News

11/16/2020

Recycling of polymers - new solutions for more efficiency

Two new projects at the Department of Polymer Engineering and Science at the Montanuniversität Leoben and the Polymer Competence Center Leoben (PCCL) explore new sorting technologies for polymers with a common goal: to increase recycling rates. The projects are funded by Zukunftsfonds Steiermark.

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The Department of Polymer Engineering and Science and the Polymer Competence Center Leoben have been researching innovative technologies for recycling polymers for years. With the two projects Plastic STRAW - Smart Technology for Recycling of Assorted Plastic Waste and Multilayer-Detection- Identification of Multilayer Films in Plastic Sorting to increase the recycling of packaging film waste, a hot topic is moving into focus: The sorting and separation of plastic waste in recycling plants. Composite materials such as multilayer films for packaging cannot be separated in a targeted manner, therefore they get usually down-cycled and thus disappear from the materials cycle.

 

Bild von Francis Ray auf Pixabay

In order to achieve the environmental policy goals set throughout the EU, a leap in innovation is needed in the coming years. Polymer Engineering and Science Leoben has been researching new approaches to polymer recycling for years.

 

The Plastic STRAW project aims to develop a new type of sorting process to separate waste that is difficult or impossible to sort. The innovative feature of the process is that the material flows are separated in the molten state. In addition to the separation of the polymer fractions, contaminants are also removed. In the course of the two-year project, a prototype is to be developed that can be connected to any conventional extrusion or compounding line. In a rotating pipe the mixed polymers are melted, the idea is that higher-density melt migrates to the pipe wall, while low-density melt and impurities remain in the middle of the pipe. The different fractions can thus be easily separated and further processed. In addition, the Institute of Fluid Mechanics and Heat Transfer at Graz University of Technology, who is a project partner, carries out detailed analyses of the all the process parameters (residence time, melt mixing, pipe speed, temperature control, etc.) to estimate the required dimensions and operating conditions.

The project Multilayer-Detection is dealing with a similar problem: the separation of small-sized films from plastic packaging from the remaining waste. The different polymer layers are an impurity which reduces the quality of the material. In the project, sensor technologies are to be developed and tested with which multilayer films can be detected and sorted in a more targeted manner. The so-called near-infrared spectroscopy - NIRS - will be used, a physical analysis technique that uses short-wave infrared light to generate molecular vibrations. Different materials generate different vibrations, which can be detected and assigned to a material. This should make it possible to distinguish more clearly between recyclable and non-recyclable materials, which ultimately means higher material quality.

 

Further information:

Plastic STRAW
Funding: Zukunftsfonds Steiermark, 13. call - 2020, Green Tech 100 - 1 Earth, 0 Carbon, 0 Waste
Runtime: 2 years
Project partners: Montanuniversität Leoben, Institute of Materials Science and Testing of Polymers, Graz University of Technology, Institute of Fluid Mechanics and Heat Transfer

Multilayer-Detection
Funding:  Zukunftsfonds Steiermark, 13. call - 2020, Green Tech 100 - 1 Earth, 0 Carbon, 0 Waste
Runtime: 2 years
Project partners: Polymer Competence Center Leoben GmbH, Montanuniversität Leoben, Chair of Waste Processing Technology and Waste Management