A “polymer-to-polymer” recycling of PET by the dissolution-precipitation strategy

The extensive production and utilization of polyethylene terephthalate (PET) products results in significant environmental pollution and waste of resources. This has focused global attention on the development of radical PET waste management strategies. Solvent-based dissolution and precipitation is a promising approach for recovering plastic from waste due to its “polymer-to-polymer” principle. However, most solvents currently used are toxic and not environmentally friendly. Herein, we have screened a bio-based solvent via Hansen Solubility Parameters (HSPs) and Conductor-like Screening Model for Real Solvents (COSMO-RS), dimethyl isosorbide (DMI), and applied it to PET recovery. DMI showed a favorable solubility (0.30 g mL −1 ) of PET in 8 min at 180 °C. Nuclear magnetic resonance (NMR) analysis and molecular dynamic (MD) simulation were combined to reveal the hydrogen bonding interaction and van der Waals interactions together contribute to the excellent PET dissolution performance. Moreover, the properties of recycled PET were similar to those of virgin PET, with minimal degradation (∼1.25 %) and negligible loss of thermal performance. DMI has satisfactory dissolution performance in Polystyrene (PS), Polyvinyl Chloride (PVC), and polylactic acid (PLA) and can effectively separate mixture plastics and multilayer films by reaction temperature-controlled and select solubility. Additives can be released to the solution system by the accessibility of the DMI, and separation from R-PET with ethanol rinse. This work provides an energy-efficient, and solvent-based process for recycling plastic waste to produce virgin-quality PET as secondary raw materials to adapt to market demand while reducing the consumption of fossil resources.