Molecular Insights into Cleavable Bond-Modified Polyethylene: High-Throughput Simulations for Circular Polymer Design

Polyethylene represents the largest fraction of materials used in global plastics production. However, chemical recycling of polyethylene ineffective in its current state due to the high energetic cost associated with breaking down the carbon-carbon sigma bond in polyethylene. We performed a systematic exploration aimed at establishing structure-property relationships in polyethylene-based polymers containing strategically incorporated cleavable bonds, with the aim of enhancing their chemical recyclability. Employing high-throughput molecular dynamics simulations guided by Gaussian process regression, we investigated six distinct telechelic functionalities across varying chain lengths: ester, aromatic ester, anhydride, carbonate, urethane, and amide linkages. Our study focused on elucidating the effects of cleavable bonds on heat of vaporization, density, diffusion, and viscosity, key parameters for polymer processing, within a range of temperatures in the melt phase. By comparing these properties with those of linear polyethylene, we establish a framework that provides crucial insights into polymer behavior. Our findings provide a roadmap for chemists engaged in sustainable polymer synthesis, guiding the design of circular polymers that align with principles of environmental responsibility.