Upcycling Waste Rubber Powders into Reprocessable Reclaimed Rubber with Excellent Damping Properties: Enabled by Dynamic Bonds and Chemical Foaming

Upcycling waste rubber into high-value products by a simple and efficient method remains a significant challenge. Herein, a synergetic strategy combining dynamic bonds and chemical foaming is proposed to fabricate reprocessable reclaimed rubber with excellent damping properties, using industrial waste rubber powders as the matrix. Waste isobutylene-isoprene rubber powders are cross-linked with polysulfide rubber (PSR) via a facile thiol–ene reaction, and 2,2′-Azobis(2-methylpropionitrile) (AIBN) is employed as a foaming agent to create microcellular structures that can enhance damping performance. By optimizing material ratios and molding conditions (first at 80 °C for 15 min and then at 100 °C for 45 min), the effective damping temperature range (tan δ >0.3) is achieved from −70 to 100 °C, with a maximum damping coefficient of 0.96, outperforming many reported damping materials containing waste rubber. Importantly, the dynamic disulfide bonds in PSR impart reprocessability to the reclaimed rubber, which can recover 95% of its virgin damping properties by adding 2 wt % AIBN during reprocessing. Practical application test shows that this reclaimed rubber can effectively protect fragile objects, such as eggs, from impact damage. Cost analysis indicates that this reclaimed rubber is much cheaper than many commercial alternatives, as cheap waste rubber accounts 70 wt % of the formulation. Thus, this reprocessable reclaimed rubber exhibits outstanding damping performance, low cost, and environmental sustainability, showing great promise for practical applications as a damping material.