Polyacrylate Vitrimer Network via In Situ Isocyanide Copolymerization: Synthesis and Molecular Dynamics

Widespread plastic pollution highlights the urgent need for materials with sustainable end-of-life management. Vitrimers, cross-linked polymers containing dynamic covalent bonds, combine the durability of thermosets with their recyclability. Here, we report a one-step photocopolymerization using multifunctional isocyanides as readily accessible cross-linkers that directly introduce vinylogous urethane-like linkages into polyacrylate networks, structures difficult to obtain via amine-β-ketoester condensation. The resulting materials show good reprocessability, maintaining a comparable mechanical performance after three processing cycles. Broadband dielectric spectroscopy (BDS) reveals that the temperature dependence of the bond-exchange relaxation times evolves from a kink-like response in fresh samples to Arrhenius behavior after annealing, visualizing topological rearrangement and defect healing. A scaling relationship between bond-exchange relaxation and electrical conductivity establishes that the former is the underlying mechanism for charge transport in vitrimers. Furthermore, dipolar intermediates generated during bond exchange increase the dielectric permittivity, providing new insight into designing sustainable dielectric materials.