Automotive BioConcept-Car – New approaches into biomaterials By Michael Thielen The rear hatch made of flax and hemp The new ‘Bio-Rocco’ (Michael Thielen as passenger) The BioConcept-Car has become a true and faithful companion of bioplastics MAGAZINE. In our first ‚automotive issue‘ in early 2007 we introduced the Ford Mustang racing car with bodywork made of flax fibre reinforced linseed acrylate. In 2009, during the Composites Europe trade show the next generation BioConcept-Car, a green Renault Mégane Trophy was shown and bioplastics MAGAZINE reported in issue 01/2010. Last autumn the current BioConcept-Car, in this case a Volkswagen Scirocco, was introduced on the famous German race track, the Nürburgring, and during this event I was invited to experience a lap in the passenger seat of the car. I must admit: “What an experience !” Thomas (Tom) von Löwis of Menar, head of the Four Motors racing team, drove me around the legendary Nordschleife (‘The green hell’) at up to 240 km/h (150 mph) — up and down the ‘Eifel’ hills and through one hairpin bend after another …. It was a great day. And after this experience I spoke with Tom von Löwis as well as with Prof. Hans-Josef Endres 1 , who consults for Four Motors with regard to the future use of bioplastics in the BioConcept-Car. On automanager.tv (an Internet platform) the editor and presenter Guido Marschall conducted an interview 2 with these two gentlemen. This article comprises parts of both these interviews. The Volkswagen Scirocco BioConcept-Car — in short the ‘Bio- Rocco’ — is a biodiesel driven racing car like its predecessors, but fuelled with a new generation of biodiesel, the so-called ‘NExBTL’. And it is becoming more and more sustainable. As a first step, the car was equipped with a rear hatch made of hemp and flax fibres. MT: What were the main reasons to convert the rear hatch to this special material? TvL: Besides the fact that we are trying to use as much biobased material as possible, lightweighting is an important issue. HJE: The topic of lightweighting is certainly important not only in order to win races, but also with a view to the fuel consumption and the exhaust emissions. But another very important fact here is the topic of resource conservation in terms of the materials used. We want to build highly efficient cars, however, not simply by using the resources that are available today. We also want to do this in 50 years from now. We want to apply plastics, with their fantastic properties, in the future, and also for demanding technical applications. Thus we need materials that do not depend on limited resources but are available even in the long term — and with the technical properties we need. 10 bioplastics MAGAZINE [01/12] Vol. 7
Automotive The ‘Bio-Rocco‘ (Photo: Four-Motors) GM: Now, these new materials are not being developed in the first place with the aim of achieving new records in car racing, but motor sport offers the possibility of testing these new materials to the limit, and then to take advantage of these experiences for series production vehicles. Besides the fun that motor sport offers, this has been common practice for years, even in Formula 1. Which new insights are being collected with biomaterials used in motor sport today? TvL: One example is lightweighting, which we just mentioned. Let us compare this new version with a component in the first Mustang in 2006. The natural fibre reinforced material at that time was slightly heavier than a fibreglass material. Today, for example with the support of Professor Endres, the new hemp/flax version is almost as light as carbon fibre. HJE: We have learned a lot. Natural fibres in fact show similar, although different, properties from those of glass or carbon fibres. And subsequently the processing is similar but also different. Here questions had to be resolved, for example concerning the draping of a fabric. How does the weaving technology have to be adopted in order to optimise the draping behaviour? What is the optimum weight per area of a fabric so that the fabric can absorb enough resin and lead to an optimum final density? What about the compatibility (fibre/matrix adhesion) of the natural fibres and the resins? What are the resulting material properties of the composite? We are at the very beginning of an exciting learning process. GM: What kind of biomaterials are we talking about here? HJE: The natural fibres we are using are flax and hemp. For the time being we are combining these with petroleum based castable crosslinked resin systems because we wanted to concentrate first on the optimisation that we mentioned in terms of fibres and weaving. But in future steps we also want to look into resin systems based on vegetable oils, such as linseed or sunflower. For the thermoplastic materials we are looking at different technical bioplastics like bio-PA or new biopolyesters, and in future also at biobased polypropylene. GM: Which components in the racing car can be replaced by components made from biobased materials? TvL: I would not venture to say all, but most probably all those body parts that can be replaced in a racing car, such as the hood, left, and right doors, the rear hatch, the front and back bumpers, fenders etc. can all be made from these new natural fibre composites. MT: Are these natural fibre composites as stable as conventional ones? HJE: They can withstand the same loads as body parts made from fibreglass or carbon fibre, and one additional advantage is that they do not splinter in crashes. GM: And this is most especially desirable if we think about converting the material to series production vehicles. HJE: Yes, and they are lighter today than fibreglass parts, and only 30 percent of the weight of a steel version. In a small production series they can even be manufactured at a lower cost. Tom von Löwis, Hans-Josef Endres and Guido Marschall on automonager.tv (photo: automanager.tv) bioplastics MAGAZINE [01/12] Vol. 7 11
