Dialkylamino Disulfide Chemistry: A Simple, Robust Catalyst-Free Chemistry for Dynamic Covalent Polymer Networks Exhibiting Full Cross-Link Density Recovery after Recycling and Excellent Creep Resistance at Elevated Temperature.

Conventionally cross-linked polymer networks known as thermosets contain permanent cross-links which prevent their recyclability, leading to major environmental issues. To overcome this problem, dynamic covalent polymer networks (DCPNs) containing dynamic covalent bonds have been explored over the past two decades. Because of their dynamic nature, DCPNs are capable of undergoing reversible or exchange reactions rendering them reprocessable, offering a sustainable alternative to thermosets. While many dynamic chemistries have been explored and employed in the synthesis of DCPNs, most of the very few reported DCPNs that exhibit full cross-link density recovery after recycling were prepared via step growth polymerization, and no study has reported full cross-link density of DCPNs prepared exclusively from vinyl monomers. Here, we present a simple one-step method to design a bifunctional bis(dialkylamino) disulfide cross-linker that can be used in the synthesis of DCPNs from any monomers or polymers that can undergo free radical polymerization without need for external catalyst. We demonstrate the robustness and reprocessability of the networks, including the full recovery of cross-link density after multiple recycling steps and excellent creep resistance at elevated temperatures.