Tailoring the Properties of Chemically Recyclable Polyethylene-Like Multiblock Polymers by Modulating the Branch Structure.

Developing plastics that fill the need of polyolefins yet are more easily recyclable is a critical need to address the plastic waste crisis. However, most efforts in this vein have focused on high-density polyethylene (PE), while many different types of PE exist. To create broadly sustainable PE with modular properties, we present the synthesis, characterization, and demonstration of materials applications for chemically recyclable PE-like multiblock polymers prepared from distinct hard and soft blocks using ruthenium-catalyzed dehydrogenative polymerization. By altering the branching pattern within the soft blocks, a series of PE-like multiblock polymers were synthesized with tunable glass transition temperatures (T) while maintaining consistent high melting temperatures (T). A clear U-shape trend between T and mechanical properties was found, showcasing their potential as sustainable materials with tailored properties spanning commercial linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE). These materials offer adjustable adhesive strength to metal and demonstrate chemical recyclability and selective depolymerization in mixed plastic streams, promoting circularity and separation.