Bio-based textile innovations
Revolutionary innovations are to be expected for the next decade on the interface between biology and technology. This applies both to the basic materials for the synthetic materials industry and the packaging industry and for the manufacturing mechanisms in the textile industry as well. By every process which uses renewable resources and bio-technological procedures with the aim of producing materials or affecting their characteristics, the biologization of industry is moving forward. An increasing number of projects are aimed at replacing conventional materials used so far with bio-based solutions.
At the same time, we are going to be faced in the next decade with a considerable shortage of resources and a reorientation of the mobility concepts. The success of the electromobility will depend decisively on how the designers will be successful in reducing the weight of the cars. The use of lightweight materials will play a very important role in this context. This is why in the past years heavy metal structural components have been more and more replaced with fiber-reinforced synthetic parts which are increasingly based on renewable raw materials thus helping to improve the carbon footprint considerably.
Techtextil will present a variety of new bio-based developments. Current and recently completed research projects include organic plates made from natural fibers (TU Dresden), light sandwich or hollow structures (ITV Denkendorf), bio-based self-reinforcing composite materials (RWTH Aachen) and highly pure alginates (Hohenstein Institute).
Organic plates made from natural fibers
With the aim of reducing the weight of automobiles and aeroplanes, new materials and manufacturing processes have been developed in the past years in order to replace metal structural elements with lightweight synthetic composite materials. By this way so-called organic plates (fiber-reinforced plastic sheets – so-called nylon composite sheets) in the form of plate-shaped and thermoductile semi-finished products are being used more frequently. In general these composite materials consist of synthetic fibres such as glass fibers, carbon fibers or aramide fibers and a matrix system made of thermoplastic synthetic or petrochemical materials. Thanks to the naturally good adhesion between the natural fibers and the biopolymer it is not necessary to use adhesives. The composite materials produced in such a manner are completely based on renewable raw materials and are distinguished by better technical characteristics compared to the materials which have been used so far. In the majority of cases their weight is lower, they do not split in case of crashes and do not develop sharp breaking edges. In addition vibration damping and sound dissipation is much better and the energy balance is considerably more favourable as well.
Spacer textiles with double-curved fabric structures
Fiber-reinforced fabric structures do not only fulfill the necessary material characteristics in terms of strength and rigidity for industrial applications but also increasingly enable free industrial design and styling of curved components. Scientists of the Institute of Textile and Process Engineering Technology at Denkendorf (Germany) have developed new methods for the production of extremely light sandwich or hollow structures and plan-parallel spacer fabrics as well as double-curved fabric structures. The scientists imitated the shell structure of the sand dollar (a species of sea urchin) and transmitted this structure to curved spacer fabrics. This species of sea urchin possesses a curved outer shell with thin inside struts which make the shell very light and pressure-resistent at the same time. The structure was implemented within the manufacturing process by procedural adaptations and the use of a double rapier weaving machine (warp knitting loom) and connecting spacer threads. By this way the space between the covering fabric layers could be extended considerably without reducing the required compressive strength. Thanks to conversion from plan-parallel to variable space between the fabrics in the warp and the weft direction the prerequisite condition for freely shapable curved surfaces of both covering layers of the fabric could be ensured.
Bio-based self-reinforcing polymer composite materials
Fiber-reinforcement of lightweight composite materials is offering a high potential for saving resources in lightweight construction. However, since fiber and matrix materials differ in general, a correctly sorted separation and recirculation into the material flow requires considerable cost and work. To avoid this, so-called self-reinforcing polymer composite materials (SRPC) can be used which even possess better mechanical qualities than fiber-reinforced materials. This is due to the conservation of the molecular structure of the partly crystalline areas in the final structure of the material. The matrix is created by the targeted initial fusing of the reinforcement fibers. A big advantage compared to the conventional fiber-reinforced composite materials is the fact that only one single polymer family is used for the production of self-reinforcing polymer composite materials (SRPC) and recycling at the end of the product life is considerably easier. Within the scope of a joint project between Centexbel and the SLC Lab from Belgium processes have been developed in the past two years with the aim of producing self-reinforcing polymer composite materials (SRPC) from renewable polylactide synthetic polymer. Within this project some detrimental characteristics of the polylactide synthetic polymer could be eliminated by developing self-reinforcing polymer composite materials (SRPC) which clearly outperform the shock resistence and the strength of conventional polylactide synthetic plates. The project should be completed right before the start of Techtextil.
Bio-technological alginate production for the textile industry
Thanks to easy and simple cultivation, quick growth and the property of binding carbon dioxide, algae offer a large number of interesting perspectives as a natural raw material source having a high value added potential. Alginates have been used for a long time in medicine for wound dressing. The salts of the alginic acid are normally extracted from algae. Since the composition of the algae varies strongly, the quality of the alginates varies as well. Therefore the partners of the AlBioTex joint project have been committed themselves to the development of a bio-technological production process for the manufacture of highly pure alginates. The primary objective of the project is the development of defined qualities and the improvement of the ecobalance in the textile industry. “By using bio-technological procedures, the use of alginates in a special textile sector has been possible for the first time in a differentiated way” said Dr. Timo Hammer, coordinator of the AlBioTex project at the Hohenstein Institute, when the project was announced in December 2013. and coordinator of the AlBioTex project. Apart from the Hohenstein Institute, the BRAIN AG, Kelheim Fibres and rökona are partners in this research co-operation.
Image above: Spacer textiles with double-curved fabric structures (Source: ITV Denkendorf)