Thermal, mechanical, and electrical properties of fluorine-containing epoxy resins

The dielectric constants of fluorine-containing epoxy resins, 2-diglycidylether of benzotrifluoride(FER)A,4'-diamino-diphenyl methane (DDM) and diglycidylether of bisphenol-A (DGEBA)/ DDM systems were evaluated by dielectric spectrometer. Glass transition. temperature and thermal stability factors, including initial decomposed temperature, temperatures of maximum rate of degradation, and decomposition activation energy of the cured specimens were investigated by dynamic mechanical analysis and thermogravimetric analysis. For the mechanical properties of the casting specimens, the fracture toughness, flexural, and impact tests were performed, and their fractured surfaces were examined by scanning electron microscope. The dielectric constant of FER/DDM system was lower than that of commercial DGEBA/DDM system, and the mechanical properties of the cured specimens showed higher values than those of DGEBA/DDM system. This was probably due to the introduction of trifluoromethyl (CF3) group into the side chain of the epoxy resins, resulting in improving the electric and mechanical properties of the epoxy cure system studied.