Upgrade SBS into vitrimers with excellent mechanical and physical properties

As the universal thermoplastic elastomers, poly(styrene- b -butadiene- b -styrene) (SBS) possesses good rubber elasticity and plasticity. However, the weak intermolecular forces upon which physical crosslinking relies also lead to unideal heat resistance, solvent resistance, and mechanical properties. Therefore, a massive challenge for developing SBS lies in the balance between performance and recyclability. Vitrimers are an emerging class of polymers with a crosslinked network containing dynamic covalent bonds. Herein, we demonstrated the preparation of SBS vitrimers based on disulfide exchange with high performance via epoxidation and esterification reactions. The introduction of chemical crosslinking significantly improved their mechanical properties and environmental resistance, especially solvent and heat resistance. Compared with pristine SBS, the tensile strength of SBS vitrimers could be increased from 1.9 MPa to 14.4 MPa without sacrificing the elongation at break. In the meantime, the dynamic nature enabled by disulfide exchange retained the recycling ability and endowed SBS vitrimers with some smart responses, including shape memory and self-healing properties. Furthermore, SBS vitrimers exhibited stronger adhesion in contrast with pristine SBS. This work provides a simple strategy for designing SBS networks with enhanced performance and good recyclability.