Polyolefin Ionomer Synthesis Enabled by C-H Thioheteroarylation

Chemical upcycling of plastic waste into high-value materials has the potential to contribute to a more sustainable plastic economy. We report the synthesis of high-value ionomers directly from commodity polyolefins enabled by amidyl radical-mediated C-H functionalization. The use of thiosulfonates as a linchpin functionality for the group transfer of a variety of heteroaryl groups provided tunable incorporation of ionizable functionality onto a variety of polyolefin substrates, including postconsumer polyethylene packaging waste. Synthetic, structural, and thermomechanical studies provided a comprehensive understanding of both structure-reactivity and structure-property relationships for polyolefin ionomers. X-ray scattering experiments conducted in the solid and melt states confirm the presence of ionic multiplets that serve as physical cross-links both below and above the melting temperature of polyolefin crystallites. The incorporation of ionic groups into the polyolefins yielded materials with significantly enhanced melt strength and tensile toughness. We anticipate that this approach to access performance-advantaged polyolefin ionomers from commodity substrates or plastic waste will enhance sustainability efforts and lead to new opportunities for this versatile class of thermoplastics.

Automated summary

Chemical upcycling of plastic waste into high-value ionomers has been achieved through amidyl radical-mediated C-H functionalization, enabling the incorporation of ionizable functionality onto various polyolefin substrates. The resulting materials exhibit enhanced melt strength and tensile toughness, contributing to a more sustainable plastic economy.