Synthesis and properties of trifluoromethyl groups containing epoxy resins cured with amine for low Dk materials

The study synthesized a trifluoromethyl (CF3) groups with a modified epoxy resin, diglycidyl ether of bisphenol F (DGEBF), using environmental friendly methods. The epoxy resin was cured with 4,4′‐diaminodiphenyl‐methane (DDM). For comparison, this study also investigated curing of commercially available diglycidyl ether of bisphenol A (DGEBA) with the same curing agent by varying the ratios of DGEBF. The structure and physical properties of the epoxy resins were characterized to investigate the effect of injecting fluorinated groups into epoxy resin structures. Regarding the thermal behaviors of the specimens, the glass transition temperatures (Tg) of 50–160°C and the thermal decomposition temperatures of 200–350 °C at 5% weight loss (Td5%) in nitrogen decreased as amount of DGEBF increased. The different ratios of cured epoxy resins showed reduced dielectric constants (Dk) (2.03–3.80 at 1 MHz) that were lower than those of pure DGEBA epoxy resins. Reduced dielectric constant is related to high electrronegativity and large free volume of fluorine atoms. In the presence of hydrophobic CF3 groups, the epoxy resins exhibited low moisture absorption and higher contact angles.