Predicting Chemical Recyclability Thermodynamics via Molecular Simulations

Abstract

Designing the next generation of circular plastics can contribute to preventing environmental pollution and the loss of embedded value. In light of this, assessing the thermodynamic parameters, i.e., the polymerization enthalpy (ΔHp) and entropy (ΔSp) of ring-opening polymerization, is becoming increasingly important as these directly connect to the chemical recyclability of polymers. However, determining the thermodynamics currently requires the synthesis of each monomer and polymer structure, consuming large amounts of time and chemicals, making it unfeasible to screen a myriad of different structures to find polymers with optimal properties and recyclability. In silico methods could mitigate these issues and drastically increase the rate at which new recyclable plastics can be developed. We demonstrate how the collision frequency between the reactive groups in polymers and monomers, derived from nonreactive (i.e., no chemical changes) molecular dynamics simulations, can be used for the simultaneous computation of ΔHp and ΔSp with respective 3.5 kJ mol-1 and 6.7 J mol-1 K-1 average deviation from experimental data.