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PolyUrethane Recycling towards a Smart Circular Economy

Periodic Reporting for period 2 - PUReSmart (PolyUrethane Recycling towards a Smart Circular Economy)

Reporting period: 2020-07-01 to 2021-12-31

Thermoset PU is well-known for its outstanding properties such as high resilience, excellent resistance to wear and long useful lifetime combined with the inherent great tunability of the PU chemistry.
Recycling of thermosetting PU is not possible by heating and reprocessing in a liquid form. Some recycling solutions exist but they poorly address the issue of the huge waste streams generated by the disposal of end-of-life products of the fast-growing PU industry.
The ambition of the PUReSmart project is to develop new concepts to reshape the value chain into a closed loop. The consortium focuses on the development of a new PU chemistry with thermoset properties under its life conditions to be recycled when applying different conditions. PUReSmart will develop Covalently Adaptable Polyurethanes (CAPU’s) based on fast reversible chemical bonds that enable the creation of cross-linked polymer networks reversible under certain conditions. The consortium aims to develop a new reprocessing technology targeting to recycle polymer foams back to foams. PUReSmart also aims at treating current PU materials. First, the partners work on the sorting of EoL PU based materials to recover the raw materials (or their precursors) used to produce these products. Therefore, detection methods will be developed to characterize and distinguish different PU foams and sorting methodologies to collect the different families in the purest form possible.
These sorted polyurethane families will be chemically broken by a chemolysis process to recover the basic raw materials. The final aim of the PUReSmart project is to recover the raw materials from existing PU products today on the market, and to use them to make the new generation of recyclable thermoset polyurethanes.
PUReSmart is supported by a consortium of 9 partners from 6 countries, committed to reshape the value chain of polyurethane.
The project shows good progress and all partners are cooperative and contributing to the committed actions no longer being impacted by the global outbreak of Covid-19. The smooth communication and efficient teamwork have permitted to keep up with the good progress and the impacts of this crisis are limited until now.
The development/selection of new comonomers to obtain CAPU foams is moving forward. Current work is carried out on the TAD/indole-based CAPUs and on the thiourethane-based CAPUs as an alternative route which is our current focus for the development of CAPU foams. For the TAD-based CAPUs, upscaling safety studies have been carried out at Weylchem, and the pilot scale synthesis of the main innovative TAD-based cross-linker was completed (>50kg scale), reaching TRL5. Foam trials at Recticel showed good results on their dynamic character but need improvement on foam properties. A detailed cost calculation revealed a too high cost for the TAD/indole compounds in foam applications. The alternative route on thiourethanes is showing some promising results on foam level (TRL 3-4), however until now, a compromise needs to be found between good physical properties and good reprocessing ability. Further work was performed at UCLM and KUL on foam-to-foam reprocessing methodologies for the new polymers showing first promising results (proof-of-concept, TRL3).
The work regarding the development of innovative sorting methods is continuing to make very good progress. NIR is confirmed as the best sorting technique. Classification models for flexible PU foam were finalized and successful sorting tests have been performed by RW with QC samples, aged foams, new (lab) foams and EoL proving that technology developed within this work package has reached TRL4.
The smart chemolysis work has progressed very positively. Optimization was carried out on split phase chemolysis regarding the type of polyols, yield and purification. High yields of high purity polyols were confirmed on intermediate scale and could replace 100% of virgin polyol for PU foaming. The valorisation of the lower-phase showed high yield conversion of amine to isocyanate with high quality. Construction of the pilot plant is finalized at COV.
Concerning the sustainability assessment and business case, the LCA modelling of the base scenario was finalized, for the social innovation aspects the relevant social topics for PUReSmart system were defined and the stakeholders were mapped. A value chain analysis was made in function of the business-case scenario, together with a supply and demand analysis, resulting in a model to further evaluate and refine the economic value
The PUReSmart project was highlighted by All partners by a wide press coverage in various media, participation to several web-conferences and an active presence on the social media including our own website. A second newsletter has been disseminated, a virtual workshop on “Chemical recycling and plastics” has been organized successfully and a first MOOC has been released.
In the first 3 years of the project, thanks to the fluent and professional cooperation between all partners, the progress is still considerable. In all WPs, breakthrough steps are made. This will move the whole project far beyond the state-of-the-art. This is also proven by the patent applications submitted by REDWAVE, Covestro and Recticel related to the progress made in smart sorting and smart chemolysis and the decision to scale-up the chemical recycling process from lab to semi-industrial level. The PUReSmart project is working on a process with complete recovery of not only the polyol, but also of the isocyanate precursors (amines), which can lead to the first recycled isocyanates in the world.
The impact of PUReSmart is extremely important in the treatment of End-of-Life (EoL) PU products. As today the recycling options are rather limited, the project will bring new solutions to recover valuable raw materials out of EoL materials to be re-used to make a new generation of CAPU foams. This will close the loop and create opportunities for a circular economy.
Figure 2 - Part of the project consortium at the online 18M and 24M GA meetings
Figure 1 - PUReSmart project organization