The Polymer Society of Korea

Abstract

Covalent adaptable networks (CANs) are reprocessable, thermoset-like polymers enabled by dynamic bond exchange above the topology-freezing transition temperature (T_v). Despite its widespread use, T_v is often defined qualitatively or in a system-specific manner, limiting its relevance to macroscopic processability. Because comonomer chemistry and network architecture govern exchange kinetics, a quantitative and process-relevant definition of T_v is required. Here, T_v is defined as the inflection point in the temperature dependence of stress-relaxation time, using three disulfide-based CANs with identical crosslinkers but different comonomers. This definition captures the transition from WLF to Arrhenius behavior and coincides with the onset of macroscopic dynamic exchange. Decoupling relaxation into diffusion- and kinetic-timescales further distinguishes T_g-controlled segmental dynamics from intrinsic disulfide exchange, establishing a practical design rule for CAN processing windows.