Center for Light and Environmentally-Friendly Structures ZELUBA®

Research project

ecoSUP – Lightweight-construction sandwich element made from natural fiber-reinforced bioplastic and recycled balsa wood  

Lightweight materials are environmentally friendly, as less energy and fewer raw materials are required for transport and production. Conventional lightweight-construction materials are based on fossil resources. Using a stand-up paddleboard as an example, we are developing a lightweight-construction sandwich element using renewable raw materials. For the core, we are using balsa wood from disused wind-energy rotor blades, thereby offering a solution for their high-quality reutilization (cascade utilization). In the future, our new bio-composite material could be used not only in other watersports equipment but also in the construction of buildings, cars, ships and trains.

Graphic representation of a stand-up paddleboard with four views: from above, from the side, from below and from the front.
© Fraunhofer WKI I Christoph Pöhler
The stand-up paddleboard “ecoSUP” will be made from renewable raw materials.
Graphic representation of the body of a stand-up paddleboard.
© Fraunhofer WKI I Christoph Pöhler
The cross-section of the paddleboard shows the sandwich construction: core made from recycled balsa wood with an outer shell of natural-fiber-reinforced bioplastics.

As a demonstration object and idea mediator, we have chosen a stand-up paddleboard, as it has to fulfill strict requirements as regards mechanical strength in combination with moisture, saltwater and UV-resistance.

Currently, petroleum-based materials such as epoxy resin, polyester resin, polyurethane and expanded or extruded polystyrene in combination with glass-fiber and carbon-fiber fabrics are used to produce watersports equipment such as surfboards. Glass fiber-reinforced plastics (GRP) are also enjoying a continuously growing market in other economic sectors. Across and beyond the industry boundaries, the European market for GRP in 2018 amounted to around 1.1 million tonnes and therefore offers a high potential for savings as regards finite resources.

Our research approach is characterized by, amongst other things, the utilization of recycled balsa wood as the core for the new bio lightweight-construction material and its corresponding modification. Balsa wood is used in large quantities in the rotor blades of wind-energy turbines and accumulates as waste at the end of the life cycle of the rotor blades. In order to achieve the longest possible CO2 binding, it would be wise to find material-recycling possibilities for the balsa wood instead of using it thermally, i.e. simply burning it. Through the reutilization as a core component in lightweight-construction materials for watersports equipment and other applications, the balsa wood could consequently be materially recycled.

In addition, we are developing an outer shell made of natural fiber-reinforced bioplastics (Bio-NFRP). We are hereby concentrating on the application of flat fibers, as they have advantageous mechanical properties and are cultivated in Europe.   

In order to ensure competitiveness against conventional lightweight-construction materials, we will subject the new bio-hybrid material to diverse tests. It should not only be more ecological but should also offer technical advantages for lightweight-construction applications as a result of its high specific strength.

The aim is to transfer the bio-hybrid material to further areas of watersports and other industries at a later stage. Conceivable applications include the construction sector, shipbuilding, the automotive and railway industries and beyond.

Overall, the substitution of petrochemical and mineral components by renewable and, in some cases, additionally recycled raw materials offers high savings potential in terms of energy requirements and finite resources.

With our project, we are supporting the development of a bio-based economy (bio-economy).


Funding body: German Federal Ministry of Education and Research (BMBF)

Funding reference: 031B0896, 031B1092A

Project management: Projektträger Jülich (PTJ)

01.10.2019 to 30.09.2020 (exploratory phase)
01.03.2021 to 28.02.2023 (feasibility study)