New Recyclable Polymer Developed for 3D Printing

A research team at the Georgia Institute of Technology has developed a new class of polymers suitable for 3D printing and fully recyclable. Known as polythioenones, these materials combine mechanical stability with chemical recyclability and could serve as a more sustainable alternative to conventional polymers. The findings were published in the journal Angewandte Chemie.

In 3D printing, particularly in Fused Filament Fabrication (FFF), thermoplastic polymers are extruded through a nozzle and deposited layer by layer to form components. While this method allows for efficient material usage, most commonly used polymers lack high recyclability and contribute to long-term environmental issues. The newly developed polythioenones could address these limitations, as they are both mechanically and chemically recyclable.

The chemical foundation of this new polymer class is a cyclic monomer composed of seven carbon atoms and one sulfur atom. These cyclic thioenones (CTE) polymerize through a Thia-Michael addition reaction. A major advantage of this reaction is its reversibility, enabling controlled depolymerization. This allows the polymer to be broken down into its original monomers, which can be re-polymerized for reuse.

One particularly promising variant is PCTE-Ph, a polymer with aromatic side groups. It exhibits high thermal stability and strong mechanical properties, making it ideal for 3D printing. The material can be re-melted and reprocessed multiple times without losing quality. Additionally, with the use of catalysts, it can be almost completely broken down into its original monomers, enabling a closed-loop material cycle.

The development of this polymer class could advance the use of sustainable materials in 3D printing. By allowing fully recyclable printed components, it could help reduce material consumption and save fossil resources over time. Whether polythioenones prove viable for industrial applications remains the subject of further research.