Optimizing Mechanical Recycling of Plastics

BASF, Endress+Hauser, TechnoCompound, the University of Bayreuth, and the Friedrich Schiller University Jena (Ulrich S. Schubert, Thomas Bocklitz) have teamed up to study how the mechanical recycling of plastics can be improved. The total project volume is €2.2 million, with two-thirds financed by the German Federal Ministry of Education and Research (BMBF) funds from its quantum systems research program and one-third financed by the project partners. The SpecReK (Spectroscopic Investigation of the Recycling of Plastics) project aims to reliably and precisely identify the composition of plastic waste during the recycling process and thus improve the quality of recycled plastics. This will be achieved by combining state-of-the-art measuring techniques with artificial intelligence (AI).

The researchers are using spectroscopic methods to analyze how recycled plastics interact with light, revealing their chemical structure. The project partners want to use this data to determine in real time during processing which plastic grades, additives, and contaminants are contained in the material. In a subsequent step, an AI algorithm will recognize patterns in the measurement data and recommend which additional components should be added or how the recycling process should be adapted to improve the quality of the recycled plastic output.

At present, most of the plastic waste that is sent for recycling is mechanically recycled. The waste is collected, sorted, crushed, cleaned, and then melted. Depending on the input material and the degree of sorting, this melted material can contain different types of plastics, additives, and contaminants. Therefore, the quality of the recycled output often varies and is not always sufficient to be transformed back into high-value plastic products. When mechanical recycling is technologically unfeasibl or too comlex, plastics can be recycled chemically. Both methods are important and complementary for a circular economy.