Dynamic Cross-Linker Facilitates a Closed-Loop Circular Economy in Upcycled Acrylonitrile-Butadiene-Styrene

With an increase in the production of plastics in the previous decade, the management of plastic waste has become an increasingly important topic for researchers to deal with. Plastic recycling, although a very prominent option, has its limitations by way of poor mechanical integrity of recycled plastic compared to virgin plastic, which severely limits the applications of this recycled plastic. To facilitate closed-loop recycling in thermoplastics, scientists have increasingly turned to dynamic covalent bonds (DCBs) as a potential solution. Incorporating DCB’s into commercially available plastics to convert them into vitrimers improves the mechanical integrity of plastics and preserves them during the recycling process. In this study, we convert acrylonitrile-butadiene-styrene (ABS) into vitrimers via reactive extrusion, which is a facile and industrially scalable method widely employed in the polymer industry. The vitrimerization process was carried out by cross-linking ABS with a commercially available polyepoxide resin, 4,4′-methylenebis(N,N-diglycidylaniline) (TGDDM). The vitrimers showed a significant improvement in the ultimate tensile strength (approximately 44%) and high retention of mechanical and thermal properties after three reprocessing runs. Additionally, the vitrimers showed good dimensional stability, good thermal stability, and fast stress relaxation at elevated temperatures. This strategy can potentially be used for recycled ABS to convert them into closed-loop recyclable plastics using commercially available cross-linkers.