Preparation and properties of polyether-based vinylogous urethane reversible crosslinked polymers

Reversible crosslinked polymers, also known as covalent adaptable networks (CANs) based on vinylogous urethane were fabricated by condensation between bis-acetoacetate terminated polyether and tris (2-aminoethyl) amine. Three different bis-acetoacetate terminated polyethers with different repeat-units but similar molecular weight were synthesized. The effects of building block on the network structure, thermal and mechanical properties, and viscoelastic behaviors of CANs are examined. The results indicate that higher flexibility of the building blocks enables easier movement of chains in the network, leading to larger ductility, and lower modulus of the resulting CAN. In addition, the network topology rearrangement of the dynamic network is faster and the stress relaxation time is shorter at high temperature. Furthermore, the activation energies of vinylogous urethane CANs exhibit dual temperature response, which is distinguished from the CANs based other dynamic chemistries that are typically have a single linear relationship with temperature. © 2023 Chemical Industry Press. All rights reserved.