Repurposing Post-Consumer Polyethylene to Access Cross-Linked Polyethylene with Reprocessability, Recyclability, and...

Area of Science:

• Materials Science
• Polymer Chemistry
• Sustainable Engineering

Background:

• Polyethylene (PE) waste is a major environmental concern due to its persistence and accumulation.
• Upcycling PE into value-added products offers a sustainable solution to the plastic waste crisis.

Purpose of the Study:

• To develop a reprocessable and chemically recyclable cross-linked polyethylene (XLPE) from mixed post-consumer PE.
• To investigate the performance and recyclability of the novel XLPE material.

Main Methods:

• Conversion of PE into telechelic oligomers.
• Repolymerization using a hybrid cross-linking system with dynamic (TETA) and non-dynamic (Tri-HDI) cross-linkers.
• Copolymerization with macrodiols to create composite XLPEs.
• Evaluation of mechanical properties, thermal stability, and creep resistance.
• Assessment of depolymerization and repolymerization for circularity.

Main Results:

• Successfully synthesized reprocessable and chemically recyclable XLPE from mixed post-consumer PE.
• XLPE exhibited improved mechanical properties, reduced creep, and high-temperature stability compared to PE.
• TETA enabled iterative reprocessing with minimal degradation; Tri-HDI ensured functional performance.
• Composite XLPEs allowed for tunable material properties.
• Efficient and selective depolymerization under mild conditions, even in mixed waste streams, enabling monomer recovery.

Conclusions:

• The developed XLPE offers a viable pathway for upcycling plastic waste into high-performance, recyclable materials.
• This approach promotes a circular economy by enabling the recovery and reuse of polymer building blocks.
• The material's properties and recyclability demonstrate significant potential for reducing plastic pollution.