One‐Pot Construction of Sulfur‐Rich Thermoplastic Elastomers Enabled by Metal‐Free Self‐Switchable Catalysis and Air‐Assisted Coupling

摘要

Abstract Construction of well‐defined sulfur‐rich macromolecules in a facile manner is an interesting but challenging topic. Herein, we disclose how to readily construct well‐defined triblock sulfur‐rich thermoplastic elastomers via a self‐switchable isothiocyanate/episulfide copolymerization and air‐assisted oxidative coupling strategy. During self‐switchable polymerization, alternating copolymerization of isothiocyanate and episulfide occurs initially due to the lower energy barrier for isothiocyanate insertion with respect to successive episulfide ring‐opening. After exhaustion of isothiocyanate, ring‐opening polymerization of episulfide begins, providing diblock polymers. Subsequent exposure of the reaction to air leads to a transformation of diblock copolymers into triblock thermoplastic elastomers. This protocol can be extended to diverse isothiocyanates and episulfides, allowing fine‐tuning of the performance of the produced sulfur‐rich thermoplastic elastomers.