Projet de recherche BL/V/20 (Action de recherche BL)
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In order to reduce the negative impact of global warming and the dependency on non-renewable materials, the rational exploitation of natural resources and the development of environment friendly new technologies are essential. BelSPO has since a few years been supporting research at KU Leuven in a joint program with two leading Vietnamese universities, to develop bamboo fibres for lightweight, structural composite materials.
Environment friendly materials
Nowadays, rational exploitation and use of sustainable natural resources are a necessity and they will play a crucial role in the near future (e.g. environmental legislation and recycling targets). For this reason, there is an increasing interest in so-called renewable materials, to which category natural fibres clearly belong.
Light-weight and strong natural fibre composite materials are an efficient alternative for energy saving in transport applications. Composite materials, often shortened to “composites”, are still relatively new materials. Most composites have strong, stiff fibres embedded in a thermoset (e.g. epoxy or polyester resin) or thermoplastic (e.g. polypropylene) matrix. These polymers are weaker in comparison with the fibres, but when the two phases are combined it is possible to make a light and strong composite material, where the fibres carry the majority of the loads and the polymers protect the fibres from e.g. abrasion and prevent the fibres from buckling.
Traditionally, glass and carbon are the most common fibres to reinforce polymer composites with a great acceptance due to their good mechanical properties. Nevertheless, they are non-renewable materials and their production has high energy consumption.
Due to their abundant resources and environmental superiority, natural fibres have already become commercially available in the fabrication of some industrial polymeric composite structures, like interior door panels in cars. Several studies involving life cycle assessment (LCA) have been performed to compare glass fibre composites and natural fibre composites. These studies agree that natural fibres are likely to be environmentally superior to glass fibre in each phase of the life cycle of the composites:
- Production phase: In terms of fossil energy consumption, the production of natural fibre, including cultivation, harvesting and fibre treatment is much more energy efficient than the production of glass fibre; consequently, the release of carbon dioxide is reduced.
- Use phase: In transport applications, the light-weight natural fibres (density around 1.4 as compared to 2.5 for glass fibre) improve fuel efficiency, thus reducing emissions during the use phase of the component.
- End of life: natural fibres are combust-able and in many cases biodegradable, thus they can be easily incinerated or decomposed in the natural environment. In case they are combined with a thermoplastic matrix, they can also be easily recycled mechanically (e.g. by grinding and injection moulding into a new product), with reduced fibre breakage.
Nowadays at Katholieke Universiteit Leuven (KU Leuven), an ambitious research program carried out in the Composite Materials Group, has the aim to use natural fibres from different parts of the world (coconut from Vietnam, jute from Bangladesh, flax from Belgium and bamboo from Colombia and Vietnam), to be used as a reinforcement in composite materials to substitute synthetic fibres like glass in several applications. More information can be found at: http://www.mtm.kuleuven.be/Onderzoek/Composites/
