Chair of Waste Processing Technology and Waste Management // Montanuniversitaet Leoben


Project long title

Improving the quality of recycled polymer waste


Project description

Improving the Circular Economy and sustainable use of materials and resources has become a major issue during the recent years. Especially the plastics industry has to focus on challenging topics along the entire life-cycle, such as reuse, recyclability, biodegradability, hazardous substances and concerns in marine litter. A major technical challenge in the industry segment has been identified by the high variation in the quality of recycled polymers. E.g., commercially available recycled “clean” PE‑HD pipe grades are based on mixtures of polyethylene grades for different applications (cast film, blow moulding, injection moulding, extrusion) or even contain fractions of polypropylene (PP). In a preceding PCCL project (VI-3.07) it was shown that the lifetime-relevant material properties such as slow crack growth resistance are significantly reduced by, e.g., only a few percent of blow moulding grade. Also, only minimum fractions (<5%) of PP incorporations result in a severe drop in slow crack growth resistance. For the time being, no specifications for the quality of polymer recyclates have been defined. The quality of the recycled polymers highly depends on the respective composition of current post-consumer resources, which is continuously changing. Additional sorting steps of state-of-the-art presorted polymer recyclates will allow for an improvement of the quality and consistency of such materials.


Project duration

01.05.2021 – 31.12.2024


Aims of the project

The project aims at the development of new sorting strategies in the mechanical recycling of post-consumer polymers to achieve recyclate qualities of better, more reproducible and less variable quality. Hence, the main objective of this project is to establish non-destructive characterization methods in order to obtain information about material composition, chemical and physical structure, the presence of additives, and the state of aging. For this purpose, multivariate data analysis in combination with modern methods of big data processing and automated decision by artificial intelligence (AI) will be applied. Additionally, possibilities for the use of fillers and dedicated additives to improve the uniformity and quality of recycled materials will be assessed.

Although these methods shall be applicable for all types of polymers inside existing recycling streams, the focus of this project will initially be limited to PE, PP and PVC.

In contrast to many other polymers, a specific characteristic of PE and - to some extent - also for PP is its high diversity based on tailored variations in the molecular and morphological structure, which results in a high variety of applications, ranging from flexible packaging to structural applications. Whilst in current recycling processes a material sorting into base polymers is well established, a further differentiation of sorted PE and PP into their different variations is not done, except from density in some cases. Based on the state-of-the-art in mechanical material recycling, the new methods developed in this project will allow for improving the degree of material sorting, based on the chemical and physical structure of the post-consumer polymer waste. Regarding PE a further separation by density, branching or molar mass distribution would be desirable. For PP the detection of structural properties like tacticity or the differentiation between homo- and copolymer are aimed at. Additional features are the recognition and separation of mineral fillers, black, printed or aged material as well as materials containing additives and fillers that are not compliant with European Guidelines on Restriction of Hazardous Substances (e.g., 2011/65/EU; RoHS 2)). A special case is the correct identification of PVC and its fillers.


Work packages, deliverables & milestones

The project PCCL-K1 consists of five work packages with several deliverables and milestones (see the figure below).

Projektbeschreibung Pccl-k1 Deutsch English



Ffg Logo The Austrian Research Promotion Agency (FFG)


Project partner

Budapest University Logo Budapest University of Technology and Economics

Pccl Logo Polymer Competence Center Leoben GmbH - PCCL

Poloplast Logo Poloplast GmbH & Co KG

Prezero Logo PreZero Polymers Austria GmbH

Redwave LogoREDWAVE, a division of BT-Wolfgang Binder GmbH



You can send a message directly to the project responsible Mister Dipl.-Ing. Karl Friedrich by using the following form.

Karl Friedrich

Karl Friedrich

Scientific staff

Phone: +43 3842 / 402-5139
Cell: +43 664 / 51 57 57 0
Fax: +43 3842 / 402-5102
E-mail: karl.friedrich@unileoben.ac.at


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