Recyclable and Reprocessable Crosslinked Rubber Enabled by Constructing Ionic Crosslinked Networks

The recycling of covalently crosslinked rubber faces paramount challenges as it is difficult to be recycled by melting or solution procedures because of its irreversible crosslinked structure formed in the vulcanization process. Here, a new ionic crosslinker was formed from two commonly used additives in the rubber industry (i.e., bis[3-(triethoxysilyl)propyl]tetrasulfide and zinc methacrylate) for crosslinking unsaturated rubber with a reversible ionic three-dimensional structure. The crosslinked styrene butadiene rubber with comparable toughness can be easily recycled via the solution process and re-formed by simply adding zinc oxide as a crosslinker. This work demonstrates that constructing ionic crosslinked structure is an effective approach to prepare recyclable and reprocessable rubber, thus solving the problem of recycling and pollution.