Scientists from the University of the United Arab Emirates conducted research to create recycled composite materials using PLA scraps from 3D prints and carbon fiber. The research is in line with the trend of reusing plastic waste, which is particularly important in the case of carbon fiber, which has seen a significant increase in demand for the last few years, being used mainly in the automotive and aviation industries. United Arab Emirates researchers found a way to recycle these two different waste streams into functional composite materials.
Filament based on PLA is one of the most popular materials in 3D printing. It was created as a more environmentally friendly alternative to petroleum based polymers and is technically biodegradable (under industrial composting conditions). In addition to 3D printing, it is widely used in the production of packaging and disposable tableware and cutlery. Unfortunately, pure PLA offers poor thermal and mechanical stability, so it is not suitable for any high-performance application.
One way to improve the properties of the material is through additives like carbon fiber, which offer an excellent combination of mechanical properties and heat resistance. To create recycled composite materials, the UAE team collected residues from 3D prints made from PLA and scraps of carbon fiber in the form of scrap CF-prepreg sheets. The waste was crushed, ground and melted mixed in various percentages. The team then hot-pressed the polymer into lab samples and tested their mechanical properties.
Scientists found that both the percentage of additive and the type of filler had an impact on the mechanical performance – e.g. the 20% carbon fiber composite had a higher modulus of elasticity than the 20% carbon fiber prepreg composite. Carbon fiber reinforcements have improved the strength of PLA, with the 20% carbon fiber composite offering the highest yield strength. However, it has been found that a higher percentage of carbon fiber has a negative effect on the ductility of the material.
Work has shown that it is possible to recycle both PLA and carbon fiber simultaneously to develop green composites with regulated properties. The authors hope their project can serve as a springboard for others to explore more efficient ways to create recycled composites for industry.
Source: www.mdpi.com via www.3dprintingindustry.com
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