Permanently Reprocessable Highly Cross-Linked Thiourethane Networks Derived from Isocyanate-Reactive Amine Catalyst

Vitrimers combine thermoset-like stability with thermoplastic-like reprocessability. Thiourethane polymers retain the advantages of classical polyurethanes while enabling efficient dynamic covalent bond exchange. We present a library of high-performance, recyclable thiourethane networks with tunable structure-property relationships and excellent shape-memory behavior. To improve recyclability, we introduce two key strategies: (1) covalently bonding the amine catalyst to an isocyanate group, which prevents catalyst leaching and ensures permanent recyclability; and (2) a reprocessing method that blends ground recycled material with uncured resin, followed by curing and compression under heat to restore mechanical and optical properties. Together, these approaches yield seamless, mechanically robust shape-memory polymer networks and support the sustainable design of smart materials with the potential for multiple life cycles and reduced environmental impact.