The paludiculture print - 3D and with reed and typha
3D printing needs a replacement for petroleum-based plastics. Scientist Jonas-Rumi Baumann is researching how plant fibers can improve the properties of new materials for this purpose at Bremen University of Applied Sciences. He also puts paludiculture plants such as cattails and reeds in his 3D printer.
Mr. Baumann, do you constantly print small figurines in the 3D printer for your research - how should we imagine that?
I would like to, but we haven't got that far yet. First of all, we're in the process of developing the printing material. I'm personally fascinated by 3D printing. If a small part on my fridge breaks, I can simply reprint it.
What exactly do you do then?
For us, it's all about compounds - combining plastic with biomass in order to reduce petroleum-based components in products. Plant fibers can improve their properties. Such mixtures are called “natural fiber composites”. I examine the mechanical properties of these new materials using so-called test specimens - test parts. We have already worked with flax, hemp and nettles, but we are always on the lookout for new fibers.
And which paludiculture plants are suitable?
Broad-leaved cattail and reed are the most suitable so far. They have the most interesting mechanical properties. These include stiffness, i.e. how much something deforms elastically and returns to its original position unchanged. Then there is strength: how much the material can withstand before it breaks.
Paper and cardboard made from paludiculture biomass - for example. molded trays - already exist. What is different for 3D printing?
For cardboard or disposable trays, the biomass has to be processed in a completely different way. In the molded fiber packaging s, which is commonly used to produce plastic parts today, the raw material comes in granules and can be processed directly. For 3D printing we need an additional step: develop and produce a thermoplastic wire. This resembles a long metal wire, which is then wound onto a roll. During printing, it is heated to 200 °C and pressed through an opening of 0.4 mm. The workpiece is created layer by layer. We use extremely fine ground biomass for this, which must be evenly mixed with the plastic in a compounder. That in itself is difficult, but thus guarantees the product’s consistent properties. In addition, after drying, biomass often still contains moisture. 1-3%g. This moisture must be removed even though the compounder is actually a closed system. If not, the components cannot be mixed properly. In the end, the printer will not deliver good workpieces.
When the compounds combine - will your existing materials end up on the compost heap or in the residual waste garbage can?
The ideal is a completely compostable composite material. Today we use the plastic polyacetide (PLA), also known as polylactic acid. It is compostable under industrial conditions, for example at a defined temperature, but not yet at home in the garden. Another plastic used is polyhydroxybutyrate (PHB). This degrades under marine conditions, for example. So it's good for combating plastic littering in the oceans.
3D printing still seems to be more of a niche - what does it look like economically? Is there a market?
3D printing will of course not be used to produce yoghurt pots at vast scale. The injection molding process is suitable for large quantities and fast production. We are also developing a material with paludiculture biomass for this purpose. 3D printing is about small quantities, often for the production of prototypes in the home, in research and development. There are more and more printers and their use is increasing. This means that there will also be a demand for bio-based, future-friendly materials for 3D printing.
Will I buy the pressure substance made from bulrush in a cartridge at some point?
Hopefully yes! With 3D printing, it's more of a role than a cartridge. There are already compounds with natural fibers. We hope that a paludiculture 3D printing wire will be competitive, as it has a very good carbon footprint.
Jonas-Rumi Baumann works in Prof. Jörg Müssig's Biological Materials working group at Bremen University of Applied Sciences. His research into paludiculture biomass for 3D printing is part of the NAPALU project.
Interview by Nina Körner.
