VDL recently published an article in the Kunststof&Rubber online editie about the work they are doing in the MC4 Project. Kunststof&Rubber online editie – Kunststof & Rubber
Here are some of the key points of the publication:
VDL has developed a technique that allows recycled thermoset composites to be used in lightweight applications. Up to now, recycled composites have mainly found their place in civil engineering in the form of relatively heavy, thick-walled profiles. VDL is currently working on the valorization of its new product, for example in the form of panels for buses. However, the availability of the raw material remains problematic. The Readership for Plastics Technology at Windesheim University of Applied Sciences has spent the last few years working with industry to develop a reuse method for End of Life thermoset composites, which are deformable after being heated, thermoset or thermoformed composites are very difficult to recycle.
Plastic is increasingly present on the market in the form of wind turbine rotor blades, polyester ship hulls or bus and train walls. Due to the difficulty in recycling, these solid materials are often burned or landfilled at the end of their lives. This is where Lectorat Plastic Technology in Windesheim has made its contribution. Their reuse method is based on the principle of leaving the composite intact as a material, but reducing it to small reinforcing elements in the form of flakes with a high L/D ratio. These flakes are bonded with a new (virgin) resin to form a new composite product. The product is then provided with a new composite outer shell to prevent fractures from occurring from the outside during its service life. According to Albert ten Besschen, Associate Professor at the Lectorat. for Plastics Technology in Windesheim, the material is characterized by its high mechanical strength and long-term resistance in the outdoor environment.
Lightweight applications for the recycled glass fibre composite
In parallel with this scaling up, VDL Fibertech has developed a technology to process composite flakes of end-of-life materials into lightweight, thin-walled products. VDL’s development took place within the framework of the MC4 project , which resulted in the presentation of a thin-walled panel for buses.
VDL’s technology encloses the composite in a matrix in a press, creates a vacuum, then inserts a foaming resin under pressure and presses the whole thing. This is similar to the production of a (virgin) glass fibre composite. In an office of the company in Hapert, VDL presented a number of products, including an apron cladding for a bus. Normal extruded aluminium profiles are used for this, but this recycled product would be an interesting alternative. . These side walls from disused buses could also be given a second life within the same company thanks to the new technology. As side walls, they are not suitable in recycled form. The fragmentation of the fibres removes some of the original strength.
To optimize strength and moisture resistance, the VDL developers worked together with the researchers in Windesheim, who used their knowledge of composite materials. This collaboration took place within the framework of the RAAK Circular Composites project, in which the VDL is participating.
Refinement of recycling
Note that imperfections can be found here and there on the smooth outer sheath of the deck veneer. These imperfections are due to contamination of the raw material. The resin has not been completely removed from the glass fibre everywhere and is rock hard and incompressible. The company Circular Recycling (CRC) is responsible for recycling thermoset composites. The company specializes in recycling thermoset composites, which consist of resin and glass or carbon fibres. The mechanical treatment carried out by CRC creates a “recyclate” of glass and carbon fibres. The latter constitutes approximately 70% of the residual flow with 30% of dust remaining. Through a chemical process, CRC transforms them into pyrolysis oil, which can be used as a raw material for new plastics
Continuous availability
CRC is the only recycler of thermoset composite and the composite recyclate is only available in limited volumes. According to him, this is currently the biggest obstacle for the future commercialization of the material. For serial work, availability is currently the bottleneck.. VDL is currently working on finding other market applications for the product. For example, discussions are underway with the Dutch Railways (NS), which is looking for a sustainable solution for the side walls of end of life trains. The recycled material could be used to make train tables or information panels.
Link to the full article: Kunststof&Rubber online editie – Kunststof & Rubber
Link to other article on VDL’s work: Glass fibre composites short-term recycling method – VDL Fibertech Industries – MC4 Project
“Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Health and Digital Executive Agency. Neither the European Union nor the granting authority can be held responsible for them.”