Rotorcraft access panel from recycled carbon PPS - World 's first flying fully recycled thermoplastic composite application in aerospace Artikel is met toestemming overgenomen uit: Composite Solutions & Technopolymers nr 2. 2020
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In the high-tech mechatronics world, aluminum and steel are well known materials, while carbon fiber is often neglected. In the RAAK project 'Composites in Mechatronics', the use of carbon fiber composites in mechatronics is investigated.
Stricter environmental policies, increased energy prices and depletion of resources are forcing industries to look for bio-based and low carbon footprint products. For industries, flax is interesting resource since it is light, strong, environmental friendly and renewable. From flax plant to fiber products involves biochemical and mechanical processes. Moreover, production and processing costs have to compete with other products, like petroleum based materials. This research focusses on sustainable process improvement from flax plant to fiber production. Flax retting is a biological process at which mainly pectin is removed. Without retting, the desired fibre remains attached to the wooden core of the flax stem. As a result, the flax fibres cannot be gained, or have a lows quality. After retting, the fibers are released from the wooden core. Furthermore, machines have been introduced in the flax production process, but the best quality fibers are still produced manually. Due to the high labor intensity the process is too expensive and the process needs to be economical optimized. Since the retting process determines all other downstream processes, retting is the first step to focus on. Lab-scale experiments were performed to investigate the retting process. Factors that were researched were low cost processing conditions like, temperature, pH, dew retting and water retting. The retting rate was low, around three weeks for complete retting. The best retting conditions were at 20°C with water and any addition of chemicals. The process could be shortened to two weeks by recycling the water phase. In a scale-up experiment, a rotating drum was used at the optimal conditions from the lab-experiment (20°C and water). First the flax did not mix with the water content in the rotating drum. The flax was too rigid and did not tumble. Therefore, bundles of flax plants were used. The inner core of the bundle seemed to be protected and the retting rate was less compared to the flax on the surface of the flax bundle. This implies that mechanical impact increased retting in the rotating drum, however heterogeneous retting should be avoided. To overcome the heterogeneous retting problem, a water column was used to improve heterogeneous retting. Retting was performed in a water column and mixing was accomplished by bubbling air. As a result of the mixing, the flax bundle was retted homogenously. And after drying, it was possible to separate the fibers from the wooden flax core. Retting with a bubble column can overcome this problem and seems to be a usable retting process step. Water samples of the lab-scale experiments, the rotating drum and the bubble column showed a chemical oxygen demand (COD) content up to 4 g/L. Overall, 1 kg Flax resulted in 40 g COD. This indicates the possibility to produce biogas that can be used for generating heat and electricity, to make the process sustainable. Around 50% of the weight consists of wooden shives. The shives can be used for pyrolysis and it was possible to produce around 30% coal and 20% oil. These compounds can be used as building blocks, but also to generate heat and electricity. Heat and electricity can be used for the flax processing. Shives were only dried for 1 day at 105°C and slow pyrolysis was used. This indicates that a higher yield can be expected at fast pyrolysis. Overall, the reported implicates that quality fiber production from flax plant can be a feasible, sustainable and a renewable production process. Feasibility of the process can be obtained by, (1) retting at low-cost process conditions of 20°C and using water without any addition of chemicals, (2) with increased flax retting rate by recycling water, (3) with increased flax retting rate by introducing mixing forces, and the ability to lower the energy consumption of the overall process, (4) producing biogas from the COD with anaerobic digestion and (5) producing pyrolysis oil and pyrolysis c
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The research for alternatives to substitute cement in concrete increased in the last years to reduce the environmental impact. Geopolymers or alkali-activated materials are one of the options. The proposed project aims to obtain a wet cell based on a geopolymer with alginate and natural fibres. The wet cell will be a final prototype composed of panels for wet construction areas such as bathrooms and kitchens. There is a lack of biobased solutions for wet areas currently in the market. And the present project, together with companies of suppliers and users from the market, aims to provide a solution for a wet cell using biobased materials. The natural fibres added to the geopolymer will substitute a portion of sand and gravel, producing a lighter product than concrete. Also, the fibres increase the thermal and acoustic insulation. Natural fibres should be pretreated to increase the bond with other materials in the mixture. The chemical used in the alkali-activated materials is the same to pretreat the fibres. Also, alginates extracted from seaweeds can be used as binders, and alkali is used in the extraction process. One of the objectives is to develop the method and technique to produce geopolymer with alginates and pretreat the fibre simultaneously during the mixture. After defining the optimum mixture for the geopolymer, panels will be produced, and in the end, a wet cell will be constructed with the geopolymer panels.
Façades have a high environmental and economic impact: they contribute 10-30% to GHG emissions and 30-40% of the building investment of new buildings [1]. Modern façades are highly optimized complex systems that consist of multiple components with varying life cycles [2]; however, many of the materials they employ are critical, and have a high CO2 footprint [3, 4]. New bio-composite facades products have emerged (a) whose mechanical properties are comparable to those of aluminum or glass fibre; (b) have a lower energy footprint; and (c) can fully or partially biodegrade [5]. Moreover, primary material sourcing from different waste streams can significantly lower the end products’ pricing. Still, their aesthetic qualities have not been sufficiently explored, so the scalability of their production remains limited. This project will develop specific combinations of bio-composites using food waste fillers and a biopolymer resin. Sheet samples will be made from these combinations and further tested against their mechanical properties, water resistance, aging and weathering. A Life Cycle Analysis will further consolidate the samples’ energy footprint. A new facade cladding tile product system with complex geometry using the overall best performing material composition will be designed and prototyped [17]. Emphasis will be given to the aesthetical properties of the tiles and their demountability. The system tiles will be further applied and tested at 1:1 scale, at The Green Village. During the project, an advisory board consisting of several companies within the building industry will be systematically consulted and their feedback will help the overall design process and their respective end products.
RECURF onderzoekt eigenschappen en duurzaamheid van materialen waarin (textiele) restvezels en biobased plastics worden gecombineerd. De mogelijkheden worden verkend om met deze nieuwe materialen producten te ontwikkelen voor in- en exterieurgebruik. De ontwerpen worden geëvalueerd op technisch, economisch en ecologisch vlak. De bedrijven die restvezels leveren (?urban fibres?) treden ook op als launching customer voor de ontwikkelde producten. Het project leidt niet alleen tot kennis over nieuwe materialen en de toepassing daarvan, het onderzoekt ook circulaire business modellen waarin afvalstromen tot waardecreatie leiden.
