Selective ABS dissolution with eutectic solvents: toward greener recycling

Acrylonitrile-butadiene-styrene (ABS) plastics, commonly found in electronics, automotive parts, and household items, continue to pose a substantial environmental challenge, with the majority still ending up in landfills or incinerators. Dissolution-based recycling methods have emerged as effective alternatives to conventional mechanical recycling, particularly for recovering high-quality fractions. This work explores the use of eutectic solvents (ESs) as renewable, low-impact alternatives for the selective dissolution and recovery of ABS components—specifically, the styrene-acrylonitrile (SAN) copolymer. A computational solvent screening of over 30 000 potential candidates was conducted using the COnductor-like Screening Model for Realistic Solvents (COSMO-RS), followed by experimental validation to assess the solubility of SAN in selected ESs. The solubility of SAN was assessed under mild conditions (60 °C, 1 h), and three ESs systems were found to be effective, with recovery yields up to 70%. The recycled polymer and residues were characterized using Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) analyses. Notably, preliminary results suggest that effective dissolution is possible even at ambient temperature and pressure. These findings highlight the potential of ESs as sustainable and scalable solutions for the recovery of difficult-to-recycle polymeric waste such as ABS.

Acknowledgements:
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, financed by national funds through the FCT/MCTES (PIDDAC). This research is also sponsored by FEDER funds through the program COMPETE—Programa Operacional Factores de Competitividade—and by national funds through the FCT under the project UID/EMS/00285/2020. AMF, FHBS, and AFS acknowledge FCT for the research contracts CEECIND/00361/2022, CEECIND/07209/ 2022, and CEECIND/02322/2020 under the Scientific Stimulus – Individual Call, respectively. VP and LC acknowledge the European Commission for the research grant under Horizon Europe ABSolEU - "Paving the way for an ABS recycling revOLution in the EU" (HORIZON-CL4-2021-RESILIENCE-01-Project: 101058636) HOP ON program.