Self-healing, Reshaping, and Recycling of Vulcanized Chloroprene Rubber: A Case Study of Multitask Cyclic Utilization of Cross-linked Polymer

To develop a new technology for sustainable application of sulfur cross-linked rubbers, a novel latent catalyst, organic complex copper­(II) methacrylate (MA-Cu), is explored to trigger disulfide metathesis at elevated temperature. When it is incorporated into vulcanized chloroprene rubber fabricated following industrial recipe, reshuffling of inherent sulfur cross-links is enabled typically at 120 °C, while microstructure of the material remains unchanged at lower temperature (typically lower than 100 °C). Such a latent character of MA-Cu is believed to ensure operation stability of the rubber under ambient conditions, and its organic nature helps to improve dispersion homogeneity. By taking advantage of the activated cross-linked networks, the sulfur bonds can be reversibly exchanged inside the vulcanized chloroprene rubber as well as across the surfaces at 120 °C. As a result, the rubber is coupled with the capabilities of repeated reshaping, self-healing, and recycling without need of changing its macromolecular structure and manufacturing parameters. These outcomes might lead to the development of energy saving and environmentally friendly all solid-state processing of cross-linked polymers toward multitask cyclic utilization