Heidelberg chemist wins Karl Freudenberg Prize for recycling innovation!

Heidelberg chemist wins Karl Freudenberg Prize for recycling innovation!

On May 25, 2025, the renowned Karl Freudenberg Prize was awarded by the Heidelberg Academy of Sciences (HAdW) to the chemist Maximilian Baur. This honor recognizes his dissertation on the production of sustainable polyethylene at the University of Konstanz. Baur was honored for his innovative research, which deals with the targeted creation of predetermined breaking points in polymer chains without compromising the material properties.

The main goal of this work is to improve the recyclability of polyethylene materials. Baur explained that he integrated keto groups into polyethylene, which are broken down by UV radiation to create targeted breaking points. This could make a decisive contribution to reducing plastic waste.

Innovative approaches to sustainable plastics

To achieve the desired properties, Baur used neutral nickel catalysts with [P,O]-phosphinophenolate ligands. These methods led to the production of high molecular weight keto-modified polyethylenes known as keto-PE. The results are promising: These materials retain the properties of conventional polyethylene and are at the same time degradable under UV radiation.

The research was carried out as part of the ERC Advanced Grant-funded project “DEEPCAT: Degradable Polyolefin Materials Enabled by Catalytic Methods” under the leadership of Stefan Mecking. Maxmiliam Baur, who completed his doctorate in June 2024, is now leading a postdoctoral position at the University of California Santa Barbara, where he is working on heterogeneous catalysis for plastic upcycling.

The Karl Freudenberg Prize, which has been awarded annually since 1986 and is endowed with 10,000 euros, honors outstanding scientific work in the natural sciences, particularly in chemistry and biology. This award underlines the importance of Baur's research in an area that is becoming increasingly relevant.

Challenges of recycling polyethylene

In the context of recycling technologies, polyethylene (PE) and polypropylene (PP) play a central role as they are the most commonly used plastics worldwide. Scientists have recently developed a new process for recycling polyethylene that converts polyethylene into propylene. This propylene can be used as a raw material to produce polypropylene, which is more versatile and easier to recycle.

Polyethylene accounts for about a third of global plastic production, but only about 14 percent of it is recycled. Current recycling often results in inferior polymer blends, with the inertness of polyethylene posing a significant obstacle. A research team led by John Hartwig of the University of California at Berkeley has found an innovative solution that could significantly increase the efficiency of recycling.

This method involves splitting hydrogen atoms using special catalysts, creating carbon double bonds that increase reactivity. In laboratory tests, the team was able to convert over 80 percent of polyethylene into propylene, which could potentially reduce the need for shale gas for polypropylene production.

Although these processes are still a long way from commercial use, researchers are optimistic. The methods are compatible with existing industrial reactions and could make a decisive contribution to reducing plastic waste. Given the challenges of waste management, the efficiency and scalability of these new processes are crucial.

Developments in the field of chemical recycling of polyethylene and polypropylene show that research in this area is making promising progress that could permanently change the future use of plastics. The synergy of innovations from scientists like Maximilian Baur could play a key role.