Improved Toughness, Flexural Strength, and Dielectric Performances of Epoxy-Dicyclopentadiene Interpenetrating Polymer Networks via Simultaneous Frontal Polymerization

With the advancement of high-frequency communication, the microelectronics and wireless communication industries require epoxy thermoset materials that feature a low dielectric constant ( D k ), low dielectric loss ( D f ), and superior mechanical properties. In this study, epoxy-based interpenetrating polymer networks (IPNs) with low D k, D f, and enhanced toughness were efficiently prepared through simultaneous frontal polymerization by incorporating dicyclopentadiene (DCPD). All synthesized IPNs exhibit no observable phase separations, and their impact strength shows significant improvement compared with the epoxy single network (SN-E). Moreover, both impact and flexural strengths of IPNs prepared by simultaneous frontal polymerization are higher than those of IPNs stepwise cured in an oven, owing to the more uniform interpenetrating structure of the epoxy and DCPD chains. The dielectric constant of prepared IPNs decreases to 2.45, while the dielectric loss reduces to 0.01, both significantly lower than those of SN-E ( D k = 3.68, D f = 0.02). The rapid frontal polymerization of epoxy/DCPD IPNs effectively combines exceptional dielectric properties with outstanding mechanical performance, making them promising candidates for microelectronics and wireless communication systems.