Recyclable and Depolymerizable Polymer Network Materials via Thiourethane Dynamic Chemistry

NU2019-126

INVENTORS

• John Torkelson*
• Lingqiao Li
• Xi Chen

SHORT DESCRIPTION
A class of reprocessable, PU-like polymer networks synthesized via thiourethane dynamic chemistry that allow for complete cross-link density recovery and offer the potential for monomer recovery under mild conditions.

BACKGROUND
Traditional cross-linked polyurethane networks, though widely used in elastomers, coatings, and foams, suffer from irreversibility and limited recyclability. Current recycling approaches often require harsh conditions or involve multi-step synthetic procedures. Against this backdrop, developing a simple, rapid, and efficient reprocessing method that maintains material properties and enables sustainable monomer recovery has become a critical need for high-value applications.

ABSTRACT
The disclosed technology leverages thiourethane dynamic chemistry to synthesize reprocessable polymer networks from commercially available thiols and isocyanates. This method utilizes a unique combination of associative exchange and dissociative reversible pathways, enabling full recovery of cross-link density after multiple reprocessing cycles conducted at significantly lower temperatures and shorter durations compared to traditional PU remolding approaches. Furthermore, the invention demonstrates a proof-of-principle for recovering thiol monomers from spent networks via benign alcohol solvolysis, thereby offering a dual sustainability benefit: reprocessing of the original network and direct monomer recycling for the creation of new materials. This innovation streamlines the synthesis process, avoids complex multi-step reactions, and provides a platform for creating diverse recyclable polymer network materials suitable for high-performance industrial applications.

APPLICATIONS

• Recyclable polymer network and network composite materials: Enable sustainable materials reuse.
• Adhesives with superior performance: Offer advanced bonding properties with recyclability.
• Coatings with advanced functions: Incorporate self-healing and enhanced durability.
• Recyclable foams: Provide environmentally friendly, high-performance foam products.

ADVANTAGES

• Simple and efficient chemistry: Reduces process steps while ensuring effective synthesis.
• Excellent property recovery after recycling: Achieves full restoration of cross-link density.
• Potential to directly recover monomers: Facilitates monomer reclamation under mild conditions.
• Fast reprocessing: Enables rapid network molding at lower temperatures and shorter durations.

PUBLICATIONS

• John Torkelson et al., Reprocessable Polymer Networks via Thiourethane Dynamic Chemistry: Recovery of Cross-link Density after Recycling and Proof-of-Principle Solvolysis Leading to Monomer Recovery, Macromolecules, 2019

IP STATUS
Issued US Patent US20200407482A1