JEC COMPOSITES MAGAZINE - Issue #37 - December 2007 - 45

Application Two of the more significant problems have been 1) the poor adhesion between the flax fibre and the resin, and 2) the tendency of the flax fibre in the composite material to absorb moisture. The process limits water uptake to 2% (equivalent to glass and carbon), thereby preventing the flax fibre from degrading within the composite material. The fibre-matrix bond created also helps to transfer the mechanical properties of the flax fibre to the composite part. Flax-epoxy prepregs A specific treatment results in a strong bond between the flax fibres and the epoxy resin, practically eliminating water uptake in the flax fibres. Fig.3: the carbon gives stiffness and the flax absorbs the vibrations A half-flax-/half-carbon-reinforced racing bicycle Former world cycling champion Johann Museeuw decided to develop a bicycle that would be 50%-50% flax/carbon reinforced. The resulting bicycle has definite advantages: the carbon gives stiffness and the flax absorbs the vibrations from flaws in the road. The bicycle has been tested by a number of cycling professionals, unanimous in their approval (Figure 3). The Museeuw Bikes Company is currently working to develop flax-reinforced wheel rims. As we have seen, flax fibre has its own specific mechanical properties and characteristics. It can be used as reinforcement in composite materials. It can even be used as reinforcement in high-performance composite materials, where the fibres are used for their strength and mechanical properties in structural parts. This is a potential outlet for the high-value-added long fibres, one that could open up to the entire flax industry. More information: www.lineo.eu Fig.2: Prepreg Samples: (from left to right) FUD 200, FUD 380, FFA 580 Five different prepregs are available so far (Figure 2): - FUD 200: unidirectional flax yarns. Flax fibre weight: 380 g/m2. Resin content: 40%. - FUD 380: unidirectional flax yarns. Flax fibre weight: 380 g/m2. Resin content: 40% - FFA 200: woven 2/2 twill of flax yarns. Flax fibre weight: 200 g/m2. Resin content: 40%. - FFA 580 : woven 2/2 twill of flax yarns. Flax fibre weight: 580 g/m2. Resin content: 40%. the experimental data are well predicted by the model lines. AN INTERVIEW WITH FRANÇOIS VANFLETEREN, PRESIDENT LINEO JEC Composites Magazine: What makes natural fibres so attractive for composite materials today? FRANÇOIS VANFLETEREN: The main attraction of natural fibres is their low weight. Some bast fibres like flax and hemp also have mechanical properties that are on a par with glass fibre. So natural fibres can be used for high-performance composite structures. There is also the environmental aspect, since these fibres are renewable and non-polluting, and have a very small carbon imprint. JCM: Why choose flax over other natural fibres? FV : Flax is the natural fibre with the best mechanical strength properties. Furthermore, in addition to these qualities, there already exists a complete industry in Europe for flax, from crops all the way to the manufacturing of fabrics. This means that we can develop a range of customized flax reinforcements relatively easily. JCM: Which application sectors are you targeting as a priority, and in which geographical areas? FV : The automotive sports sector is very interested in hybrid flax/carbon composites. These are both stiff and vibration-free, thanks to the flax properties – an aspect that also has a broader appeal in the sports and leisure industry and for machine builders. We also note that the transportation sector is interested, as a way to replace glass-fibre reinforcement while retaining the same mechanical properties and making the materials lighter. Because flax has roughly the same coefficient of expansion as carbon, Axson, our distributor, is helping us develop a range of tooling products to replace carbon moulds with flax-based ones, which will enable us to save a lot of money.We are established mainly in France and Europe. No37 December 2007 / JEC Composites Magazine 45

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JEC COMPOSITES MAGAZINE - Issue #37 - December 2007

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #37 - December 2007