Feedstock recycling of PLA – a biobased polymer goes circular

Plastics from renewable resources like polylactide (PLA) are gaining more and more market share. With the proliferation of PLA, issues concerning the end-of-life options of PLA products gain more and more importance. One possibility, regarded as being the most favorable several years ago, is the processing of PLA in industrial composting plants.

However, this end-of-life scenario is an adequate route only in specific cases (such as bio-waste collection bags) as it runs counter to important social objectives such as the conservation of natural resources and the reduction of CO2 emissions. Therefore, it is essential to accompany the progressive introduction of PLA with an exploration and implementation of alternative recycling options, which can be effective in the context of a sustainable circular economy.

Since conventional mechanical recycling processes often involve a deterioration of the characteristic property profile of a polymeric material, chemical recycling can be an attractive alternative. In the lecture, we will put chemical recycling routes in the overall context of different possible recycling processes for PLA and we will present results concerning the simple reintegration of PLA waste into its technical synthesis process. The results reveal the feasibility of adding variable amounts of PLA waste into the dilactide producing process step without adversely affecting the process performance or the product quality.

The advantage of this feedstock recycling process compared to other chemical recycling options is that it runs on existing synthesis lines for PLA without significant extra investments. The chemical background of the recycling process and the results obtained for various possible PLA recycling streams will be highlighted. Additionally, a life cycle assessment of this recycling route will be presented.

A presentation by Daniel Maga, Group Manager at Fraunhofer Institute for Environmental, Safety, and Energy Technology UMSICHT.

Interview

Question 1: What drives you?
As global warming and plastic pollution attract more and more public attention, we see our R&D work as contribution to open new routes into more sustainable and circular ways to treat plastics. We are convinced that plastics help to make our lifes easier, safer, more comfortable and also more sustainable – in case we do not deny the associated problems but actively investigate possibilities for a real circularity of this important materials and make them available for implementation.

Question 2: Why should the delegate attend your presentation?
The presentation will highlight that a biobased polymer like PLA can contribute to circularity not only by saving fossile resources but also by being recycled by different routes, dependent on the intended application of the recycled material. There is no ideal circular path that fits all needs but the route to circularity has to be adopted to material particularities and application needs. The related LCA will show that a chemical recycling of PLA to virgin qualitites saves CO2 and has positive impacts in other environmental categories.

Question 3: What emerging technologies / trends do you see as having the greatest potential in the short and long run?
Design for reuse and recycling is definitely one of the key trends to change the game in the plastic world, combined with expanded deposit systems and new sorting technologies. Also, using CO2 as raw material for building blocks for polymers.

Question 4: What kind of impact do you expect them to have?
If most of the plastic products are designed in a way that they can either be reused or disassembled into unmixed polymers and sorting facilities are able to create unmixed polymer fractions (and really do so), all options for „second lifes“ of the plastics remain open. Combined with biobased or CO2 based building blocks, a true circularity of C becomes possible.

Question 5: What are the barriers that might stand in the way?
Waste quantities, an appropriate waste collection and sorting as well as economic feasibility are crucial for the implementation. Unsolved technical problems – for instance how to avoid mixed plastics or how to provide disassembling options without loosing functionality – and economic barriers. Without purposeful incentives and regulations from politics the developments will take too long.

About Daniel Maga
Dr.-Ing. Daniel Maga graduated in Landscape Ecology at the University of Münster and in Business Administration and Economics at the FernUniversität in Hagen. Afterwards he worked at the Institute of Energy and Environmental Technology e.V. (IUTA) in the Air Quality & Sus-tainable Nanotechnology division at Duisburg. In 2009 he joined Fraunhofer UMSICHT in Oberhausen with the key activities sustainability analysis of bio-based materials. In 2015 he completed his doctoral thesis at the Faculty of Mechanical Engineering at the Ruhr-University Bochum titled “A methodology to assess the contribution of biorefineries to a sustainable bio-based econo-my”.
Since January 2016 he has been manager of the group “Sustainability Assessment” which belongs to the department “Sustainability and Resources Management” at Fraunhofer UMSICHT. Additionally, he is scientific lecturer of the interdisciplinary study programme “environmental sciences” (Open University Hagen and Fraunhofer UMSICHT), focusing on environmental chemical engineering, integrated environmental protection and innovation management. He is an expert in LCA and has carried out more than 50 LCA studies focusing on different topics such as circular packaging, recycling or bioplastics.

About Fraunhofer UMSICHT
Fraunhofer UMSICHT is a pioneer for a sustainable world. With our research in the areas of climate-neutral energy systems, resource-efficient processes and circular products, we make concrete contributions to achieving the 17 Sus-tainable Development Goals (SDGs) of the United Nations.
We develop innovative, industrially feasible technologies, products and ser-vices for the circular economy and bring them to application. The focus is on the balance of economically successful, socially equitable and sustainable de-velopments.
The institute has sites in Oberhausen, Willich and Sulzbach-Rosenberg. In 2020, Fraunhofer UMSICHT generated a turnover of more than 53.9 million euros with a workforce of 577 employees.

Daniel Maga is speaker at the 2022 edition of the Circular Chemistry Conference.

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