Cover Story Mobility of the future by Christoph Habermann Project leader IfBB – Institut für Biokunststoffe und Bioverbundwerkstoffe University Hanover Hanover, Germany The future of mobility goes green – the IfBB (Institute for Bioplastics and Biocomposites, University of Hanover, Germany) as well as the race driver Smudo (our front cover hero, who is a well-known celebrity in Germany as a singer of the German hip-hop group Die Fantastischen Vier) and the Four Motors Racing Team are convinced of this trend. The co-operation is funded by the Agency for Renewable Resources (FNR Fachagentur Nachwachsende Rohstoffe e.V.) on behalf of the German Federal Ministry of Food, Agriculture and Consumer Protection. The joint operation is focused on the development of biobased materials and sustainable parts for the automotive industry as well as the change towards a ready-for-the-future mobility. Being constructed with more and more biobased parts, the Bioconcept Car (bM has reported on the development on a regular basis since 2007) can even take part in longdistance races such as the VLN Endurance Championship or the ADAC 24 hour races on the famous Nürburgring circuit. The aim of this project is, therefore, to develop parts for the automotive industry and racing by using bioplastic materials and biocomposites. Thus, the Bioconcept-Car sets out a path for a change to a ready-for-the-future mobility not only in racing but also in normal traffic. It gives evidence that biobased materials can be used in modern, technical and heavily used automobile constructions. Materials An increasing number of components for the Bioconcept Car are made of resource-saving biobased materials which are extremely lightweight in order to minimize the vehicle’s petrol consumption i.e. energy consumption. To reach this target different materials are used and material combinations are being evaluated (Compare the illustration Materials, cf Fig. 3). On the one hand thermoplastics which are biobased or petrochemical-based (in this case they are used in combination with natural fibres in order to obtain a bio composite) are used reinforced with different fibres or modified without fibre reinforcement; on the other hand biobased or petrochemical-based thermosetting materials are combined with various fibres. At least the developed materials are fully or partly biobased – either the fibre and/ or the resin. For the lightweight car body resins reinforced with natural fibres are used: lighter than fibre-glass, cheaper than carbon fibre and made from renewable raw materials. Table 1: Examples for biobased components of the Bioconcept Car: Natural Fibre reinforced resins (thermosetting materials): Doors Tailgate Hood Front Underbody (Diffusor) Natural Fibre reinforced plastics (thermoplastic materials) or bioplastics: Fuel filler flap Covering of steering column Various technical boxes Mirror bodies 10 bioplastics MAGAZINE [01/13] Vol. 8
Automotive Fig.1: The current Bioconcept Car is a specially modified Volkswagen Scirocco 2.0 TDI (photo: Four Motors) Using natural fibres as a reinforcement for thermoset resins is a sustainable alternative for lightweight car bodies and is even successful under the extreme stresses applied during racing. This will give those composites the chance to be the key material for the future in automobile construction. Weight saving is a magic word in the automotive industry – not only with regard to minimizing fuel consumption and thus reducing CO 2 emissions, but also to achieving longer distances for electrically driven cars. Furthermore, other more complex shaped parts - for example components under the hood and the interior part of a car - are designed with injection-moulded biobased plastics or biocomposites. The IfBB preselect the materials i.e. material components and their configuration according to the requirements of the application and the part that has to be realized. The next step is a laboratory-confirmed specific development and optimization of different material concepts and biobased materials. Actually the range of biobased plastic, biobased additives and biobased reinforcements is so abundant that the new fuel filler flap of the Bioconcept Car was produced in a comparable quality on a large-scale production injectionmoulding machine with the standard mould. Especially for this application a commercially available biobased Polyamid 6.10 from DuPont was modified with talc and different additives. The proportion of renewable raw materials in the vehicle is thereby successively increased. Other thermoplastics to be investigated include polytrimethylene terephthalate (PTT, (see also page 46). Before and after a race season, the construction parts are examined and analysed by material testing. The results are compared in order to analyse possible changes of the materials caused by the stresses applied during a race. The main innovation of 2012 was a combination of natural (flax) fibres with a biobased (epoxy) matrix which is being used for the tailgate, and, in the next stages, for hood and spoiler of the Bioconcept-Car. Different natural fabrics with variable weight and variable weave were produced and tested in order to achieve the necessary quality/character in terms of stability or processing properties and to ensure the desired results in combination with the biobased resin. After the initial trials with fabrics made of different natural fibres the engineers from Hanover decided on a pure flax twill weave. The result of this investigation is a flax fibre which offers a high tenacity, and is readily available. It is a particularly fine, homogeneous, flexible and drapable material. i.e. it can be put into the shape of the part to be moulded without significant problems in terms of folds etc. The raw materials for a biobased epoxy resin can be different vegetable oils in order to achieve the necessary properties, e.g. hardness, viscosity or a quick curing time, as well as the ability to be combined with natural fibres. bioplastics MAGAZINE [01/13] Vol. 8 11
