The SpectralAIge research project focuses on developing a new measurement method for assessing the degree of ageing in recycled plastics. The aim is to create a reliable tool that will make it possible to determine material degradation and thus better assess its suitability for further processing. This is important for mechanical recycling, where repeated circulation of material within the loop leads to changes in plastic properties. With successive processing cycles, ageing and degradation may occur, making it more difficult to manufacture new products from recyclates and affecting their quality. As stated in the project description, there is currently no industry-ready method that would enable a reliable assessment of the degradation state of plastic waste and recycled materials. A decline in quality over multiple recycling cycles is observed, but it still cannot be predicted reliably.
The project involves four entities: SKZ Plastics Centre in Würzburg, the Fraunhofer Institute for Factory Operation and Automation IFF in Magdeburg, Silicann Systems GmbH from Rostock and HAIP Solutions GmbH from Hanover. The partners are jointly developing a method intended to support a sustainable circular economy through more accurate assessment of the ageing of secondary materials.
Combining spectroscopy and data analysis
The premise of the SpectralAIge project is to combine modern spectroscopic methods with advanced data analysis. This approach is intended to enable users to make a more informed assessment of the ageing of recyclates. The work uses hyperspectral imaging, HSI, systems supplemented with LED light sources for targeted fluorescence excitation. This makes it possible to record the fluorescence spectra of aged samples of common plastics such as PE, PP and PET.
Based on the measurement data obtained, chemometric models used in polymer analysis are being developed. In parallel, various artificial intelligence approaches are being tested and then systematically compared in terms of effectiveness.
From research to industrial application
The most effective modelling approach is to be translated into a software solution enabling automated determination of process-induced ageing. At the same time, the project partners point to cost issues. HSI technology provides high performance, but it is also expensive, which is why lower-cost inverse spectrometers are being developed as a complementary solution.
These devices are intended to be designed for specific applications with a limited scope. The assessment of PET in the returnable bottle loop was indicated as an example. This approach is intended to increase the industrial accessibility of the measurement method being developed.
Relevance for quality and circularity
As Cosima Güttler, a scientist at SKZ Plastics Centre, explains, "The findings from the project make a significant contribution to ensuring high product quality and safety within a circular economy. At the same time, in the SpectralAIge project we are also focusing on the practical, industrial application of the results."
The project runs from 1 October 2024 to 30 September 2027. Funding is provided by BMFTR under the "KMU-innovativ: Photonics and Quantum Technologies" programme. The project number is 13N17199.
