A Cleavable Crosslinking Strategy for Commodity Polymer Functionalization and Generation of Reprocessable Thermosets

Area of Science:

• Polymer Science
• Materials Chemistry

Background:

• Thermosets offer superior mechanical and thermal properties due to covalent crosslinks.
• These crosslinks hinder reprocessing and recycling, creating plastic waste.
• Developing recyclable thermosets is crucial for a sustainable plastics economy.

Purpose of the Study:

• To introduce chemically cleavable groups into crosslinkers for polyolefins.
• To enable reprocessing and recycling of covalently crosslinked polymers.
• To explore the potential for a circular economy in plastics manufacturing and use.

Main Methods:

• Synthesized a bis-diazirine crosslinker incorporating chemically cleavable groups.
• Applied the crosslinker to commercial low-functionality polyolefins and a small-molecule model.
• Investigated the uncoupling of introduced molecular crosslinks using specific chemical inputs.

Main Results:

• Successfully introduced molecular crosslinks into polyolefins using the novel crosslinker.
• Demonstrated that these crosslinks can be efficiently and rapidly cleaved by specific chemical stimuli.
• Showcased the potential for reprocessing and re-using crosslinked polyolefins without material degradation.

Conclusions:

• The developed cleavable crosslinker offers a viable strategy for creating recyclable thermoset materials.
• This approach supports the circularization of the plastics economy, reducing waste and preserving material value.
• The method also provides a means to introduce functionality into commodity polymers.