Synthesis of Novel Polyphosphonate Flame Retardants for Epoxy Resins

Abstract

Abstract.A novel halogen-free flame retardant of polyphosphonate (PDDP), has been synthesized by the melt polymerization. The structure of PDDP has been characterized by fourier transform infrared spectroscopy and nuclear magnetic resonance spectra. Results of vertical burning (UL-94), limiting oxygen index (LOI), and the cone calorimeter test rereveal that the PDDP could effectively improve the flame-retardant performance of EP, and PDDP also have a synergistic effect with APP. With the 12wt. % PDDP loading, the EP composites reached UL-94 V-0 rating with a LOI value of 35.0%, the peak of heat release rate and total heat release value decreased by 54.8 % and 26.8%, respectively. The comprehensive test results shows that the improvement of flame retardancy of the EP composites is attributed to the synergistic action of the condensed and gas phases.