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

## TL;DR

This paper introduces recyclable thiourethane networks that can be reprocessed multiple times without losing their mechanical and optical properties, enabling sustainable smart materials.

## Contribution

The novelty lies in covalently bonding the amine catalyst and a new reprocessing method for permanent recyclability.

## Key findings

- Covalently bonded amine catalyst prevents leaching and enables permanent recyclability.
- Reprocessing method restores mechanical and optical properties of the polymer networks.
- The networks exhibit excellent shape-memory behavior and tunable properties.

## Abstract

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.