Modulating Polyethylene Mimics with Degradability via Synthesis and Modeling

Polyethylene (PE) is one of the most important and widely used commodity polymers in the world. It is also among the vital and notoriously nondegradable plastics. Recent efforts are revisiting different approaches to create new generations of PE mimics. We report a model system to explore mimics of functionalized high-density polyethylene (HDPE) and low-density polyethylene (LDPE) via ring-opening metathesis polymerization (ROMP) and thiol–ene click chemistry. By combining experimental and computational studies, we demonstrated that the properties of PE mimics are highly tunable by changing the ester-to-methylene ratio (E:M), with low E:M (e.g., 1:413) functional polymers having characteristics similar to those of HDPE. Controlling the branch-to-methylene ratio (B:M) from 1:159 to 1:22 provided a handle for mimicking the transformation from HDPE to LDPE characteristics. The PE mimics exhibit competitive mechanical properties, melting temperature, and high molecular weight comparable to PE while being accessible via an efficient synthetic route. Notably, the PE mimics can be degraded into oligomers and then recycled, demonstrating the potential for circularity and sustainability. This study provides valuable insights into predicting the properties of aliphatic long-chain functional polymers to mimic PE.