A Norbornene-Derived Epoxy/Cyanate Ester System with Enhanced Thermal and Dielectric Properties as Electronic Materials

In this work, to meet the requirements of high-performance electronic devices for high-frequency/speed telecommunication and semiconductor packaging, we developed a norbornene (NB)-backboned epoxy/cyanate ester compound system to modify the commercial bisphenol-A (BPA) diglycidyl ether (DGEBA) epoxy resin. A norbornene-based epoxy monomer (ENBDE) and cyanate ester (ENBCY) were synthesized using 5-ethylidene-2-norbornene (ENB) as the key starting material. The ENBDE was blended with DGEBA as the epoxy resin compound, which was cured using ENBCY as the curing agent to form a cross-linked thermoset. The effect of ENBDE content on thermal stability, mechanical properties, dielectric performance, and bonding strength of the thermosets was investigated. The optimized formula showed a significantly improved thermal stability of the cured resin with a glass-transition temperature of 249.2 °C and a 5% weight-loss temperature (T5%) of 351.5 °C; the dielectric constant and dissipation factor at a high frequency of 10 GHz were measured to be as small as 2.57 and 0.0068, respectively, showcasing great potential as a high-performance dielectric epoxy material for high-frequency/speed electronic applications.