Aziridine-Derived Polysulfide Elastomers for Self-Healable, Strong, and Reusable Adhesives

Inverse vulcanization offers an efficient method for synthesizing high-sulfur content polymers. However, the resulting polysulfides often exhibit poor mechanical properties, particularly a lack of high ductility or elasticity. In this study, we present a straightforward one-pot tandem strategy for the synthesis of functionalized polysulfides with improved elastomeric properties. Initially, heterofunctional monomer alkene-substituted aziridine, specifically 2-(oct-7-en-1-yl)-1-tosylaziridine, was easily prepared by treating 1,9-decadiene with chloramine-T, a byproduct in saccharin production. Subsequently, sulfonamide and thioether-bifunctionalized polysulfides were synthesized through a tandem ring-opening reaction/thio-ene "click"/inverse vulcanization process. These reactions were conducted in a one-pot procedure without the need for solvents or metal catalysts. Various thiols can be employed in this approach, providing flexibility in altering the chemical composition of the polysulfide. The resulting polysulfides exhibit enhanced elasticity, demonstrating an elongation of up to 666% and a tensile strength of 0.39 MPa. Enhancement of the tensile strength to 1.94 MPa, with a 192% strain at break, is achievable. Furthermore, the functionalized polysulfides undergo rapid self-healing at 50 degrees C. They can be directly utilized as adhesives without requiring a tedious curing process, demonstrating exceptional adhesive properties on wood, iron, and aluminum substrates (up to 3.35, 1.83, and 1.56 MPa, respectively). Notably, these polysulfides can be recycled and reused 8 times while retaining robust adhesion. We anticipate that the simple construction process, potent adhesive capabilities, and recyclable/reusable features of this kind of polysulfide adhesive will contribute to the advancement of environmentally friendly adhesive technologies.