Mechanistic kinetic Monte Carlo modeling of the synthesis of hyperbranched polyesters

Most plastics recycled today are recycled mechanically, often referred to as downcycling due to the inevitable degradation of the polymer material. One alternative is to chemically recycle these materials back to a monomer, but this works most efficiently for intrinsically circular polymers (iCPs) that exhibit appropriate depolymerization thermodynamics and kinetics. In order to help design such iCP materials, modeling can provide insight into the effect of reaction conditions on their polymerization and depolymerization characteristics. Most iCPs reported are linear polymers, so architecturally complex hyperbranched polymers that exhibit complete chemical circularity are rare, and modeling on hyperbranched iCPs has not been reported. Here, we report a mechanistic model that incorporates chain-length-dependent transport phenomena and tracks the full polymer structure during the reversible polymerization of a hydroxyl-functionalized lactone leading to this hyperbranched polyester. This lays the groundwork for future modeling of this material's depolymerization behavior and provides a framework that can be employed to study other iCPs.