Vat Photopolymerization Additive Manufacturing of Tough, Fully Recyclable Thermosets

Area of Science:

• Materials Science
• Polymer Chemistry
• Additive Manufacturing

Background:

• Additive manufacturing requires advanced resins for high-fidelity, mechanically robust, and recyclable parts.
• Current materials often lack the combination of toughness, recyclability, and dynamic properties.

Purpose of the Study:

• To develop novel thiol-ene-based resin formulations for additive manufacturing.
• To incorporate semicrystallinity and dynamic thioester bonds for enhanced material properties and recyclability.

Main Methods:

• Synthesis of a thiol-ene polymer network with integrated semicrystallinity and dynamic thioester bonds.
• Characterization of mechanical properties, including ultimate toughness.
• Demonstration of network degradation into functional oligomers via thiol-thioester exchange.
• Repolymerization of oligomers into networks with tunable thermomechanical properties.
• 3D printing of lattice structures using stereolithography.

Main Results:

• Achieved ultimate toughness values exceeding 16 MJ cm^-3.
• Demonstrated efficient degradation and repolymerization of polymer networks.
• Fabricated elastomeric networks capable of recovering from >100% strain.
• Printed stiff (E ~ 10-100 MPa) and soft (E ~ 1-10 MPa) lattice structures.
• Incorporated self-healing and shape-memory functionalities.

Conclusions:

• The developed thiol-ene system offers a promising platform for high-performance, recyclable additive manufacturing.
• The combination of dynamic chemistry and crystallinity enables advanced material properties and functionalities.
• These materials advance the development of functional 3D printed objects with tailored performance.