Rapid degradation of disulfide-based thermosets through thiol-disulfide exchange reaction

Development of a methodology to achieve the rapid degradation of thermosets under mild conditions is an important challenge. In this paper, we present a new method for rapid disassembly of thermosetting polyurethanes (PUs), using synergism of multiple stimuli. The PUs were prepared using multi-sensitivity dynamic disulfide bonds as the cross-linker. When soaked in DMF, the fabricated PUs only swell but undissolve. While reducing agent was added, the polymer completely dissolved after 12 h immersion at 25 °C, owing to the thiol-disulfide exchange mechanism. Moreover, as the temperature increases from 25 °C to 60 °C, the time required for complete dissolution of the PUs decreases from 12 h to 50 min, indicating that the synergistic effect of reducing agent and temperature can accelerate the degradation. In addition, other combined multi-stimuli, including reducing agent and ultrasound, can also be used to adjust the dissolution rate of the disulfide bonds cross-linked thermosets. When used as adhesives, the rapidly detachable PUs have potential applications in recycling the valuable adhesive components conveniently. [Display omitted] •Polyurethanes cross-linked by multi-responsive dynamic disulfide bonds are prepared.•Obtained polyurethanes can degrade rapidly under mild conditions.•Degradation is controlled by DTT concentration, temperature, and ultrasound.•External stimuli synergistic effect can efficiently accelerate the degradation.•Detachable polyurethanes have applications in recycling the valuable components.