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Issue 01/2018

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Highlights Automotive Foam

Automotive Bioplastics

Automotive Bioplastics made with wood fibres Researchers in Halle and Potsdam (both Germany) are experimenting with composite-materials made of beech fibres and bioplastics. Among others, Patrick Hirsch and his colleagues at the Halle-based Fraunhofer Institute for Microstructure of Materials and Systems (IMWS) are working to make biobased materials an everyday reality. Together with partners in research and industry, they have developed a beech wood-based biopolymer that could one day find application in the automotive industry, and even children’s toys. Pine and spruce supplanted by beech The IMWS in Halle is a member of the leading-edge BioEconomy cluster and is responsible for the joint project “Polymer materials and components from biomass”, funded by the German Federal Ministry of Education and Research (BMBF). Patrick Hirsch, an industrial engineer, is heading a sub-project which is known by the name BioWPC (WPC stands for wood plastic composites). The researchers’ raw material of choice is beech wood. This broad-leafed tree is becoming increasingly prevalent in Germany’s forests, and is taking the place of spruce as an industrial raw material. “Our sub-project is focused on the molecular level, and was aimed at finding out how we could utilise lignin and cellulose derived from beech, and even use these to create new materials,” says Hirsch. New co-biopolymer lowers melting point Wood has been used as a reinforcement in synthetic materials for many years now, and numerous biopolymers are already manufactured using these so-called matrix materials. “The advantage of biopolymers is that they bond extremely well with the reinforcing fibres, and thus provide better mechanical properties in the end product,” explains Hirsch. Unfortunately, it was precisely this quality that contributed to the project’s difficulties: “The melting and processing temperatures of the biopolymers we prefer to work with are around 240 to 250 °C. However, most of the wood fibres that we use will degrade at these high temperatures.” In cooperation with the Fraunhofer Institute for Applied Polymer Research IAP in Potsdam, Germany, the researchers in Halle used two different bio-polyamides in order to create an entirely new and completely biobased copolymer. “This permitted a lower processing temperature, and the wood fibres could thus be incorporated with the low-melting bio-polyamides without being damaged by the heat,” explains Hirsch. Biobased but not biodegradable As the focus of the project was on the biobased origins of the material, biodegradability was not part of the equation. From the outset, Hirsch and his cooperation partners worked closely alongside the automotive industry. Carmakers tend primarily to be interested in the use of bioplastics for interior parts, such as doors or seat structures, as these are frequently much lighter when from biobased materials. For potential customers, however, what matters is that the interior of the car looks like new, even after several years, with everything still in perfect working order - without starting to degrade after 10 or 15 years. Without hemicellulose, thermal stability increases In a different subproject, Hirsch and his colleagues also examined why beech wood fibres are so susceptible to heat, and which specific constituents are the most sensitive. “We studied the microstructures of the fibres in detail, both chemically as well as their molecular-biological basis, and were able to demonstrate that it is due to the hemicellulose, which is the glue between the lignin and the cellulose.” In a subsequent phase, the scientists developed a series of chemical processes for removing these hemicellulose constituents, both on the surface and a few microns below the surface, which had the effect of improving thermal stability. “By solving this problem from two sides – with a lower melting point and less hemicellulose – we were able to increase the process window for our new biopolymers by ever-increasing amounts,” says Hirsch. As a result, the materials can now be processed with conventional machines and standard injection moulding technology. Industry-ready production To underline the effectiveness of their new developments, the researchers briefly tested the large-scale production of the material, during which the partners produced around 500 kilograms of material in a single day. This involved the processing of 80 to 90 kilograms of material per hour into granules, from which components could be produced using conventional injection moulding technology. On the process side, there is now little standing in the way of a large-scale application. Price, however, remains a stumbling block, says Hirsch: “Despite our successes, the finished biobased objects are still more expensive than conventionally produced materials.” Biopolyamides are currently around EUR 8 to EUR 10 per kilogram, while petroleum-based types are around EUR 2 to EUR 3 per kilogram. “The costs are unlikely to be fully brought into line,” foresees Hirsch. “Rather, we need the willingness and understanding on the side of consumers that these biobased materials are of greater value because they are higherquality, last longer due to better properties, and are good for the environment.” In short, the aspect of sustainability has to catch on in people’s minds and be perceived as valuable. 24 bioplastics MAGAZINE [01/18] Vol. 13

Automotive (Photo: Fraunhofer IMWS) By: Dr. Judith Reichel bioö Berlin, Germany Know-how being put to use for bicycle seats and toys (Photo: Fraunhofer IMWS) Marketing and market placement played no part in the BioWPC project, meaning that despite the technical possibilities now available, no product from the research project has made it onto the commercial market. Nevertheless, Hirsch and his colleagues have already begun to apply their expertise in a number of follow-up projects. “We’re now working on so-called add-on solutions, such as child seats made of biobased material, both for bikes and cars. We’re also developing sustainable, biobased children’s toys,” he reports. His conclusion: “In our subproject, we were able to demonstrate that everything previously made of thermoplastics can now be manufactured using biopolymers, and the technology needed to do this is already available.” What is needed now is for this appreciation and acceptance to take hold among the general public, so that in the future, these products also make economic sense for industry and manufacturers. | Organiser VOTE FOR the Innovation Award “Bio-based Material of the Year 2018”! HIGHLIGHTS OF THE WORLDWIDE BIOECONOMY • Feedstocks for the Bio-based Economy • Bio-based Building Blocks & Polymers • Lignocellulose – Lignin & Cellulose • Environmental Solutions • Yeast as Platform Technology for Bio-based Chemicals • Innovation Award „Bio-based Material of the Year 2018” The 11 th International Conference on Bio-based Materials is aimed at providing international major players from the biobased building blocks, polymers and industrial biotechnology industries with an opportunity to present and discuss their latest developments and strategies. The conference builds on successful previous conferences: 250 participants and 30 exhibitors are expected. Contact Dominik Vogt Conference Manager +49 (0)2233 4814-49 Find more information at: bioplastics MAGAZINE [01/18] Vol. 13 25

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