Abstract: N,N′-\[1,3-phenylenebis (methylene)\] bis-P,P,P′,P′-tetraphenyl ester (PNBE) was synthesized and characterized by elemental analysis (EA), mass spectra (MS), infrared spectroscopy (IR), and nuclear magnetic resonance (NMR). PNBE was introduced into epoxy resins as a flame retardant by solution casting. PNBE of 5 % could increase the limit oxygen index to 31.8 %, and the flame retardant grade was V-0 level. It worked in both condensed and gas phases but mainly followed the condensed phase mechanism.

Key words: Flame retardants, Epoxy resin, Flame retardancy, PNBE