Polyethylene Solubility for Solvent-Based Recycling: Experiments and Modelling using a multireactor crystalliser

The increasing demand for sustainable plastic waste management has heightened interest in solvent-based recycling as an alternative to traditional recycling methods. Unlike mechanical recycling, solvent-based recycling selectively dissolves target polymers, allowing for the efficient separation of contaminants, additives, and other plastics prior to polymer recovery. The success of this process relies on identifying solvents that offer high polymer solubility while adhering to environmental, safety, and economic standards. In this study, the solubility behavior of four polyethylene (PE) samples with varying molecular weights and melting properties was experimentally examined in ten solvents using the Technobis Crystal16 instrument. The experimental data were further utilized to assess the predictive capability of the SAFT-γ Mie group-contribution equation of state for modeling polyethylene solubility.

This research offers extensive experimental and modeling data on polyethylene solubility pertinent to solvent-based recycling methods. The findings affirm that decalin and aromatic solvents are highly effective, while several bio-derived solvents present sustainable alternatives with minimal performance reduction. The SAFT-γ Mie equation of state accurately predicted polyethylene solubility in various solvent systems. In summary, the integration of Crystal16 measurements and thermodynamic modeling delivers an efficient strategy for crafting sustainable solvent-based recycling processes for polyethylene.