Flax, hemp and nettle fibres have been used for centuries to make clothes, sacks, sails, ropes and nets, but fell into disuse with the advent of synthetic (oil-based) fibres. But a turnaround is visible. In the new DuroBast project, for example, a broad consortium is working on the application of bast fibres in composite construction parts for the automotive industry. The bast fibres are used in thermoplastically deformable plastics reinforced with natural fibres. Concrete applications include car interiors (such as door panels), sports equipment (snowboards) and public transport (bus bellows).
One of the objectives of the DuroBast project is to significantly reduce the moisture absorption of the bast fibres through modification and then process them into yarns, nonwovens and fabrics. During pretreatment, fibre cavities and spaces between the fibres are filled with a thermoplastic that prevents water absorption, even in damaged areas and at the cutting edges of the composites. To make the product 100% biobased, a polymer matrix with biobased plastics will be used. All selected components must meet the target criteria of processability, economic efficiency, availability and durability.
Hemp
An additional focus of the DuroBast project is the support of regional and national agriculture and forestry and their supplying and consuming sectors. Consequently, the project team is exclusively researching bast fibres that can be easily grown in Western Europe. Besides flax, the hemp plant is particularly suitable. It is cheaper than flax and grows well in the region, which offers security of supply in times of uncertain global logistics. Moreover, it is possible to use the entire plant, for example in medical and food applications.
Initial trials with the production of organic material from hemp polypropylene yielded promising results. These fibre-reinforced thermoplastics are strong and light and as easy to process as conventional metal sheet components.
In the DuroBast project, a German interdisciplinary research consortium with eleven partners from science and industry is working together under the leadership of the Fraunhofer Institute for Structural Sustainability and System Reliability LBF. The project is financed by the German Federal Ministry of Food and Agriculture. For more information, visit the project website.
Image: DuroBast
