Constructing Thermoreversible Diels–Alder Networks in SBS Elastomers via a Green Fabrication Strategy

A thermoreversible cross-linked styrene–butadiene–styrene (SBS) based on Diels–Alder (DA) chemistry was fabricated via a solvent-free melt processing approach. Maleated SBS was adopted so that furfurylamine could be grafted onto pendant anhydride groups to introduce furan moieties. Functionalized SBS was then cross-linked with bismaleimide through DA coupling. Thermoreversibility and network dynamics of the DA-crosslinked SBS (DSBS) were characterized by FTIR spectroscopy, solubility assessment, DSC analysis, and tensile testing. FTIR spectroscopy results verified the successful furfurylamine grafting and DA cross-linking mediated by bismaleimide in the DSBS. The DSBS exhibited enhanced solvent resistance, thermal stability and mechanical performance. The Diels–Alder (DA) linkages within the DSBS network undergo thermally induced dissociation at elevated temperatures (>140 °C) and readily reform at 110 °C, thereby enabling reversible and repeatable network reconstruction. Furthermore, the mechanical properties of DSBS can be systematically tailored by varying the bismaleimide content. Specifically, increasing the bismaleimide concentration results in enhanced ultimate tensile strength and elastic modulus, accompanied by a reduction in ductility. These findings demonstrate an efficient, cost-effective, and environmentally sustainable approach for the fabrication of high-performance, recyclable SBS elastomers.