Recyclable Polymethacrylate Networks Containing Dynamic Dialkylamino Disulfide Linkages and Exhibiting Full Property Recovery

Reprocessable polymer networks with dynamic covalent bonds exhibit thermoplastic-like properties at elevated processing temperatures while maintaining thermoset responses under service conditions, offering a sustainable solution to the recycling of conventional, permanently cross-linked polymers. Most studies on reprocessable networks that report full cross-link density recovery after recycling have focused on step-growth polymer networks; no study has previously reported full cross-link density recovery of reprocessable networks prepared directly from only monomers via addition polymerization. Here, we report the utilization of dialkylamino disulfide chemistry as a fast, robust dynamic chemistry in the synthesis of reprocessable networks from monomers and/or polymers with carbon-carbon double bonds that are amenable to free-radical polymerization. In particular, we have employed a simple one-step method to design a bifunctional bis(dialkylamino) disulfide cross-linker. With this dynamic cross-linker, we synthesized a catalyst-free, reprocessable polymethacrylate network that exhibits full property recovery (within error) associated with cross-link density after multiple reprocessing steps. This achievement could allow for the facile development of chemically recyclable versions of common, commercially important addition-type polymer networks.