Synthesis of a novel silicon-containing epoxy resin and its effect on flame retardancy, thermal, and mechanical properties of thermosetting resins

A novel high-performance epoxy resin diphenyldi (9,9-Di-(4-(2,3-epoxypropoxy) phenyl)-4,5-diazafluorenoxysilane) (DEPFS) containing the diazafluorene and silicon group was synthesized by the nucleophilic substitution for the first time and added to bisphenol A epoxy resin (E-51) to form a thermoset blend. We observed that the incorporation of DEPFS remarkably enhanced the flame retardancy and thermal properties of E-51. The cured E-51-30% DEPFS thermoset exhibited a glass transition temperature of 187 °C and a limiting oxygen index of 30.1%, much higher than 153 °C and 22.6% for those of pristine E-51 thermoset, respectively. In addition, the incorporation of DEPFS has dual enhancement effects on the toughness and tensile strength of E-51. This study provides an effective means to prepare a high-performance epoxy resins and proposes flame retardancy and simultaneous reinforcing and toughening mechanism. It was found that the DEPFS with diverse performance has allowed an increasing number of versatile industrial application such as microelectronics, electronics, aerospace and so on.