Reprocessable and Recyclable Materials for 3D Printing via Reversible Thia-Michael Reactions.

Area of Science:

• Polymer Chemistry
• Materials Science
• Sustainable Manufacturing

Background:

• Plastic waste is a significant environmental concern, necessitating the development of recyclable materials.
• Additive manufacturing, or 3D printing, offers design flexibility but often relies on non-recyclable plastics.
• Achieving a circular economy for polymers requires innovative materials with inherent recyclability.

Purpose of the Study:

• To introduce a novel class of chemically recyclable polymers, polythioenones (PCTE).
• To evaluate the synthesis, mechanical properties, and 3D printing performance of these new polymers.
• To demonstrate the closed-loop recyclability of PCTE for sustainable additive manufacturing.

Main Methods:

• Synthesis of cyclic thioenone (CTE) monomers via Michael addition-elimination ring-opening polymerization (MAEROP).
• Characterization of the resulting polythioenones (PCTE) for mechanical performance and thermal stability.
• 3D printing of PCTE using fused-filament fabrication (FFF) and assessment of printability and recyclability.

Main Results:

• PCTE monomers are easily synthesized, scalable, and modular.
• PCTE exhibits superior mechanical properties compared to commodity polyolefins like polyethylene and polypropylene.
• PCTE-Ph demonstrated excellent 3D printability and retained mechanical strength and thermal stability after recycling.
• PCTE-Ph achieved a 90% yield upon depolymerization, enabling successful repolymerization.

Conclusions:

• Polythioenones (PCTE) represent a promising class of sustainable polymers for 3D printing.
• The developed MAEROP process allows for the creation of high-performance, recyclable materials.
• PCTE facilitates a closed-loop life cycle, offering a viable alternative to conventional plastics in additive manufacturing.