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PolyUrethane Recycling towards a Smart Circular Economy

Periodic Reporting for period 3 - PUReSmart (PolyUrethane Recycling towards a Smart Circular Economy)

Reporting period: 2022-01-01 to 2022-12-31

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 (CAPUs) 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 PU families will be chemically broken by a chemolysis process to recover the basic raw materials. The final aim of PUReSmart 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 had through the whole trajectory the dynamics we are experiencing from the beginning; a good understanding and cooperation between the partners combined with utmost dedication, which lead to increasing results.
The development of new comonomers to obtain CAPUs has been moving forward via 2 parallel routes. The traditional TAD/indole based CAPUs, which were not performing in foaming, have in the last period been modified to be more compatible with standard flexible foam raw materials and are now showing promising foaming and foam properties. The alternative route on thiourethanes has progressed as well allowing to get good flexible foam and both routes are scalable in terms of synthesis quantities. The limitation still relies in the balance between foam properties and recyclability and in the final price of synthesis for the TAD-based compounds.
The work regarding the development of innovative sorting methods proved that NIR sensor is suitable for discrimination of PU types and enables sorting of EOL foams.
The smart chemolysis work is evaluated as very positively. Due to the good technical results of the chemolysis in yield and purity, for the first time in the PU flexible foam recycling, we are able to combine both recycled polyol (up to 100% replacement of virgin polyol) and recycled isocyanate (up to 100% replacement of the virgin TDI) and the resulting PU foam satisfies the needed comfort foam properties. Enabling the use of recycled polyol and recycled TDI in the same applications as virgin materials.
The finished environmental life cycle assessment study of the PUReSmart scenario shows a positive impact on climate change. The results in particular highlight the relevance of the sorting and dismantling phase of the EoL management system and the importance of implementing the collection of mattresses and the recovery of materials other than PU, i.e. textiles. The social material topics for the PUReSmart system are finalised. This social life cycle assessment gave insight on the social risks and benefits by implementation of PUReSmart: no negative effects were mentioned, and overall the positive effects dominated the analysis., Exploring the barriers for scale up (TIS analysis) of PUReSmart revealed that a fundamental shift in market demand/legislation is expected making this an opportunity for closing the loop.
The PUReSmart project was highlighted by all partners with good press coverage in various media, participation to web conferences and an active presence on the social media including our own website. A third newsletter has been disseminated, a final workshop has been organized successfully and four MOOCs have been released.
Thanks to the fluent and professional cooperation between all partners, the progress is considerable. In all WPs, breakthrough steps are made. This will move the whole project far beyond the state-of-the-art of PU sorting, efficient chemical recycling. This is also proven by the 4 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.
PUReSmart worked on a process with complete recovery of not only the polyol, but also of the isocyanate precursors (amines), which leaded to the first recycled isocyanates in the world, and to the first time polyurethane foams, with the needed properties, made out of 100% recycled polyol and 100% recycled isocyanate.
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 polyurethane foams for the same applications. 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