Curing-Induced Network Topology for Tailoring Structure and Functional Properties of Epoxy-Urethane Materials

This study investigates the relationship between polymer network topology, curing kinetics, and functional properties of epoxy-urethane (EU) compositions. The initial curing stage was analyzed using a dielectric method, while pot life, degree of curing, network parameters, viscoelastic, damping, and physicomechanical properties were also systematically evaluated. The curing kinetics were strongly dependent on both composition and temperature. The apparent activation energy for ED-20 cured with diethylenetriamine (DETA) was 50.3 kJ/mol, whereas the curing rate of oligoethercyclocarbonate (OTC) at 303 K was 1.7 times higher due to the higher reactivity of primary amine groups. Increasing ED-20 content to 10-30 wt.% reduced the curing rate and pot life, while promoting the formation of a denser crosslinked network with a gel fraction up to 95 %. Compositions containing ~20 wt.% ED-20 exhibited increased crosslinking density, higher glassy-state modulus, and improved damping capacity. Adhesive strength and abrasion resistance were enhanced through stronger interfacial interactions and a denser network, while elasticity was maintained; impact strength showed a moderate decrease at the highest ED-20 fraction. These results demonstrate that composition and curing conditions can be used to effectively tailor network topology, viscoelastic behavior, and overall functional performance, providing guidance for the design of EU materials for structural applications under cyclic mechanical loading.