A 2,6-dimethyl phenol-dicyclopentadiene novolac was synthesized from dicyclopentadiene and 2,6-dimethyl phenol, and the resultant 2,6-dimethyl phenol-dicyclopentadiene novolac was epoxidized to 2,6-dimethyl phenol-dicyclopentadiene epoxy. The structures of novolac and epoxy were confirmed by Fourier transform infrared spectroscopy (FUR), elemental analysis, mass spectroscopy (MS), nuclear magnetic resonance spectroscopy (NMR), and epoxy equivalent weight titration. The synthesized 2,6-dimethyl phenol-dicyclopentadiene epoxy was then cured with 4,4-diaminodiphenyl methane (DDM), phenol novolac (PN), 4,4-diaminodiphenyl sulfone (DDS), and 4,4-diaminodiphenyl ether (DDE). Thermal properties of cured epoxy resins were studied by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), dielectric analysis (DEA), and thermal gravimetric analysis (TGA). These data were compared with those of the commercial bisphenol A epoxy system. Compared with the bisphenol A epoxy system, the cured 2,6-dimethyl phenol-dicyclopentadiene epoxy resins exhibited lower dielectric constants (similar to3.0 at 1 MHz and 2.8 at 1 GHz), dissipation factors (similar to0.007 at 1 MHz and 0.004 at 1 GHz), glass transition temperatures (140-188degreesC), thermal stability (5% degradation temperature at 382-404degreesC), thermal expansion coefficients [50-60 ppm/degreesC before glass-transition temperature (T-g)], and moisture absorption (0.9-1.1%), but higher modulus (similar to2 Gpa at 60degreesC). (C) 2003 Wiley Periodicals, Inc.