Automotive Fig. 2: Fuel
Automotive Fig. 2: Fuel filler flap glass fibres (GF) Fig. 3: Materials E-Modulus of composite [MPa] 25000 20000 carbon fibres (CF) short fibres (< 4mm) glass fibres (GF) Adaption Adaption Bioconcept Car Adaption biobased fibres (CF) long fibres (fabric) natural fibres (NF) Adaption Composite Density vs. E-Modulus Thermoset-resins biobased Biobased polymer fibres (BF) thermoplastics petrobased biobased petrobased 15000 glass fibre carbon fibre 10000 viskose fibre flax fibre 5000 0 0,4 0,5 0,6 0,7, 0,8 0,9 1 Composite Density [g/cm 3 ] Fig 4.: Modulus of elasticity of the composites for various fibre types Tensile strength of composites [MPa] Composite Density vs. Tensile Strength 800 700 600 500 400 300 200 100 0 0,4 0,5 0,6 0,7, 0,8 0,9 1 Composite Density [g/cm 3 ] Fig 5.: Tensile strength of the composites for various fibre types glass fibre carbon fibre viskose fibre flax fibre “Within this project we not only try to optimize the material components themselves. We also determine for example the optimum fibre/matrix ratio using test panels in order to achieve the targeted stability in combination with minimized weight”, explained Prof. Endres. The test panels are then subjected to tensile tests, impact tests or crash behaviour before real parts for use in the race car are produced. The biobased resin actually used in the tailgate of the Bioconcept Car is made from an epoxy resin based on oil from pinewood and by-products of biodiesel. This process is steadily being optimized and will be also be adopted for the design of further parts for the car. Award winning project With the tailgate the Bioconcept-Car was a winner of the 7 th Global Bioplastics Award 2012 (see bM 06/2012) 60% Weight savings With a tailgate, bonnet and doors made from a thermoset resin reinforced with natural fibres the Bioconcept-Car weighs now 67 kilograms less. In comparison with the same components made from steel the weight saving is 60 %. The standard door weighed in at 38.5 kilograms, and the door made from the material reinforced with plant fibres weighed only 14 kilograms. “When we think that 100 kilograms could be saved in the weight of a standard car, which means a fuel saving of about half a litre per 100 kilometres, the importance of our project for the automobile industry is clear”, said Prof. Endres. Technically it is possible to use thermoset resins in serial car production. At the end of this project a catalogue will be prepared that contains full details of the materials used for each component, and the production processes involved, together with recommended applications for biomaterials. The tool will help the automotive designer to check the application and potential of the biobased materials. It will however be a long road. A comparison of potential lightweight materials shows the advantages and disadvantages of the different fibres (see Figs. 4 and 5, and table 2). The advantage of carbon fibres lies in their construction performance, but which come at a price – both economical and environmental. The glass fibres are certainly cheaper but are heavier and have similar ecological disadvantages to carbon fibres. Both types of fibre have negative acoustic qualities to be considered. Viscose fibres have advantages in their light weight and better ecological and acoustic properties, but do not have the higher mechanical performance of carbon or glass fibres. Even flax fibres cannot reach these levels but have their advantages in terms of weight, cost, ecology and acoustics. Thanks to their very low weight (and price) an increase in their use for those parts where the required mechanical performance is in fact achieved, is still a very attractive cost saving proposition. 12 bioplastics MAGAZINE [01/13] Vol. 8
Cover Story Table 2 design-relevant properties Economic factors Additional properties Carbon fibre Glass fibre Flax fibre Density + - + + Tensile strength + + - - E-Modulus + + - - Costs - + + + Acoustics - - + + Ecology Sustainability - - + 0 Viscose fibre Within the next stages further parts of the Bioconcept Car will be produced using biobased polymers. Hereby the Bioconcept Car paves the way for future sustainable mobility. It brings the ideas generated in the laboratories to the street and makes them applicable for future series production in the automobile industry. Not only alternative parts for motor sport are being developed, but these parts can also be included in the series production of standard cars. The Institute for Bioplastics and Biocomposites (IfBB) In the Bioconcept Car project the recently established Institute for Bioplastics and Biocomposites (IfBB) at the University of Applied Sciences and Arts Hanover will hold the primary responsibility for materials engineering concerning the car. Sponsored by the German Federal Ministry of Food, Agriculture and Consumer Protection, and supported by the Agency for Renewable Resources (Fachagentur Nachwachsende Rohstoffe e.V.), Prof. Hans-Josef Endres and his team are in charge of material development and the selection of raw materials, as well as the production of the various biobased parts, for example, hood, doors, or tailgate. www.ifbb-hannover.de www.fourmotors.com http://mediathek.fnr.de/broschuren/nachwachsende-rohstoffe/ biowerkstoffe/bioconcept-car.html C B D E I A G F H Now: Before: A Tailgate: Bio-based plastic (epoxy resin) with flax fabric Sheet steel B Rear spoiler: Bio-based plastic (epoxy resin) with flax fabric Petroleum-based plastic (epoxy resin) with carbon fiber C Roof spoiler: Bio-based plastic (epoxy resin) with flax fabric Petroleum-based plastic D Fuel filler flap: Bio-based plastic (polyamide) filled with talc Petroleum-based plastic E Door: Petroleum-based plastic (epoxy resin) with flax fabric Sheet steel F Closed underbody: Bio-based plastic (epoxy resin) with flax fabric Petroleum-based plastic (epoxy resin) with carbon fiber G Diffuser: Bio-based plastic (epoxy resin) with flax fabric Petroleum-based plastic (epoxy resin) with carbon fiber H Front splitter: Bio-based plastic (epoxy resin) with flax fabric Petroleum-based plastics I Bonnet: Bio-based plastic (epoxy resin) with flax fabric. Sheet steel bioplastics MAGAZINE [01/13] Vol. 8 13
