Tuneable and degradable thermosets possessing dynamic aliphatic disulfide bonds via stereoselective thiol-yne polymerisation

Abstract

The permanent chemical structure that makes thermosets strong and stretchable materials also hinders their reprocessability and leads to their accumulation in the environment. To favour material reprocessability and reuse, polymers have been endowed with dynamic covalent bonds. However, when the dynamic bond is the network-forming bond, a significant trade-off between the robustness of the material and the dynamic behaviour can be encountered. In this study, nucleophilic thiol-yne click polymerisation was used to synthesise different materials possessing tuneable amounts of reversible disulfide bonds, thus achieving diverse thermomechanical properties. Furthermore, by leveraging different catalyst systems, the cis/trans conformer ratio on the backbone could be modulated to provide an additional degree of control over the thermomechanical properties. Finally, the presence of dynamic bonds was used as a handle to enable promotion of degradation and material reprocessing.