June 22, 2022 feature
by Thamarasee Jeewandara , Phys.org
If bioengineers can upcycle commodity plastics into higher-performance materials, they can establish sustained closed-loop manufacturing with broader industrial and environmental benefits. For example, upcycled plastics can be reprocessed to form custom-designed structures via an energy-resource-efficient additive manufacturing circuit based on fused filament fabrication (the FFF method). In a new report now published in Science Advances, Sungjin Kim and a team of researchers in chemistry, materials science and interdisciplinary research at the Oak Ridge National Laboratory and the University of Tennessee, U.S., introduced a circular model to upcycle a prominent thermoplastic known as acrylonitrile butadiene styrene (ABS). The team upcycled the material into a recyclable and robust covalent network, reprintable via fused filament fabrication. The process overcame major challenges of reprinting cross-linked materials to produce strong, tough and solvent-resistant 3D objects separate from unsorted plastic waste. The outcomes provide an adaptable approach for advanced manufacture of circular plastics.
Plastic production has reached a significant surge from 2.13% in 2013 to a projected 16% of the net global carbon emission by 2050. As a best-case scenario, researchers therefore aim to increase plastic recycling to reduce the production demand growth and lower carbon dioxide emission by 93%. By establishing a closed-loop circulation of plastics, they can achieve net-zero carbon emission to develop manufacturing paths of plastics for the best possible outcomes. Of the existing manufacturing methods, additive manufacture provides 3D materials production on demand to convert plastic wastes into useful 3D constructs with better material performance and thereby uphold the circular plastics economy. The team incorporated the method of fused filament fabrication for its user-friendly and approachable printing protocols. In this work, Kim et al converted acrylonitrile butadiene styrene (abbreviated as ABS) into a high-performance vitrimer by using the technique of full fused filament fabrication.