Priority Programme “New recyclable composites” (SPP 2528)

In March 2025, the Senate of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) established the Priority Programme “New recyclable composites” (SPP 2528). The programme is designed to run for six years. The present call invites proposals for the first three-year funding period.

Research Topic of the Priority Programme

In November 2019, the European Union (EU) committed to becoming the world's first climate-neutral continent by 2050. One important measure is the “decarbonisation” of industry. The polymer industry in particular is petroleum-based and, unlike the energy-generating industry, cannot be “decarbonised” because it requires carbon as an elementary component of the (polymer) materials themselves. However, the polymer industry can be “de-fossilised”. In order for polymers and composites to do without fossil carbon, the following three approaches are available on the material side:

i) use of renewable raw materials;

ii) multiple use of carbon through closed-loop solutions; and

iii) use of CO₂ as a carbon source (“Carbon Capture and Utilisation”, CCU).

In particular, solutions i) and ii) also address the research and development of recyclable fibre-reinforced polymers (FRP). This represents a paradigm shift, as in previous decades the successful developments of FRP mostly concentrated on optimising processing and usage performance, while there was less focus on recyclability. The present SPP 2528 therefore addresses new technical approaches for recycling-friendly composites.

Focus of the Projects within the Priority Programme

In order to achieve a fundamental change in the paradigms for the recyclability of FRPs, the planned SPP “New recyclable composites” is pursuing ambitious goals. The aim is to develop alternative FRPs that are recyclable and enable at least one, and ideally several, material cycles while maintaining product and performance. In principle, the highest possible value retention in the recycling process must be guaranteed. The target performance should be at least 80% of selected mechanical benchmark properties (e.g. specific modulus of elasticity/strength/fatigue life, etc.) after the first cycle. Furthermore, the technical or mechanical properties of the new FRP in the initial state must correspond to the current industrial standard. The reference here is either continuous or short-fibre-reinforced FRP. In addition, a qualitative and ideally quantitative consideration (if necessary up to an LCA) of ecological sustainability in terms of defossilisation and energy and resource consumption compared to the benchmark must be ensured, e.g. through bio-based base materials/resources, recycled petrochemical carbon or multiple use of reinforcing components. The research proposals must also plausibly explain which concepts and methods will be used to achieve the target figure(s) (80%) based on the state of the art.

Potential research is divided into approaches that seek solutions for recyclability at different levels. Bio-based, recyclable material components for reinforcing and matrix materials are welcome in all areas.

1. In the area of “soluble matrix materials”, fibres and matrix of the FRP are to be separated from each other and returned to the material cycle. In addition to the matrix, the aim is to maintain the quality and usability of the fibres and, if necessary, the matrix. In the case of continuous fibres, these should also be able to be reused as continuous fibres.

2. At the “disposable FRP” level, the layered structure of the FRP is to be used to separate the individual fibre layers from each other. The fibres and matrix remain bonded together in the layer, enabling direct processing into new FRP components. This approach can be applied to all FRPs with a polymer matrix. In addition to the suitable matrix materials, the respective technologies for separating the layers and for the subsequent reassembly and joining of the individual layers to form the FRP must also be developed.

3. In the area of “self-reinforced FRP”, direct reuse, e.g. reshaping or melting of the unmixed FRP, should take place, as fibres and matrix consist of the same polymer, the same polymer group or very compatible materials. In addition to material development, concepts must also be developed as to how further processing can be carried out in the cycle of pure but heterogeneous polymers in order to obtain FRP with correspondingly good properties.

The SPP 2528 focuses primarily on material and polymer engineering issues or approaches to the creation and investigation of new, recycling-friendly, polymer-based composite materials. This also means that a delimitation of the approaches to be funded is necessary. The SPP does not focus on:

• Hybrid material composites, such as fibre-metal laminates or extrinsically joined material systems as well as metal or ceramic-based composites (MMC or CMC).
• The recycling of unreinforced polymers or polymer waste or existing waste.
• Exclusive downcycling, composting or thermal/raw material recycling as well as pure chemical or process engineering process developments – in particular with complete material degradation to low-molecular substances or basic chemicals. Depending on the material system under consideration, chemical processes can play a role in mechanical recycling, but the approaches pursued should be considered on a material level.
• The development of new polymer materials based on research approaches in the field of macromolecular chemistry. Based on the current state of research, work should concentrate on essentially known material systems.
• An exclusive evaluation of the use-limiting deterioration (e.g. aging) without the development of a relevant solution approach for resource conservation or the purely model-based consideration of the material properties without experimental validation.
• An exclusively theoretical consideration using an LCA or approaches that only improve the contribution to resource conservation by reducing energy consumption in processing, without pursuing technical material solutions. In terms of resource conservation and sustainability, numerous factors naturally play a role that can be taken into account, e.g. via an LCA. This also applies to other circular economy concepts beyond material recycling – in particular reuse, refurbishing, sharing, renting or other non-material-based principles. The material aspects of “repair” can be considered as a sub-aspect in individual work packages if necessary.

An online round table for further information will take place on 13 June 2025 from 9:30 to 12:00 a.m. to improve the coherence of the Priority Programme. Possible collaborations or joint proposals can also be discussed (bilaterally) at this meeting. If you are interested, please contact the coordinator of the Priority Programme in advance (spp2528@tuhh.de).

Notes on Submitting a Proposal

Proposals must be written in English and submitted to the DFG by 29 October 2025. Please note that proposals can only be submitted via elan, the DFG’s electronic proposal processing system. To enter a new project within the existing Priority Programme, go to Proposal Submission – New Project/Draft Proposal – Priority Programmes and select “SPP 2528” from the current list of calls. Further information can be found on the DFG website.

The proposals will be evaluated as part of a colloquium at the TU Hamburg with presentations, which is currently planned for February 2026. The date and location of the colloquium and any further relevant updates will be published in due course.

Further Information

The elan system can be accessed at:
https://elan.dfg.de/en/

DFG forms 50.05 and 54.01 can be downloaded at:
www.dfg.de/formulare/50_05/
www.dfg.de/formulare/54_01/

For scientific enquiries please contact the Priority Programme coordinator:

Professor Dr.-Ing. Bodo Fiedler
Technische Universität Hamburg
Institute of Polymers and Composites
Denickestraße 15
21073 Hamburg
Phone +49 (0)40  42878 3238
E-Mail: spp2528@tuhh.de

Questions on the DFG proposal process can be directed to:

Programme contact:
Dr.-Ing. Tobias Standau, phone +49 228 885-3257,

Administrative contact:
Christoph Dahlmeier, phone +49 228 885-3259,