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The Road to Molecular Circularity of Polyurethane: Quality Control on Steroids

At the latest EUROPUR conference in Antwerp, Prof. Pieter Billen was invited to speak about polyurethane recycling. The main message of his talk was: let's use circularity as a pretext to deeply understand polyurethane chemistry, and from there design comfortable, durable, desirable, AND sustainable materials.

The main takeaways are:

1. We can make a business case for polyol tagging, allowing tracing and circularity even for complex formulations. (Jonas Cassimon)
   
2. We are going to model polyurethane, ensuring consolidated knowledge on physical chemistry and polymer engineering, together with leading experts from Universiteit Gent (Dagmar D'Hooge and Paul Van Steenberge), Vrije Universiteit Brussel (Frank De Proft and Guy Van Assche), and Rijksuniversiteit Groningen (Remco Havenith). With support of these partners: Ana Cunha, Joost Brancart, Attila Kovacs, and others.
3. We need to talk about circular isocyanates. We can make them from waste, the technology is feasible and seems economic. Support our , whereby the academic consortium consists of iPRACS (Pieter Billen, Christophe Vande Velde and Yoshi Marien), together with Universiteit Gent (Yi Ouyang) and Vrije Universiteit Brussel (Joost Brancart and Guy Van Assche).

Do not hesitate to reach out to Elke Theeuwes for more information. 

A special thanks to the organizers and the audience for fruitful interactions during the conference and FWO for providing the opportunity to do this research. 

Together with  an event was held to shed light on how we can kick-start chemical recycling plastic opportunities in Tunsia. To explore this topic in more depth lectures were given, as well as introductions and a panel discussion (including experts of the European Commission, University of Hasselt, Arab-Belgian-Luxembourgh Chamber of Commerce and University of Mons). 

During this event we had the opportunity to celebrate and create a basis of understanding for a new collaboration between iPRACS and the University of Sfax on the doctoral research of Makram Elabed, who received a Fonds Bruyns scholarship from UCSIA.

How do you measure how 'recycleable' a polymer is - before you've made it?

​Attila Kovács presented at the Brightland Polymer Days 2026, tackling exactly this question. 

Polymers gain performance from structural diversity - but the same diversity makes recycling harder and more energy-intensive. Current descriptors like dispersity simply do not capture this well enough to guide circular design. 

At iPRACS we propose to apply Statistical Entropy Analysis (SEA), rooted in Shannon's information theory, at the molecular level of polymers. Hereby applying a four-level model: chain length -> topology -> graft length -> monomer identity. 

Using kinetic Monte Carlo simulations of polybutadiene/styrene grafting, we showed that molecular entropy:

• Tracks complexity monotonically with conversion, where dispersity fails.
  
• Captures multimodel distributions that single-number metrics miss.
• Quantifies the complexity penalty of blending mixed polymer feedstocks.

The vision: a metric that links molecular design choices to recyclability from the earliest stages of synthesis.

Next-generation rubber recycling process using ozone

At the ETRA conference 2026 (European Tyre Recycling Association), Elke Theeuwes presented an update on the tyre recycling research performed at iPRACS by Yanou Fishel and Prof. Christophe Vande Velde. 

​During the lifetime of tyres, degradation by ozone must be avoided. However, at end-of-life, an ozone treatment can be beneficial as a recycling technique in order to obtain chemical platform molecules, oxidized carbon black, and a gaseous stream. It is a fully electrified process, thereby creating opportunities in the circular economy after successful upscaling. This ozonolysis technology could become the next-generation recycling technology after pyrolysis.

The NCO cycle: a two-step complete recycling process for polyurethanes

Marthe Nees defended successfully her PhD thesis, whereby she demonstrated an elegant approach to circularity. In order to recover isocyanates from polyurethante waste, she used a two-step apporoach consisting of:

1. Polyurethane alcoholysis to recover polyols
   
2. The remaining carbamates are thermolysed into isocyanates

Congratulations on this achievement!

Water polluted with PFAS and air with far too much COâ‚‚. Two serious problems for which one type of substance could well be the answer: MOFs. In 2025, their discoverers won the Nobel Prize for Chemistry for this. And rightly so, according to chemist Prof. Dr. Christophe Vande Velde. He also enjoys tinkering with them at the University of Antwerp and joyfully announces the MOF era in this !

​Pieter Billen explains in how we should keep demanding more sustainable packaging materials, yet not be unrealistic about the timing, and certainly be careful when replacing plastics with other materials. (Knack)​

​Pieter Billen explains in Knack how we should keep demanding more sustainable packaging materials, yet not be unrealistic about the timing, and certainly be careful when replacing plastics with other materials. Industry is working hard on new recycling technologies, driven by upcoming legislation. We at iPRACS are doing our share to contribute to this effort. (article in Dutch)