Interview with Professor Sonja Herres-Pawlis


Bioplastics are too valuable to be used only once.

  Professor Sonja Herres-Pawlis Copyright: © Peter Winandy Professor Sonja Herres-Pawlis

The Center for Circular Economy at RWTH Aachen University, or CCE for short, serves as a holistic platform for gathering the expertise of currently 15 institutes in the field of materials recycling and thus creating the exchange of information that is necessary.

The common goal is to develop innovative solutions that enable sustainable future business models. Specifically, waste is to be minimized, the respective value of circulating materials is to be increased, and society is to be convinced of the need for a sustainable circular economy. The Chair of Bioinorganic Chemistry is involved in the project. We talked to Professor Sonja Herres-Pawlis, who holds the chair.


Please describe what your chair is investigating here.

At my chair, we have been developing non-toxic, robust catalysts for the production of bioplastics for 15 years. In the beginning, they were rather slow, but now they are significantly faster than the industrial, toxic tin-based system. Our bioplastics come from renewable resources and are biodegradable. Meanwhile, we have also found ways to recycle them, as they are too valuable to simply throw away.

A world entirely without plastics - is that conceivable in the future, or does it even make sense? After all, they are used in numerous areas of application and bring with them various advantages. If only there were not the large amount of plastic waste...

We don't need a world without plastics; we just need to design packaging so that it is completely recyclable. Some of the conventional plastics should be replaced with biodegradable plastics that can be broken down in the environment if needs be, but can be recycled just as easily if collected properly. There is simply still a lot of small-scale packaging that unintentionally ends up in the environment. But in many areas (medicine, for example), it is impossible to do without plastics for hygienic reasons.

If plastics could be brought more efficiently into a sustainable circular economy, the use of resources could be minimized and the recycling rate increased at the same time. What new recycling strategies are there for this?

Chemical and biological recycling opens up completely new possibilities for breaking down used plastics back into their monomers, which are used to produce absolutely new plastics. Efficient recycling of plastic mixtures, which have tended to be downcycled up to now, is thus also coming within realistic reach. In addition, there are also new processes for producing solvents from used plastics, for example, so the used plastic becomes a valuable material.

You said, "Bioplastics are too valuable to be used only once. Recycling must be carried out in all areas of plastics use." Please explain what makes bioplastics so valuable.

They come from renewable raw materials, have great material properties and they are too good to just be burned or composted after a single use. Circulating the bioplastics several times reduces their environmental footprint. Until now, one criticism has been that bioplastics production competes with biodiesel or food production. This is no longer the case.

Your chair is working on the development of better catalysts for the production of bioplastics. What is the current state of research here?

Our catalysts are significantly faster than industrial catalysts, but they are still quite costly to produce. In scale-up tests, we now want to work our way from the gram scale to the kilogram scale, so that our catalysts will actually be used on a large scale in a few years.

The interview was conducted by Nives Sunara.