projected to triple up to 1014 Mt in 2060. Plastic waste represents nowadays a big problem, but it can turn into a valuable resource if shared objectives and coordinated efforts to reduce plastics pollution at global level will be implemented. These could drastically reduce the projections of plastic use and waste for 2060 by more than 30% (global ambition policy scenario 2060), if all relevant phases of the plastics lifecycle are targeted.
In this article we will discuss some of the key plastics lifecycle steps, with particular emphasis on plastics recycling, their existing different types (e.g. mechanical recycling or chemical recycling) and the limits and opportunities of them. Good news is that 29 Mt of plastics use was satisfied by plastics recycling on the base year 2019, but this is still too low proportion, compared to the higher 431 Mt contribution of primary plastics. Projections of plastics recycling in 2060 without coordinated global and regional action could reach 143 Mt (5 times the 29 Mt of 2019), counting for a plastics lifecycle that would only be 14% circular in 2060 (=143 Mt out of 1014 Mt of plastic waste).
Mechanical recycling represented nearly the entirety of the 29 Mt figure, as it was the only commercially mature processing infrastructure at scale in 2019. Chemical recycling on the other hand was in early and unquantified pilot stages. Mechanically recycling has a low environmental impact and an established infrastructure that must grow further, but there are some relevant limitations. The first limitation of mechanical recycling depends on the quality and purity of the waste input, visible when we compare the 29 Mt with the 55 Mt volume of plastics that was collected for recycling in 2019. This means that 22 Mt of plastic residues could not be mechanically recycled due to the materials composition or to the high level of degradation, mix and contamination. In addition, there were additional 4 Mt of process losses to be considered. The content of fillers (e.g. glass fibers) or of other component materials alone (e.g. multi materials) are very difficult to separate. In addition, the degradation of the polymer itself (e.g. molecular weight reduction, increase of monomer content depending on the considered polymer like BPA, formaldehyde, degraded halogen content etc..) and of the additives contained in the original formulation (e.g. flame retardants, colour pigments, UV additives, demolding agents etc..) make them not reusable and in some cases prejudicial for a second life purpose. Furthermore, waste feedstocks can come from virgin plastics that were already containing dangerous or restricted substances intentionally included (IAS: Intentionally Added Substances) to comply with their first life application purpose (e.g. FR materials with halogen content, Chlorinated organic compounds, etc..). Last but not least, there is the important issue of the Not Intentionally Added Substances (NIAS), that not only refer to the production of the plastic when it was a prime material, but also to the NIAS that will have migrated into the materials during the first application use, and after the end of life of the application, during the status of mixed waste plastics and during the recycling process itself. The study “Chemical content validation of recycled plastics” (OECD, 2026) quantifies in 13.000 the number of chemicals contained in virgin plastics alone, summing up IAS and NIAS substances. Several of them are chemicals of concern that can persist, migrate and accumulate in plastic waste, increasing environment and human health concerns. All these points set a second limitation of mechanically recycled plastics, which is related to the possible uses in existing applications: these are more restricted than prime plastics, as consequence of different reasons, like wider tolerances of material properties, lower batch stability or lower colour properties.
