Preparation and curing behaviour of microencapsulated curing agents for cold-mixed epoxy asphalt

This study aimed to improve control over the curing behaviour of cold-mixed epoxy asphalt by using a microencapsulated curing agent (2-PZ@PC). Prepared through solvent evaporation, the 2-PZ@PC microcapsules had 2-phenylimidazole as the core material and polycarbonate as the shell material. The research examined the impact of core-shell mass ratio on microcapsule morphology and composition. Various equations, including the kinetics equation, Kissinger equation, Flynn-Wall-Ozawa, and Crane equations, were employed to assess the sustained release effect of 2-PZ@PC microcapsules on epoxy resin curing behaviour. Fluorescence microscopy and viscosity experiments were used to observe the release state of microcapsules and confirm the retardation phenomenon during construction. Optimal 2-PZ@PC microcapsules displayed a smooth spherical morphology and a maximum encapsulation rate of 32 wt% at a 1:1 core-shell ratio. The microencapsulated curing agent effectively regulated cold-mixed epoxy asphalt's curing behaviour, enhancing retention time control and application reliability.