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Issue 04/2017

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bioplasticsMAGAZINE_1704

Biocomposites

Biocomposites Biocomposite footbridges Seeking a durable and sustainable alternative to steel footbridges, the Port of Rotterdam contacted Dutch composite experts Fibercore Europe in 2010. This year, 14 new biobased polymer composite footbridges made by FiberCore will be installed in the port of Rotterdam, bringing the total to 22. “Steel bridges have to be removed from their site after 25 years, for re-blasting and a preservation coat. In addition, you have to monitor possible damage to the preservation coat to prevent corrosion (rust). After they’ve been refurbished and reinstalled, the bridges should last another 25 years. But after that, metal fatigue basically means the end of their useful service life, and it’s back to the furnaces for them,” explains Simon de Jong, founder of FiberCore Europe, at the firm’s headquarters close to the production location in Rotterdam. By contrast, the bridges built by FiberCore, in cooperation with the Port of Rotterdam and Max Design, are designed for a guaranteed lifespan of at least 100 years and next to no maintenance requirements. In December 2012 the first two port bridges were installed. The footbridges – which have a modular truss bridge design – consist of units made from fibreglass and resin, among other things. 25 % of this resin is biobased. “This biobased share is the glycol-component of the dicyclopentadiene or DCPD, a raw material for an unsaturated polyester resin”, as Martijn Veltkamp of FiberCore Europe told bioplastics MAGAZINE. But technical developments haven’t stopped there. “We can presently increase the share of bioresin to 45 % without sacrificing any mechanical properties,” says Ed Hoogstad, Director Operations COO at FiberCore Europe. “This project perfectly aligns with our sustainability ambitions. The realisation of the bridges demonstrates how as a Port Authority, we are investing in sustainable innovation in the region. Through such initiatives, we hope to stimulate other companies to follow suit,” says Port Authority project manager Matthijs Tromp. “Ever since our establishment in 2008, FiberCore has taken a different approach to infrastructure,” says De Jong. “We construct bridges using composites, as an alternative to concrete, wooden and steel bridges. Our technology comes from the aviation and aerospace industries. My partner Jan Peeters originally worked in aircraft construction and is very familiar with these sectors. Working together with Rijkswaterstaat’s Civil Engineering Division, Jan realised Europe’s first composite bridge in 1997. This ‘scoop’ ultimately led to the InfraCore technology, which has been patented worldwide.” He explained that using InfraCore technology, the problems caused by delamination and crack formation are a thing of the past. Even when a bridge is subjected to external mechanical stresses – caused by a heavy object falling on the deck, for example – the material retains its full original structural strength. In a more recent development, FiberCore now also builds lock gates and bridges. Integrated cable systems FiberCore’s first composite bridge for the Port Authority consisted of two sections with innovations that clearly distinguish it from the steel bridges: integrated cable systems, integrated lighting and a bright white finish that makes the structure highly visible for approaching vessels. The latter feature is also important in connection with safety. This bridge was constructed on site in 2012 and tested for a full year. Hoogstad calls it a ‘plug and play’ bridge: an easyto-install structure that will not only last for at least a century but also has very low maintenance requirements. “You could say the only maintenance you have to perform on this bridge is clean off the gull droppings and replace the LEDs every now and then,” says Tromp. After a year of testing, the Port Authority wanted to continue with the development of the composite footbridges – but then at 1.5 times the original span. A feasibility study indicated that this was technically and economically ‘doable’. Fibercore, however, wished to take this development a step further, with the development of an even more environmentally-friendly construction process. As it is, composite bridges already form a ‘green’ alternative to their steel counterparts; lightweight, they are easier to transport, and have a far longer service life. Yet there were other gains to be made, as well. “Using bioresin: that was truly the cherry on the cake for us,” said Hoogstad. At present, the bioresin content of the composite bridges is 25 %. This could be increased to 45% – without sacrificing any mechanical properties – in the future. The sustainability of the composite material can be enhanced in a different way as well, said FiberCore, i.e., by replacing the fibreglass components with basalt. However, the company would have to purchase the basalt in sufficient bulk, since it is a relatively expensive raw material. The company said it would have to wait for a growth in demand – “a batch of 15 bridges” – for the use of basalt to become interesting in terms of cost. MT www.portofrotterdam.com | www.fibercore-europe.com 26 bioplastics MAGAZINE [04/17] Vol. 12

Biocomposites Continuous production of all-natural fibre composites the continuous procedure, a new rolling mill, a so-called calender, had to be developed. Scientists at Germany’s first and only Federal Cluster of Excellence MERGE have developed a promising method for sustainable large-scale production of biobased fibre-plastic compounds. Ahmed-Amine Ouali, research associate at the Institute of Lightweight Structures (Technical University of Chemnitz, Germany) explained: “We replace the glass or carbon fibre with natural fibres such as flax. Our plastic matrix is a biopolymer of renewable resources, such as biobased polyamide 11 or biobased polyamide 10.10. Thus, the carbon footprint in the product’s life cycle is significantly better.” Also biobased polyethylene was already tested. The material characteristics are also interesting: The use of continuous filaments renders the compound extremely stiff and highly rigid in the direction of the fibres. As an additional plus point, flax is lighter than glass and cheaper than carbon fibre. The researcher’s main objective was to develop a procedure for the large-scale production of so-called semifinished products made from plastics and natural fibres. Film-stacking-technology – a discontinuous procedure – is currently common practice. In this procedure, single layers (for example plastic film, non-crimp fabric, plastic film) are stacked into a heat press, fused under pressure, removed and further processed into sheets in another machine. For “Natural fibres have a special characteristic in contrast to glass or carbon fibres: they readily absorb fluids. Thus, prior to the processing, they have to dry”, explained Ouali. “At the institute, we developed a dryer plant that could be attached to the calender almost without space in between. This way the dried fibre has almost no contact to the moist ambient air.” The Omega calender, named after its shape, is the heart of the continuous production path. It consists of several cylinders through which the flax fibre plastic films can theoretically be continuously fed, heated up, and pressed together. After the impregnation process and the cooling of the so-called thermoplastic prepregs, the fibre matrix semifinished product, is complete. It is wound up on a role and can be further processed in various ways. Cut to size and with numerous layers pressed as a stack a rigid sheet emerges. “We can also form the semi-finished product once more and combine it with injection moulded products. Both in just one process. This way we produced our technology demonstrator, the lightweight carrier component”, said Ouali. The production procedure is currently intermittent, with a stop after the continuous production of the prepreg semifinished product. Depending on the researcher’s need, production then continues in numerous different plants. For large-scale production, the manufacturing path can be supplemented or combined accordingly. “We developed promising, sustainable, durable materials, whose production is significantly more energy-efficient and thus shows a better carbon footprint than in conventional fibre-plastic compounds”, said Ouali. Looking to the future he explained: “We will further experiment with various fibre structures as knitted or non-crimp fabrics, or in other forms and with different matrix combinations for example films or spun-bonded fabric.” MT www.tu-chemnitz.de/MERGE bioplastics MAGAZINE [04/17] Vol. 12 27

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