Tailoring the Reprocessability of Thiol-Ene Networks through Ring Size Effects

Area of Science:

• Polymer Chemistry
• Materials Science
• Sustainable Materials

Background:

• Recycling thermosetting materials is difficult, hindering sustainable material use.
• Dynamic covalent cross-linking offers a solution by combining thermoset integrity with thermoplastic processability.
• Thioether linkages are common but typically slow to exchange via transalkylation.

Purpose of the Study:

• To design novel dynamic polymer networks utilizing thioether cross-links.
• To enhance the speed of thioether bond exchange reactions.
• To achieve reprocessable thermoset-like materials.

Main Methods:

• Rational design of dynamic polymer networks using dithiol-based monomers and a fatty acid derived triene.
• Investigating thioether bond exchange dynamics.
• Tuning exchange rates by adjusting the distance between thioether functionalities.

Main Results:

• Developed dynamic polymer networks with neighboring thioethers enabling faster bond exchange.
• Demonstrated tunability of exchange dynamics over three orders of magnitude.
• Created thioether-cross-linked materials processable by extrusion.
• Materials exhibited good creep resistance below 70°C.

Conclusions:

• Fast-exchanging thioether networks offer a viable route to reprocessable thermoset-like materials.
• Extrusion processing is now accessible for these advanced cross-linked materials.
• This approach contributes to sustainable material solutions by enabling recycling.